,,the ,,story ,,of  ,a ,,piece ,,of     
,,coal    ,,what ,,it ,,is1 ,,whence    
,,it ,,comes1  ,,and ,,whither ,,it     
,,goes    ,,by  ,,edward ,a4 ,,martin1  
,f4,g4,s4    #ahif            ,,preface4
      ,the knowledge of the marvels     
which a piece of coal possesses within  
itself1 and which in obedience to       
processes of man's invention it is      
always willing to exhibit to an         
observant enquirer1 is not so           
widespread1  perhaps1 as it should be1  
and the aim of this little book1 this   
record of  one page of geological       
history1 has been to bring together the 
principal  facts and wonders connected  
with it into the focus of a few pages1  
where1  side by side1 would be found the
 record of its vegetable and mineral    
history1 its discovery and early use1   
its bearings on the great  fog-problem1 
its useful illuminating gas and oils1   
the question of the  possible exhaustion
 of ,british supplies1 and other        
important and  interesting bearings of  

coal or its products4    ,in the whole  
realm of natural history1 in the widest 
sense of the term1  there is nothing    
which could be cited which has so       
benefited1 so  interested1 ,i might     
almost say1 so excited mankind1 as have 
the wonderful  discoveries of the       
various products distilled from gas-tar1
 itself a  distillate of coal4    ,coal 
touches the interests of the botanist1  
the geologist1 and the  physicist2 the  
chemist1 the sanitarian1 and the        
merchant4    ,in the little work now    
before the reader ,i have endeavoured to
 recount1  without going into           
unnecessary detail1 the wonderful story 
of a piece of  coal4    ,e4,a4,m4       
,,thornton ,,heath1    ,february1 #ahif4
          ,,contents4         ,i4 ,,the 
,,origin ,,of ,,coal ,,and ,,the        
,,plants ,,of ,,which ,,it ,,is         
,,composed      ,,ii4 ,a ,,general      
,,view ,,of ,,the ,,coal-,,bearing      
,,strata     ,,iii4 ,,various ,,forms   
,,of ,,coal ,,and ,,carbon      ,,iv4   

,,the ,,coal-,,mine ,,and ,,its         
,,dangers       ,v4 ,,early             
,,history--,,its ,,use ,,and ,,its      
,,abuse      ,,vi4 ,,how ,,gas ,,is     
,,made--,,illuminating ,,oils ,,and     
,,bye-,,products     ,,vii4 ,,the ,,coal
 ,,supplies ,,of ,,the ,,world          
,,viii4 ,,the ,,coal-,,tar ,,colours    
,,chart ,,shewing ,,the ,,products ,,of 
,,coal    ,,general ,,index             
,,list ,,of ,,illustrations4    ,,fig4  
#a4 ,stigmaria       #b4 ,annularia     
radiata       #c4 ,rhacopteris          
inaequilatera       #d4 ,frond of       
,pecopteris       #e4 ,pecopteris       
,serlii       #f4 ,sphenopteris affinis 
#g4 ,catamites ,suckowii       #h4      
,calamocladus grandis       #i4         
,asterophyllites foliosa      #aj4      
,spenophyllum cuneifolium      #aa4     
,cast of ,lepidodendron      #ab4       
,lepidodendron longifolium      #ac4    
,lepidodendron aculeatum      #ad4      
,lepidostrobus      #ae4 ,lycopodites   
#af4 ,stigmaria ficoides      #ag4      

,section of ,stigmaria      #ah4        
,sigillarian trunks in sandstone        
#ai4 ,productus      #bj4 ,encrinite    
#ba4 ,encrinital limestone      #bb4    
,various encrinites      #bc4           
,cyathophyllum      #bd4 ,archegosaurus 
minor      #be4 ,psammodus porosus      
#bf4 ,orthoceras      #bg4 ,fenestella  
retepora      #bh4 ,goniatites      #bi4
 ,aviculopecten papyraceus      #cj4    
,fragment of ,lepidodendron      #ca4   
,engine-house at head of a ,coal-,pit   
#cb4 ,gas ,jet and ,davy ,lamp      #cc4
 ,part of a ,sigillarian trunk      #cd4
 ,inside a ,gas-holder      #ce4        
,filling ,retorts by ,machinery         
#cf4 ,condensers      #cg4 ,washers     
#ch4 ,purifiers          ,,chapter ,i4  
,,the ,,origin ,,of ,,coal ,,and ,,the  
,,plants ,,of  ,,which ,,it ,,is        
,,composed4      ,from the homely       
scuttle of coal at the side of the      
hearth to the  gorgeously verdant       
vegetation of a forest of mammoth trees1
 might have  appeared a somewhat far cry

 in the eyes of those who lived some    
fifty  years ago4 ,but there are few now
 who do not know what was the origin of 
the coal which they use so freely1 and  
which in obedience to their demand  has 
been brought up more than a thousand    
feet from the bowels of the  earth2 and1
 although familiarity has in a sense    
bred contempt for that  which a few     
shillings will always purchase1 in all  
probability a stray  thought does       
occasionally cross one's mind1 giving   
birth to feelings of a  more or less    
thankful nature that such a store of    
heat and light was long  ago laid up in 
this earth of ours for our use1 when as 
yet man was not  destined to put in an  
appearance for many1 many ages to come4 
,we can  scarcely imagine the industrial
 condition of our country in the absence
  of so fortunate a supply of coal2 and 
the many good things which are  obtained
 from it1 and the uses to which1 as we  
shall see1 it can be put1  do indeed    
demand recognition4    ,were our present

 forests uprooted and overthrown1 to be 
covered by  sedimentary deposits such as
 those which cover our coal-seams1 the  
amount  of coal which would be thereby  
formed for use in some future age1 would
  amount to a thickness of perhaps two  
or three inches at most1 and yet1 in    
one coal-field alone1 that of           
,westphalia1 the #aag most important    
seams1  if placed one above the other in
 immediate succession1 would amount to  
no  less than #bid feet of coal4 ,from  
this it is possible to form a faint idea
  of the enormous growths of vegetation 
required to form some of our            
representative coal beds4 ,but the coal 
is not found in one continuous  bed4    
,these numerous seams of coal are       
interspersed between many thousands  of 
feet of sedimentary deposits1 the whole 
of which form the  coal-measures4 ,now1 
each of these seams represents the      
growth of a  forest1 and to explain the 
whole series it is necessary to suppose 
that  between each deposit the land     

became overwhelmed by the waters of the 
sea  or lake1 and after a long          
subaqueous period1 was again raised into
 dry  land1 ready to become the         
birth-place of another forest1 which    
would  again beget1 under similarly     
repeated conditions1 another seam of    
coal4  ,of the conditions necessary to  
bring these changes about we will speak 
later on1 but this instance is          
sufficient to show how inadequate the   
quantity of fuel would be1 were we      
dependent entirely on our own existing  
forest growths4    ,however1 we will    
leave for the present the fascinating   
pursuit of  theorising as to the how and
 wherefore of these vast beds of coal1  
relegating  the geological part of the  
study of the carboniferous system  to a 
future chapter1 where will be found some
 more detailed account of  the position 
of the coal-seams in the strata which   
contain them4 ,at  present the actual   
details of the coal itself will demand  
our attention4    ,coal is the mineral  

which has resulted1 after the lapse of  
thousands of  thousands of years1 from  
the accumulations of vegetable material1
 caused  by the steady yearly shedding  
of leaves1 fronds and spores1 from      
forests  which existed in an early age2 
these accumulated where the trees grew  
that bore them1 and formed in the first 
place1 perhaps1 beds of peat2 the  beds 
have since been subjected to an         
ever-increasing pressure of             
accumulating strata above them1         
compressing the sheddings of a whole    
forest into a thickness in some cases of
 a few inches of coal1 and have  been   
acted upon by the internal heat of the  
earth1 which has caused them  to part1  
to a varying degree1 with some of their 
component gases4 ,if we  reason from    
analogy1 we are compelled to admit that 
the origin of coal is  due to the       
accumulation of vegetation1 of which    
more scattered1 but more  distinct1     
representative specimens occur in the   
shales and clays above  and below the   

coal-seams4 ,but we are also able to    
examine the texture  itself of the      
various coals by submitting extremely   
thin slices to a  strong light under the
 microscope1 and are thus enabled to    
decide whether  the particular coal we  
are examining is formed of conifers1    
horse-tails1  club-mosses1 or ferns1 or 
whether it consists simply of the       
accumulated  sheddings of all1 or       
perhaps1 as in some instances1 of       
innumerable  spores4    ,in this way the
 structure of coal can be accurately    
determined4 ,were we  artificially to   
prepare a mass of vegetable substance1  
and covering it up  entirely1 subject it
 to great pressure1 so that but little  
of the  volatile gases which would be   
formed could escape1 we might in the    
course  of time produce something       
approaching coal1 but whether we        
obtained  lignite1 jet1 common          
bituminous coal1 or anthracite1 would   
depend upon  the possibilities of escape
 for the gases contained in the mass4   

,everybody has doubtless noticed that1  
when a stagnant pool which contains  a  
good deal of decaying vegetation is     
stirred1 bubbles of gas rise to the     
surface from the mud below4 ,this gas is
 known as marsh-gas1 or light           
carburetted hydrogen1 and gives rise to 
the ignis fatuus which hovers  about    
marshy land1 and which is said to lure  
the weary traveller to his  doom4 ,the  
vegetable mud is here undergoing rapid  
decomposition1 as there  is nothing to  
stay its progress1 and no superposed    
load of strata  confining its resulting 
products within itself4 ,the gases      
therefore  escape1 and the breaking-up  
of the tissues of the vegetation goes on
  rapidly4    ,the chemical changes     
which have taken place in the beds of   
vegetation of  the carboniferous epoch1 
and which have transformed it into coal1
 are  even now but imperfectly          
understood4 ,all we know is that1 under 
certain  circumstances1 one kind of coal
 is formed1 whilst under other          

conditions1  other kinds have resulted2 
whilst in some cases the processes have 
resulted in the preparation of large    
quantities of mineral oils1 such as     
naphtha and petroleum4 ,oils are also   
artificially produced from the          
so-called waste-products of the         
gas-works1 but in some parts of the     
world  the process of their manufacture 
has gone on naturally1 and a yearly     
increasing quantity is being utilised4  
,in ,england oil has been pumped up     
from the carboniferous strata of        
,coalbrook ,dale1 whilst in ,sussex it  
has  been found in smaller quantities1  
where1 in all probability1 it has had   
its origin in the lignitic beds of the  
,wealden strata4 ,immense quantities    
are used for fuel by the ,russian       
steamers on the ,caspian ,sea1 the ,baku
  petroleum wells being a most valuable 
possession4 ,in ,sicily1 ,persia1 and1  
far more important1 in the ,united      
,states1 mineral oils are found in great
  quantity4    ,in all probability      

coniferous trees1 similar to the living 
firs1 pines1  larches1 c41 gave rise for
 the most part to the mineral oils4 ,the
 class  of living coniferae is well     
known for the various oils which it     
furnishes naturally1 and for others     
which its representatives yield on      
being subjected to distillation4 ,the   
gradually increasing amount of heat     
which we meet the deeper we go beneath  
the surface1 has been the cause of  a   
slow and continuous distillation1 whilst
 the oil so distilled has found  its way
 to the surface in the shape of         
mineral-oil springs1 or has  accumulated
 in troughs in the strata1 ready for    
use1 to be drawn up when  a well has    
been sunk into it4    ,the plants which 
have gone to make up the coal are not at
 once apparent  to the naked eye4 ,we   
have to search among the shales and     
clays and  sandstones which enclose the 
coal-seams1 and in these we find        
petrified  specimens which enable us to 
build up in our mind pictures of the    

vegetable creation which formed the     
jungles and forests of these  immensely 
remote ages1 and which1 densely packed  
together on the old  forest floor of    
those days1 is now apparent to us as    
coal4    ,illustration3 ,fig4           
#b4--;,annularia radiata4 ,carboniferous
 sandstone4    ,a very large proportion 
of the plants which have been found in  
the  coal-bearing strata consists of    
numerous species of ferns1 the number of
  actual species which have been        
preserved for us in our ,english coal1  
being double the number now existing in 
,europe4 ,the greater part of these  do 
not seem to have been very much larger  
than our own living ferns1 and1  indeed1
 many of them bear a close resemblance  
to some of our own living  species4 ,the
 impressions they have left on the      
shales of the  coal-measures are most   
striking1 and point to a time when the  
sandy clay  which imbedded them was     
borne by water in a very tranquil       
manner1 to be  deposited where the ferns

 had grown1 enveloping them gradually1  
and  consolidating them into their mass 
of future shale4 ,in one species known  
as the neuropteris1 the nerves of the   
leaves are as clear and as  apparent as 
in a newly-grown fern1 the name being   
derived from two ,greek  words meaning  
nerve-fern4 ,it is interesting to       
consider the history of  such a leaf1   
throughout the ages that have elapsed   
since it was part of a  living fern4    
,first it grew up as a new frond1 then  
gradually unfolded  itself1 and         
developed into the perfect fern4 ,then  
it became cut off by  the rising waters1
 and buried beneath an accumulation of  
sediment1 and  while momentous changes  
have gone on in connection with the     
surface of  the earth1 it has lain      
dormant in its hiding-place exactly as  
we see it1  until now excavated1 with   
its contemporaneous vegetation1 to form 
fuel  for our winter fires4             
,illustration3 ,,fig4 #c4--,rhacopteris 
inaequilatera4 ,carboniferous           

limestone4    ,although many of the     
ferns greatly resembled existing        
species1 yet there  were others in these
 ancient days utterly unlike anything   
indigenous to  ,england now4 ,there were
 undoubted tree-ferns1 similar to those 
which  thrive now so luxuriously in the 
tropics1 and which throw out their      
graceful crowns of ferns at the head of 
a naked stem1 whilst on the bark  are   
the marks at different levels of the    
points of attachment of former  leaves4 
,these have left in their places        
cicatrices or scars1 showing the  places
 from which they formerly grew4 ,amongst
 the tree-ferns found are  megaphyton1  
paloeopteris1 and caulopteris1 all of   
which have these  marks upon them1 thus 
proving that at one time even tree-ferns
 had a  habitat in ,england4            
,illustration3 ,fig4 #d4--;,frond of    
,pecopteris4 ,coal-shale4    ,one form  
of tree-fern is known by the name of    
,psaronius1 and this was  peculiar in   
the possession of masses of aerial roots

 grouped round the  stem4 ,some of the  
smaller species exhibit forms of leaves 
which are  utterly unknown in the       
nomenclature of living ferns4 ,most have
 had names  assigned to them in         
accordance with certain characteristics 
which they  possess4 ,this was the more 
possible since the fossilised           
impressions had  been retained in so    
distinct a manner4 ,here before us is a 
specimen in a  shale of pecopteris1 as  
it is called1 7pekos1 a comb74 ,the leaf
 in  some species is not altogether     
unlike the well-known living fern       
osmunda4 ,the position of the pinnules  
on both sides of the central  stalk are 
seen in the fossil to be shaped         
something like a comb1 or a  saw1 whilst
 up the centre of each pinnule the vein 
is as prominent and  noticeable as if   
the fern were but yesterday waving      
gracefully in the  air1 and but to-day  
imbedded in its shaly bed4              
,illustration3 ,,fig4 #e4--,pecopteris  
,serlii4 ,coal-shale4    ,sphenopteris1 

or wedge-fern1 is the name applied to   
another  coal-fern2 glossopteris1 or    
tongue-leaf2 cyclopteris1 or            
round-leaf2 odonlopteris1 or tooth-leaf1
 and many others1 show  their chief     
characteristics in the names which they 
individually bear4  ,alethopteris       
appears to have been the common brake of
 the coal-period1  and in some respects 
resembles pecopteris4    ,illustration3 
,fig4 #f4--,sphenopteris ,affinis4      
,coal-shale4    ,in some species of     
ferns so exact are the representations  
which they have  impressed on the shale 
which contains them1 that not only are  
the veins  and nerves distinctly        
visible1 but even the fructification    
still remains  in the shape of the marks
 left by the so-called seeds on the     
backs of the  leaves4 ,something more   
than a passing look at the coal         
specimens in a  good museum will well   
repay the time so spent4    ,what are   
known as septarian nodules1 or          
snake-stones1 are1 at certain  places1  

common in the carboniferous strata4     
,they are composed of layers  of        
ironstone and sandstone which have      
segregated around some central  object1 
such as a fern-leaf or a shell4 ,when   
the leaf of a fern has been  found to be
 the central object1 it has been noticed
 that the leaf can  sometimes be        
separated from the stone in the form of 
a carbonaceous film4    ,experiments    
were made many years ago by ,m4 ,goppert
 to illustrate the  process of          
fossilisation of ferns4 ,having placed  
some living ferns in a  mass of clay and
 dried them1 he exposed them to a red   
heat1 and obtained  thereby striking    
resemblances to fossil plants4          
,according to the degree  of heat to    
which they were subjected1 the plants   
were found to be either  brown1 a       
shining black1 or entirely lost4 ,in the
 last mentioned case1  only the         
impression remained1 but the            
carbonaceous matter had gone to  stain  
the surrounding clay black1 thus        

indicating that the dark colour of  the 
coal-shales is due to the carbon derived
 from the plants which they  included4  
,another very prominent member of the   
vegetation of the coal period1 was  that
 order of plants known as the           
,calamites4 ,the generic distinctions   
between fossil and living ferns were so 
slight in many cases as to be  almost   
indistinguishable4 ,this resemblance    
between the ancient and the  modern is  
not found so apparent in other plants4  
,the ,calamites of the  coal-measures   
bore indeed a very striking resemblance1
 and were closely  related1 to our      
modern horse-tails1 as the equiseta are 
popularly  called2 but in some respects 
they differed considerably4    ,most    
people are acquainted with the          
horse-tail 7equisetum fluviatile7  of   
our marshes and ditches4 ,it is a       
somewhat graceful plant1 and stands     
erect with a jointed stem4 ,the foliage 
is arranged in whorls around the        
joints1 and1 unlike its fossil          

representatives1 its joints are         
protected  by striated sheaths4 ,the    
stem of the largest living species      
rarely  exceeds half-an-inch in         
diameter1 whilst that of the calamite   
attained a  thickness of five inches4   
,but the great point which is noticeable
 in the  fossil calamites and           
equisetites is that they grew to a far  
greater  height than any similar plant  
now living1 sometimes being as much as  
eight feet high4 ,in the nature of their
 stems1 too1 they exhibited a more      
highly organised arrangement than their 
living representatives1 having1         
according to ,dr ,williamson1 a fistular
 pith1 an exogenous woody stem1  and a  
thick smooth bark4 ,the bark having     
almost al ways disappeared has  left the
 fluted stem known to us as the         
calamite4 ,the foliage consisted  of    
whorls of long narrow leaves1 which     
differed only from the fern             
asterophyllites in the fact that they   
were single-nerved4 ,sir ,william       

,dawson assigns the calamites to four   
sub-types3 calamite proper1             
calamopitus1 calamodendron1 and         
eucalamodendron4    ,image3 ,,fig4      
#g4--,root of ,catamites ,suckowii4     
,coal-shale4    ,image3 ,,fig           
#h4--;,calamocladus grandis4            
,carboniferous sandstone4    ,having    
used the word exogenous1 it might be as 
well to pay a little  attention1 in     
passing1 to the nomenclature and broad  
classification of  the various kinds of 
plants4 ,we shall then doubtless find it
 far easier  thoroughly to understand   
the position in the scale of            
organisation to  which the coal plants  
are referable4    ,illustration3 ,,fig4 
#i4--;,asterophyllites foliosa4         
,coal-measures4    ,the plants which are
 lowest in organisation are known as    
,cellular4 ,they  are almost entirely   
composed of numerous cells built up one 
above the  other1 and possess none of   
the higher forms of tissue and          
organisation  which are met with        

elsewhere4 ,this division includes the  
lichens1  sea-weeds1 confervae 7green   
aquatic scum71 fungi 7mushrooms1        
dry-rot71  c4    ,the division of       
,vascular plants includes the far larger
 proportion of  vegetation1 both living 
and fossil1 and these plants are built  
up of  vessels and tissues of various   
shapes and character4    ,all plants are
 divided into 7#a7 ,cryptogams1 or      
,flowerless1 such as  mosses1 ferns1    
equisetums1 and 7#b7 ,phanerogams1 or   
,flowering4 ,flowering  plants are again
 divided into those with naked seeds1 as
 the conifers and  cycads 7gymnosperms71
 and those whose seeds are enclosed in  
vessels1 or  ovaries 7angiosperms74     
,angiosperms are again divided into the 
monocotyledons1 as the palms1 and       
dicotyledons1 which include most        
,european trees4    ,thus3--            
----------------------------------------
---------------------------     7,m4,a4 
,brongniart74                           
7,lindley74   ,,cellular                

,cryptogams 7,flowerless7     ,fungi1   
seaweeds1     ,thallogens               
lichens                                 
,,vascular                              
,cryptogams 7,flowerless7     ,ferns1   
equisetums1   ,acrogens                 
mosses1 lycopodiums                     
,phanerogams 7,flowering7               
,gymnosperms 7having       ,conifers and
         ,gymnogens            naked    
seeds7             cycads               
,two or more ,cotyledons                
,angiosperms 7having                    
enclosed seeds7                         
,monocotyledons            ,palms1      
lilies1       ,endogens                 
grasses                                 
,dicotyledons              ,most        
,european        ,exogens               
trees and shrubs                        
----------------------------------------
---------------------------    ,adolphe 
,brongniart termed the coal era the ,age
 of ,acrogens1 because1 as  we shall    
see1 of the great predominance in those 

times of vascular  cryptogamic plants1  
known in ,dr ,lindley's nomenclature as 
,acrogens4    ,illustration3 ,,fig4     
#aj4--,spenophyllum cuneifolium4        
,coal-shale4    ,two of these families  
have already been dealt with1 viz41 the 
ferns  7felices71 and the equisetums1   
7calamites and equisetites71 and we  now
 have to pass on to another family4     
,this is that which includes the  fossil
 representatives of the ,lycopodiums1 or
 ,club-mosses1 and which goes  to make  
up in some coals as much as two-thirds  
of the whole mass4  ,everyone is more or
 less familiar with some of the living  
,lycopodiums1  those delicate little    
fern-like mosses which are to be found  
in many a  home4 ,they are but lowly    
members of our ,british flora1 and it   
may seem  somewhat astounding at first  
sight that their remote ancestors       
occupied  so important a position in the
 forests of the ancient period of which 
we  are speaking4 ,some two hundred     
living species are known1 most of them  

being confined to tropical climates4    
,they are as a rule1 low creeping       
plants1 although some few stand erect4  
,there is room for astonishment  when we
 consider the fact that the fossil      
representatives of the family1  known as
 ,lepidodendra1 attained a height of no 
less than fifty feet1  and1 there is    
good ground for believing1 in many      
cases1 a far greater  magnitude4 ,they  
consist of long straight stems1 or      
trunks which branch  considerably near  
the top4 ,these stems are covered with  
scars or scales1  which have been caused
 by the separation of the petioles or   
leaf-stalks1  and this gives rise to the
 name which the genus bears4 ,the scars 
are  arranged in a spiral manner the    
whole of the way up the stem1 and the   
stems often remain perfectly upright in 
the coal-mines1 and reach into  the     
strata which have accumulated above the 
coal-seam4    ,illustration3 ,,fig4     
#aa4--;,cast of lepidodendron in        
sandstone4    ,count ,sternberg remarked

 that we are unacquainted with any      
existing  species of plant1 which like  
the ,lepidodendron1 preserves at all    
ages1  and throughout the whole extent  
of the trunk1 the scars formed by the   
attachment of the petioles1 or          
leaf-stalks1 or the markings of the     
leaves  themselves4 ,the yucca1         
dracaena1 and palm1 entirely shed their 
scales  when they are dried up1 and     
there only remain circles1 or rings1    
arranged  round the trunk in different  
directions4 ,the flabelliform palms     
preserve  their scales at the inferior  
extremity of the trunk only1 but lose   
them  as they increase in age2 and the  
stem is entirely bare1 from the middle  
to the superior extremity4 ,in the      
ancient ,lepidodendron1 on the other    
hand1 the more ancient the scale of the 
leaf-stalk1 the more apparent it  still 
remains4 ,portions of stems have been   
discovered which contain  leaf-scars far
 larger than those referred to above1   
and we deduce from  these fragments the 

fact that those individuals which have  
been found  whole1 are not by any means 
the largest of those which went to form 
so  large a proportion of the ancient   
coal-forests4 ,the lepidodendra bore    
linear one-nerved leaves1 and the stems 
always branched dichotomously and       
possessed a central pith4 ,specimens    
variously named knorria1  lepidophloios1
 halonia1 and ulodendron are all        
referable to this  family4              
,illustration3 ,,fig4                   
#ab4--,lepidodendron longifolium4       
,coal-shale4    ,illustration3 ,,fig4   
#ac4--,lepidodendron aculeatum in       
sandstone4    ,in some strata1 as for   
instance that of the ,shropshire        
coalfield1  quantities of elongated     
cylindrical bodies known as lepidostrobi
 have  been found1 which1 it was early  
conjectured1 were the fruit of the giant
  club-mosses about which we have just  
been speaking4 ,their appearance can  be
 called to mind by imagining the        
cylindrical fruit of the maize or       

,indian corn to be reduced to some three
 or four inches in length4 ,the         
sporangia or cases which contained the  
microscopic  spores or seeds were       
arranged around a central axis in a     
somewhat similar manner to that in      
which maize is found4 ,these bodies have
 since been found actually  situated at 
the end of branches of lepidodendron1   
thus placing their  true nature beyond a
 doubt4 ,the fossil seeds 7spores7 do   
not appear to  have exceeded in volume  
those of recent club-mosses1 and this   
although  the actual trees themselves   
grew to a size very many times greater  
than  the living species4 ,this         
minuteness of the seed-germs goes to    
explain the  reason why1 as ,sir        
,charles ,lyell remarked1 the same      
species of  lepidodendra are so widely  
distributed in the coal measures of     
,europe  and ,america1 their spores     
being capable of an easy transportation 
by the  wind4    ,illustration3 ,,fig4  
#ad4--,lepidostrobus4 ,coal-shale4      

,one striking feature in connection with
 the fruit of the lepidodendron  and    
other ancient representatives of the    
club-moss tribe1 is that the  bituminous
 coals in many1 if not in most1         
instances1 are made up almost  entirely 
of their spores and spore-cases4 ,under 
a microscope1 a piece of  such coal is  
seen to be thronged with the minute     
rounded bodies of the  spores           
interlacing one another and forming     
almost the whole mass1 whilst  larger   
than these1 and often indeed enclosing  
them1 are flattened  bag-like bodies    
which are none other than the compressed
 sporangia which  contained the former4 
,illustration3 ,,fig4                   
#ae4--,lycopodites4 ,coal sandstone4    
,now1 the little ,scottish or ,alpine   
club-moss which is so familiar1         
produces its own little cones1 each with
 its series of outside scales or        
leaves2 these are attached to the bags  
or spore-cases1 which are crowded  with 
spores4 ,although in miniature1 yet it  

produces its fruit in just the  same    
way1 at the terminations of its little  
branches1 and the spores1 the  actual   
germs of life1 when examined            
microscopically1 are scarcely           
distinguishable from those which are    
contained in certain bituminous  coals4 
,and1 although ancient club-mosses have 
been found in a fossilised  condition at
 least forty-nine feet high1 the spores 
are no larger than  those of our        
miniature club-mosses of the present    
day4    ,the spores are more or less    
composed of pure bitumen1 and the       
bituminous  nature of the coal depends  
largely on the presence or absence of   
these  microscopic bodies in it4 ,the   
spores of the living club-mosses contain
 so  much resinous matter that they are 
now largely used in the making of       
fireworks1 and upon the presence of this
 altered resinous matter in coal        
depends its capability of providing a   
good blazing coal4    ,at first sight it
 seems almost impossible that such a    

minute cause should  result in the      
formation of huge masses of coal1 such  
an inconceivable  number of spores being
 necessary to make even the smallest    
fragment of  coal4 ,but if we look at   
the cloud of spores that can be shaken  
from a  single spike of a club-moss1    
then imagine this to be repeated a      
thousand  times from each branch of a   
fairly tall tree1 and then finally      
picture a  whole forest of such trees   
shedding in due season their copious    
showers  of spores to earth1 we shall   
perhaps be less amazed than we were at  
first  thought1 at the stupendous result
 wrought out by so minute an object4    
,another well-known form of             
carboniferous vegetation is that known  
as the  ,sigillaria1 and1 connected with
 this form is one1 which was long       
familiar under the name of ,stigmaria1  
but which has since been  satisfactorily
 proved to have formed the branching    
root of the  sigillaria4 ,the older     
geologists were in the habit of placing 

these  plants among the tree-ferns1     
principally on account of the cicatrices
  which were left at the junctions of   
the leaf-stalks with the stem1 after    
the former had fallen off4 ,no foliage  
had1 however1 been met with which  was  
actually attached to the plants1 and    
hence1 when it was discovered  that some
 of them had long attenuated leaves not 
at all like those  possessed by ferns1  
geologists were compelled to abandon    
this  classification of them1 and even  
now no satisfactory reference to        
existing orders of them has been made1  
owing to their anomalous  structure4    
,the stems are fluted from base to stem1
 although this is not  so apparent near 
the base1 whilst the raised prominences 
which now form  the cicatrices1 are     
arranged at regular distances within the
 vertical  grooves4    ,when they have  
remained standing for some length of    
time1 and the strata  have been allowed 
quietly to accumulate around the trunks1
 they have  escaped compression4 ,they  

were evidently1 to a great extent1      
hollow like  a reed1 so that in those   
trees which still remain vertical1 the  
interior  has become filled up by a coat
 of sandstone1 whilst the bark has      
become  transformed into an envelope of 
an inch1 or half an inch of coal4 ,but  
many are found lying in the strata in a 
horizontal plane4 ,these have been  cast
 down and covered up by an              
ever-increasing load of strata1 so that 
the weight has1 in the course of time1  
compressed the tree into simply  the    
thickness of the double bark1 that is1  
of the two opposite sides of  the       
envelope which covered it when living4  
,sigillarae grew to a very great height 
without branching1 some  specimens      
having measured from #fj to #gj feet    
long4 ,in accordance with  their outside
 markings1 certain types are known as   
syringodendron1  favularia1 and         
clathraria4 ,diploxylon is a term       
applied to an  interior stem referable  
to this family4    ,illustration3 ,,fig4

 #af4--,stigmaria ficoides4 ,coal-shale4
    ,but the most interesting point     
about the sigillariae is the root4 ,this
  was for a long time regarded as an    
entirely distinct individual1 and the   
older geologists explained it in their  
writings as a species of succulent      
aquatic plant1 giving it the name of    
stigmaria4 ,they realized the fact  that
 it was almost universally found in     
those beds which occur  immediately     
beneath the coal seams1 but for a long  
time it did not strike  them that it    
might possibly be the root of a tree4   
,in an old edition of  ,lyell's         
,elements of ,geology1 utterly unlike   
existing editions in  quality1 quantity1
 or comprehensiveness1 after describing 
it as an  extinct species of            
water-plant1 the author hazarded the    
conjecture that  it might ultimately be 
found to have a connection with some    
other  well-known plant or tree4 ,it was
 noticed that above the coal1 in the    
roof1 stigmariae were absent1 and that  

the stems of trees which occurred       
there1 had become flattened by the      
weight of the overlying strata4 ,the    
stigmariae on the other hand1 abounded  
in the underclay1 as it is  called1 and 
were not in any way compressed but      
retained what appeared to  be their     
natural shape and position4 ,hence to   
explain their appearance1  it was       
thought that they were water-plants1    
ramifying the mud in every  direction1  
and finally becoming overwhelmed and    
covered by the mud  itself4 ,on         
botanical grounds1 ,brongniart and      
,lyell conjectured that they  formed the
 roots of other trees1 and this became  
the more apparent as it  came to be     
acknowledged that the underclays were   
really ancient soils4  ,all doubt was1  
however1 finally dispelled by the       
discovery by ,mr ,binney1  of a         
sigillaria and a stigmaria in actual    
connection with each other1 in  the     
,lancashire coal-field4    ,stigmariae  
have since been found in the ,cape      

,breton coal-field1 attached  to        
,lepidodendra1 about which we have      
already spoken1 and a similar  discovery
 has since been made in the ,british    
coal-fields4 ,this1  therefore1 would   
seem to shew the affinity of the        
sigillaria to the  lepidodendron1 and   
through it to the living lycopods1 or   
club-mosses4    ,some few species of    
stigmarian roots had been discovered1   
and various  specific names had been    
given to them before their actual nature
 was made  out4 ,what for some time were
 thought to be long cylindrical leaves1 
have  now been found to be simply       
rootlets1 and in specimens where these  
have  been removed1 the surface of the  
stigmaria has been noticed to be covered
  with large numbers of protuberant     
tubercles1 which have formed the bases  
of the rootlets4 ,there appears to have 
also been some special kind of          
arrangement in their growth1 since1     
unlike the roots of most living  plants1
 the tubercles to which these rootlets  

were attached1 were  arranged spirally  
around the main root4 ,each of these    
tubercles was  pitted in the centre1 and
 into these the almost pointed ends of  
the  rootlets fitted1 as by a ball and  
socket joint4    ,illustration3 ,,fig4  
#ag--,section of stigmaria4    ,a single
 trunk of sigillaria in an erect forest 
presents an epitome of  a coal-seam4    
,its roots represent the stigmaria      
underclay2 its bark the  compact coal2  
its woody axis1 the mineral charcoal2   
its fallen leaves and  fruits1 with     
remains of herbaceous plants growing in 
its shade1 mixed  with a little earthy  
matter1 the layers of coarse coal4 ,the 
condition of  the durable outer bark of 
erect trees1 concurs with the chemical  
theory  of coal1 in showing the especial
 suitableness of this kind of tissue for
  the production of the purer compact   
coals4--7,dawson1 ,structures in        
,coal47    ,there is yet one other      
family of plants which must be          
mentioned1 and  which forms a very      

important portion of the constituent    
flora of the  coal period4 ,this is the 
great family of the coniferae1 which    
although  differing in many respects    
from the highly organised dicotyledons  
of the  present day1 yet resembled them 
in some respects1 especially in the     
formation of an annual ring of woody    
growth4    ,the conifers are those trees
 which1 as the name would imply1 bear   
their  fruit in the form of cones1 such 
as the fir1 larch1 cedar1 and others4   
,the order is one which is familiar to  
all1 not only on account of the  cones  
they bear1 and their sheddings1 which in
 the autumn strew the  ground with a    
soft carpet of long needle-like leaves1 
but also because of  the gum-like       
secretion of resin which is contained in
 their tissues4 ,only  a few species    
have been found in the coal-beds1 and   
these1 on examination  under the        
microscope1 have been discovered to be  
closely related to the  araucarian      
division of pines1 rather than to any of

 our common firs4 ,the  living species  
of this tree is a native of ,norfolk    
,island1 in the  ,pacific1 and here it  
attains a height of #bjj feet1 with a   
girth of #cj  feet4 ,from the peculiar  
arrangement of the ducts in the         
elongated  cellular tissue of the tree1 
as seen under the microscope1 the fossil
  conifers1 which exhibit this          
structure1 have been placed in the same 
division4    ,the familiar fossil known 
to geologists as ,sternbergia has now   
been  shown to be the cast of the       
central pith of these conifers1 amongst 
which  may be mentioned cordaites1      
araucarites1 and dadoxylon44 ,the       
central  cores had become replaced with 
inorganic matter after the pith had     
shrunk  and left the space empty4 ,this 
shrinkage of the pith is a process which
  takes place in many plants even when  
living1 and instances will at once      
occur1 in which the stems of various    
species of shrubs when broken open      
exhibit the remains of the shrunken     

pith1 in the shape of thin discs  across
 the interval cavity4    ,we might      
reasonably expect that where we find the
 remains of fossil  coniferous trees1 we
 should also meet with the cones or     
fruit which they  bear4 ,and such is the
 case4 ,in some coal-districts fossil   
fruits1 named  cardiocarpum and         
trigonocarpum1 have been found in great 
quantities1  and these have now been    
decided by botanists to be the fruits of
 certain  conifers1 allied1 not to those
 which bear hard cones1 but to those    
which  bear solitary fleshy fruits4 ,sir
 ,charles ,lyell referred them to a     
,chinese  genus of the yew tribe called 
salisburia4 ,dawson states that they are
  very similar to both taxus and        
salisburia44 ,they are abundant in some 
coal-measures1 and are contained1 not   
only in the coal itself1 but also  in   
the sandstones and shales4 ,the         
under-clays appear to be devoid of      
them1 and this is1 of course1 exactly   
what might have been expected1  since   

the seeds would remain upon the soil    
until covered up by vegetable  matter1  
but would never form part of the clay   
soil itself4    ,in connection with the 
varieties which have been distinguished 
in the  families of the conifers1       
calamites1 and sigillariae1 ,sir        
,william ,dawson  makes the following   
observations3 ,i believe that there was 
a  considerably wide range of           
organisation in cordaitinae as well as  
in  calamites and sigillariae1 and that 
it will eventually be found that  there 
were three lines of connection between  
the higher cryptogams  7flowerless7 and 
the phaenogams 7flowering71 one leading 
from the  lycopodes by the sigillariae1 
another leading by the cordaites1 and   
the third leading from the equisetums by
 the calamites4 ,still further  back the
 characters1 afterwards separated in the
 club-mosses1  mare's-tails1 and ferns1 
were united in the rhizocarps1 or1 as   
some  prefer to call them1 the          
heterosporous filicinae4    ,in         

concluding this chapter dealing with the
 various kinds of plants which  have    
been discovered as contributing to the  
formation of  coal-measures1 it would be
 as well to say a word or two concerning
 the  climate which must have been      
necessary to permit of the growth of    
such an  abundance of vegetation4 ,it is
 at once admitted by all botanists that 
a  moist1 humid1 and warm atmosphere was
 necessary to account for the  existence
 of such an abundance of ferns4 ,the    
gorgeous waving  tree-ferns which were  
doubtless an important feature of the   
landscape1  would have required a moist 
heat such as does not now exist in this 
country1 although not necessarily a     
tropical heat4 ,the magnificent giant   
lycopodiums cast into the shade all our 
living members of that class1 the       
largest of which perhaps are those that 
flourish in ,new ,zealand4 ,in ,new     
,zealand1 too1 are found many species of
 ferns1 both those which are            
arborescent and those which are of more 

humble stature4 ,add to these the       
numerous conifers which are there found1
 and we shall find that a forest  in    
that country may represent to a certain 
extent the appearance  presented by a   
forest of carboniferous vegetation4 ,the
 ferns1 lycopods1  and pines1 however1  
which appear there1 it is but fair to   
add1 are mixed  with other types allied 
to more recent forms of vegetation4     
,there are many reasons for believing   
that the amount of carbonic acid gas    
then existing in the atmosphere was     
larger than the quantity which we now   
find1 and ,professor ,tyndall has shown 
that the effect of this would be to     
prevent radiation of heat from the      
earth4 ,the resulting forms of          
vegetation would be such as would be    
comparable with those which are now     
reared in the green-house or            
conservatory in these latitudes4 ,the   
gas  would1 in fact1 act as a glass     
roof1 extending over the whole world4   
,,chapter ,,ii4    ,a ,,general ,,view  

,,of ,,the ,,coal-,,bearing ,,strata4   
,in considering the source whence coal  
is derived1 we must be careful to       
remember that coal itself is but a minor
 portion of the whole formation  in     
which it occurs4 ,the presence of coal  
has indeed given the name to the        
formation1 the word carboniferous       
meaning coal-bearing1 but in taking  a  
comprehensive view of the position which
 it occupies in the bowels of  the      
earth1 it will be necessary to take into
 consideration the strata in  which it  
is found1 and the conditions1 so far as 
are known1 under which  these were      
deposited4    ,geologically speaking1   
the ,carboniferous formation occurs near
 the close  of that group of systems    
which have been classed as palaeozoic1  
younger  in point of age than the well  
known ,devonian and ,old ,red ,sandstone
  strata1 but older by far than the     
,oolites1 the ,wealden1 or the          
,cretaceous  strata4    ,in ,south      
,wales the coal-bearing strata have been

 estimated at between  #aa1jjj and      
#ab1jjj feet1 yet amongst this enormous 
thickness of strata1  the whole of the  
various coal-seams1 if taken together1  
probably does not  amount to more than  
#abj feet4 ,this great disproportion    
between the total  thickness and the    
thickness of coal itself shows itself in
 every  coal-field that has been worked1
 and when a single seam of coal is      
discovered attaining a thickness of #i  
or #aj feet1 it is so unusual a  thing  
in ,great ,britain as to cause it to be 
known as the nine or  ten-foot seam1 as 
the case may be4 ,although abroad many  
seams are found  which are of greater   
thicknesses1 yet similarly the other    
portions of the  formation are          
proportionately greater4    ,it is not  
possible therefore to realise completely
 the significance of  the coal-beds     
themselves unless there is also a       
knowledge of the  remaining constituents
 of the whole formation4 ,the strata    
found in the  various coal-fields differ

 considerably amongst themselves in     
character4  ,there are1 however1 certain
 well-defined characteristics which find
  representation in most of the         
principal coal-fields1 whether ,british 
or  ,european4 ,professor ,hull         
classifies these carboniferous beds as  
follows3--      ,,upper ,,carboniferous4
      ,upper coal-measures4             
,reddish and purple sandstones1 red and 
grey clays  and  shales1          thin  
bands of coal1 ironstone and limestone1 
with spirorbis          and fish4       
,middle coal-measures4        ,yellow   
and gray sandstones1 blue and black     
clays and shales1          bands of coal
 and ironstone1 fossil plants1 bivalves 
and fish1 occasional marine bands4      
,,middle ,,carboniferous4               
,gannister beds or ,lower coal-measures4
        ,millstone grit4 ,flagstone     
series in ,ireland4        ,yoredale    
beds4 ,upper shale series of ,ireland4  
,,lower ,,carboniferous4      ,mountain 
limestone4        ,limestone shale4     

,each of the three principal divisions  
has its representative in ,scotland1    
,belgium1 and ,ireland1 but1            
unfortunately for the last-named        
country1 the  whole of the upper        
coal-measures are there absent4 ,it is  
from these  measures that almost all our
 commercial coals are obtained4    ,this
 list of beds might be further curtailed
 for all practical purposes  of the     
geologist1 and the three great divisions
 of the system would thus  stand3--     
,upper ,carboniferous1 or ,coal-measures
 proper4      ,millstone grit4          
,lower ,carboniferous1 or ,mountain     
limestone4    ,in short1 the formation  
consists of masses of sandstone1 shale1 
limestone  and coal1 these also         
enclosing clays and ironstones1 and1 in 
the  limestone1 marbles and veins of the
 ores of lead1 zinc1 and antimony1 and  
occasionally silver4    ,illustration3  
,,fig4 #ah4--,sigillarian trunks in     
current-bedded sandstone4  ,st ,etienne4
    ,as the most apparent of the rocks  

of the system are sandstone1 shale1     
limestone1 and coal1 it will be         
necessary to consider how these were    
deposited in the waters of the          
carboniferous ages1 and this we can best
  do by considering the laws under which
 strata of a similar nature are now     
being deposited as sedimentary beds4    
,a great proportion consists of         
sandstone4 ,now sandstone is the result 
of  sand which has been deposited in    
large quantities1 having become         
indurated or hardened by various        
processes brought to bear upon it4 ,it  
is  necessary1 therefore1 first to      
ascertain whence came the sand1 and     
whether there are any peculiarities in  
its method of deposition which  will    
explain its stratification4 ,it will be 
noticed at once that it bears  a        
considerable amount of evidence of what 
is called current-bedding1  that is to  
say1 that the strata1 instead of being  
regularly deposited1  exhibit series of 
wedge-shaped masses1 which are          

constantly thinning out4    ,sand and   
quartz are of the same chemical         
composition1 and in all  probability the
 sand of which every sandstone in       
existence is composed1  appeared on this
 earth in its first solid form in the   
shape of quartz4  ,now quartz is a      
comparatively heavy mineral1 so also1   
therefore1 will  sand be4 ,it is also   
very hard1 and in these two respects it 
differs  entirely from another product  
of sedimentary deposition1 namely1 mud  
or  clay1 with which we shall have      
presently to deal when coming to the    
shales4 ,since quartz is a hard mineral 
it necessarily follows that it  will    
suffer1 without being greatly affected1 
a far greater amount of  wearing and    
knocking about when being transported by
 the agency of  currents and rivers1    
than will a softer substance1 such as   
clay4 ,an equal  amount of this wearing 
action upon clay will reduce it to a    
fine  impalpable silt4 ,the grains of   
sand1 however1 will still remain of an  

appreciable average size1 and where both
 sand and clay are being  transported to
 the sea in one and the same stream1 the
 clay will be  transported to long      
distances1 whilst the sand1 being       
heavier1 bulk for  bulk1 and also       
consisting of grains larger in size than
 grains of clay1  will be rapidly       
deposited1 and form beds of sand4 ,of   
course1 if the  current be a violent    
one1 the sand is transported1 not by    
being held in  suspension1 but rather by
 being pushed along the bed of the      
river2 such  an action will then tend to
 cause the sand to become powdered into 
still  finer sand4    ,when a river     
enters the sea it soon loses its        
individuality2 it becomes  merged in the
 body of the ocean1 where it loses its  
current1 and where  therefore it has no 
power to keep in suspension the sediment
 which it had  brought down from the    
higher lands4 ,when this is the case1   
the sand borne  in suspension is the    
first to be deposited1 and this         

accumulates in banks  near the entrance 
of the river into the sea4 ,we will     
suppose1 for  illustration1 that a small
 river has become charged with a supply 
of  sand4 ,as it gradually approaches   
the sea1 and the current loses its      
force1 the sand is the more sluggishly  
carried along1 until finally it  falls  
to the bottom1 and forms a layer of sand
 there4 ,this layer  increases in       
thickness until it causes the depth of  
water above it to  become comparatively 
shallow4 ,on the shallowing process     
taking place1 the  current will still   
have a certain1 though slighter1 hold on
 the sand in  suspension1 and will      
transport it yet a little further       
seaward1 when it  will be thrown down1  
at the edge of the bank or layer already
 formed1  thus tending to extend the    
bank1 and to shallow a wider space of   
river-bed4    ,as a result of this      
action1 strata would be formed1 shewing 
stratification diagonally as well as    
horizontally1 represented in section  as

 a number of banks which had seemingly  
been thrown down one above the  other1  
ending in thin wedge-shaped terminations
 where the particular  supply of        
sediment to which each owed its         
formation had failed4    ,the masses of 
sandstone which are found in the        
carboniferous formation1  exhibit in a  
large degree these wedge-shaped strata1 
and we have  therefore a clue at once1  
both as to their propinquity to sea and 
land1  and also as to the manner in     
which they were formed4                 
,illustration3 ,,fig4 #ai4--,productus4 
,coal-measures4    ,there is one thing  
more1 too1 about them4 ,just as1 in the 
case we were  considering1 we could     
observe that the wedge-shaped strata    
always pointed  away from the source of 
the material which formed them1 so we   
can  similarly judge that in the        
carboniferous strata the same deduction 
holds  good1 that the                   
diagonally-pointing strata were formed  
in the same way1  and that their        

thinning out was simply owing to        
temporary failure of  sediment1 made    
good1 however1 by a further deposition  
of strata when the  next supply was     
borne down4    ,it is scarcely likely1  
however1 that sand in a pure state was  
always  carried down by the currents to 
the sea4 ,sometimes there would be some 
silt mixed with it4 ,just as in many    
parts large masses of almost pure       
sandstone have been formed1 so in other 
places shales1 or1 as they are          
popularly known by miners1 bind1 have   
been formed4 ,shales are formed  from   
the clays which have been carried down  
by the rivers in the shape of  silt1 but
 which have since become hardened1 and  
now split up easily into  thin parallel 
layers4 ,the reader has no doubt often  
handled a piece of  hard clay when fresh
 from the quarry1 and has remembered how
 that1 when  he has been breaking it up1
 in order1 perhaps1 to excavate a       
partially-hidden fossil1 it has readily 
split up in thin flakes or layers  of   

shaly substance4 ,this exhibits1 on a   
small scale1 the chief  peculiarity of  
the coal shales4    ,the formation of   
shales will now demand our attention4   
,when a river is  carrying down with it 
a quantity of mud or clay1 it is        
transported as a  fine1 dusty silt1 and 
when present in quantities1 gives the   
muddy tint to  the water which is so    
noticeable4 ,we can very well see how   
that silt will  be carried down in      
greater quantities than sand1 since     
nearly all rivers  in some part of their
 course will travel through a clayey    
district1 and  finely-divided clay1     
being of a very light nature1 will be   
carried  forward whenever a river passes
 over such a district4 ,and a very      
slight  current being sufficient to     
carry it in a state of suspension1 it   
follows  that it will have little       
opportunity of falling to the bottom1   
until1 by  some means or other1 the     
current1 which is the means of its      
conveyance1  becomes stopped or hindered

 considerably in its flow4    ,when the 
river enters a large body of water1 such
 as the ocean or a lake1  in losing its 
individuality1 it loses also the        
velocity of its current1  and the silt  
tends to sink down to the bottom4 ,but  
being less heavy than  the sand1 about  
which we have previously spoken1 it does
 not sink all at  once1 but partly with 
the impetus it has gained1 and partly on
 account of  the very slight velocity   
which the current still retains1 even   
after  having entered the sea1 it will  
be carried out some distance1 and will  
the more gradually sink to the bottom4  
,the deeper the water in which it  falls
 the greater the possibility of its     
drifting farther still1 since in        
sinking1 it would fall1 not vertically1 
but rather as the drops of rain  in a   
shower when being driven before a gale  
of wind4 ,thus we should  notice that   
clays and shales would exhibit a        
regularity and uniformity of  deposition
 over a wide area4 ,currents and tides  

in the sea or lake would  tend still    
further to retard deposition1 whilst any
 stoppages in the  supply of silt which 
took place would give the former layer  
time to  consolidate and harden1 and    
this would assist in giving it that     
bedded  structure which is so noticeable
 in the shales1 and which causes it to  
split up into fine laminae4 ,this       
uniformity of structure in the shales   
over wide areas is a well ascertained   
characteristic of the coal-shales1  and 
we may therefore regard the method of   
their deposition as given here  with a  
degree of certainty4    ,there is a     
class of deposit found among the        
coal-beds1 which is known as  the       
underclay1 and this is the most regular 
of all as to the position  in which it  
is found4 ,the underclays are found     
beneath every bed of coal4  ,warrant1   
spavin1 and gannister are local names   
which are sometimes  applied to it1 the 
last being a term used when the clay    
contains such a  large proportion of    

silicious matter as to become almost    
like a hard  flinty rock4 ,sometimes1   
however1 it is a soft clay1 at others it
 is mixed  with sand1 but whatever the  
composition of the underclays may be1   
they  always agree in being             
unstratified4 ,they also agree in this  
respect that  the peculiar fossils known
 as stigmariae abound in them1 and in   
some  cases to such an extent that the  
clay is one thickly-matted mass of the  
filamentous rootlets of these fossils4  
,we have seen how these gradually  came 
to be recognised as the roots of trees  
which grew in this age1 and  whose      
remains have subsequently become        
metamorphosed into coal1 and it is  but 
one step farther to come to the         
conclusion that these underclays are    
the ancient soils in which the plants   
grew4    ,no sketch of the various beds 
which go to form the coal-measures would
 be  complete which did not take into   
account the enormous beds of mountain   
limestone which form the basis of the   

whole system1 and which in thinner      
bands are intercalated amongst the upper
 portion of the system1 or the  true    
coal-measures4    ,now1 limestones are  
not formed in the same way in which we  
have seen that  sandstones and shales   
are formed4 ,the last two mentioned owe 
their origin  to their deposition as    
sediment in seas1 estuaries or lakes1   
but the  masses of limestone which are  
found in the various geological         
formations  owe their origin to causes  
other than that of sedimentary          
deposition4    ,in carboniferous times  
there lived numberless creatures which  
we know  nowadays as encrinites4 ,these1
 when growing1 were fixed to the bed of 
the ocean1 and extended upward in the   
shape of pliant stems composed of       
limestone joints or plates2 the stem of 
each encrinite then expanded at  the top
 in the shape of a gorgeous and graceful
 starfish1 possessed of  numberless and 
lengthy arms4 ,these encrinites grew in 
such profusion that  after death1 when  

the plates of which their stems         
consisted1 became  loosened and         
scattered over the bed of the sea1 they 
accumulated and  formed solid beds of   
limestone4 ,besides the encrinites1     
there were of  course other creatures   
which were able to create the hard parts
 of their  structures by withdrawing    
lime from the sea1 such as foraminifera1
  shell-fish1 and especially corals1 so 
that all these assisted after death  in 
the accumulation of beds of limestone   
where they had grown and lived4         
,illustration3 ,,fig4 #bj4--;,encrinite4
    ,illustration3 ,,fig4               
#ba4--;,encrinital limestone4    ,there 
is one peculiarity in connection with   
the habitats of the  encrinites and     
corals which goes some distance in      
supplying us with a  useful clue as to  
the conditions under which this portion 
of the  carboniferous formation was     
formed4 ,these creatures find it a      
difficult  matter1 as a rule1 to live   
and secrete their calcareous skeleton in

 any  water but that which is clear1 and
 free from muddy or sandy sediment4     
,they are therefore not found1 generally
 speaking1 where the other  deposits    
which we have considered1 are forming1  
and1 as these are always  found near the
 coasts1 it follows that the habitats of
 the creatures  referred to must be far 
out at sea where no muddy sediments1    
borne by  rivers1 can reach them4 ,we   
can therefore safely come to the        
conclusion  that the large masses of    
encrinital limestone1 which attain such 
an  enormous thickness in some places1  
especially in ,ireland1 have been       
formed far away from the land of the    
period2 we can at the same time draw    
the conclusion that if we find the      
encrinites broken and snapped asunder1  
and the limestone deposits becoming     
impure through being mingled with a     
proportion of clayey or sandy deposits1 
that we are approaching a  coast-line   
where perhaps a river opened out1 and   
where it destroyed the  growth of       

encrinites1 mixing with their dead      
remains the sedimentary  dbris of the   
land4    ,illustration3 ,,fig4          
#bb4--;,encrinites3 various4 ,mountain  
limestone4    ,we have lightly glanced  
at the circumstances attending the      
deposition of  each of the principal    
rocks which form the beds amongst which 
coal is  found1 and have now to deal    
with the formation of the coal itself4  
,we  have already considered the various
 kinds of plants and trees which have   
been discovered as contributing their   
remains to the formation of coal1  and  
have now to attempt an explanation of   
how it came to be formed in so  regular 
a manner over so wide an area4    ,each 
of the ,british coal-fields is fairly   
extensive4 ,the ,yorkshire and          
,derbyshire coal-fields1 together with  
the ,lancashire coal-field1 with  which 
they were at one time in geological     
connection1 give us an area of  nearly  
#ajjj square miles1 and other ,british  
coal-fields show at least  some hundreds

 of square miles4 ,and yet1 spread over 
them1 we find a  series of beds of coal 
which in many cases extend throughout   
the whole  area with apparent           
regularity4 ,if we take it1 as there    
seems every reason  to believe was the  
case1 that almost all these coal-fields 
were not only  being formed at the same 
time1 but were in most instances in     
continuation  with one another1 this    
regularity of deposition of             
comparatively narrow  beds of coal1     
appears all the more remarkable4    ,the
 question at once suggests itself1      
,which of two things is probable8  ,are 
we to believe that all this vegetable   
matter was brought down by some  mighty 
river and deposited in its delta1 or    
that the coal-plants grew  just where we
 now find the coal8    ,formerly it was 
supposed that coal was formed out of    
dead leaves and  trees1 the refuse of   
the vegetation of the land1 which had   
been carried  down by rivers into the   
sea and deposited at their mouths1 in   

the same  way that sand and mud1 as we  
have seen1 are swept down and deposited4
 ,if  this were so1 the extent of the   
deposits would require a river with an  
enormous embouchure1 and we should be   
scarcely warranted in believing  that   
such peaceful conditions would there    
prevail as to allow of the  layers of   
coal to be laid down with so little     
disturbance and with such  regularity   
over these wide areas4 ,but the great   
objection to this theory  is1 that not  
only do the remains still retain their  
perfection of  structure1 but they are  
comparatively pure1--i4e41 unmixed with 
sedimentary depositions of clay or sand4
 ,now1 rivers would not bring down  the 
dead vegetation alone2 their usual      
burden of sediment would also be        
deposited at their mouths1 and thus dead
 plants1 sand1 and clay would be  mixed 
up together in one black shaly or sandy 
mass1 a mixture which would  be useless 
for purposes of combustion4 ,the only   
theory which explained  all the         

recognised phenomena of the             
coal-measures was that the plants       
forming the coal actually grew where the
 coal was formed1 and where1  indeed1 we
 now find it4 ,when the plants and trees
 died1 their remains  fell to the ground
 of the forest1 and these soon turned to
 a black1  pasty1 vegetable mass1 the   
layer thus formed being regularly       
increased  year by year by the continual
 accumulation of fresh carbonaceous     
matter4  ,by this means a bed would be  
formed with regularity over a wide area2
 the  coal would be almost free from an 
admixture of sandy or clayey sediment1  
and probably the rate of formation would
 be no more rapid in one part of  the   
forest than another4 ,thus there would  
be everywhere uniformity of  thickness4 
,the warm and humid atmosphere1 which it
 is probable then  existed1 would not   
only have tended towards the production 
of an abnormal  vegetation1 but would   
have assisted in the decaying and       
disintegrating  processes which went on 

amongst the shed leaves and trees4      
,when at last it was announced as a     
patent fact that every bed of coal      
possessed its underclay1 and that trees 
had been discovered actually  standing  
upon their own roots in the clay1 there 
was no room at all for  doubt that the  
correct theory had been hit upon--viz41 
that coal is now  found just where the  
trees composing it had grown in the     
past4    ,but we have more than one     
coal-seam to account for4 ,we have to   
explain  the existence of several layers
 of coal which have been formed over one
  another on the same spot at successive
 periods1 divided by other periods  when
 shale and sandstones only have been    
formed4    ,a careful estimate of the   
,lancashire coal-field has been made by 
,professor ,hull for the ,geological    
,survey4 ,of the #gjjj feet of          
carboniferous strata here found1 spread 
out over an area of #bag square  miles1 
there are on the average eighteen seams 
of coal4    ,this is only an instance of

 what is to be found elsewhere4         
,eighteen  coal-seams6 what does this   
mean8 ,it means that1 during            
carboniferous  times1 on no less than   
eighteen occasions1 separate and        
distinct forests  have grown on this    
self-same spot1 and that between each of
 these  occasions changes have taken    
place which have brought it beneath the 
waters of the ocean1 where the          
sandstones and shales have been formed  
which divide the coal-seams from each   
other4 ,we are met here by a  wonderful 
demonstration of the instability of the 
surface of the earth1  and we have to do
 our best to show how the changes of    
level have been  brought about1 which   
have allowed of this game of geological 
see-saw to  take place between sea and  
land4 ,changes of level6 ,many a hard   
geological  nut has only been overcome  
by the application of the principle of  
changes  of level in the surface of the 
earth1 and in this we shall find a sure 
explanation of the phenomena of the     

coal-measures4    ,great changes of the 
level of the land are undoubtedly taking
 place even  now on the earth's surface1
 and in assuming that similar changes   
took  place in carboniferous times1 we  
shall not be assuming the former        
existence of an agent with which we are 
now unfamiliar4 ,and when we  consider  
the thicknesses of sandstone and shale  
which intervene beneath  the coal-seams1
 we can realise to a certain extent the 
vast lapses of  years which must have   
taken place between the existence of    
each forest2  so that although now an   
individual passing up a coal-mine shaft 
may  rapidly pass through the remains of
 one forest after another1 the rise of  
the strata above each forest-bed then   
was tremendously slow1 and the  period  
between the growth of each forest must  
represent the passing away  of countless
 ages4 ,perhaps it would not be too much
 to say that the  strata between some of
 the coal-seams would represent a period
 not less  than that between the        

formation of the few tertiary coals with
 which we  are acquainted1 and a time   
which is still to us in the far-away    
future4    ,the actual seams of coal    
themselves will not yield much          
information1 from  which it will be     
possible to judge of the contour of the 
landmasses at  this ancient period4 ,of 
one thing we are sure1 namely1 that at  
the time  each seam was formed1 the spot
 where it accumulated was dry land4 ,if1
  therefore1 the seams which appear one 
above the other coincide fairly  well as
 to their superficial extent1 we can    
conclude that each time the  land was   
raised above the sea and the forest     
again grew1 the contour of  the land was
 very similar4 ,this conclusion will be 
very useful to go  upon1 since whatever 
decision may be come to as an           
explanation of one  successive          
land-period and sea-period on the same  
spot1 will be  applicable to the        
eighteen or more periods necessary for  
the completion  of some of the          

coal-fields4    ,we will therefore look 
at one of the sandstone masses which    
occur between  the coal-seams1 and learn
 what lessons these have to teach us4   
,in  considering the formation of strata
 of sand in the seas around our         
river-mouths1 it was seen that1 owing to
 the greater weight of the  particles of
 the sand over those of clay1 the former
 the more readily  sank to the bottom1  
and formed banks not very far away from 
the land4 ,it  was seen1 too1 that each 
successive deposition of sand formed a  
wedge-shaped layer1 with the point of   
the wedge pointing away from the  source
 of origin of the sediment1 and         
therefore of the current which  conveyed
 the sediment4 ,therefore1 if in the    
coal-measure sandstones the  layers were
 found with their wedges all pointing in
 one direction1 we  should be able to   
judge that the currents were all from   
one direction1  and that1 therefore1    
they were formed by a single river4 ,but
 this is just  what we do not find1 for 

instead of it the direction of the      
wedge-shaped  strata varies in almost   
every layer1 and the current-bedding has
 been  brought about by currents        
travelling in every direction4 ,such    
diverse  current-bedding could only     
result from the fact that the spot where
 the  sand was laid down was subject to 
currents from every direction1 and the  
inference is that it was well within the
 sphere of influence of numerous        
streams and rivers1 which flowed from   
every direction4 ,the only condition  of
 things which would explain this is that
 the sandstone was originally  formed in
 a closed sea or large lake1 into which 
numerous rivers flowing  from every     
direction poured their contents4        
,now1 in the sandstones1 the remains of 
numerous plants have been found1  but   
they do not present the perfect         
appearance that they do when found in   
the shales2 in fact they appear to have 
suffered a certain amount of  damage    
through having drifted some distance4   

,this1 together with the fact  that     
sandstones are not formed far out at    
sea1 justify the safe  conclusion that  
the land could not have been far off4   
,wherever the  current-bedding shows    
itself in this manner we may be sure we 
are  examining a spot from which the    
land in every direction could not have  
been at a very great distance1 and also 
that1 since the heavy materials  of     
which sandstone is composed could only  
be transported by being  impelled along 
by currents at the bed of the sea1 and  
that in deep water  such currents could 
not exist1 therefore we may safely      
decide that the  sea into which the     
rivers fell was a comparatively shallow 
one4    ,although the present           
coal-fields of ,england are divided from
 one another  by patches of other beds1 
it is probable that some of them were   
formerly  connected with others1 and a  
very wide sheet of coal on each occasion
 was  laid down4 ,the question arises as
 to what was the extent of the inland   

sea or lake1 and did it include the area
 covered by the coal basins of          
,scotland and ,ireland1 of ,france and  
,belgium8 ,and if these1 why not those  
of ,america and other parts8 ,the       
deposition of the coal1 according to the
  theory here advanced1 may as well have
 been brought about in a series of      
large inland seas and lakes1 as by one  
large comprehensive sea1 and  probably  
the former is the more satisfactory     
explanation of the two4 ,but  the       
astonishing part of it is that the      
changes in the level of the land  must  
have been taking place simultaneously   
over these large areas1  although1 of   
course1 while one quarter may have been 
depressed beneath  the sea1 another may 
have been raised above it4    ,in       
connection with the question of the     
contour of the land during the          
existence of the large lakes or inland  
seas1 ,professor ,hull has prepared1  in
 his series of maps illustrative of the 
,palaeo-,geography of the ,british      

,islands1 a map showing on incontestible
 grounds the existence during the       
coal-ages of a great central barrier or 
ridge of high land stretching  across   
from ,anglesea1 south of ,flint1        
,staffordshire1 and ,shropshire         
coal-fields1 to the eastern coast of    
,norfolk4 ,he regards the ,british      
coal-measures as having been laid down  
in two1 or at most three1 areas of      
deposition--one south of this ridge1 the
 remainder to the north of it4 ,in      
regard to the extent of the former      
deposits of coal in ,ireland1 there is  
every probability that the sister island
 was just as favourably treated  in this
 respect as ,great ,britain4 ,most      
unfortunately1 ,ireland has since       
suffered extreme denudation1 notably    
from the great convulsions of nature  at
 the close of the very period of their  
deposition1 as well as in more  recent  
times1 resulting in the removal of      
nearly all the valuable upper           
carboniferous beds1 and leaving only the

 few unimportant  coal-beds to which    
reference has been made4                
,illustration3 ,,fig4                   
#bc4--;,cyathophyllum4 ,coral in        
encrinital limestone4    ,we are unable 
to believe in the continuity of our     
coal-beds with those of  ,america1 for  
the great source of sediment in those   
times was a continent  situated on the  
site of the ,atlantic ,ocean1 and it is 
owing to this  extensive continent that 
the forms of flora found in the         
coal-beds in  each country bear so close
 a resemblance to one another1 and also 
that  the encrinital limestone which was
 formed in the purer depths of the      
ocean on the east1 became mixed with    
silt1 and formed masses of shaly  impure
 limestone in the south-western parts of
 ,ireland4    ,it must be noted that1   
although we may attribute to upheaval   
from beneath  the fact that the bed of  
the sea became temporarily raised at    
each period  into dry land1 the deposits
 of sand or shale would at the same time

 be  tending to shallow the bed1 and    
this alone would assist the process of  
upheaval by bringing the land at least  
very near to the surface of the  water4 
,each upheaval1 however1 could have been
 but a temporary arrest of the  great   
movement of crust subsidence which was  
going on throughout the coal  period1 so
 that1 at its close1 when the last coal 
forest grew upon the  surface of the    
land1 there had disappeared1 in the case
 of ,south ,wales1 a  thickness of      
#aa1jjj feet of material4    ,of the    
many remarkable things in connection    
with coal-beds1 not the least  is the   
state of purity in which coal is found4 
,on the floor of each  forest there     
would be many a streamlet or even small 
river which would  wend its way to meet 
the not very distant sea1 and it is     
surprising at  first that so little     
sediment found its way into the coal    
itself4 ,but  this was cleverly         
explained by ,sir ,charles ,lyell1 who  
noticed1 on one of  his visits to       

,america1 that the water of the         
,mississippi1 around the rank  growths  
of cypress which form the cypress swamps
 at the mouths of that  river1 was      
highly charged with sediment1 but that1 
having passed through  the close        
undergrowth of the swamps1 it issued in 
almost a pure state1  the sediment which
 it bore having been filtered out of it 
and  precipitated4 ,this very           
satisfactorily explained how in some    
places  carbonaceous matter might be    
deposited in a perfectly pure state1    
whilst  in others1 where sandstone or   
shale was actually forming1 it might be 
impregnated by coaly matter in such a   
way as to cause it to be stained  black4
 ,in times of flood sediment would be   
brought in1 even where pure  coal had   
been forming1 and then we should have a 
thin parting of  sandstone or shale1    
which was formed when the flood was at  
its height4 ,or  a slight sinking of the
 land might occur1 in which case also   
the  formation of coal would temporarily

 cease1 and a parting of foreign  matter
 would be formed1 which1 on further     
upheaval taking place1 would  again give
 way to another forest growth4 ,some of 
the thicker beds have  been found       
presenting this aspect1 such as the     
,south ,staffordshire  ten-yard coal1   
which in some parts splits up into a    
dozen or so smaller  beds1 with partings
 of sediment between them4    ,in the   
face of the stupendous movements which  
must have happened in order  to bring   
about the successive growth of forests  
one above another on the  same spot1 the
 question at once arises as to how these
 movements of the  solid earth came     
about1 and what was the cause which     
operated in such a  manner4 ,we can only
 judge that1 in some way or other1 heat1
 or the  withdrawal of heat1 has been   
the prime motive power4 ,we can         
perceive1  from what is now going on in 
some parts of the earth1 how great an   
influence it has had in shaping the     
land1 for volcanoes owe their  activity 

to the hidden heat in the earth's       
interior1 and afford us an  idea of the 
power of which heat is capable in the   
matter of building up  and destroying   
continents4 ,no less certain is it that 
heat is the prime  factor in those more 
gradual vertical movements of the land  
to which we  have referred elsewhere1   
but in regard to the exact manner in    
which it  acts we are very much in the  
dark4 ,everybody knows that1 in the     
majority  of instances1 material        
substances of all kinds expand under the
 influence  of heat1 and contract when  
the source of heat is withdrawn4 ,if we 
can  imagine movements in the quantity  
of heat contained in the solid crust1   
the explanation is easy1 for if a       
certain tract of land receive an        
accession of heat beneath it1 it is     
certain that the principal effect  will 
be an elevation of the land1 consequent 
on the expansion of its  materials1 with
 a subsequent depression when the heat  
beneath the tract  in question becomes  

gradually lessened4 ,should the heat be 
retained for a  long period1 the strata 
would be so uplifted as to form an      
anticlinal1 or  saddle-back1 and then1  
should subsequent denudation take place1
 more  ancient strata would be brought  
to view4 ,it was thus in the instance of
  the tract bounded by the ,north and   
,south ,downs1 which were formerly      
entirely covered by chalk1 and in the   
instance of the uprising of the         
carboniferous limestone between the     
coal-fields of ,lancashire1             
,staffordshire1 and ,derbyshire4    ,how
 the heat-waves act1 and the laws1 if   
any1 which they obey in their           
subterranean movements1 we are unable to
 judge4 ,from the properties which  heat
 possesses we know that its presence or 
absence produces marked  differences in 
the positions of the strata of the      
earth1 and from  observations made in   
connection with the closing of some     
volcanoes1 and  the opening up of fresh 
earth-vents1 we have gone a long way    

towards  establishing the probability   
that there are even now slow and        
ponderous  movements taking place in the
 heat stored in the earth's crust1 whose
  effects are appreciably communicated  
to the outside of the thin rind of      
solid earth upon which we live4         
,owing to the great igneous and volcanic
 activity at the close of the           
deposition of the carboniferous system  
of strata1 the coal-measures  exhibit   
what are known as faults in abundance4  
,the mountain limestone1  where it      
outcrops at the surface1 is observed to 
be much jointed1 so much  so that the   
work of quarrying the limestone is      
greatly assisted by the  jointed        
structure of the rock4 ,faults differ   
from joints in that1 whilst  the strata 
in the latter are still in relative     
position on each side of  the joint1    
they have in the former slipped out of  
place4 ,in such a case  the continuation
 of a stratum on the opposite side of a 
fault will be  found to be depressed1   

perhaps a thousand feet or more4 ,it    
will be seen  at once how that1 in      
sinking a new shaft into a coal-seam1   
the  possibility of an unknown fault has
 to be brought into consideration1      
since the position of the seam may prove
 to have been depressed to such  an     
extent as to cause it to be beyond      
workable depth4 ,many seams1 on the     
other hand1 which would have remained   
altogether out of reach of mining       
operations1 have been brought within    
workable depth by a series of           
step-faults1 this being a term applied  
to a series of parallel faults1  in none
 of which the amount of down-throw is   
great4    ,the amount of the down-throw1
 or the slipping-down of the beds1 is   
measured1 vertically1 from the point of 
disappearance of a layer to an          
imaginary continuation of the same layer
 from where it again appears  beyond the
 fault4 ,the plane of a fault is usually
 more or less inclined1  the amount of  
the inclination being known as the hade 

of the fault1 and  it is a remarkable   
characteristic of faults that1 as a     
general rule1 they  hade to the         
down-throw4 ,this will be more clearly  
understood when it is  explained that1  
by its action1 a seam of coal1 which is 
subject to  numerous faults1 can never  
be pierced more than once by one and the
 same  boring4 ,in mountainous          
districts1 however1 there are occasions 
when the  hade is to the up-throw1 and  
this kind of fault is known as an       
inverted  fault4    ,lines of faults    
extend sometimes for hundreds of miles4 
,the great ,pennine  ,fault of ,england 
is #acj miles long1 and others extend   
for much greater  distances4 ,the       
surfaces on both sides of a fault are   
often smooth and  highly polished by the
 movement which has taken place in the  
strata4 ,they  then show the phenomenon 
known as slicken-sides4 ,many faults    
have  become filled with crystalline    
minerals in the form of veins of ore1   
deposited by infiltrating waters        

percolating through the natural         
fissures4    ,in considering the        
formation and structure of the          
better-known  coal-bearing beds of the  
carboniferous age1 we must not lose     
sight of the  fact that important beds  
of coal also occur in strata of much    
more recent  date4 ,there are important 
coal-beds in ,india of ,permian age4    
,there are  coal-beds of ,liassic age in
 ,south ,hungary and in ,texas1 and of  
,jurassic  age in ,virginia1 as well as 
at ,brora in ,sutherlandshire2 there are
 coals  of ,cretaceous age in ,moravia1 
and valuable ,miocene ,tertiary coals in
  ,hungary and the ,austrian ,alps4     
,again1 older than the true             
carboniferous age1 are the ,silurian    
anthracites of ,co4 ,cavan1 and certain 
,norwegian coals1 whilst in ,new  ,south
 ,wales we are confronted with an       
assemblage of coal-bearing strata  which
 extend apparently from the ,devonian   
into ,mesozoic times4    ,still1 the age
 we have considered more closely has an 

unrivalled right to  the title1 coal    
appearing there not merely as an        
occasional bed1 but as a  marked        
characteristic of the formation4    ,the
 types of animal life which are found in
 this formation are varied1  and        
although naturally enough they do not   
excel in number1 there are yet          
sufficient varieties to show            
probabilities of the existence of many  
with  which we are unfamiliar4 ,the     
highest forms yet found1 show an advance
 as  compared with those from earlier   
formations1 and exhibit amphibian       
characteristics intermediate between the
 two great classes of fishes and        
reptiles4 ,numerous specimens proper to 
the extinct order of  labyrinthodontia  
have been arranged into at least a score
 of genera1  these having been drawn    
from the coal-measures of ,newcastle1   
,edinburgh1  ,kilkenny1 ,sarbruck1      
,bavaria1 ,pennsylvania1 and elsewhere4 
,the  ,archegosaurus1 which we have     
figured1 and the ,anthracosaurus1 are   

forms which appear to have existed in   
great numbers in the swamps and  lakes  
of the age4 ,the fish of the period     
belong almost entirely to the  ancient  
orders of the ganoids and placoids4 ,of 
the ganoids1 the great  megalichthys    
,hibberti ranges throughout the whole of
 the system4  ,wonderful accumulations  
of fish remains are found at the base of
 the  system1 in the bone-bed of the    
,bristol coal-field1 as well as in a    
similar bed at ,armagh4 ,many fishes    
were armed with powerful conical  teeth1
 but the majority1 like the existing    
,port ,jackson shark1 were  possessed of
 massive palates1 suited in some cases  
for crushing1 and in  others for        
cutting4    ,illustration3 ,,fig4       
#bd4--;,archegosaurus minor4            
,coal-measures4    ,illustration3 ,,fig4
 #be4--,psammodus porosus4 ,crushing    
palate of a fish4    ,illustration3     
,,fig4 #bf4--,orthoceras4 ,mountain     
limestone4    ,in the mountain limestone
 we see1 of course1 the predominance of 

marine  types1 encrinital remains       
forming the greater proportion of the   
mass4  ,there are occasional plant      
remains which bear evidence of having   
drifted  for some distance from the     
shore4 ,but next to the encrinites1 the 
corals are the most important and       
persistent4 ,corals of most beautiful   
forms and capable of giving polished    
marble-like sections1 are in  abundance4
 ,polyzoa are well represented1 of which
 the lace-coral  7fenestella7 and       
screw-coral 7archimedopora7 are         
instances4  ,cephalopoda are represented
 by the orthoceras1 sometimes five or   
six  feet long1 and goniatites1 the     
forerunner of the familiar ammonite4    
,many species of brachiopods and        
lammellibranchs are met with4 ,lingula1 
most persistent throughout all          
geological time1 is abundant in the     
coal-shales1 but not in the limestones4 
,aviculopecten is there abundant  also4 
,in the mountain limestone the last of  
the trilobites 7,phillipsia7  is found4 

,illustration3 ,,fig4 #bg4--;,fenestella
 retipora4 ,mountain limestone4         
,illustration3 ,,fig4                   
#bh4--;,goniatites4 ,mountain limestone4
    ,we have evidence of the existence  
in the forests of a variety of          
centipede1 specimens having been found  
in the erect stump of a hollow  tree1   
although the fossil is an extremely rare
 one4 ,the same may be said  of the only
 two species of land-snail which have   
been found connected  with the coal     
forests1 viz41 pupa vetusta and zonites 
priscus1 both  discovered in the cliffs 
of ,nova ,scotia4 ,these are sufficient 
to  demonstrate that the fauna of the   
period had already reached a high stage 
of development4 ,in the estuaries of the
 day1 masses of a species of  freshwater
 mussel 7anthracosia7 were in existence1
 and these have left  their remains in  
the shape of extensive beds of shells4  
,they are familiar  to the miner as     
mussel-binds1 and are as noticeable a   
feature of this  long ago period1 as are

 the aggregations of mussels on every   
coast  at  the present day4             
,illustration3 ,,fig4                   
#bi4--;,aviculopecten papyraceus4       
,coal-shale4          ,,chapter ,,iii4  
,,various ,,forms ,,of ,,coal ,,and     
,,carbon4      ,in considering the      
various forms and combinations into     
which coal enters1  it is necessary that
 we should obtain a clear conception of 
what the  substance called carbon is1   
and its nature and properties generally1
  since this it is which forms such a   
large percentage of all kinds of  coal1 
and which indeed forms the actual basis 
of it4 ,in the shape of  coke1 of       
course1 we have a fairly pure form of   
carbon1 and this being  produced1 as we 
shall see presently1 by the driving off 
of the volatile  or vaporous            
constituents of coal1 we are able to    
perceive by the residue  how great a    
proportion of coal consists of carbon4  
,in fact1 the two have  almost an       
identical meaning in the popular mind1  

and the fact that the  great masses of  
strata1 in which are contained our      
principal and most  valuable seams of   
coal1 are termed carboniferous1 from the
 ,latin  carbo1 coal1 and fero1 ,i bear1
 tends to perpetuate the existence of   
the idea4    ,there is always a certain1
 though slight1 quantity of carbon in   
the air1  and this remains fairly       
constant in the open country4 ,small    
though it may  be in proportion to the  
quantity of pure air in which it is     
found1 it is  yet sufficient to provide 
the carbon which is necessary to the    
growth of  vegetable life4 ,just as some
 of the animals known popularly as the  
zoophytes1 which are attached during    
life to rocks beneath the sea1 are  fed 
by means of currents of water which     
bring their food to them1 so the        
leaves1 which inhale carbon-food during 
the day through their  under-surfaces1  
are provided with it by means of the    
currents of air  which are always       
circulating around them2 and while the  

fuel is being  taken in beneath1 the    
heat and light are being received from  
above1 and  the sun supplies the motive 
power to digestion4    ,it is assumed   
that it is1 within the knowledge of all 
that1 for the  origin of the various    
seams and beds of coaly combinations    
which exist in  the earth's crust1 we   
must look to the vegetable world4 ,if1  
however1 we  could go so far back in the
 world's history as the period when our 
incandescent orb had only just severed  
connection with a  gradually-diminishing
 sun1 we should probably find the carbon
 there1 but  locked up in the bonds of  
chemical affinities with other elements1
 and  existing therewith in a gaseous   
condition4 ,but1 as the solidifying     
process went on1 and as the vegetable   
world afterwards made its  appearance1  
the carbon became1 so to speak1 wrenched
 from its  combinations1 and being      
absorbed by trees and plants1 finally   
became  deposited amongst the ruins of a
 former vegetable world1 and is now     

presented to us in the form of coal4    
,we are able to trace the gradual       
changes through which the pasty mass of 
decaying vegetation passed1 in          
consequence of the fact that we have    
this  material locked up in various     
stages of carbonisation1 in the strata  
beneath our feet4 ,these we propose to  
deal with individually1 in as           
unscientific and untechnical a manner as
 possible4    ,first of all1 when a mass
 of vegetable matter commences to decay1
 it soon  loses its colour4 ,there is no
 more noticeable proof of this1 than    
that  when vitality is withdrawn from   
the leaves of autumn1 they at once      
commence to assume a rusty or an ashen  
colour4 ,let the leaves but fall to  the
 ground1 and be exposed to the early    
frosts of ,october1 the damp mists  and 
rains of ,november1 and the rapid change
 of colour is at once  apparent4        
,trodden under foot1 they soon assume a 
dirty blackish hue1 and  even when      
removed they leave a carbonaceous trace 

of themselves behind  them1 where they  
had rested4 ,another proof of the rapid 
acquisition of  their coaly hue is      
noticeable in the spring of the year4   
,when the trees  have burst forth and   
the buds are rapidly opening1 the cases 
in which the  buds of such trees as the 
horse-chestnut have been enclosed will  
be found  cast off1 and strewing the    
path beneath4 ,moistened by the rains   
and the  damp night-mists1 and trodden  
under foot1 these cases assume a jet    
black  hue1 and are to all appearance   
like coal in the very first stages of   
formation4    ,but of course coal is not
 made up wholly and only of leaves4 ,the
 branches  of trees1 twigs of all sizes1
 and sometimes whole trunks of trees are
  found1 the last often remaining in    
their upright position1 and piercing    
the strata which have been formed above 
them4 ,at other times they lie          
horizontally on the bed of coal1 having 
been thrown down previously to  the     
formation of the shale or sandstone1    

which now rests upon them4 ,they  are   
often petrified into solid sandstone    
themselves1 whilst leaving a  rind of   
coal where formerly was the bark4       
,although the trunk of a tree  looks so 
very different to the leaves which it   
bears upon its branches1  it is only    
naturally to be supposed that1 as they  
are both built up after  the same manner
 from the juices of the earth and the   
nourishment in the  atmosphere1 they    
would have a similar chemical           
composition4 ,one very  palpable proof  
of the carbonaceous character of        
tree-trunks suggests  itself4 ,take in  
your hand a few dead twigs or sticks    
from which the  leaves have long since  
dropped2 pull away the dead parts of the
 ivy which  has been creeping over the  
summer-house2 or clasp a gnarled old    
monster  of the forest in your arms1 and
 you will quickly find your hand covered
  with a black smut1 which is nothing   
but the result of the first stage  which
 the living plant has made1 in its      

progress towards its condition as  dead 
coal4 ,but an easy1 though rough1       
chemical proof of the constituents  of  
wood1 can be made by placing a few      
pieces of wood in a medium-sized        
test-tube1 and holding it over a flame4 
,in a short time a certain  quantity of 
steam will be driven off1 next the      
gaseous constituents of  wood1 and      
finally nothing will be left but a few  
pieces of black brittle  charcoal4 ,the 
process is of course the same in a      
fire-grate1 only that  here more        
complete combustion of the wood takes   
place1 owing to its being  intimately   
exposed to the action of the flames4 ,if
 we adopt the same  experiment with some
 pieces of coal1 the action is similar1 
only that in  this case the quantity of 
gases given off is not so great1 coal   
containing a greater proportion of      
carbon than wood1 owing to the fact     
that1 during its long burial in the     
bowels of the earth1 it has been  acted 
upon in such a way as to lose a great   

part of its volatile  constituents4     
,from processes1 therefore1 which are to
 be seen going on around us1 it is      
easily possible to satisfy ourselves    
that vegetation will in the long run    
undergo such changes as will result in  
the formation of coal4    ,there are    
certain parts in most countries1 and    
particularly in ,ireland1  where masses 
of vegetation have undergone a still    
further stage in  metamorphism1 namely1 
in the well-known and famous peat-bogs4 
,ireland is  par excellence the land of 
bogs1 some three millions of acres being
  said to be covered by them1 and they  
yield an almost inexhaustible supply  of
 peat4 ,one of the peat-bogs near the   
,shannon is between two and three  miles
 in breadth and no less than fifty in   
length1 whilst its depth  varies from   
#ac feet to as much as #dg feet4        
,peat-bogs have in no way  ceased to be 
formed1 for at their surfaces the       
peat-moss grows afresh  every year2 and 
rushes1 horse-tails1 and reeds of all   

descriptions grow  and thrive each year 
upon the ruins of their ancestors4 ,the 
formation of  such accumulations of     
decaying vegetation would only be       
possible where  the physical conditions 
of the country allowed of an abundant   
rainfall1  and depressions in the       
surface of the land to retain the       
moisture4 ,where  extensive deforesting 
operations have taken place1 peat-bogs  
have often  been formed1 and many of    
those in existence in ,europe           
undoubtedly owe  their formation to that
 destruction of forests which went on   
under the  sway of the ,romans4 ,natural
 drainage would soon be obstructed by   
fallen  trees1 and the formation of     
marsh-land would follow2 then with the  
growth  of marsh-plants and their       
successive annual decay1 a peaty mass   
would  collect1 which would quickly grow
 in thickness without let or hindrance4 
,in considering the existence of inland 
peat-bogs1 we must not lose sight  of   
the fact that there are subterranean    

forest-beds on various parts of  our    
coasts1 which also rest upon their own  
beds of peaty matter1 and very          
possibly1 when in the future they are   
covered up by marine deposits1 they     
will have fairly started on their way   
towards becoming coal4    ,peat-bogs do 
not wholly consist of peat1 and nothing 
else4 ,the trunks of  such trees as the 
oak1 yew1 and fir1 are often found      
mingled with the  remains of mosses and 
reeds1 and these often assume a         
decidedly coaly  aspect4 ,from the      
famous ,bog of ,allen in ,ireland1      
pieces of oak1 generally  known as      
bog-oak1 which have been buried for     
generations in peat1 have  been         
excavated4 ,these are as black as any   
coal can well be1 and are  sufficiently 
hard to allow of their being used in the
 manufacture of  brooches and other     
ornamental objects4 ,another use to     
which peat of some  kinds has been put  
is in the manufacture of yarn1 the      
result being a  material which is said  

to resemble brown worsted4 ,on digging a
 ditch to  drain a part of a bog in     
,maine1 ,u4,s41 in which peat to a depth
 of twenty  feet had accumulated1 a     
substance similar to cannel coal itself 
was  found4 ,as we shall see presently1 
cannel coal is one of the earliest      
stages of true coal1 and the discovery  
proved that under certain  conditions as
 to heat and pressure1 which in this    
case happened to be  present1 the       
materials which form peat may also be   
metamorphosed into  true coal4          
,darwin1 in his well-known ,voyage in   
the ,beagle gives a peculiarly          
interesting description of the condition
 of the peat-beds in the ,chonos        
,archipelago1 off the ,chilian coast1   
and of their mode of formation4 ,in     
these islands1 he says1 cryptogamic     
plants find a most congenial  climate1  
and within the forest the number of     
species and great abundance  of mosses1 
lichens1 and small ferns1 is quite      
extraordinary4 ,in ,tierra  del ,fuego  

every level piece of land is invariably 
covered by a thick bed  of peat4 ,in the
 ,chonos ,archipelago where the nature  
of the climate more  closely approaches 
that of ,tierra del ,fuego1 every patch 
of level ground  is covered by two      
species of plants 7,astelia pumila and  
,donatia  megellanica71 which by their  
joint decay compose a thick bed of      
elastic  peat4    ,in ,tierra del       
,fuego1 above the region of wood-land1  
the former of these  eminently sociable 
plants is the chief agent in the        
production of peat4  ,fresh leaves are  
always succeeding one to the other round
 the central  tap-root2 the lower ones  
soon decay1 and in tracing a root       
downwards in  the peat1 the leaves1 yet 
holding their places1 can be observed   
passing  through every stage of         
decomposition1 till the whole becomes   
blended in  one confused mass4 ,the     
,astelia is assisted by a few other     
plants1--here  and there a small        
creeping ,myrtus 7,m4 nummularia71 with 

a woody stem  like our cranberry and    
with a sweet berry1--an ,empetrum 7,e4  
rubrum71  like our heath1--a rush       
7,juncus grandiflorus71 are nearly the  
only ones  that grow on the swampy      
surface4 ,these plants1 though          
possessing a very  close general        
resemblance to the ,english species of  
the same genera1 are  different4 ,in the
 more level parts of the country the    
surface of the peat  is broken up into  
little pools of water1 which stand at   
different  heights1 and appear as if    
artificially excavated4 ,small streams  
of water1  flowing underground1 complete
 the disorganisation of the vegetable   
matter1 and consolidate the whole4      
,the climate of the southern part of    
,america appears particularly           
favourable to the production of peat4   
,in the ,falkland ,islands almost  every
 kind of plant1 even the coarse grass   
which covers the whole surface  of the  
land1 becomes converted into this       
substance3 scarcely any  situation      

checks its growth2 some of the beds are 
as much as twelve feet  thick1 and the  
lower part becomes so solid when dry    
that it will hardly  burn4 ,although    
every plant lends its aid1 yet in most  
parts the ,astelia  is the most         
efficient4    ,it is rather a singular  
circumstance1 as being so very different
 from  what occurs in ,europe1 that ,i  
nowhere saw moss forming by its decay   
any  portion of the peat in ,south      
,america4 ,with respect to the northern 
limit  at which the climate allows of   
that peculiar kind of slow decomposition
  which is necessary for its production1
 ,i believe that in ,chiloe 7lat4 #da   
to #db71 although there is much swampy  
ground1 no well characterised peat      
occurs2 but in the ,chonos ,islands1    
three degrees farther southward1 we     
have seen that it is abundant4 ,on the  
eastern coast in ,la ,plata 7lat4  #ce7 
,i was told by a ,spanish resident1 who 
had visited ,ireland1 that he  had often
 sought for this substance1 but had     

never been able to find any4  ,he showed
 me1 as the nearest approach to it which
 he had discovered1 a  black peaty soil1
 so penetrated with roots as to allow of
 an extremely  slow and imperfect       
combustion4    ,the next stage in the   
making of coal is one in which the      
change has  proceeded a long way from   
the starting-point4 ,lignite is the name
 which  has been applied to a form of   
impure coal1 which sometimes goes under 
the  name of brown coal4 ,it is not a   
true coal1 and is a very long way from  
that final stage to which it must attain
 ere it takes rank with the most        
valuable of earth's products4 ,from the 
very commencement1 an action has  being 
going on which has caused the amount of 
the gaseous constituents to  become less
 and less1 and which has consequently   
caused the carbon  remaining behind to  
occupy an increasingly large proportion 
of the whole  mass4 ,so1 when we arrive 
at the lignite stage1 we find that a    
considerable quantity of volatile matter

 has already been parted with1  and that
 the carbon1 which in ordinary living   
wood is about #ej per cent4  of the     
whole1 has already increased to about   
#fg per cent4 ,in most  lignites there  
is1 as a rule1 a comparatively large    
proportion of  sulphur1 and in such     
cases it is rendered useless as a       
domestic fuel4 ,it  has been used as a  
fuel in various processes of            
manufacture1 and the  lignite of the    
well-known ,bovey ,tracey beds has been 
utilised in this way  at the            
neighbouring potteries4 ,as compared    
with true coal1 it is  distinguished by 
the abundance of smoke which it produces
 and the choking  sulphurous fumes which
 also accompany its combustion1 but it  
is largely  used in ,germany as a useful
 source of paraffin and illuminating    
oils4 ,in  ,silesia1 ,saxony1 and in the
 district about ,bonn1 large quantities 
of  lignite are mined1 and used as fuel4
 ,large stores of lignite are known to  
exist in the ,weald of the south-east of

 ,england1 and although the mining      
operations which were carried on at one 
time at ,heathfield1 ,bexhill1 and      
other places1 were failures so far as   
the actual discovery of true coal  was  
concerned1 yet there can be no doubt as 
to the future value of the  lignite in  
these parts1 when ,england's supplies of
 coal approach  exhaustion1 and         
attention is turned to other directions 
for the future  source of her gas and   
paraffin oils4    ,beside the ,bovey    
,tracey lignitic beds to which we have  
above referred1  other tertiary clays   
are found to contain this early promise 
of coal4 ,the  eocene beds of ,brighton 
are an important instance of a tertiary 
lignite1 the seam of surturbrand1 as it 
is locally called1 being a  somewhat    
extensive deposit4    ,we have now      
closely approached to true coal1 and the
 next step which we  shall take will be 
to consider the varieties in which the  
black mineral  itself is found4 ,the    
principal of these varieties are as     

follows1 against  each being placed the 
average proportion of pure carbon which 
it  contains3--      ,splint or ,hard   
,coal1 #hc per cent42    ,cannel1       
,candle or ,parrott ,coal1 #hd per      
cent42    ,cherry or ,soft ,coal1 #he   
per cent42    ,common ,bituminous1 or   
,caking ,coal1 #hh per cent42           
,anthracite1 ,blind ,coal1 ,culm1       
,glance1 or ,stone ,coal1 from ,south   
,wales1 #ic per cent4    ,as far as the 
gas-making properties of the first three
 are concerned1 the  relative           
proportions of carbon and volatile      
products are much the same4  ,everybody 
knows a piece of cannel coal when it is 
seen1 how it appears  almost to have    
been once in a molten condition1 and how
 it breaks with a  conchoidal fracture1 
as opposed to the cleavage of bituminous
 coal into  thin layers2 and1 most      
apparent and most noticeable of all1 how
 it does  not soil the hands after the  
manner of ordinary coal4 ,it is at times
 so  dense and compact that it has been 

fashioned into ornaments1 and is        
capable of receiving a polish like jet4 
,from the large percentage of  volatile 
products which it contains1 it is       
greatly used in gasworks4    ,caking    
coal and the varieties of coal which    
exist between it and  anthracite1 are   
familiar to every householder2 the more 
it approaches the  composition of the   
latter the more difficult it is to get  
it to burn1 but  when at last fairly    
alight it gives out great heat1 and what
 is more  important1 a less quantity of 
volatile constituents in the shape of   
gas1  smoke1 ammonia1 ash and sulphurous
 acid4 ,for this reason it has been     
proposed to compel consumers to adopt   
anthracite as the domestic coal  by ,act
 of ,parliament4 ,certainly by this     
means the amount of impurities in  the  
air might be appreciably lessened1 but  
as it would involve the  reconstruction 
of some millions of fire-places1 and an 
increase in price  in consequence of the
 general demand for it1 it is not likely

 that a  government would be so rash as 
to attempt to pass such a measure2 even 
if  passed1 it would probably soon      
become as dead and obsolete and impotent
  as those many laws with which our     
ancestors attempted1 first to arrest1   
and then to curb the growth in the use  
of coal of any sort4 ,anthracite is  not
 a homely coal4 ,if we use it alone it  
will not give us that bright  and       
cheerful blaze which ,english-speaking  
people like to obtain from  their fires4
    ,it is a significant fact1 and one  
which proves that the various kinds of  
coal which are found are nothing but    
stages begotten by different degrees  of
 disentanglement of the contained gases1
 that where1 as in some parts1  a mass  
of basalt has come into contact with    
ordinary bituminous coal1 the  coal has 
assumed the character of anthracite1    
whilst the change has in  some instances
 gone so far as to convert the          
anthracite into graphite4  ,the basalt1 
which is one of the igneous rocks1 has  

been erupted into the  coal-seam in a   
state of fusion1 and the heat contained 
in it has been  sufficient to cause the 
disentanglement of the gases1 the       
extraction of  which from the coal      
brings about the condition of anthracite
 and  graphite4    ,the mention of      
graphite brings us to the next stage4   
,graphite1 plumbago1  or1 as it is more 
commonly called1 black-lead1 which1 we  
may say in  passing1 has nothing of lead
 about it at all1 is best known in the  
shape  of that very useful and          
cosmopolitan article1 the black-lead    
pencil4 ,this  is even purer carbon than
 anthracite1 not more than #e per cent4 
of ash  and other impurities being      
present4 ,it is well-known by its grey  
metallic  lustre2 the chemist uses it   
mixed with fire-clay to make his        
crucibles2  the engineer uses it1 finely
 powdered1 to lubricate his machinery2  
the  house-keeper uses it to black-lead 
her stoves to prevent them from         
rusting4 ,an imperfect graphite is found

 inside some of the hottest  retorts    
from which gas is distilled1 and this is
 used as the negative  element in zinc  
and carbon electricity-making cells1    
whilst its use as  the electrodes or    
carbons of the arc-lamp is becoming more
 and more  widely adopted1 as           
installations of electric light become  
more general4    ,one great source of   
true graphite for many years was the    
famous mine at  ,borrowdale1 in         
,cumberland1 but this is now almost     
exhausted4 ,the vein lay  between strata
 of slate1 and was from eight to nine   
feet thick4 ,as much  as #ajj1jjj is    
said to have been realised from it in   
one year4 ,extensive  supplies of       
graphite are found in rocks of the      
,laurentian age in ,canada4  ,in this   
formation nothing which can undoubtedly 
be classed as organic has  yet been     
discovered4 ,life at this early period  
must have found its home  in low and    
humble forms1 and if the eozon of       
,dawson1 which has been  thought to     

represent the earliest type of life1    
turns out after all not  to be organic1 
but only a deceptive appearance assumed 
by certain of the  strata1 we at least  
know that it must have been in similarly
 humble forms  that life1 if it existed 
at all1 did then exist4 ,we can         
scarcely1  therefore1 expect that the   
vegetable world had made any great      
advance in  complexity of organism at   
this time1 otherwise the supplies of    
graphite  or plumbago which are found in
 the formation1 would be attributed to  
dense forest growths1 acted upon1 after 
death1 in a similar manner to  that     
which awaited the vegetation which1 ages
 after1 went to form beds of  coal4 ,at 
present we know of no source of carbon  
except through the  intervention and the
 chemical action of plants4 ,like iron1 
carbon is  seldom found on the earth    
except in combination4 ,if there were no
 growth  of vegetation at this far-away 
period to give rise to these deposits of
  graphite1 we are compelled to ask     

ourselves whether1 perchance1 there did 
not then exist conditions of which we   
are not now cognisant on the earth1  and
 which allowed graphite to be formed    
without assistance from the  vegetable  
kingdom4 ,at present1 however1 science  
is in the dark as to any  other process 
of its formation1 and we are left to    
assume that the  vegetable growth of the
 time was enormous in quantity1 although
 there is  nothing to show the kind of  
vegetation1 whether humble mosses or    
tall  forest trees1 which went to       
constitute the masses of graphite4      
,geologists  will agree that this is no 
small assumption to make1 since1 if     
true1 it  may show that there was an    
abundance of vegetation at a time when  
animal  life was hidden in one or more  
very obscure forms1 one only of which   
has  so far been detected1 and whose    
very identity is strongly doubted by    
nearly all competent judges4 ,at the    
same time there may have been an        
abundance of both animal and vegetable  

life at the time4 ,we must not  forget  
that it is a well-ascertained fact that 
in later ages1 the minute  seed-spores  
of forest trees were in such abundance  
as to form important  seams of coal in  
the true carboniferous era1 the trees   
which gave birth  to them being now     
classed amongst the humble cryptogams1  
the ferns1 and  club-mosses1 c4 ,the    
graphite of ,laurentian age may not     
improbably have  been caused by deposits
 of minute portions of similar lowly    
specimens of  vegetable life1 and if the
 eozon the dawn-animalcule1 does        
represent  the animal life of the time1 
life whose types were too minute to     
leave  undoubted traces of their        
existence1 both animal life and         
vegetable life  may be looked upon as   
existing side by side in extremely      
humble forms1  neither as yet having    
taken an undoubted step forward in      
advance of the  other in respect to     
complexity of organism4                 
,illustration3 ,,fig                    

#cj4--,lepidodendron4 ,portion of       
,sandstone stem after  removal of bark  
of a giant club-moss    ,there is but   
one more form of carbon with which we   
have to deal in  running through the    
series4 ,we have seen that coal is not  
the summum  bonum of the series4 ,other 
transformations take place after the    
stage of  coal is reached1 which1 by the
 continued disentanglement of gases1    
finally bring about the plumbago stage4 
,what the action is which transforms    
plumbago or some other form of carbon   
into the condition of a diamond cannot  
be stated4 ,diamond is the purest  form 
of carbon found in nature4 ,it is a     
beautiful object1 alike from the        
results of its powers of refraction1 as 
also from the form into which its       
carbon has been crystallised4 ,how      
,nature1 in her wonderful laboratory1   
has precipitated the diamond1 with its  
wonderful powers of spectrum  analysis1 
we cannot say with certainty4 ,certain  
chemists have1 at a great  expense1     

produced crystals which1 in every       
respect1 stand the tests of  true       
diamonds2 but the process of their      
production at a great expense has  in no
 way diminished the value of the natural
 product4    ,the process by which      
artificial diamonds have been produced  
is so  interesting1 and the subject may 
prove to be of so great importance1 that
  a few remarks upon the process may not
 be unacceptable4    ,the experiments of
 the great ,french chemist1 ,dumas1 and 
others1  satisfactorily proved the fact1
 which has ever since been considered   
thoroughly established1 that the diamond
 is nothing but carbon  crystallised in 
nearly a pure state1 and many chemists  
have since been  engaged in the hitherto
 futile endeavour to turn ordinary      
carbon into the  true diamond4          
,despretz at one time considered that he
 had discovered the process1 which      
consisted in his case of submitting a   
piece of charcoal to the action of  an  
electric battery1 having in his mind the

 similar process of  electrolysis1 by   
which water is divided up into the two  
gases1 hydrogen  and oxygen4 ,he        
obtained a microscopic deposit on the   
poles of the  battery1 which he         
pronounced to be diamond dust1 but      
which1 a long time  after1 was proved to
 be nothing but graphite in a           
crystallised state4  ,this was1 however1
 certainly a step in the right          
direction4    ,the honour of first      
accomplishing the task fell to ,mr      
,hannay1 of ,glasgow1  who succeeded in 
producing very small but comparatively  
soft diamonds1 by  heating lampblack    
under great pressure1 in company with   
one or two other  ingredients4 ,the     
process was a costly one1 and beyond    
being a great  scientific feat1 the     
discovery led to little result4    ,a   
young ,french chemist1 ,m4 ,henri       
,moissau1 has since come to the front1  
and the diamonds which he has produced  
have stood every test for the true      
diamond to which they could be          

subjected2 above all1 the density of the
  product is #c4e1 i4e41 that of the    
diamond1 that of graphite reaching #b   
only4    ,he recognised that in all     
diamonds which he had consumed--and he  
consumed  some #aej worth in order to   
assure himself of the fact--there were  
always  traces of iron in their         
composition4 ,he saw that iron in       
fusion1 like  other metals1 always      
dissolves a certain quantity of carbon4 
,might it not  be that molten iron1     
cooling in the presence of carbon1 deep 
in volcanic  depths where there was     
little scope for the iron to expand in  
assuming  the solid form1 would exert   
such tremendous pressure upon the       
particles  of carbon which it absorbed1 
that these would assume the crystalline 
state8    ,he packed a cylinder of soft 
iron with the carbon of sugar1 and      
placed  the whole in a crucible filled  
with molten iron1 which was raised to a 
temperature of #cjjj by means of an     
electric furnace4 ,the soft cylinder    

melted1 and dissolved a large portion of
 the carbon4 ,the crucible was  thrown  
into water1 and a mass of solid iron was
 formed4 ,it was allowed  further to    
cool in the open air1 but the expansion 
which the iron would  have undergone on 
cooling1 was checked by the crucible    
which contained  it4 ,the result was a  
tremendous pressure1 during which the   
carbon1 which  was still dissolved1 was 
crystallised into minute diamonds4      
,these showed themselves as minute      
points which were easily separable from 
the mass by the action of acids4 ,thus  
the wonderful transformation from  sugar
 to the diamond was accomplished4    ,it
 should be mentioned that iron1 silver1 
and water1 alone possess the  peculiar  
property of expanding when passing from 
the liquid to the solid  state4    ,the 
diamonds so obtained were of both kinds4
 ,the particles of white  diamond       
resembled in every respect the true     
brilliant4 ,but there was also  an      
appreciable quantity of the variety     

known as the black diamond4  ,these     
diamonds seem to approximate more       
closely to carbon as we are most        
familiar with it4 ,they are not         
considered as of such value as the      
transparent form1 but they are still of 
considerable commercial value4  ,the    
carbonado1 as this kind is called1      
possesses so great a degree of  hardness
 that by means of it it is possible to  
bore through the hardest  rocks4 ,the   
diamond drill1 used for boring purposes1
 is furnished around  the outer edge of 
the cylinder of the boring bit1 as it is
 called1 with  perhaps a dozen black    
diamonds1 together with another row of  
,brazilian  diamonds on the inside4 ,by 
the rotation of the boring tool the     
sharp  edges of the diamonds cut their  
way through rocks of all degrees of     
hardness1 leaving a core of the rock cut
 through1 in the centre of the          
cylindrical drill4 ,it is found that the
 durability of the natural edge of  the 
diamond is far greater than that of the 

edge caused by artificial  cutting and  
trimming4 ,the cutting of a pane of     
glass by means of a ring  set with an   
artificially-cut diamond1 cannot        
therefore be done without  injuring to a
 slight extent the edge of the stone4   
,the diamond is the hardest of all known
 substances1 leaving a scratch on  any  
substance across which it may be drawn4 
,yet it is one whose form can  be       
changed1 and whose hardness can be      
completely destroyed1 by the simple     
process of combustion4 ,it can be       
deprived of its high lustre1 and of its 
power of breaking up by refraction the  
light of the sun into the various  tints
 of the solar spectrum1 simply by       
heating it to a red heat1 and then      
plunging it into a jar of oxygen gas4   
,it immediately expands1 changes  into a
 coky mass1 and burns away4 ,the product
 left behind is a mixture of  carbon and
 oxygen1 in the proportions in which it 
is met with in  carbonic-anhydride1 or1 
carbonic acid gas deprived of its water4

 ,this is  indeed a strange             
transformation1 from the most valuable  
of all our  precious stones to a        
compound which is the same in chemical  
constituents  as the poisonous gas which
 we and all animals exhale4 ,but there  
is this  to be said4 ,probably in the   
far-away days when the diamond began to 
be  formed1 the tree or other vegetable 
product which was its far-removed       
ancestor abstracted carbonic acid gas   
from the atmosphere1 just as do our     
plants in the present day4 ,by this     
means it obtained the carbon wherewith  
to build up its tissues4 ,thus the      
combustion of the diamond into          
carbonic-anhydride now is1 after all1   
only a return to the same compound  out 
of which it was originally formed4 ,how 
it was formed is a secret3  probably the
 time occupied in the formation of the  
diamond may be counted  by centuries1   
but the time of its re-transformation   
into a mass of coky  matter is but the  
work of seconds6    ,there is another   

form of carbon which was formerly of    
much greater  importance than it is now1
 and which1 although not a natural      
product1 is  yet deserving of some      
notice here4 ,charcoal is the substance 
referred to4    ,in early days the word 
coal1 or1 as it was also spelt1 cole1   
was  applied to any substance which was 
used as fuel2 hence we have a  reference
 in the ,bible to a fire of coals1 so   
translated when the  meaning to be      
conveyed was probably not coal as we    
know it4 ,wood was  formerly known as   
coal1 whilst charred wood received the  
name of  charred-coal1 which was soon   
corrupted into charcoal4 ,the           
charcoal-burners of years gone by were a
 far more flourishing community  than   
they are now4 ,when the old baronial    
halls and country-seats depended  on    
them for the basis of their fuel1 and   
the log was a more frequent  occupant of
 the fire-grate than now1 these         
occupiers of midforest were a  people of
 some importance4    ,we must not       

overlook the fact that there is another 
form of charcoal1  namely1 animal       
charcoal or bone-black4 ,this can be    
obtained by heating  bones to redness in
 closed iron vessels4 ,in the refining  
of raw sugar the  discoloration of the  
syrup is brought about by filtering it  
through  animal-charcoal2 by this means 
the syrup is rendered colourless4       
,when properly prepared1 charcoal       
exhibits very distinctly the rings of   
annual growth which may have            
characterised the wood from which it was
  formed4 ,it is very light in          
consequence of its porous nature1 and it
 is  wonderfully indestructible4    ,but
 its greatest1 because it is its most   
useful property1 is undoubtedly  the    
power which it has of absorbing great   
quantities of gas into itself4  ,it is  
in fact what may be termed an all-round 
purifier4 ,it is a  deodoriser1 a       
disinfectant1 and a decoloriser4 ,it is 
an absorbent of bad  odours1 and        
partially removes the smell from tainted

 meat4 ,it has been  used when offensive
 manures have been spread over soils1   
with the same  object in view1 and its  
use for the purification of water is    
well known  to all users of filters4    
,some idea of its power as a            
disinfectant may be  gained by the fact 
that one volume of wood-charcoal will   
absorb no less  than #ij volumes of     
ammonia1 #ce volumes of carbonic        
anhydride1 and #fe  volumes of          
sulphurous anhydride4    ,other forms of
 carbon which are well-known are 7#a7   
coke1 the residue left  when coal has   
been subjected to a great heat in a     
closed retort1 but from  which all the  
bye-products of coal have been allowed  
to escape2 7#b7 soot  and lamp-black1   
the former of which is useful as a      
manure in consequence  of ammonia being 
present in it1 whilst the latter is a   
specially prepared  soot1 and is used in
 the manufacture of ,indian ink and     
printers' ink4          ,,chapter ,,iv4 
,,the ,,coal-,,mine ,,and ,,its         

,,dangers4      ,it is somewhat strange 
to think that where once existed the    
solitudes of  an ancient carboniferous  
forest now is the site of a busy        
underground  town4 ,for a town it really
 is4 ,the various roads and passages    
which are  cut through the solid coal as
 excavation of a coal-mine proceeds1    
represent to a stranger all the         
intricacies of a well-planned town4 ,nor
  is the extent of these underground    
towns a thing to be despised4 ,there is 
an old pit near ,newcastle which        
contains not less than fifty miles of   
passages4 ,other pits there are whose   
main thoroughfares in a direct line  are
 not less than four or five miles in    
length1 and this1 it must be  borne in  
mind1 is the result of excavation       
wrought by human hands and  human       
labour4    ,so great an extent of       
passages necessarily requires some      
special means of  keeping the air within
 it in a pure state1 such as will render
 it fit for  the workers to breathe4    

,the further one would go from the main 
thoroughfare in such a mine1 the less   
likely one would be to find air of      
sufficient purity for the purpose4 ,it  
is as a consequence necessary to  take  
some special steps to provide an        
efficient system of ventilation         
throughout the mine4 ,this is           
effectually done by two shafts1 called  
respectively the downcast and the upcast
 shaft4 ,a shaft is in reality a  very  
deep well1 and may be circular1         
rectangular or oval in form4 ,in  order 
to keep out water which may be struck in
 passing through the  various strata1 it
 is protected by plank or wood tubbing1 
or the shaft is  bricked over1 or       
sometimes even cast-iron segments are   
sunk4 ,in many  shafts which1 owing to  
their great depth1 pass through strata  
of every  degree of looseness or        
viscosity1 all three methods are        
utilised in turn4  ,in ,westphalia1     
where coal is worked beneath strata of  
more recent  geological age1 narrow     

shafts have been1 in many cases1 sunk by
 means of  boring apparatus1 in         
preference to the usual process of      
excavation1 and  the practice has since 
been adopted in ,south ,wales4 ,in      
,england the usual  form of the pit is  
circular1 but elliptical and rectangular
 pits are also  in use4 ,on the         
,continent polygonal-shaped shafts are  
not uncommon1 all of  them1 of whatever 
shape1 being constructed with a view to 
resist the  great pressure exerted by   
the rock around4    ,illustration3      
,,fig4 #ca4--;,engine-,house and        
,buildings at head of a  ,coal-,pit4    
,if there be one of these shafts at one 
end of the mine1 and another at a       
remote distance from it1 a movement of  
the air will at once begin1 and a  rough
 kind of ventilation will ensue4 ,this  
is1 however1 quite  insufficient to     
provide the necessary quantity of air   
for inhalation by  the army of workers  
in the coal-mine1 for the current thus  
set up does  not even provide sufficient

 force to remove the effete air and     
impurities  which accumulate from       
hundreds of perspiring human bodies4    
,it is therefore necessary to introduce 
some artificial means1 by which a       
strong and regular current shall pass   
down one shaft1 through the mine in  all
 its workings1 and out at the other     
shaft4 ,this is accomplished in  various
 ways4 ,it took many years before those 
interested in mines came  thoroughly to 
understand how properly to secure       
ventilation1 and in  bygone days the    
system was so thoroughly bad that a     
tremendous amount of  sickness prevailed
 amongst the miners1 owing to the       
poisonous effects of  breathing the same
 air over and over again1 charged1 as it
 was1 with more  or less of the gases   
given off by the coal itself4 ,now1     
those miners who  do so great a part in 
furnishing the means of warming our     
houses in  winter1 have the best        
contrivances which can be devised to    
furnish them  with an ever-flowing      

current of fresh air4    ,amongst the   
various mechanical appliances which have
 been used to ensure  ventilation may be
 mentioned pumps1 fans1 and pneumatic   
screws4 ,there is1  as we have said1 a  
certain1 though slight1 movement of the 
air in the two  columns which constitute
 the upcast and the downcast shafts1 but
 in order  that a current may flow which
 shall be equal to the necessities of   
the  miners1 some means are necessary1  
by which this condition of almost       
equilibrium shall be considerably       
disturbed1 and a current created which  
shall sweep all foul gases before it4   
,one plan was to force fresh air  into  
the downcast1 which should in a sense   
push the foetid air away by  the upcast4
 ,another was to exhaust the upcast1 and
 so draw the gases in  the train of the 
exhausted air4 ,in other cases the plan 
was adopted of  providing a continual   
falling of water down the downcast      
shaft4    ,these various plans have     
almost all given way to that which is   

the most  serviceable of all1 namely1   
the plan of having an immense furnace   
constantly burning in a                 
specially-constructed chamber at the    
bottom of  the upcast4 ,by this means   
the column of air above it becomes      
rarefied  under the heat1 and ascends1  
whilst the cooler air from the downcast 
rushes in and spreads itself in all     
directions whence the bad air has       
already been drawn4 ,on the other hand1 
to so great a state of perfection  have 
ventilating fans been brought1 that one 
was recently erected which  would be    
capable of changing the air of          
,westminster ,hall thirty times in  one 
hour4    ,having procured a current of  
sufficient power1 it will be at once    
understood that1 if left to its own     
will1 it would take the nearest path    
which might lie between its entrance and
 its exit1 and1 in this way1            
ventilating the principal street only1  
would leave all the many  off-shoots    
from it undisturbed4 ,it is consequently

 manipulated by means  of barriers and  
tight-fitting doors1 in such a way that 
the current is  bound in turn to        
traverse every portion of the mine4 ,a  
large number of  boys1 known as         
trappers1 are employed in opening the   
doors to all comers1  and in carefully  
closing the doors immediately after they
 have passed1 in  order that the current
 may not circulate through passages     
along which it  is not intended that it 
should pass4    ,the greatest dangers   
which await the miners are those which  
result1 in  the form of terrible        
explosions1 from the presence of        
inflammable gases  in the mines4 ,the   
great walls of coal which bound the     
passages in mines  are constantly       
exuding supplies of gas into the air4   
,when a bank of coal  is brought down by
 an artificial explosion1 by dynamite1  
by lime  cartridges1 or by some other   
agency1 large quantities of gas are     
sometimes disengaged1 and not only is   
this highly detrimental to the  health  

of the miners1 if not carried away by   
proper ventilation1 but it  constitutes 
a constant danger which may at any time 
cause an explosion  when a naked light  
is brought into contact with it4        
,fire-damp may be  sometimes heard      
issuing from fiery seams with a peculiar
 hissing sound4  ,if the volume be      
great1 the gas forms what is called a   
blower1 and this  often happens in the  
neighbourhood of a fault4 ,when coal is 
brought down  in any large volume1 the  
blowers which commence may be exhausted 
in a few  moments4 ,others1 however1    
have been known to last for years1 this 
being  the case at ,wallsend1 where the 
blower gave off #abj feet of gas per    
minute4 ,in such cases the gas is       
usually conveyed in pipes to a place    
where it can be burned in safety4    ,in
 the early days of coal-mining the      
explosions caused by this gas soon      
received the serious attention of the   
scientific men of the age4 ,in the      
,philosophical ,transactions of the     

,royal ,society we find a record of a   
gas explosion in #afgg4 ,the amusing    
part of such records was that the       
explosions were ascribed by the miners  
to supernatural agencies4 ,little       
attention seemed to have been paid to   
the fact1 which has since so  thoroughly
 been established1 that the explosions  
were caused by  accumulations of gas1   
mixed in certain proportions with air4  
,as a  consequence1 tallow candles with 
an exposed flame were freely used1      
especially in ,britain4 ,these were     
placed in niches in the workings1 where 
they would give to the pitman the       
greatest amount of light4 ,previous to  
the introduction of the safety-lamp1    
workings were tested before the men     
entered them1 by trying the candle4     
,owing to the specific gravity of       
fire-damp 74#eee7 being less than that  
of air1 it always finds a lodgement  at 
the roofs of the workings1 so that1 to  
test the condition of the air1  it was  
necessary to steadily raise the candle  

to the roof at certain  places in the   
passages1 and watch carefully the action
 of the flame4 ,the  presence of        
fire-damp would be shown by the flame   
assuming a blue colour1  and by its     
elongation2 the presence of other gases 
could be detected by  an experienced man
 by certain peculiarities in the tint of
 the flame4  ,this testing with the open
 flame has almost entirely ceased since 
the  introduction of the perfected ,davy
 lamp4    ,the use of candles for       
illumination soon gave place in most of 
the large  collieries to the            
introduction of small oil-lamps4 ,in the
 less fiery  mines on the ,continent1   
oil-lamps of the well-known ,etruscan   
pattern are  still in use1 whilst small 
metal lamps1 which can conveniently be  
attached to the cap of the worker1      
occasionally find favour in the         
shallower ,scotch mines4 ,these lamps   
are very useful in getting the coal     
from the thinner seams1 where progress  
has to be made on the hands and  feet4  

,at the close of the last century1 as   
workings began to be carried  deeper1   
and coal was obtained from places more  
and more infested with  fire-damp1 it   
soon came to be realised that the old   
methods of  illumination would have to  
be replaced by others of a safer nature4
    ,it is noteworthy that mere red heat
 is insufficient in itself to ignite    
fire-damp1 actual contact with flame    
being necessary for this purpose4       
,bearing this in mind1 ,spedding1 the   
discoverer of the fact1 invented what   
is known as the steel-mill for          
illuminating purposes4 ,in this a       
toothed  wheel was made to play upon a  
piece of steel1 the sparks thus caused  
being sufficient to give a moderate     
amount of illumination4 ,it was found1  
however1 that this method was not always
 trustworthy1 and lamps were  introduced
 by ,humboldt in #agif1 and by ,clanny  
in #ahjf4 ,in these lamps the  air which
 fed the flame was isolated from the air
 of the mine by having  to bubble       

through a liquid4 ,many miners were not1
 however1 provided with  these lamps1   
and the risks attending naked lights    
went on as merrily as  ever4    ,in     
order to avoid explosions in mines which
 were known to give off large           
quantities of gas1 fiery pits as they   
are called1 ,sir ,humphrey ,davy in     
#ahae invented his safety lamp1 the     
principle of which can be stated in a   
few words4    ,if a piece of fine wire  
gauze be held over a gas-jet before it  
is lit1  and the gas be then turned on1 
it can be lit above the gauze1 but the  
flame will not pass downwards towards   
the source of the gas2 at least1  not   
until the gauze has become over-heated4 
,the metallic gauze so rapidly  conducts
 away the heat1 that the temperature of 
the gas beneath the gauze  is unable to 
arrive at the point of ignition4 ,in the
 safety-lamp the  little oil-lamp is    
placed in a circular funnel of fine     
gauze1 which  prevents the flame from   
passing through it to any explosive gas 

that may  be floating about outside1 but
 at the same time allows the rays of    
light  to pass through readily4 ,sir    
,humphrey ,davy1 in introducing his     
lamp1  cautioned the miners against     
exposing it to a rapid current of air1  
which  would operate in such a way as to
 force the flame through the gauze1 and 
also against allowing the gauze to      
become red-hot4 ,in order to minimise1  
as far as possible1 the necessity of    
such caution the lamp has been          
considerably modified since first       
invented1 the speed of the ventilating  
currents not now allowing of the use of 
the simple ,davy lamp1 but the          
principle is the same4    ,during the   
progress of ,sir ,humphrey ,davy's      
experiments1 he found that  when        
fire-damp was diluted with #he per cent4
 of air1 and any less  proportion1 it   
simply ignited without explosion4 ,with 
between #he per  cent4 and #hi per cent4
 of air1 fire-damp assumed its most     
explosive form1  but afterwards         

decreased in explosiveness1 until with  
#id-a_/d per cent4 of  air it again     
simply ignited without explosion4 ,with 
between #aa and #ab per  cent4 of       
fire-damp the mixture was most          
dangerous4 ,pure fire-damp itself1      
therefore1 is not dangerous1 so that    
when a small quantity enters the  gauze 
which surrounds the ,davy lamp1 it      
simply burns with its  characteristic   
blue flame1 but at the same time gives  
the miner due  notice of the danger     
which he was running4    ,illustration3 
,,fig4 #cb4--;,gas ,jet and ,davy ,lamp4
    ,with the  complicated improvements 
which have since been made in the ,davy 
lamp1 a state of almost absolute safety 
can be guaranteed1 but still from  time 
to time explosions are reported4 ,of the
 cause of many we are  absolutely       
ignorant1 but occasionally a light is   
thrown upon their origin  by a paragraph
 appearing in a daily paper4 ,two men   
are charged before the  magistrates with
 being in the possession of keys used   

exclusively for  unlocking their miners'
 safety-lamps4 ,there is no defence4    
,these men know  that they carry their  
lives in their hands1 yet will risk     
their own and  those of hundreds of     
others1 in order that they may be able  
to light  their pipes by means of their 
safety-lamps4 ,sometimes in an          
unexpected  moment there is a great     
dislodgement of coal1 and a tremendous  
quantity  of gas is set free1 which may 
be sufficient to foul the passages for  
some  distance around4 ,the introduction
 or exposure of a naked light for even  
so much as a second is sufficient to    
cause explosion of the mass2 doors  are 
blown down1 props and tubbing are       
charred up1 and the volume of  smoke1   
rushing up by the nearest shaft and     
overthrowing the engine-house  and other
 structures at the mouth1 conveys its   
own sad message to those  at the        
surface1 of the dreadful catastrophe    
that has happened below4  ,perhaps all  
that remains of some of the workers     

consists of charred and  scorched       
bodies1 scarcely recognisable as human  
beings4 ,others escape  with scorched   
arms or legs1 and singed hair1 to tell  
the terrible tale to  those who were    
more fortunately absent2 to speak of    
their own sufferings  when1 after having
 escaped the worst effects of the       
explosion1 they  encountered the        
asphyxiating rush of the after-damp or  
choke-damp1 which  had been caused by   
the combustion of the fire-damp4        
,choke-damp in very  truth it is1 for it
 is principally composed of our old     
acquaintance  carbonic acid gas 7carbon 
dioxide71 which is well known as a      
non-supporter of combustion and as an   
asphyxiator of animal life4    ,it seems
 a terrible thing that on occasions the 
workings and walls  themselves of a     
coal-mine catch fire and burn           
incessantly4 ,yet such is  the case4    
,years ago this happened in the case of 
an old colliery near  ,dudley1 at the   
surface of which1 by means of the heat  

and steam thus  afforded1 early potatoes
 for the ,london market1 we are told1   
were grown2  and it was no unusual thing
 to see the smoke emerging from cracks  
and  crevices in the rocks in the       
vicinity of the town4    ,from fire on  
the one hand1 we pass1 on the other1 to 
the danger which  awaits miners from a  
sudden inrush of water4 ,during the     
great coal strike  of #ahic1 certain    
mines became unworkable in consequence  
of the quantity  of water which flooded 
the mines1 and which1 continually       
passing along  the natural fractures in 
the earth's crust1 is always ready to   
find a  storage reservoir in the        
workings of a coal-mine4 ,this is a     
difficulty  which is always experienced 
in the sinking of shafts1 and the       
shutting  off of water engages the best 
efforts of mining engineers4    ,added  
to these various dangers which exist in 
the coal-mine1 we must not  omit to     
notice those accidents that are         
continually being caused by the         

falling-in of roofs or of walls1 from   
the falling of insecure timber1 or  of  
what are known as coal-pipes or         
bell-moulds4 ,then1 again1 every  man   
that enters the mine trusts his life to 
the cage by which he descends  to his   
labour1 and shaft accidents are not     
infrequent4    ,the following table     
shows the number of deaths from colliery
 accidents  for a period of ten years1  
compiled by a ,government inspector1 and
 from  this it will be seen that those  
resulting from falling roofs number     
considerably more than one-third of the 
whole4                                  
----------------------------------------
---------------------------             
,causes of ,death4                 ,no4 
of    ,proportion                       
,deaths4    per cent4                   
----------------------------------------
---------------------------   ,deaths   
resulting from fire-damp                
explosions                              
#bjai        #bj4cf                     

,deaths resulting from falling          
roofs and coals                         
#ciec        #ci4hg                     
,deaths resulting from shaft            
accidents                               
#agaj        #ag4bd                     
,deaths resulting from miscellaneous    
causes and above ground                 
#bbcd        #bb4ec                     
------------------------                
#iiaf       #ajj4jj                     
----------------------------------------
--------------------------    ,every    
reader of the daily papers is familiar  
with the harrowing accounts  which are  
there given of coal-mine explosions4    
,this kind of accident is one1 which is1
 above all1 associated in the  public   
mind with the dangers of the coal-pit4  
,yet the accidents arising  from this   
cause number but #bj per cent4 of those 
recorded1 and granted  there be proper  
inspection1 and the use of naked lights 
be absolutely  abolished1 this low      
percentage might still be considerably  

reduced4    ,a terrific explosion       
occurred at ,whitwick ,colliery1        
,leicestershire1 in  #ahic1 when two    
lads were killed1 whilst a third was    
rescued after a very  narrow escape4    
,the lads1 it is stated1 were working   
with naked lights1  when a sudden fall  
of coal released a quantity of gas1 and 
an immediate  explosion was the natural 
result4 ,accidents had been so rare at  
this pit  that it was regarded as       
particularly safe1 and it was alleged   
that the  use of naked lights was not   
uncommon4    ,this is an instance of    
that large number of accidents which are
  undoubtedly preventable4    ,an       
interesting commentary on the careless  
manner in which miners risk  their lives
 was shown in the discoveries made after
 an explosion at a  colliery near       
,wrexham in #ahhi4 ,near the scene of   
the explosion an  unsecured safety lamp 
was found1 and the general opinion at   
the time was  that the disaster was     
caused by the inexcusable carelessness  

of one of  the twenty victims4 ,besides 
this1 when the clothing of the bodies   
recovered was searched1 the contents1   
taken1 it should be noted1 with the     
pitmen into the mines1 consisted of     
pipes1 tobacco1 matches1 and even  keys 
for unlocking the lamps4 ,it is a       
strange reflection on the manner in     
which this mine had been examined       
previous to the men entering upon their 
work1 that the under-looker1 but half an
 hour previously1 had reported  the pit 
to be free from gas4    ,another        
instance of the same foolhardiness on   
the part of the miners is  contained in 
the report issued in regard to an       
explosion which occurred  at ,denny1 in 
,stirlingshire1 on ,april #bfth1 #ahie4 
,by this accident  thirteen men lost    
their lives1 and upon the bodies of     
eight of the number  the following      
articles were found2 upon ,patrick      
,carr1 tin matchbox half  full of       
matches and a contrivance for opening   
lamps2 ,john ,comrie1 split  nail for   

opening lamps2 ,peter ,conway1 seven    
matches and split key for  opening      
lamps2 ,patrick ,dunton1 split nail for 
opening lamps2 ,john ,herron1  clay pipe
 and piece of tobacco2 ,henry           
,m',govern1 tin matchbox half full of   
matches2 ,robert ,mitchell1 clay pipe   
and piece of tobacco2 ,john ,nicol1     
wooden pipe1 piece of tobacco1 one      
match1 and box half full of matches4    
,the report stated that the immediate   
cause of the disaster was the  ignition 
of fire-damp by naked light1 the        
conditions of temperature being  such as
 to exclude the possibility of          
spontaneous combustion4 ,henry          
,m',govern had previously been convicted
 of having a pipe in the mine4 ,with    
regard to the question of sufficient    
ventilation it continued3--,and we  are 
therefore led1 on a consideration of the
 whole evidence1 to the  conclusion that
 the accident cannot be attributed to   
the absence of  ventilation1 which the  
mine owners were bound under the ,mines 

,regulation  ,act and the special rules 
to provide4 ,the report concluded as    
follows3--  ,on the whole matter we have
 to report that1 in our opinion1 the    
explosion at ,quarter ,pit on ,april    
#bfth1 #ahie1 resulting in the loss of  
thirteen lives1 was caused by the       
ignition of an accumulation or an       
outburst of gas coming in contact with a
 naked light1 'other than an open       
safety-lamp1' which had been unlawfully 
kindled by one of the miners who  were  
killed4 ,in our opinion1 the intensity  
of the explosion was  aggravated1 and   
its area extended1 by the ignition of   
coal-dust4    ,we have mentioned that   
accidents have frequently occurred from 
the  falling of coal-pipes1 or1 as they 
are also called1 bell-moulds4 ,we  must 
explain what is meant by this term4     
,they are simply what appear to  be     
solid trunks of trees metamorphosed into
 coal4 ,if we go into a  tropical forest
 we find that the woody fibre of dead   
trees almost  invariably decays faster  

than the bark4 ,the result is that what 
may  appear to be a sound tree is       
nothing but an empty cylinder of bark4  
,this  appears to have been the case    
with many of the trees in coal-mines1   
where  they are seen to pierce the      
strata1 and around which the miners are 
excavating the coal4 ,as the coaly mass 
collected around the trunk when  the    
coal was being formed1 the interior was 
undergoing a process of  decomposition1 
while the bark assumed the form of coal4
 ,the hollow  interior then became      
filled with the shale or sandstone which
 forms the  roof of the coal1 and its   
sole support when the coal is removed   
from  around it1 is the thin rind of    
carbonised bark4 ,when this falls to    
pieces1 or loses its cohesion1 the      
sandstone trunk falls of its own        
weight1 often causing the death of the  
man that works beneath it4 ,sir         
,charles ,lyell mentions that in a      
colliery near ,newcastle1 no less than  
thirty sigillaria trees were standing in

 their natural position in an  area of  
fifty yards square1 the interior in each
 case being sandstone1  which was       
surrounded by a bark of friable coal4   
,illustration3 ,fig4 #cc--,part of a    
trunk of ,sigillaria1 showing the thin  
outer carbonised bark1 with leaf-scars1 
and the seal-like impressions  where the
 bark is removed4    ,the last great    
danger to which we have here to make    
reference1 is the  explosive action of a
 quantity of coal-dust in a dry         
condition4 ,it is  only now commencing  
to be fully recognised that this is     
really a most  dangerous explosive4 ,as 
we have seen1 large quantities of coal  
are formed  almost exclusively of       
lepidodendron spores1 and such coal is  
productive  of a great quantity of dust4
 ,explosions which are always more or   
less  attributable to the effects of    
coal-dust are generally considered1 in  
the  official statistics1 to have been  
caused by fire-damp4 ,the ,act          
regulating  mines in ,great ,britain is 

scarcely up to date in this respect4    
,there is a  regulation which provides  
for the watering of all dry and dusty   
places  within twenty yards from the    
spot where a shot is fired1 but the     
enforcement of this regulation in each  
and every pit necessarily devolves  on  
the managers1 many of whom in the       
absence of an inspector leave the       
requirement a dead letter4 ,every       
improvement which results in the better 
ventilation of a coal-mine tends to     
leave the dust in a more dangerous      
condition4 ,the air1 as it descends the 
shaft and permeates the workings1       
becomes more and more heated1 and licks 
up every particle of moisture it  can   
touch4 ,thorough ventilation results in 
more greatly freeing a mine of  the     
dangerous fire-damp1 but the remedy     
brings about another disease1  viz41 the
 drying-up of all moisture4 ,the dust is
 thus left in a  dangerously inflammable
 condition1 acting like a train of      
gunpowder1 to  be started1 it may be1 by

 the slightest breath of an explosion4  
,there is  apparently little doubt that 
the presence of coal-dust in a dry state
 in  a mine appreciably increases the   
liability of explosion in that mine4    
,so far as ,great ,britain is concerned1
 a ,royal ,commission was appointed by  
,lord ,rosebery's ,government to inquire
 into and investigate the facts         
referring to coal-dust4 ,generally      
speaking1 the conclusion arrived at was 
that fine coal-dust was inflammable     
under certain conditions4 ,there was    
considerable difference of opinion as to
 what these conditions were4 ,some  were
 of opinion that coal-dust and air alone
 were of an explosive nature1  whilst   
others thought that alone they were not1
 but that the addition of  a small      
quantity of fire-damp rendered the      
mixture explosive4 ,an  important       
conclusion was come to1 that1 with the  
combustion of coal-dust  alone1 there   
was little or no concussion1 and that   
the flame was not of  an explosive      

character4    ,coal-dust was1 however1  
admittedly dangerous1 especially if in a
 dry  condition4 ,the effects of an     
explosion of gas might be considerably  
extended by its presence1 and there     
seems every reason to believe that1     
with a suitable admixture of air and a  
very small proportion of gas1 it  forms 
a dangerous explosive4 ,legislation in  
the direction of the report  of the     
,commission is urgently needed4    ,we  
have seen elsewhere what it is in the   
dust which makes it dangerous1  how     
that1 for the most part1 it consists of 
the dust-like spores of the             
lepidodendron tree1 fine and impalpable 
as the spores on the backs of  some of  
our living ferns1 and the fact that this
 consists of a large  proportion of     
resin makes it the easily inflammable   
substance it is4  ,nothing but an       
incessant watering of the workings in   
such cases will  render the dust        
innocuous4 ,the dust is extremely fine1 
and is easily  carried into every nook  

and crevice1 and when1 as at ,bridgend  
in #ahib1 it  explodes1 it is driven up 
and out of the shaft1 enveloping        
everything  temporarily in dust and     
darkness4    ,in some of the pits in    
,south ,wales a system of fine sprays of
 water is in  use1 by which the water is
 ejected from pin-holes pricked in a    
series of  pipes which are carried      
through the workings4 ,a fine mist is   
thus caused  where necessary1 which is  
carried forward by the force of the     
ventilating  current4    ,a thorough    
system of inspection in coal-mines      
throughout the world is  undoubtedly    
urgently called for1 in order to ensure 
the proper carrying  out of the various 
regulations framed for their safety4 ,it
 is extremely  unfortunate that so many 
of the accidents which happen are       
preventable1  if only men of knowledge  
and of scientific attainments filled the
  responsible positions of the          
overlookers4          ,,chapter ,v4     
,,early ,,history--,,its ,,use ,,and    

,,its ,,abuse4      ,the extensive use  
of coal throughout the civilised world  
for purposes of  heating and            
illumination1 and for the carrying on of
 manufactures and  industries1 may be   
regarded as a well-marked characteristic
 of the age in  which we live4    ,coal 
must have been in centuries past a      
familiar object to many  generations4   
,people must have long been living in   
close proximity to its  outcrops at the 
sides of the mountains and at the       
surface of the land1  yet without being 
acquainted with its practical value1 and
 it seems  strange that so little use   
was made of it until about three        
centuries  ago1 and that its use did not
 spread earlier and more quickly        
throughout  civilised countries4    ,a  
mineral fuel is mentioned by            
,theophrastus about #cjj ,b4,c41 from   
which it  is inferred that thus early it
 was dug from some of the more shallow  
depths4 ,the ,britons before the time of
 the ,roman invasion are credited  with 

some slight knowledge of its industrial 
value4 ,prehistoric  excavations have   
been found in ,monmouthshire1 and at    
,stanley1 in  ,derbyshire1 and the flint
 axes there actually found imbedded in  
the layer  of coal are reasonably held  
to indicate its excavation by neolithic 
or  palaeolithic 7stone-age7 workmen4   
,the fact that coal cinders have been   
found on old ,roman walls in            
conjunction with ,roman tools and       
implements1 goes to prove that its use1 
at least for heating purposes1 was known
 in ,england prior to the ,saxon        
invasion1 whilst some polygonal chambers
 in the six-foot seam near the  river   
,douglas1 in ,lancashire1 are supposed  
also to be ,roman4    ,the ,chinese were
 early acquainted with the existence of 
coal1 and knew of  its industrial value 
to the extent of using it for the baking
 of  porcelain4    ,the fact of its     
extensive existence in ,great ,britain1 
and the valuable  uses to which it might
 be put1 did not1 however1 meet with    

much notice  until the ninth century1   
when1 owing to the decrease of the      
forest-area1 and consequently of the    
supply of wood-charcoal therefrom1  it  
began to attract attention as affording 
an excellent substitute for  charcoal4  
,the coal-miner was1 however1 still a   
creation of the future1 and even as     
peat is collected in ,ireland at the    
present day for fuel1 without the       
laborious process of mining for it1 so  
those people living in  coal-bearing    
districts found their needs satisfied by
 the quantity of  coal1 small as it was1
 which appeared ready to hand on the    
sides of the  carboniferous mountains4  
,till then1 and for a long time         
afterwards1 the  principal source of    
fuel consisted of vast forests1 amidst  
which the  charcoal-burners1 or colliers
 as they were even then called1 lived   
out  their lonely existence in preparing
 charcoal and hewing wood1 for the      
fires of the baronial halls and stately 
castles then swarming throughout  the   

land4 ,as the forests became used up1   
recourse was had more and more  to coal1
 and in #abci the first charter dealing 
with and recognising the  importance of 
the supplies was granted to the freemen 
of ,newcastle1  according them          
permission to dig for coals in the      
,castle fields4 ,about  the same time a 
coal-pit at ,preston1 ,haddingtonshire1 
was granted to the  monks of ,newbattle4
    ,specimens of ,newcastle coal were  
sent to ,london1 but the city was loth  
to  adopt its use1 objecting to the     
innovation as one prejudicial to the    
health of its citizens4 ,by the end of  
the #afth century1 two ships only  were 
found sufficient to satisfy the demand  
for stone-coal in ,london4  ,this slow  
progress may1 perhaps1 have been        
partially owing to the  difficulties    
which were placed in the way of its     
universal use4 ,great  opposition was   
experienced by those who imported it    
into the metropolis1  and the increasing
 amount which was used by brewers and   

others about the  year #acjj1 caused    
serious complaints to be made1 the      
effect of which was  to induce          
,parliament to obtain a proclamation    
from the ,king prohibiting  its use1 and
 empowering the justices to inflict a   
fine on those who  persisted in burning 
it4 ,the nuisance which coal has since  
proved itself1  in the pollution of the 
atmosphere and in the denuding of wide  
tracts of  country of all vegetation1   
was even thus early recognised1 and had 
the  efforts which were then made to    
stamp out its use1 proved successful1   
those who live now in the great cities  
might never have become acquainted  with
 that species of black winter fog which 
at times hangs like a pall  over them1  
and transforms the brightness of day    
into a darkness little  removed from    
that of night4 ,at the same time1 we    
must bear in mind that  it is           
universally acknowledged that ,england  
owes her prosperity1 and her            
pre-eminence in commerce1 in great part1

 to her happy possession of wide  and   
valuable coal-fields1 and many          
authorities have not hesitated to say1  
that1 in their opinion1 the length of   
time during which ,england will         
continue to hold her prominent position 
as an industrial nation is  limited by  
the time during which her coal will     
last4    ,the attempt to prohibit the   
burning of coal was not1 however1 very  
successful1 for in the reign of ,edward 
,,iii4 a license was again granted  to  
the freemen of ,newcastle to dig for    
coals4 ,newcastle was thus the  first   
town to become famous as the home of the
 coal-miner1 and the fame  which it     
early acquired1 it has held unceasingly 
ever since4    ,other attempts at       
prohibition of the article were made at 
various times  subsequently1 amongst    
them being one which was made in        
,elizabeth's reign4  ,it was supposed   
that the health of the country squires1 
who came to town  to attend the session 
of ,parliament1 suffered considerably   

during their  sojourn in ,london1 and1  
to remedy this serious state of affairs1
 the use  of stone-coal during the time 
,parliament was sitting was once more   
prohibited4    ,coal was1 however1 by   
this time beginning to be recognised as 
a most  valuable and useful article of  
fuel1 and had taken a position in the   
industrial life of the country from     
which it was difficult to remove it4    
,rather than attempt to have arrested   
the growing use of coal1 ,parliament    
would have been better employed had it  
framed laws compelling the              
manufacturers and other large burners to
 consume their own smoke1 and  instead  
of aiming at total prohibition1 have    
encouraged an intelligent  and more     
economical use of it4    ,in spite of   
all prohibition its use rapidly spread1 
and it was soon  applied to the smelting
 of iron and to other purposes4 ,iron   
had been  largely produced in the south 
of ,england from strata of the ,wealden 
formation1 during the existence of the  

great forest which at one time  extended
 for miles throughout ,surrey and       
,sussex4 ,the discovery of coal1        
however1 and the opening up of many     
mines in the north1 gave an important   
impetus to the smelting of iron in those
 counties1 and as the forests of  the   
,weald became exhausted1 the iron trade 
gradually declined4 ,furnace  after     
furnace became extinguished1 until in   
#ahji that at ,ashburnham1  which had   
lingered on for some years1 was         
compelled to bow to the  inevitable fate
 which had overtaken the rest of the    
iron blast-furnaces4    ,in referring to
 this subject1 ,sir ,james ,picton      
says3--,ironstone of  excellent quality 
is found in various parts of the county1
 and was very  early made use of4 ,even 
before the advent of the ,romans1 the   
,forest of  ,dean in the west1 and the  
,forest of ,anderida1 in ,sussex1 in the
 east1  were the two principal sources  
from which the metal was derived1 and   
all  through the mediaeval ages the     

manufacture was continued4 ,after the   
discovery of the art of smelting and    
casting iron in the sixteenth  century1 
the manufacture in ,sussex received a   
great impulse from the  abundance of    
wood for fuel1 and from that time down  
to the middle of the  last century it   
continued to flourish4 ,one of the      
largest furnaces was at  ,lamberhurst1  
on the borders of ,kent1 where the noble
 balustrade  surrounding ,st ,paul's    
,cathedral was cast at a cost of about  
#aa1jjj4 ,it  is stated by the historian
 ,holinshed that the first cast-iron    
ordnance  was manufactured at ,buxted4  
,two specialities in the iron trade     
belonged  to ,sussex1 the manufacture of
 chimney-backs1 and cast-iron plates for
  grave-stones4 ,at the time when wood  
constituted the fuel the backs of       
fire-places were frequently ornamented  
with neat designs4 ,specimens1 both  of 
the chimney-backs and of the monuments1 
are occasionally met with4  ,these      
articles were exported from ,rye4 ,the  

iron manufacture1 of course1  met with  
considerable discouragement on the      
discovery of smelting with  pit-coal1   
and the rapid progress of iron works in 
,staffordshire and the  ,north1 but it  
lingered on until the great forest was  
cut down and the  fuel exhausted4    ,in
 his interesting work1 ,sylvia1         
published in #affa1 ,evelyn1 in speaking
  of the noxious vapours poured out into
 the air by the increasing number  of   
coal fires1 writes1 ,this is that       
pernicious smoke which sullies all  her 
glory1 superinducing a sooty crust or   
furr upon all that it lights1  spoiling 
movables1 tarnishing the plate1 gildings
 and furniture1 and  corroding the very 
iron bars and hardest stones with those 
piercing and  acrimonious spirits which 
accompany its sulphur1 and executing    
more in  one year than the pure air of  
the country could effect in some        
hundreds4  ,the evils here mentioned are
 those which have grown and have become 
intensified a hundred-fold during the   

two centuries and a half which have     
since elapsed4 ,when the many efforts   
which were made to limit its use in  the
 years prior to #afjj are remembered2 at
 which time1 we are informed1  two ships
 only were engaged in bringing coal to  
,london1 it at once  appears how paltry 
are the efforts made now to moderate    
these same  baneful influences on our   
atmosphere1 at a time when the annual   
consumption of coal in the ,united      
,kingdom has reached the enormous total 
of #aij millions of tons4 ,the various  
smoke-abatement associations which  have
 started into existence during the last 
few years are doing a little1  although 
very little1 towards directing popular  
attention to the subject2  but there is 
an enormous task before them1 that of   
awakening every  individual to an       
appreciation of the personal interest   
which he has in  their success1 and to  
realise how much might at once be done  
if each were  to do his share1 minute   
though it might be1 towards mitigating  

the evils  of the present mode of       
coal-consumption4 ,probably very few    
householders  ever realise what         
important factories their chimneys      
constitute1 in  bringing about air      
pollution1 and the more they do away    
with the use of  bituminous coal for    
fuel1 the nearer we shall be to the time
 when yellow  fog will be a thing of the
 past4    ,a large proportion of smoke  
consists of particles of pure unconsumed
  carbon1 and this is accompanied in its
 passage up our chimneys by  sulphurous 
acid1 begotten by the sulphur which is  
contained in the coal  to the amount of 
about eight pounds in every thousand2 by
 sulphuretted  hydrogen1 by             
hydro-carbons1 and by vapours of various
 kinds of oils1  small quantities of    
ammonia1 and other bodies not by any    
means  contributing to a healthy        
condition of the atmosphere4 ,a good    
deal of the  heavier carbon is deposited
 along the walls of chimneys in the form
 of  soot1 together with a small        

percentage of sulphate of ammonia2 this 
is as  a consequence very generally used
 for manure4 ,the remainder is poured   
out  into the atmosphere1 there to      
undergo fresh changes1 and to become a  
fruitful cause of those thick black fogs
 with which town-dwellers are so        
familiar4 ,sulphuretted hydrogen        
7,h#b,s7 is a gas well known to students
  of chemistry as a most powerful       
reagent1 its most characteristic        
external  property being the extremely  
offensive odour which it possesses1 and 
which bears a strong resemblance to that
 of rotten eggs or decomposing  fish4   
,it tarnishes silver work and picture   
frames very rapidly4 ,on  combustion it 
changes to sulphurous acid 7,,so#b71 and
 this in turn has  the power of taking  
up from the air another atom of oxygen1 
forming  sulphuric acid 7,,so#c  water71
 or1 as we more familiarly know it1 oil 
of vitriol4    ,yet the smoke itself1   
including as it does all the many       
impurities which  exist in coal1 is not 

only evil in itself1 but is evil in its 
influences4  ,dr ,siemens has said3--,it
 has been shown that the fine dust      
resulting  from the imperfect combustion
 of coal was mainly instrumental in the 
formation of fog2 each particle of solid
 matter attracting to itself  aqueous   
vapour4 ,these globules of fog were     
rendered particularly  tenacious and    
disagreeable by the presence of tar     
vapour1 another result  of imperfect    
combustion of raw fuel1 which might be  
turned to better  account at the        
dyeworks4 ,the hurtful influence of     
smoke upon public  health1 the great    
personal discomfort to which it gave    
rise1 and the vast  expense it          
indirectly caused through the           
destruction of our monuments1  pictures1
 furniture1 and apparel1 were now being 
recognised4    ,the most effectual      
remedy would result from a general      
recognition of the  fact that wherever  
smoke was produced1 fuel was being      
consumed  wastefully1 and that all our  

calorific effects1 from the largest     
furnace  to the domestic fire1 could be 
realised as completely1 and more        
economically1 without allowing any of   
the fuel employed to reach the          
atmosphere unburnt4 ,this most desirable
 result might be effected by the  use of
 gas for all heating purposes1 with or  
without the additional use  of coke or  
anthracite4 ,the success of the         
so-called smoke-consuming  stoves is    
greatly open to question1 whilst some of
 them have been  reported upon by those 
appointed to inspect them as actually   
accentuating  the incomplete combustion1
 the abolition of which they were       
invented to  bring about4    ,the smoke 
nuisance is one which cuts at the very  
basis of our business  life4 ,the cloud 
which1 under certain atmospheric        
conditions1 rests like a  pall over our 
great cities1 will not even permit at   
times of a single ray  of sunshine      
permeating it4 ,no one knows whence it  
rises1 nor at what hour  to expect it4  

,it is like a giant spectre which1      
having lain dormant since  the          
carboniferous age1 has been raised into 
life and being at the call of  restless 
humanity2 it is now punishing us for our
 prodigal use of the  wealth it left us1
 by clasping us in its deadly arms1     
cutting off our  brilliant sunshine1 and
 necessitating the use in the daytime of
  artificial light2 inducing all kinds  
of bronchial and throat affections1     
corroding telegraph and telephone wires1
 and weathering away the masonry  of    
public buildings4    ,the immense value 
to us of the coal-deposits which lie    
buried in such  profusion in the earth  
beneath us1 can only be appreciated when
 we  consider the many uses to which    
coal has been put4 ,we must remember1 as
  we watch the ever-extending railway   
ramifying the country in every          
direction1 that the first railway and   
the first locomotive ever built1  were  
those which were brought into being in  
#ahad by ,george ,stephenson1  for the  

purpose of the carriage of coals from   
the ,killingworth ,colliery4  ,to the   
importance of coal in our manufactures1 
therefore1 we owe the  subsequent       
development of steam locomotive power as
 the means of the  introduction of      
passenger traffic1 and by the use of    
coal we are enabled  to travel from one 
end of the country to the other in a    
space of time  inconceivably small as   
compared with that occupied on the same 
journey in  the old coaching days4 ,the 
increased rapidity with which our       
vessels  cross the wide ocean we owe to 
the use of coal2 our mines are carried  
to  greater depths owing to the power   
our pumping-engines obtain from coal in 
clearing the mines of water and in      
ensuring ventilation2 the enormous      
development of the iron trade only      
became possible with the increased      
blast power obtained from the           
consumption of coal1 and the very hulls 
and  engines of our steamships are made 
of this iron2 our railroads and  engines

 are mostly of iron1 and when we think  
of the extensive use of  iron utensils  
in every walk in life1 we see how       
important becomes the  power we possess 
of obtaining the necessary fuel to feed 
the smelting  furnaces4 ,evaporation by 
the sun was at one time the sole means  
of  obtaining salt from seawater2 now   
coal is used to boil the salt pans and  
to purify the brine from the salt-mines 
in the triassic strata of  ,cheshire4   
,the extent to which gas is used for    
illuminating purposes  reminds us of    
another important product obtained from 
coal4 ,paraffin oil  and petroleum we   
obtain from coal1 whilst candles1 oils1 
dyes1  lubricants1 and many other useful
 articles go to attest the importance of
  the underground stores of that mineral
 which has well and deservedly been     
termed the black diamond4               
,,chapter ,,vi4    ,,how ,,gas ,,is     
,,made--,,illuminating ,,oils ,,and     
,,bye-,,products4      ,accustomed as we
 are at the present day to see street   

after street of  well-lighted           
thoroughfares1 brilliantly illuminated  
by gas-lamps  maintained by public      
authority1 we can scarcely appreciate   
the fact that  the use of gas is1       
comparatively speaking1 of but recent   
growth1 and  that1 like the use of coal 
itself1 it has not yet existed a century
 in  public favour4 ,valuable as coal is
 in very many different ways1 perhaps   
next in value to its actual use as fuel1
 ranks the use of the immediate  product
 of its distillation--viz41 gas2 and    
although gas is in some  respects waning
 before the march of the electric light 
in our day1 yet1  even as gas at no time
 has altogether superseded old-fashioned
 oil1 so we  need not anticipate a time 
when gas in turn will be likely to be   
superseded by the electric light1 there 
being many uses to which the one  may be
 put1 to which the latter would be      
altogether inapplicable2 for1 in  the   
words of ,dr ,siemens1 assuming the cost
 of electric light to be  practically   

the same as gas1 the preference for one 
or other would in  each application be  
decided upon grounds of relative        
convenience1 but  gas-lighting would    
hold its own as the poor man's friend4  
,gas is an  institution of the utmost   
value to the artisan2 it requires hardly
 any  attention1 is supplied upon       
regulated terms1 and gives1 with what   
should  be a cheerful light1 a genial   
warmth1 which often saves the lighting  
of a  fire4    ,the revolution which gas
 has made in the appearance of the      
streets1 where  formerly the only       
illumination was that provided by each  
householder1  who1 according to his     
means1 hung out a more or less efficient
 lantern1  and consequently a more or   
less smoky one1 cannot fail also to have
  brought about a revolution in the     
social aspects of the streets1 and      
therefore is worthy to be ranked as a   
social reforming agent2 and some  slight
 knowledge of the process of its        
manufacture1 such as it is here         

proposed to give1 should be in the      
possession of every educated            
individual4 ,yet the subjects which must
 be dealt with in this chapter are  so  
numerous and of such general interest1  
that we shall be unable to  enter more  
than superficially into any one part of 
the whole1 but shall  strive to give a  
clear and comprehensive view1 which     
shall satisfy the  inquirer who is not a
 specialist4    ,the credit of the first
 attempt at utilising the gaseous       
product of coal  for illumination       
appears to be due to ,murdock1 an       
engineer at ,redruth1  who1 in #agib1   
introduced it into his house and        
offices1 and who1 ten  years afterwards1
 as the result of numerous experiments  
which he made  with a view to its       
utilisation1 made a public display at   
,birmingham on  the occasion of the     
,peace of ,amiens1 in #ahjb4    ,more   
than a century before1 however1 the gas 
obtained from coal had been             
experimented upon by a ,dr ,clayton1    

who1 about #afij1 conceived the idea of 
heating coal until its gaseous          
constituents were forced out of it4 ,he 
described how he obtained steam first of
 all1 then a black oil1 and  finally a  
spirit1 as our ancestors were wont to   
term the gas4 ,this1 to  his surprise1  
ignited on a light being applied to it1 
and he considerably  amused his friends 
with the wonders of this inflammatory   
spirit4 ,for a  century afterwards it   
remained in its early condition1 a      
chemical wonder1  a thing to be amused  
with2 but it required the true genius   
and energy of  ,murdock to show the     
great things of which it was capable4   
,london received its first instalment of
 gas in #ahjg1 and during the next  few 
years its use became more and more      
extended1 houses and streets  rapidly   
receiving supplies in quick succession4 
,it was not1 however1 till  about the   
year #ahbj that its use throughout the  
country became at all  general1 ,st     
,james' ,park being gas-lit in the      

succeeding year4 ,this is not  yet      
eighty years ago1 and amongst the many  
wonderful things which have  sprung up  
during the present century1 perhaps we  
may place in the  foremost rank for     
actual utility1 the gas extracted from  
coal1 conveyed  as it is through miles  
upon miles of underground pipes into the
 very  homes of the people1 and         
constituting now almost as much a       
necessity of a  comfortable existence as
 water itself4    ,the use of gas thus  
rapidly extended for illuminating       
purposes1 and to a  very great extent   
superseded the old-fashioned means of   
illumination4    ,illustration3 ,,fig4  
#cd4--;,inside a ,gas-,holder4    ,the  
gas companies which sprang up were not  
slow to notice that1 seeing  the gas was
 supplied by meter1 it was to their     
pecuniary advantage to  give merely the 
prescribed illuminating power1 and to   
discourage the  invention of economical 
burners1 in order that the consumption  
might  reach a maximum4 ,the application

 of gas for heating purposes had not    
been  encouraged1 and was still made    
difficult in consequence of the         
objectionable practice of reducing the  
pressure in the mains during  daytime to
 the lowest possible point consistent   
with prevention of  atmospheric         
indraught4    ,the introduction of an   
important rival into the field in the   
shape of the  electric light has now    
given a powerful impetus to the         
invention and  introduction of effective
 gas-lamps1 and amongst inventors of    
recent  years no name is1 perhaps1 in   
this respect so well known as the name  
of  ,sugg4 ,as long as gas retained     
almost the monopoly1 there was no       
incentive  to the gas companies to      
produce an effective light cheaply2 but 
now that  the question of the relative  
cheapness of gas and electricity is     
being  actively discussed1 the gas      
companies1 true to the instinct of      
self-preservation1 seem determined to   
show what can be done when gas is       

consumed in a scientific manner4    ,in 
order to understand how best a burner   
should be constructed in order  that the
 gas that is burnt should give the      
greatest possible amount of             
illumination1 let us consider for a     
moment the composition of the gas       
flame4 ,it consists of three parts1 7#a7
 an interior dark space1 in which  the  
elements of the gas are in an unconsumed
 state2 7#b7 an inner ring  around the  
former1 whence the greatest amount of   
light is obtained1 and  in which are    
numerous particles of carbon at a white 
heat1 each awaiting  a supply of oxygen 
in order to bring about combustion2 and 
7#c7 an outer  ring of blue flame in    
which complete combustion has taken     
place1 and from  which the largest      
amount of heat is evolved4    ,the      
second of these portions of the flame   
corresponds with the reducing  flame of 
the blow-pipe1 since this part1 if      
turned upon an oxide1 will  reduce it1  
i4e41 abstract its oxygen from it4 ,this

 part also corresponds  with the jet of 
the ,bunsen burner1 when the holes are  
closed by which  otherwise air would    
mingle with the gas1 or with the flame  
from a  gas-stove when the gas ignites  
beneath the proper igniting-jets1 and   
which gives consequently a white or     
yellow flame4    ,the third portion1 on 
the other hand1 corresponds with the    
oxidising  flame of the blow-pipe1 since
 it gives up oxygen to bodies that are  
thirsting for it4 ,this also corresponds
 with the ordinary blue flame of  the   
,bunsen burner1 and with the blue flame 
of gas-stoves where heat1 and  not      
light1 is required1 the blue flame in   
both cases being caused by the          
admixture of air with the gas4    ,thus1
 in order that gas may give the best    
illumination1 we must increase  the     
yellow or white space of carbon         
particles at a white heat1 and a  burner
 that will do this1 and at the same time
 hold the balance so that  unconsumed   
particles of carbon shall not escape in 

the way of smoke1 will  give the most   
successful illuminating results4 ,with  
this end in view the  addition of       
albo-carbon to a bulb in the gas-pipe   
has proved very  successful1 and the    
incandescent gas-jet is constructed on  
exactly the  same chemical principle4   
,the invention of burners which brought 
about  this desirable end has doubtless 
not been without effect in acting as a  
powerful obstacle to the widespread     
introduction of the electric light4     
,without entering into details of the   
manufacture of gas1 it will be as  well 
just to glance at the principal parts of
 the apparatus used4    ,the gasometer1 
as it has erroneously been called1 is a 
familiar object to  most people1 not    
only to sight but unfortunately also to 
the organs of  smell4 ,it is in reality 
of course only the gas-holder1 in which 
the final  product of distillation of   
the coal is stored1 and from which the  
gas  immediately passes into the        
distributing mains4    ,the first1 and  

perhaps1 most important portion of the  
apparatus used in  gas-making is the    
series of retorts into which the coal is
 placed1 and  from which1 by the        
application of heat1 the various        
volatile products  distil over4 ,these  
retorts are huge cast-iron vessels1     
encased in strong  brick-work1 usually  
five in a group1 and beneath which a    
large furnace is  kept going until the  
process is complete4 ,each retort has an
 iron exit  pipe affixed to it1 through 
which the gases generated by the furnace
 are  carried off4 ,the exit pipes all  
empty themselves into what is known as  
the hydraulic main1 a long horizontal   
cylinder1 and in this the gas  begins to
 deposit a portion of its impurities4   
,the immediate products of  distillation
 are1 after steam and air1 gas1 tar1    
ammoniacal liquor1  sulphur in various  
forms1 and coke1 the last being left    
behind in the  retort4 ,in the hydraulic
 main some of the tar and ammoniacal    
liquor  already begin to be deposited4  

,the gas passes on to the condenser1    
which consists of a number of ,u-shaped 
pipes4 ,here the impurities are  still  
further condensed out1 and are collected
 in the tar-pit whilst  the gas         
proceeds1 still further lightened of its
 impurities4 ,it may be  mentioned that 
the temperature of the gas in the       
condenser is reduced to  about #fj ,f41 
but below this some of the most valuable
 of the illuminants  of coal-gas would  
commence to be deposited in liquid form1
 and care has  to be taken to prevent a 
greater lowering of temperature4 ,a     
mechanical  contrivance known as the    
exhauster is next used1 by which the gas
 is1  amongst other things1 helped      
forward in its onward movement through  
the  apparatus4 ,the gas then passes to 
the washers or scrubbers1 a series  of  
tall towers1 from which water is allowed
 to fall as a fine spray1 and  by means 
of which large quantities of ammonia1   
sulphuretted hydrogen1  carbonic acid   
and oxide1 and cyanogen compounds1 are  

removed4 ,in the  scrubber the water    
used in keeping the coke1 with which it 
is filled1  damp1 absorbs these         
compounds1 and the union of the ammonia 
with certain  of them takes place1      
resulting in the formation of carbonate 
of ammonia  7smelling salts71 sulphide  
and sulphocyanide of ammonia4           
,illustration3 ,,fig4 #ce4--;,filling   
,retorts by ,machinery4                 
,illustration3 ,,fig4                   
#cf4--;,,condensers4    ,hitherto the   
purification of the gas has been brought
 about by mechanical  means1 but the gas
 now enters the purifier1 in which it   
undergoes a  further cleansing1 but this
 time by chemical means4                
,illustration3 ,,fig4 #cg4    ,the agent
 used is either lime or hydrated oxide  
of iron1 and by their  means the gas is 
robbed of its carbonic acid and the     
greater part of its  sulphur compounds4 
,the process is then considered         
complete1 and the gas  passes on into   
the water chamber over which the        

gas-holder is reared1 and  in which it  
rises through the water1 forcing the    
huge cylinder upward  according to the  
pressure it exerts4    ,the gas-holder  
is poised between a number of upright   
pillars by a series  of chains and      
pulleys1 which allow of its easy ascent 
or descent  according as the supply is  
greater or less than that drawn from it 
by the  gas mains4    ,illustration3    
,,fig4 #ch4    ,when we see the process 
which is necessary in order to obtain   
pure gas1  we begin to appreciate to    
what an extent the atmosphere is fouled 
when  many of the products of           
distillation1 which1 as far as the      
production of  gas is concerned1 may be 
called impurities1 are allowed to escape
 free  without let or hindrance4 ,in    
these days of strict sanitary inspection
 it  seems strange that the air in the  
neighbourhood of gas-works is still     
allowed to become contaminated by the   
escape of impure compounds from the     
various portions of the gas-making      

apparatus4 ,go where one may1 the       
presence of these compounds is at once  
apparent to the nostrils within a  none 
too limited area around them1 and yet   
their deleterious effects can  be almost
 reduced to a minimum by the use of     
proper purifying agents1 and  by a      
scientific oversight of the whole       
apparatus4 ,it certainly behoves  all   
sanitary authorities to look well after 
any gas-works situated within  their    
districts4    ,now let us see what these
 first five products of distillation    
actually  are4    ,firstly1 house-gas4  
,everybody knows what house-gas is4 ,it 
cannot1  however1 be stated to be any   
one gas in particular1 since it is a    
mechanical mixture of at least three    
different gases1 and often contains     
small quantities of others4    ,a very  
large proportion consists of what is    
known as marsh-gas1 or light            
carburetted hydrogen4 ,this occurs      
occluded or locked up in the pores of   
the coal1 and often oozes out into the  

galleries of coal-mines1 where it  is   
known as firedamp 7,german dampf1       
vapour74 ,it is disengaged wherever     
vegetable matter has fallen and has     
become decayed4 ,if it were thence      
collected1 together with an admixture of
 ten times its volume of air1 a         
miniature coal-mine explosion could be  
produced by the introduction of a  match
 into the mixture4 ,alone1 however1 it  
burns with a feebly luminous  flame1    
although to its presence our house-gas  
owes a great portion of its  heating    
power4 ,marsh-gas is the first of the   
series of hydro-carbons  known          
chemically as the paraffins1 and is an  
extremely light substance1  being little
 more than half the weight of an equal  
bulk of air4 ,it is  composed of four   
atoms of hydrogen to one of carbon      
7,,ch#d74    ,marsh-gas1 together with  
hydrogen and the monoxide of carbon1 the
 last of  which burns with the dull blue
 flame often seen at the surface of     
fires1  particularly coke and charcoal  

fires1 form about #hg per cent4 of the  
whole volume of house-gas1 and are none 
of them anything but poor  illuminants4 
,the illuminating power of house-gas    
depends on the presence therein of      
olefiant gas 7ethylene71 or1 as it is   
sometimes termed1 heavy  carburetted    
hydrogen4 ,this is the first of the     
series of hydro-carbons  known as the   
olefines1 and is composed of two atoms  
of carbon to every  four atoms of       
hydrogen 7,c#b;,h#d74 ,others of the    
olefines are present  in minute         
quantities4 ,these assist in increasing 
the illuminosity1 which  is sometimes   
greatly enhanced1 too1 by the presence  
of a small quantity  of benzene vapour4 
,these illuminants1 however1 constitute 
but about #f per  cent4 of the whole4   
,added to these1 there are four other   
usual constituents which in no way      
increase the value of gas1 but which    
rather detract from it4 ,they are       
consequently as far as possible removed 
as impurities in the process of         

gas-making4 ,these are nitrogen1        
carbonic acid gas1 and the destructive  
sulphur compounds1 sulphuretted hydrogen
 and carbon bisulphide vapour4 ,it  is  
to the last two to which are to be      
attributed the injurious effects  which 
the burning of gas has upon pictures1   
books1 and also the  tarnishing which   
metal fittings suffer where gas is      
burnt1 since they  give rise to the     
formation of oil of vitriol 7sulphuric  
acid71 which is  being incessantly      
poured into the air4 ,of course the     
amount so given off  is little as       
compared with that which escapes from a 
coal fire1 but1  fortunately for the    
inmates of the room1 in this case the   
greater  quantity goes up the chimney2  
this1 however1 is but a method of       
postponing the evil day1 until the      
atmosphere becomes so laden with        
impurities that what proceeds at first  
up the chimney will finally again  make 
its way back through the doors and      
windows4 ,a recent official report      

tells us that1 in the town1 of ,st      
,helen's alone1 sufficient sulphur      
escapes annually into the atmosphere to 
finally produce #aaj1ehj tons of        
sulphuric acid1 and a computation has   
been made that every square mile of     
land in ,london is deluged annually with
 #ahj tons of the same                  
vegetation-denuding acid4 ,it is a      
matter for wonder that any green thing  
continues to exist in such places at    
all4    ,the chief constituents of      
coal-gas are1 therefore1 briefly as     
follows3--    _/ 7#a7  ,hydrogen1   7#b7
  ,marsh-gas 7carburetted hydrogen or   
fire-damp71   7#c7  ,carbon monoxide1   
7#d7  ,olefiant gas 7ethylene1 or heavy 
carburetted hydrogen71 with        other
 olefines1  _/ 7#e7  ,nitrogen1   7#f7  
,carbonic acid gas1   7#g7              
,sulphuretted hydrogen1   7#h7 ,carbon  
bisulphide 7vapour71    the last four   
being regarded as impurities1 which are 
removed as far as  possible in the      
manufacture4    ,in the process of      

distillation of the coal1 we have seen  
that various  other important substances
 are brought into existence4 ,the final 
residue  of coke1 which is impregnated  
with the sulphur which has not been     
volatilised in the form of sulphurous   
gases1 we need scarcely more than       
mention here4 ,but the gas-tar and the  
ammoniacal liquor are two important     
products which demand something more    
than our casual attention4 ,at one  time
 regarded by gas engineers as           
unfortunately necessary nuisances in    
the manufacture of gas1 they have both  
become so valuable on account of        
materials which can be obtained from    
them1 that they enable gas itself to  be
 sold now at less than half its original
 price4 ,the waste of former            
generations is being utilised in this1  
and an instance is recorded in  which   
tar1 which was known to have been lying 
useless at the bottom of a  canal for   
years1 has been purchased by a gas      
engineer for distilling  purposes4 ,it  

has been estimated that about #eij1jjj  
tons of coal-tar are  distilled         
annually4    ,tar in its primitive      
condition has been used1 as every one is
 aware1 for  painting or tarring a      
variety of objects1 such as barges and  
palings1 in  fact1 as a kind of         
protection to the object covered from   
the ravages of  insects or worms1 or to 
prevent corrosion when applied to metal 
piers4  ,but it is worthy of a better   
purpose1 and is capable of yielding far 
more  useful and interesting substances 
than even the most imaginative          
individual could have dreamed of fifty  
years ago4    ,in the process of        
distillation1 the tar1 after standing in
 tanks for some  time1 in order that any
 ammoniacal liquor which may be present 
may rise  to the surface and be drawn   
off1 is pumped into large stills1 where 
a  moderate amount of heat is applied to
 it4 ,the result is that some of the    
more volatile products pass over and are
 collected in a receiver4 ,these  first 

products are known as first light oils1 
or crude coal-naphtha1  and to this     
naphtha all the numerous natural        
naphthas which have been  discovered in 
various portions of the world1 and to   
which have been  applied numerous local 
names1 bear a very close resemblance4   
,such an one1  for instance1 was that   
small but famous spring at ,biddings1 in
  ,derbyshire1 from which the late ,mr  
,young--,paraffin ,young--obtained his  
well-known paraffin oil1 which gave the 
initial impetus to what has since       
developed into a trade of immense       
proportions in every quarter of the     
globe4    ,after a time the crude       
coal-naphtha ceases to flow over1 and   
the heat is  increased4 ,the result is  
that a fresh series of products1 known  
as  medium oils1 passes over1 and these 
oils are again collected and kept       
separate from the previous series4      
,these in turn cease to flow1 when1 by  
a further increase of heat1 what are    
known as the heavy oils finally  pass   

over1 and when the last of these1 green 
grease1 as it is called1  distils over1 
pitch alone is left in the still4 ,pitch
 is used to a large  extent in the      
preparation of artificial asphalte1 and 
also of a fuel  known as briquettes4    
,the products thus obtained at the      
various stages of the process are       
themselves subjected to further         
distillation1 and by the exercise of    
great care1 requiring the most delicate 
and accurate treatment1 a large  variety
 of oils is obtained1 and these are     
retailed under many and  various        
fanciful names4    ,one of the most     
important and best known products of the
 fractional  distillation of crude      
coal-naphtha is that known as benzene1  
or  benzole1 7,c#f;,h#f74 ,this1 in its 
unrefined condition1 is a light  spirit 
which distils over at a point somewhat  
below the boiling point of  water1 but a
 delicate process of rectification is   
necessary to produce  the pure spirit4  
,other products of the same light oils  

are toluene and  xylene4    ,benzene of 
a certain quality is of course a very   
familiar and useful  household          
supplement4 ,it is sometimes known and  
sold as benzene collas1  and is used for
 removing grease from clothing1 cleaning
 kid gloves1 c4  ,if pure it is in      
reality a most dangerous spirit1 being  
very inflammable2  it is also extremely 
volatile1 so much so that1 if an        
uncorked bottle be  left in a warm room 
where there is a fire or other light    
near1 its vapour  will probably ignite4 
,should the vapour become mixed with air
 before  ignition1 it becomes a most    
dangerous explosive1 and it will thus be
 seen  how necessary it is to handle the
 article in household use in a most     
cautious manner4 ,being highly volatile1
 a considerable degree of cold is       
experienced if a drop be placed on the  
hand and allowed to evaporate4          
,benzene1 which is only a compound of   
carbon and hydrogen1 was first          
discovered by ,faraday in #ahbe2 it is  

now obtained in large quantities  from  
coal-tar1 not so much for use as        
benzene2 is for its conversion1 in  the 
first place1 by the action of nitric    
acid1 into nitro-benzole1 a  liquid     
having an odour like the oil of bitter  
almonds1 and which is much  used by     
perfumers under the name of essence de  
mirbane2 and1 in the  second place1 for 
the production from this nitro-benzole  
of the far-famed  aniline4 ,after the   
distillation of benzene from the crude  
coal-naphtha  is completed1 the chief   
impurities in the residue are charred   
and  deposited by the action of strong  
sulphuric acid4 ,by further distillation
  a lighter oil is given off1 often     
known as artificial turpentine oil1     
which is used as a solvent for varnishes
 and lackers4 ,this is very  familiar to
 the costermonger fraternity as the oil 
which is burned in the  flaring lamps   
which illuminate the ,new ,cut or the   
,elephant and ,castle on  ,saturday and 
other market nights4    ,by distillation

 of the heavy oils1 carbolic acid and   
commercial  anthracene are produced1 and
 by a treatment of the residue1 a white 
and  crystalline substance known as     
naphthalin 7,c#aj;,h#h7 is finally      
obtained4    ,thus1 by the continued    
operation of the chemical process known 
as  fractional distillation of the      
immediate products of coal-tar1 these   
various series of useful oils are       
prepared4    ,the treatment is much the 
same which has resulted in the          
production of  paraffin oil1 to which we
 have previously referred1 and an       
account of the  production of coal-oils 
would be very far from satisfactory1    
which made  no mention of the production
 of similar commodities by the direct   
distillation of shale4 ,oil-shales1 or  
bituminous shales1 exist in all  parts  
of the world1 and may be regarded as    
mineral matter largely  impregnated by  
the products of decaying vegetation4    
,they therefore  greatly resemble some  
coals1 and really only differ therefrom 

in degree1  in the quantity of vegetable
 matter which they contain4 ,into the   
subject  of the various native          
petroleums which have been found--for   
these  rock-oils are better known as    
petroleums--in ,south ,america1 in      
,burmah  7,rangoon ,oil71 at ,baku1 and 
the shores of the ,caspian1 or in the   
,united  ,states of ,america1 we need   
not enter1 except to note that in all   
probability the action of heat on       
underground bituminous strata of        
enormous extent has been the cause of   
their production1 just as on a  smaller 
scale the action of artificial heat has 
forced the reluctant  shale to give up  
its own burden of mineral oil4 ,however1
 previous to  #ahdg1 although native    
mineral oil had been for some years a   
recognised  article of commerce1 the    
causes which gave rise to the oil-wells1
 and the  source1 probably a deep-seated
 one1 of the supply of oil1 does not    
appear  to have been well known1 or at  
least was not enquired after4 ,but in   

that  year ,mr ,young1 a chemist at     
,manchester1 discovered that by         
distilling  some petroleum1 which he    
obtained from a spring at ,riddings in  
,derbyshire1 he was able to procure a   
light oil1 which he used for burning  in
 lamps1 whilst the heavier product which
 he also obtained proved a most  useful 
lubricant for machinery4 ,this naturally
 distilled oil was soon  found to be    
similar to that oil which was noticed   
dripping from the roof  of a coal-mine4 
,judging that the coal1 being under the 
influence of heat1  was the cause of the
 production of the oil1 ,mr ,young      
tested this  conclusion by distilling   
the coal itself4 ,success attended his  
endeavour  thus to procure the oil1 and 
indelibly ,young stamped his name upon  
the  roll of famous men1 whose          
industrial inventions have done so much 
towards  the accomplishment of the      
marvellous progress of the present      
century4  ,from the distillation he     
obtained the well-known ,young's        

,paraffin ,oil1  and the astonishing    
developments of the process which have  
taken place  since he obtained his      
patent in #ahej1 for the manufacture of 
oils and  solid paraffin1 must have been
 a source of great satisfaction to him  
before his death1 which occurred in     
#ahhc4    ,cannel coal1 ,boghead or     
,bathgate coal1 and bituminous shales of
 various  qualities1 have all been      
requisitioned for the production of     
oils1 and  from these various sources   
the crude naphthas1 which bear a variety
 of  names according to some peculiarity
 in their origin1 or place of           
occurrence1 are obtained4 ,boghead coal1
 also known as ,torebanehill  mineral1  
gives ,boghead naphtha1 while the crude 
naphtha obtained from  shales is often  
quoted as shale-oil4 ,in chemical       
composition these  naphthas are closely 
related to one another1 and by          
fractional  distillation of them similar
 series of products are obtained as     
those we  have already seen as obtained 

from the crude coal-naphtha of coal-tar4
    ,in the direct distillation of      
cannel-coal for the production of       
paraffin1  it is necessary that the     
perpendicular tubes or retorts into     
which the  coal is placed be heated only
 to a certain temperature1 which is     
considerably lower than that applied    
when the object is the production of    
coal-gas4 ,by this means nearly all the 
volatile matters pass over in the  form 
of condensible vapours1 and the crude   
oils are at once formed1 from  whence   
are obtained at different temperatures  
various volatile ethers1  benzene1 and  
artificial turpentine oil or petroleum  
spirit4 ,after these1  the well-known   
safety-burning paraffin oil follows1 but
 it is essential  that the previous     
three volatile products be completely   
cleared first1  since1 mixed with air1  
they form highly dangerous explosives4  
,to the fact  that the operation is     
carried on in the manufactories with    
great care and  accuracy can only be    

attributed the comparative rareness of  
explosions of  the oil used in          
households4    ,after paraffin1 the     
heavy lubricating oils are next given   
off1 still  increasing the temperature1 
and1 the residue being in turn subjected
 to a  very low temperature1 the white  
solid substance known as paraffin1 so   
much used for making candles1 is the    
result4 ,by a different treatment of    
the same residue is produced that       
wonderful salve for tender skins1 cuts1 
and burns1 known popularly as vaseline4 
,probably no such  widely-advertised    
remedial substance has so deserved its  
success as this  universally-used waste 
product of petroleum4    ,we have       
noticed the fact that in order to       
procure safety-burning oils1 it  is     
absolutely necessary that the more      
volatile portions be completely         
distilled over first4 ,by ,act of       
,parliament a test is applied to all    
oils  which are intended for purposes of
 illumination1 and the test used        

consists of what is known as the        
flashing-point4 ,many of the more       
volatile ethers1 which are highly       
inflammable1 are given off even at      
ordinary temperatures1 and the          
application of a light to the oil will  
cause the volatile portion to flash1 as 
it is called4 ,a safety-burning  oil1   
according to the ,act1 must not flash   
under #ajj ,fahrenheit open  test1 and  
all those portions which flash at a less
 temperature must be  volatilised off   
before the residue can be deemed a safe 
oil4 ,it seems  probable that the       
flashing-point will sooner or later be  
raised4    ,one instance may be cited to
 show how necessary it is that the      
native  mineral oils which have been    
discovered should have this effectual   
test  applied to them4    ,when the     
oil-wells were first discovered in      
,america1 the oil was obtained  simply  
by a process of boring1 and the fountain
 of oil which was bored  into at times  
was so prolific1 that it rushed out with

 a force which  carried all obstacles   
before it1 and defied all control4 ,in  
one instance  a column of oil shot into 
the air to a height of forty feet1 and  
defied  all attempts to keep it under4  
,in order to prevent further accident1  
all  lights in the immediate            
neighbourhood were extinguished1 the    
nearest  remaining being at a distance  
of four hundred feet4 ,but in this crude
  naphtha there was1 as usual1 a        
quantity of volatile spirit which was   
being given off even at the temperature 
of the surrounding atmosphere4  ,this   
soon became ignited1 and with an        
explosion the column of oil was         
suddenly converted into a roaring column
 of fire4 ,the owner of the  property   
was thrown a distance of twenty feet by 
the explosion1 and soon  afterwards died
 from the burns which he had received   
from it4 ,such an  accident could not   
now1 however1 happen4 ,the tapping1     
stopping1 and  regulating of gushing    
wells can now be more effectually dealt 

with1 and  in the process of refining2  
the most inflammable portions are       
separated1  with a result that1 as no   
oil is used in the country which flashes
 under  #ajj ,f4 open test1 and as our  
normal temperature is considerably less 
than this1 there is little to be feared 
in the way of explosion if the  ,act be 
complied with4    ,when the results of  
,mr ,young's labours became publicly    
known1 a number of  companies were      
started with the object of working on   
the lines laid down  in his patent1 and 
these not only in ,great ,britain but   
also in the ,united  ,states1 whither   
quantities of cannel coal were shipped  
from ,england and  other parts to feed  
the retorts4 ,in #ahfj1 according to the
 statistics  furnished1 some seventy    
factories were established in the       
,united ,states  alone with the object  
of extracting oil from coal and other   
mineral  sources1 such as bituminous    
shale1 etc4 ,when ,young's patent       
finally  expired1 a still greater       

impetus was given to its production1 and
 the  manufacture would probably have   
continued to develop were it not that   
attention had1 two years previously1    
been forcibly turned to those           
discoveries of great stores of natural  
oil in existence beneath a              
comparatively thin crust of earth1 and  
which1 when bored into1 spouted  out to 
tremendous heights4    ,the discovery of
 these oil-fountains checked for a time 
the development  of the industry1 but   
with the great production there has     
apparently been  a greatly increased    
demand for it1 and the ,british industry
 once again  appears to thrive1 until   
even bituminous shales have been brought
 under  requisition for their           
contribution to the national wealth4    
,were it not for the nuisance and       
difficulty experienced in the proper    
cleaning and trimming of lamps1 there   
seems no other reason why mineral  oil  
should not in turn have superseded the  
use of gas1 even as gas had1  years     

before1 superseded the expensive animal 
and vegetable oils which  had formerly  
been in use4    ,although this great    
development in the use of mineral oils  
has taken  place only within the last   
thirty years1 it must not be thought    
that  their use is altogether of modern 
invention4 ,that they were not          
altogether unknown in the fifth century 
before ,christ is a matter of           
certainty1 and at the time when the     
,persian ,empire was at the zenith of   
its glory1 the fires in the temples of  
the fire-worshippers were  undoubtedly  
kept fed by the natural petroleum which 
the districts around  afforded4 ,it is  
thought by some that the legend which   
speaks of the fire  which came down from
 heaven1 and which lit the altars of the
  ,zoroastrians1 may have had its origin
 in the discovery of a hitherto  unknown
 petroleum spring4 ,more recently1 the  
remarks of ,marco ,polo in his  account 
of his travels in ,a4,d4 #abfj and      
following years1 are particularly       

interesting as showing that1 even then1 
the use of mineral oil for  various     
purposes was not altogether unknown4 ,he
 says that on the north of  ,armenia the
 ,greater is ,zorzania1 in the confines 
of which a fountain is  found1 from     
which a liquor like oil flows1 and      
though unprofitable for  the seasoning  
of meat1 yet is very fit for the        
supplying of lamps1 and to  anoint other
 things2 and this natural oil flows     
constantly1 and that in  plenty enough  
to lade camels4    ,from this we can    
infer that the nature of the oil was    
entirely unknown1  for it was a liquor  
like oil1 and was also1 strange to say1 
unprofitable for the seasoning of meat6 
,in another place in ,armenia1  ,marco  
,polo states that there was a fountain  
whence rises oil in such  abundance that
 a hundred ships might be at once loaded
 with it4 ,it is not  good for eating1  
but very fit for fuel1 for anointing the
 camels in  maladies of the skin1 and   
for other purposes2 for which reason    

people  come from a great distance for  
it1 and nothing else is burned in all   
this  country4    ,the remedial effects 
of the oil1 when used as an ointment1   
were thus  early recognised1 and the    
far-famed vaseline of the present day   
may be  regarded as the lineal          
descendent1 so to speak1 of the crude   
medicinal  agent to which ,marco ,polo  
refers4    ,the term asphalt has been   
applied to so many and various mixtures1
 that  one scarcely associates it with  
natural mineral pitch which is found in 
some parts of the world4 ,from time     
immemorial this compact1 bituminous1    
resinous mineral has been discovered in 
masses on the shores of the ,dead  ,sea1
 which has in consequence received the  
well-known title of ,lake  ,asphaltites4
 ,like the naphthas and petroleums which
 have been noticed1  this has had its   
origin in the decomposition of vegetable
 matter1 and  appears to be thrown up in
 a liquid form by the volcanic energies 
which1  are still believed to be active 

in the centre of the lake1 and which may
  be existent beneath a stratum1 or bed1
 of oil-producing bitumen4    ,in       
connection with the formation of this   
substance1 the remarks of ,sir  ,charles
 ,lyell1 the great geologist1 may well  
be quoted1 as showing the               
transformation of vegetable matter into 
petroleum1 and afterwards into          
solid-looking asphalt4 ,at ,trinidad is 
a lake of bitumen which is a mile  and a
 half in circumference4 ,the ,orinoco   
has for ages been rolling down  great   
quantities of woody and vegetable bodies
 into the surrounding sea1  where1 by   
the influence of currents and eddies1   
they may be arrested1 and  accumulated  
in particular places4 ,the frequent     
occurrence of earthquakes  and other    
indications of volcanic action in those 
parts1 lend countenance  to the opinion 
that these vegetable substances may have
 undergone1 by the  agency of           
subterranean fire1 those transformations
 or chemical changes  which produce     

petroleum2 and this may1 by the same    
causes1 be forced up  to the surface1   
where1 by exposure to the air1 it       
becomes inspissated1  and forms those   
different varieties of earth-pitch or   
asphaltum so  abundant in the island4   
,it is interesting to note also that it 
was obtained1 at an ancient  period1    
from the oil-fountains of ,is1 and that 
it was put to considerable  use in the  
embalming of the bodies of the          
,egyptians4 ,it appears1 too1 to  have  
been employed in the construction of the
 walls of ,babylon1 and thus  from very 
early times these wonderful products and
 results of decayed  vegetation have    
been brought into use for the service of
 man4    ,aniline has been previously   
referred 7p4 #ace7 to as having been    
prepared  from nitro-benzole1 or essence
 de mirbane1 and its preparation1 by    
treating this substance with            
iron-filings and acetic acid1 was one of
 the  early triumphs of the chemists who
 undertook the search after the unknown 

contained in gas-tar4 ,it had previously
 been obtained from oils distilled  from
 bones4 ,the importance of the substance
 lies in the fact that1 by the  action  
of various chemical reagents1 a series  
of colouring matters of  very great     
richness are formed1 and these are the  
well-known aniline  dyes4    ,as early  
as #ahcf1 it was discovered that        
aniline1 when heated with  chloride of  
lime1 acquired a beautiful blue tint4   
,this discovery led to  no immediate    
practical result1 and it was not until  
twenty-one years  after that a further  
discovery was made1 which may indeed be 
said to have  achieved a world-wide     
reputation4 ,it was found that1 by      
adding bichromate  of potash to a       
solution of aniline and sulphuric acid1 
a powder was  obtained from which the   
dye was afterwards extracted1 which is  
known as  mauve4 ,since that time dyes  
in all shades and colours have been     
obtained from the same source4 ,magenta 
was the next dye to make its            

appearance1 and in the fickle history of
 fashion1 probably no colours  have had 
such extraordinary runs of popularity as
 those of mauve and  magenta4 ,every    
conceivable colour was obtained in due  
course from the  same source1 and       
chemists began to suspect that1 in the  
course of time1  the colouring matter of
 dyer's madder1 which was known as      
alizarin1  would also be obtained       
therefrom4 ,hitherto this had been      
obtained from  the root of the          
madder-plant1 but by dint of careful and
 well-reasoned  research1 it was        
obtained by ,dr ,groebe1 from a solid   
crystalline coal-tar  product1 known as 
anthracene1 7,c#ab;,h#ad74 ,this        
artificial alizarin  yields colours     
which are purer than those of natural   
madder1 and being  derived from what was
 originally regarded as a waste product1
 its cost of  production is considerably
 cheaper4    ,we have endeavoured thus  
far to deal with 7#a7 gas1 and 7#b7 tar1
 the two  principal products in the     

distillation of coal4 ,we have yet to   
say a few  words concerning the useful  
ammoniacal liquor1 and the final residue
 in  the retorts1 i4e41 coke4    ,the   
ammoniacal liquor which has been passing
 over during distillation of  the coal1 
and which has been collecting in the    
hydraulic main and in  other parts of   
the gas-making apparatus1 is set aside  
to be treated to a  variety of chemical 
reactions1 in order to wrench from it   
its useful  constituents4 ,amongst      
these1 of course1 ammonia stands in the 
first  rank1 the others being           
comparatively unimportant4 ,in order to 
obtain  this1 the liquor is first of all
 neutralised by being treated with a    
quantity of acid1 which converts the    
principal constituent of the liquor1    
viz41 carbonate of ammonia 7smelling    
salts71 into either sulphate of         
ammonia1 or chloride of ammonia1        
familiarly known as sal-ammoniac1       
according as sulphuric acid or          
hydrochloric acid is the acid used4     

,thus  carbonate of ammonia with        
sulphuric acid will give sulphate of    
ammonia1  but carbonate of ammonia with 
hydrochloric acid will give sal-ammoniac
  7chloride of ammonia74 ,by a further  
treatment of these with lime1 or1 as  it
 is chemically known1 oxide of calcium1 
ammonia is set free1 whilst  chloride of
 lime 7the well-known disinfectant71 or 
sulphate of lime  7gypsum1 or plaster of
 ,paris 71 is the result4    ,thus3     
,sulphate of ammonia  lime  plaster of  
,paris  ammonia4    or1    ,sal-ammoniac
  lime  chloride of lime  ammonia4      
,ammonia itself is a most powerful gas1 
and acts rapidly upon the eyes4 ,it  has
 a stimulating effect upon the nerves4  
,it is not a chemical element1  being   
composed of three parts of hydrogen by  
weight to one of nitrogen1  both of     
which elements alone are very harmless1 
and1 the latter indeed1  very necessary 
to human life4 ,ammonia is fatal to     
life1 producing great  irritation of the
 lungs4    ,it has also been called     

hartshorn1 being obtained by destructive
  distillation of horn and bone4 ,the   
name ammonia is said to have been       
derived from the fact that it was first 
obtained by the ,arabs near the  temple 
of ,jupiter ,ammon1 in ,lybia1 ,north   
,africa1 from the excrement of  camels1 
in the form of sal-ammoniac4 ,there are 
always traces of it in the  atmosphere1 
especially in the vicinity of large     
towns and manufactories  where large    
quantities of coal are burned4    ,coke1
 if properly prepared1 should consist of
 pure carbon4 ,good coal  should yield  
as much as #hj per cent4 of coke1 but   
owing to the  unsatisfactory manner of  
its production1 this proportion is      
seldom  yielded1 whilst the coke which  
is familiar to householders1 being the  
residue left in the retorts after       
gas-making1 usually contains so large a 
proportion of sulphur as to make its    
combustion almost offensive4 ,no  doubt 
the result of its unsatisfactory        
preparation has been that it has  failed

 to make its way into households as it  
should have done1 but there  is also    
another objection to its use1 namely1   
the fact that1 owing to the  quantity of
 oxygen required in its combustion1 it  
gives rise to feelings  of suffocation  
where insufficient ventilation of the   
room is provided4    ,large quantities  
of coke are1 however1 consumed in the   
feeding of furnace  fires1 and in the   
heating of boilers of locomotives1 as   
well as in  metallurgical operations2   
and in order to supply the demand1 large
  quantities of coal are coked1 a       
process by which the volatile products  
are completely combusted1 pure coke     
remaining behind4 ,this process is      
therefore the direct opposite to that of
 distillation1 by which the  volatile   
products are carefully collected and    
re-distilled4    ,the sulphurous        
impurities which are always present in  
the coal1 and which  are1 to a certain  
extent1 retained in coke made at the    
gas-works1  themselves have a value1    

which in these utilitarian days is not  
long  likely to escape the attention of 
capitalists4 ,in coal1 bands of bright  
shining iron pyrites are constantly     
seen1 even in the homely scuttle1 and   
when coal is washed1 as it is in some   
places1 the removal of the pyrites      
increases the value of the coal1 whilst 
it has a value of its own4    ,the      
conversion of the sulphur which escapes 
from our chimneys into  sulphuretted    
hydrogen1 and then into sulphuric acid1 
or oil of vitriol1  has already been    
referred to1 and we can only hope that  
in these days  when every available     
source of wealth is being looked up1 and
 when there  threatens to remain nothing
 which shall in the future be known as  
waste1 that the atmosphere will be      
spared being longer the receptacle  for 
the unowned and execrated brimstone of  
millions of fires and  furnaces4        
,,chapter ,,vii4    ,,the ,,coal        
,,supplies ,,of ,,the ,,world4      ,as 
compared with some of the ,american     

coal-fields1 those of ,britain are  but 
small1 both in extent and thickness4    
,they can be regarded as falling        
naturally into three principal areas4   
,the northern coal-field1 including     
those of ,fife1 ,stirling1 and ,ayr     
in  ,scotland2 ,cumberland1 ,newcastle1 
and ,durham in ,england2 ,tyrone      in
 ,ireland4      ,the middle coal-field1 
all geologically in union1 including    
those of      ,yorkshire1 ,derbyshire1  
,shropshire1 ,staffordshire1 ,flint1 and
      ,denbigh4      ,the southern      
coal-field1 including ,south ,wales1    
,forest of ,dean1      ,bristol1 ,dover1
 with an offshoot at ,leinster1 c41 and 
,millstreet1      ,cork4    ,thus it    
will be seen that while ,england and    
,scotland are1 in comparison  with their
 extent of surface1 bountifully supplied
 with coal-areas1 in  the sister island 
of ,ireland coal-producing areas are    
almost absent4 ,the  isolated beds in   
,cork and ,tipperary1 in ,tyrone and    
,antrim1 are but the  remnants left of  

what were formerly beds of coal         
extending the whole  breadth and length 
of ,ireland4 ,such beds as there remain 
undoubtedly  belong to the base of the  
coal-measures1 and observations all go  
to show  that the surface suffered such 
extreme denudation subsequent to the    
growth of the coal-forests1 that the    
wealth which once lay there1 has  been  
swept away from the surface which       
formerly boasted of it4    ,on the      
continent of ,europe the coal-fields1   
though not occupying so large  a        
proportion of the surface of the country
 as in ,england1 are very far  from     
being slight or to be disregarded4 ,the 
extent of forest-lands still  remaining 
in ,germany and ,austria are sufficing  
for the immediate needs of  the         
districts where some of the best seams  
occur4 ,it is only where there  is a    
dearth of handy fuel1 ready to be had1  
perhaps1 by the simple  felling of a few
 trees1 that man commences to dig into  
the earth for his  fuel4 ,but although  

on the continent not yet occupying so   
prominent a  position in public         
estimation as do coal-fields in ,great  
,britain1 those  of the former have one 
conspicuous characteristic1 viz41 the   
great  thickness of some of the         
individual seams4    ,in the coal-field 
of ,midlothian the seams of coal vary   
from #b feet to #e  feet in thickness4  
,one of them is known as the great seam1
 and in spite  of its name attains a    
thickness only of from #h to #aj feet   
thick4 ,there  are altogether about     
thirty seams of coal4 ,when1 however1 we
 pass to the  continent1 we find many   
instances1 such as that of the          
coal-field of  ,central ,france1 in     
which the seams attain vast thicknesses1
 many of them  actually reaching #dj and
 #fj feet1 and sometimes even #hj feet4 
,one of the  seams in the district of   
,st4 ,etienne varies from #cj to #gj    
feet thick1  whilst the fifteen to      
eighteen workable seams give a thickness
 of #aab  feet1 although the total area 

of the field is not great4 ,again1 in   
the  remarkable basin of the            
,sane-et-,loire1 although there are but 
ten beds  of coal1 two of them run from 
#cj to #fj feet each1 whilst at ,creusot
 the  main seam actually runs locally to
 a thickness varying between #dj and    
#acj  feet4    ,the ,belgian coal-field 
stretches in the form of a narrow strip 
from #g to  #i miles wide by about #ajj 
miles long1 and is divided into three   
principal  basins4 ,in that stretching  
from ,lige to ,verviers there are       
eighty-three  seams of coal1 none of    
which are less than #c feet thick4 ,in  
the basin of  the ,sambre1 stretching   
from ,namur to ,charleroi1 there are    
seventy-three  seams which are workable1
 whilst in that between ,mons and       
,thulin there  are no less than one     
hundred and fifty-seven seams4 ,the     
measures here are  so folded in zigzag  
fashion1 that in boring in the          
neighbourhood of ,mons  to a depth of   
#cej yards vertical1 a single seam was  

passed through no  less than six times4 
,germany1 on the west side of the       
,rhine1 is exceptionally fortunate in   
the  possession of the famous           
,pfalz-,saarbrcken coal-field1 measuring
 about #fj  miles long by #bj miles     
wide1 and covering about #age square    
miles4 ,much of  the coal which lies    
deep in these coal-measures will always 
remain  unattainable1 owing to the      
enormous thickness of the strata1 but a 
careful computation made of the coal    
which can be worked1 gives an  estimate 
of no less than #bgej millions of tons4 
,there is a grand total of  two hundred 
and forty-four seams1 although about    
half of them are  unworkable4    ,beside
 other smaller coal-producing areas in  
,germany1 the coal-fields of  ,silesia  
in the southeastern corner of ,prussia  
are a possession unrivalled  both on    
account of their extent and thickness4  
,it is stated that there  exist #ccc    
feet of coal1 all the seams of which    
exceed #b-a_/b feet1 and  that in the   

aggregate there is here1 within a       
workable depth1 the  scarcely           
conceivable quantity of #ej1jjj million 
tons of coal4    ,the coal-field of     
,upper ,silesia1 occupying an area about
 #bj miles long by  #ae miles broad1 is 
estimated to contain some #aj1jjj feet  
of strata1 with  #ccc feet of good coal4
 ,this is about three times the         
thickness contained  in the ,south      
,wales coal-field1 in a similar         
thickness of coal-measures4  ,there are 
single seams up to #fj feet thick1 but  
much of the coal is  covered by more    
recent rocks of ,new ,red and           
,cretaceous age4 ,in ,lower  ,silesia   
there are numerous seams #c-a_/b feet to
 #e feet thick1 but owing to  their     
liability to change in character even in
 the same seam1 their value  is inferior
 to the coals of ,upper ,silesia4       
,when ,british supplies are at length   
exhausted1 we may anticipate that  some 
of the earliest coals to be imported1   
should coal then be needed1  will reach 

,britain from the upper waters of the   
,oder4    ,the coal-field of ,westphalia
 has lately come into prominence in     
connection with the search which has    
been made for coal in ,kent and         
,surrey1 the strata which are mined at  
,dortmund being thought to be           
continuous from the ,bristol coal-field4
 ,borings have been made through  the   
chalk of the district north of the      
,westphalian coal-field1 and these  have
 shown the existence of further         
coal-measures4 ,the coal-field extends  
between ,essen and ,dortmund a distance 
of #cj miles east and west1 and         
exhibits a series of about one hundred  
and thirty seams1 with an  aggregate of 
#cjj feet of coal4    ,it is estimated  
that this coal-field alone contains no  
less than #ci1bjj  millions of tons of  
coal4    ,russia possesses supplies of  
coal whose influence has scarcely yet   
been  felt1 owing to the sparseness of  
the population and the abundance of     
forest4 ,carboniferous rocks abut       

against the flanks of the ,ural         
,mountains1 along the sides of which    
they extend for a length of about a     
thousand miles1 with                    
inter-stratifications of coal4 ,their   
actual contents  have not yet been      
gauged1 but there is every reason to    
believe that those  coal-beds which have
 been seen are but samples of many      
others which will1  when properly       
worked1 satisfy the needs of a much     
larger population than  the country now 
possesses4    ,like the lower coals of  
,scotland1 the ,russian coals are found 
in the  carboniferous limestone4 ,this  
may also be said of the coal-fields in  
the  governments of ,tula and ,kaluga1  
and of those important coal-bearing     
strata near the river ,donetz1          
stretching to the northern corner of the
  ,sea of ,azov4 ,in the last-named1 the
 seams are spread over an area of       
#aa1jjj square miles1 in which there are
 forty-four workable seams  containing  
#aad feet of coal4 ,the thickest of     

known ,russian coals occur at           
,lithwinsk1 where three seams are       
worked1 each measuring #cj feet to #dj  
feet thick4    ,an extension of the     
,upper ,silesian coal-field appears in  
,russian ,poland4  ,this is of upper    
,carboniferous age1 and contains an     
aggregate of #fj feet  of coal4    ,at  
,ostrau1 in ,upper ,silesia 7,austria71 
there is a remarkable coal-field4  ,of  
its #cgj seams there are no less than   
#aag workable ones1 and these  contain  
#cej feet of coal4 ,the coals here are  
very full of gas1 which even  percolates
 to the cellars of houses in the town4  
,a bore hole which was  sunk in #aheb to
 a depth of #aej feet1 gave off a stream
 of gas1 which  ignited1 and burnt for  
many years with a flame some feet long4 
,the ,zwickau coal-field in ,saxony is  
one of the most important in ,europe4   
,it contains a remarkable seam of coal1 
known as ,russokohle or soot-coal1      
running at times #be feet thick4 ,it was
 separated by ,geinitz and others  into 

four zones1 according to their vegetable
 contents1 viz43--    #a4 ,zone of      
,ferns4    #b4 ,zone of ,annularia and  
,calamites4    #c4 ,zone of ,sigillaria4
    #d4 ,zone of ,sagenaria 7in         
,silesia71 equivalent to the            
culm-measures of     ,devonshire4       
,coals belonging to other than true     
,carboniferous age are found in ,europe 
at ,steyerdorf on the ,danube1 where    
there are a few seams of good coal in   
strata of ,liassic age1 and in ,hungary 
and ,styria1 where there are  tertiary  
coals which approach closely to those of
 true ,carboniferous age  in composition
 and quality4    ,in ,spain there are a 
few small scattered basins4 ,coal is    
found overlying  the carboniferous      
limestone of the ,cantabrian chain1 the 
seams being from  #e feet to #h feet    
thick4 ,in the ,satero valley1 near     
,sotillo1 is a single  seam measuring   
from #fj feet to #ajj feet thick4 ,coal 
of ,neocomian age  appears at           
,montalban4    ,when we look outside the

 continent of ,europe1 we may well be   
astonished  at the bountiful manner in  
which nature has laid out beds of coal  
upon  these ancient surfaces of our     
globe4    ,professor ,rogers estimated  
that1 in the ,united ,states of         
,america1 the  coal-fields occupy an    
area of no less than #aif1hej square    
miles4    ,here1 again1 it is extremely 
probable that the coal-fields which     
remain1  in spite of their gigantic     
existing areas1 are but the remnants of 
one  tremendous area of deposit1 bounded
 only on the east by the ,atlantic1 and 
on the west by a line running from the  
great lakes to the frontiers of         
,mexico4 ,the whole area has been       
subjected to forces which have produced 
foldings and flexures in the            
,carboniferous strata after deposition4 
,these  undulations are greatest near   
the ,alleghanies1 and between these     
mountains and the ,atlantic1 whilst the 
flexures gradually dying out  westward1 
cause the strata there to remain fairly 

horizontal4 ,in the  troughs of the     
foldings thus formed the coal-measures  
rest1 those  portions which had been    
thrown up as anticlines having suffered 
loss by  denudation4 ,where the foldings
 are greatest there the coal has been   
naturally most altered2 bituminous and  
caking-coals are characteristic of  the 
broad flat areas west of the mountains1 
whilst1 where the contortions  are      
greatest1 the coal becomes a pure       
anthracite4    ,it must not be thought  
that in this huge area the coal is all  
uniformly  good4 ,it varies greatly in  
quality1 and in some districts it occurs
 in  such thin seams as to be worthless1
 except as fuel for consumption by the  
actual coal-getters4 ,there are1 too1   
areas of many square miles in  extent1  
where there are now no coals at all1 the
 formation having been  denuded right   
down to the palaeozoic back-bone of the 
country4    ,amongst the actual         
coal-fields1 that of ,pennsylvania      
stands  pre-eminent4 ,the anthracite    

here is in inexhaustible quantity1 its  
output  exceeding that of the ordinary  
bituminous coal4 ,the great field of    
which  this is a portion1 extends in an 
unbroken length for #hge miles ,n4,e4   
and  ,s4,w41 and includes the basins of 
,ohio1 ,maryland1 ,virginia1 ,kentucky1 
and  ,tennessee4 ,the workable seams of 
anthracite about ,pottsville measure in 
the aggregate from #gj to #bjg feet4    
,some of the lower seams individually   
attain an exceptional thickness1 that at
 ,lehigh ,summit mine containing a      
seam1 or rather a bed1 of #cj feet of   
good coal4    ,a remarkable seam of coal
 has given the town of ,pittsburg its   
name4 ,this  is #h feet thick at its    
outcrop near the town1 and although its 
thickness  varies considerably1         
,professor ,rogers estimates that the   
sheet of coal  measures superficially   
about #ad1jjj square miles4 ,what a     
forest there  must have existed to      
produce so widespread a bed6 ,even as it
 is1 it has  at a former epoch suffered 

great denudation1 if certain detached   
basins  should be considered as         
indicating its former extent4    ,the   
principal seam in the anthracite        
district of central ,pennsylvania1      
which extends for about #fej miles along
 the left bank of the ,susquehanna1  is 
known as the ,mammoth vein1 and is      
#bi-a_/b feet thick at ,wilkesbarre1    
whilst at other places it attains to1   
and even exceeds1 #fj feet4    ,on the  
west of the chain of mountains the      
foldings become gentler1 and  the coal  
assumes an almost horizontal position4  
,in passing through ,ohio  we find a    
saddle-back ridge or anticline of more  
ancient strata than the  coal1 and in   
consequence of this1 we have a physical 
boundary placed upon  the coal-fields on
 each side4    ,passing across this     
older ridge of denuded ,silurian and    
other rocks1 we  reach the famous       
,illinois and ,indiana coal-field1 whose
  coal-measures lie in a broad trough1  
bounded on the west by the uprising  of 

the carboniferous limestone of the upper
 ,mississippi4 ,this limestone          
formation appears here for the first    
time1 having been absent on the  eastern
 side of the ,ohio anticline4 ,the area 
of the coal-field is  estimated at      
#ea1jjj square miles4    ,in connection 
with the coal-fields of the ,united     
,states1 it is  interesting to notice   
that a wide area in ,texas1 estimated at
 #cjjj square  miles1 produces a large  
amount of coal annually from strata of  
the  ,liassic age4 ,another important   
area of production in eastern ,virginia 
contains coal referable to the ,jurassic
 age1 and is similar in fossil  contents
 to the ,jurassic of ,whitby and ,brora4
 ,the main seam in eastern  ,virginia   
boasts a thickness of from #cj to #dj   
feet of good coal4    ,very serviceable 
lignites of ,cretaceous age are found on
 the ,pacific  slope1 to which age those
 of ,vancouver's ,island and            
,saskatchewan ,river  are referable4    
,other coal-fields of less importance   

are found between ,lakes ,huron and     
,erie1 where the measures cover an area 
of #ejjj square miles1 and also in      
,rhode ,island4    ,in ,british ,north  
,america we find extensive deposits of  
valuable  coal-measures4 ,large         
developments occur in ,new ,brunswick   
and ,nova ,scotia4  ,at ,south ,joggins 
there is a thickness of #ad1gej feet of 
strata1 in which  are found seventy-six 
coal-seams of #de feet in total         
thickness4 ,at ,picton  there are six   
seams with a total of #hj feet of coal4 
,in the lower  carboniferous group is   
found the peculiar asphaltic coal of the
 ,albert  mine in ,new ,brunswick4      
,extensive deposits of lignite are met  
with both in  the ,dominion and in the  
,united ,states1 whilst true            
coal-measures flank  both sides of the  
,rocky ,mountains4 ,coal-seams are often
 encountered in  the ,arctic            
archipelago4    ,the principal areas of 
deposit in ,south ,america are in       
,brazil1 ,uruguay1  and ,peru4 ,the     

largest is the ,candiota coal-field1 in 
,brazil1 where  sections in the valley  
of the ,candiota ,river show five good  
seams with a  total of #fe feet of coal4
 ,it is1 however1 worked but little1 the
  principal workings being at ,san      
,jeronimo on the ,jacahahay ,river4     
,in ,peru the true carboniferous        
coal-seams are found on the higher      
ground  of the ,andes1 whilst coal of   
secondary age is found in considerable  
quantities on the rise towards the      
mountains4 ,at ,porton1 east of         
,truxillo1 the same metamorphism which  
has changed the ridge of sandstone  to a
 hard quartzite has also changed the    
ordinary bituminous coal into an        
anthracite1 which is here vertical in   
position4 ,the coals of ,peru usually   
rise to more than #aj1jjj feet above the
 sea1 and they are practically          
inaccessible4    ,cretaceous coals have 
been found at ,lota in ,chili1 and at   
,sandy ,point1  ,straits of ,magellan4  
,turning to ,asia1 we find that coal has

 been worked from time to time at       
,heraclea in ,asia ,minor4 ,lignites are
 met with at ,smyrna and ,lebanon4      
,the coal-fields of ,hindoostan are     
small but numerous1 being found in all  
parts of the peninsula4 ,there is an    
important coal-field at ,raniganj1  near
 the ,hooghly1 #adj miles north of      
,calcutta4 ,it has an area of #ejj      
square miles4 ,in the ,raniganj district
 there are occasional seams #bj feet  to
 #hj feet in thickness1 but the coals   
are of somewhat inferior quality4       
,the best quality amongst ,indian coals 
has come from a small coal-field of     
about #aa square miles in extent1       
situated at ,kurhurbali on the ,east    
,indian ,railway4 ,other coal-fields are
 found at ,jherria and on the ,sone     
,river1 in ,bengal1 and at ,mopani on   
the ,nerbudda4 ,much is expected in     
future from the large coal-field of the 
,wardha and ,chanda districts1 in  the  
,central ,provinces1 the coal of which  
may eventually prove to be of  ,permian 

age4    ,the coal-deposits of ,china are
 undoubtedly of tremendous extent1      
although  from want of exploration it is
 difficult to form any satisfactory     
estimate of them4 ,near ,pekin there are
 beds of coal #ie feet thick1 which     
afford ample provision for the needs of 
the city4 ,in the mountainous  districts
 of western ,china the area over which  
carboniferous strata are  exposed has   
been estimated at #ajj1jjj square miles4
 ,the coal-measures  extend westward to 
the ,mongolian frontier1 where          
coal-seams #cj feet thick  are known to 
lie in horizontal plane for #bjj miles4 
,most of the ,chinese  coal-deposits are
 rendered of small value1 either owing  
to the  mountainous nature of the       
valleys in which they outcrop1 or to    
their  inaccessibility from the sea4    
,japan is not lacking in good supplies  
of  coal4 ,a colliery is worked by the  
government on the island of ,takasima1  
near ,nagasaki1 for the supply of coals 
for the use of the navy4    ,the        

,british possession of ,labuan1 off the 
island of ,borneo1 is rich in a  coal of
 tertiary age1 remarkable for the       
quantity of fossil resin which1  it     
contains4 ,coal is also found in        
,sumatra1 and in the ,malayan           
,archipelago4    ,in ,cape ,colony and  
,natal the coal-bearing ,karoo beds are 
probably of ,new  ,red age4 ,the coal is
 reported to be excellent in quantity4  
,in ,abyssinia lignites are frequently  
met with in the high lands of the       
interior4    ,coal is very extensively  
developed throughout ,australasia4 ,in  
,new ,south  ,wales1 coal-measures occur
 in large detached portions between #bi 
and #ce  ,s4 latitude4 ,the ,newcastle  
district1 at the mouth of the ,hunter   
river1 is  the chief seat of the coal   
trade1 and the seams are here found up  
to #cj  feet thick4 ,coal-bearing strata
 are found at ,bowen ,river1 in         
,queensland1  covering an area of       
#bd1jjj square miles1 whilst important  
mines of  ,cretaceous age are worked at 

,ipswich1 near ,brisbane4 ,in ,new      
,zealand  quantities of lignite1        
described as a hydrous coal1 are found  
and  utilised2 also an anhydrous coal   
which may prove to be either of         
,cretaceous or ,jurassic age4    ,we    
have thus briefly sketched the supplies 
of coal1 so far as they are  known1     
which are to be found in various        
countries4 ,but ,england has of  late   
years been concerned as to the possible 
failure of her home supplies  in the not
 very distant future1 and the effects   
which such failure would  be likely to  
produce on the commercial prosperity of 
the country4    ,great ,britain has long
 been the centre of the universe in the 
supply of  the world's coal1 and as a   
matter of fact1 has been for many years 
raising considerably more than one half 
of the total amount of coal  raised     
throughout the whole world4 ,there is1  
as we have seen1 an  abundance of coal  
elsewhere1 which will1 in the course of 
time1 compete  with her when properly   

worked1 but ,britain seems to have early
 taken the  lead in the production of   
coal1 and to have become the great      
universal  coal distributor4 ,those who 
have misgivings as to what will happen  
when  her coal is exhausted1 receive    
little comfort from the fact that in    
,north  ,america1 in ,prussia1 in ,china
 and elsewhere1 there are tremendous    
supplies of coal as yet untouched1      
although a certain sense of relief is   
experienced when that fact becomes      
generally known4    ,if by the time of  
exhaustion of the home mines ,britain is
 still dependent  upon coal for fuel1   
which1 in this age of electricity1      
scarcely seems  probable1 her trade and 
commerce will feel with tremendous      
effect the  blow which her prestige will
 experience when the first vessel1 laden
 with  foreign coal1 weighs anchor in a 
,british harbour4 ,in the great coal    
lock-out of #ahic1 when1 for the greater
 part of sixteen weeks scarcely a  ton  
of coal reached the surface in some of  

her principal coal-fields1 it  was      
rumoured1 falsely as it appeared1 that a
 collier from ,america had  indeed      
reached those shores1 and the importance
 which attached to the  supposed event  
was shown by the anxious references to  
it in the public  press1 where the truth
 or otherwise of the alarm was actively 
discussed4  ,should such a thing at any 
time actually come to pass1 it will     
indeed be  a retribution to those who   
have for years been squandering their   
inheritance in many a wasteful manner of
 coal-consumption4    ,thirty years ago1
 when so much small coal was wasted and 
wantonly  consumed in order to dispose  
of it in the easiest manner possible at 
the  pitmouths1 and when only the best  
and largest coal was deemed to be of    
any value1 louder and louder did        
scientific men speak in protest against 
this great and increasing prodigality4  
,wild estimates were set on foot        
showing how that1 sooner or later1 there
 would be in ,britain no native  supply 

of coal at all1 and finally a ,royal    
,commission was appointed in  #ahff1 to 
collect evidence and report upon the    
probable time during which  the supplies
 of ,great ,britain would last4    ,this
 ,commission reported in #ahga1 and the 
outcome of it was that a period  of     
twelve hundred and seventy-three years  
was assigned as the period  during which
 the coal would last1 at the            
then-existing rate of  consumption4 ,the
 quantity of workable coal within a     
depth of #djjj feet  was estimated to be
 #ij1bjg millions of tons1 or1 including
 that at  greater depths1 #adf1dhj      
millions of tons4 ,since that date1     
however1 there  has been a steady annual
 increase in the amount of coal         
consumed1 and  subsequent estimates go  
to show that the supplies cannot last   
for more  than #bej years1 or1 taking   
into consideration a possible decrease  
in  consumption1 #cej years4 ,most of   
the coal-mines will1 indeed1 have been  
worked out in less than a hundred years 

hence1 and then1 perhaps1 the           
competition brought about by the demand 
for1 and the scarcity of1 coal  from the
 remaining mines1 will have resulted in 
the dreaded importation  of coal from   
abroad4    ,in referring to the outcome 
of the ,royal ,commission of #ahff1     
although the  ,commissioners fixed so   
comparatively short a period as the     
probable  duration of the coal supplies1
 it is but fair that it should be stated
  that other estimates have been made   
which have materially differed from     
their estimate4 ,whereas one estimate   
more than doubled that of the ,royal    
,commission1 that of ,sir ,william      
,armstrong in #ahfc gave it as #bab     
years1  and ,professor ,jevons1 speaking
 in #ahge concerning ,armstrong's       
estimate1  observed that the annual     
increase in the amount used1 which was  
allowed  for in the estimate1 had so    
greatly itself increased1 that the #bab 
years  must be considerably reduced4    
,one can scarcely thoroughly appreciate 

the enormous quantity of coal that  is  
brought to the surface annually1 and the
 only wonder is that there are  any     
supplies left at all4 ,the ,great       
,pyramid which is said by ,herodotus to 
have been twenty years in building1 and 
which took #ajj1jjj men to build1       
contains #c1cid1cjg cubic yards of      
stone4 ,the coal raised in #ahib would  
make a pyramid which would contain      
#aha1ejj1jjj cubic yards1 at the low    
estimate that one ton could be squeezed 
into one cubic yard4    ,the increase in
 the quantity of coal which has been    
raised in succeeding  years can well be 
seen from the following facts4    ,in   
#ahbj there were raised  in ,great      
,britain about #bj millions of tons4 ,by
  #ahee this amount had increased to    
#fd-a_/b millions4 ,in #ahfe this again 
had  increased to #ih millions1 whilst  
twenty years after1 viz41 in #ahhe1 this
  had increased to no less than #aei    
millions1 such were the giant strides   
which the increase in consumption made4 

,in the return for #ahib1 this amount   
had farther increased to #aha-a_/b      
millions of tons1 an advance in eight   
years of a quantity more than equal  to 
the total raised in #ahbj1 and in #ahid 
the total reached  #aii-a_/b millions2  
this was produced by #gie1bdj persons1  
employed in and  about the mines4       
,,chapter ,,viii4    ,,the ,,coal-,,tar 
,,colours4      ,in a former chapter    
some slight reference has been made to  
those  bye-products of coal-tar which   
have proved so valuable in the          
production  of the aniline dyes4 ,it is 
thought that the subject is of so       
interesting  a nature as to deserve more
 notice than it was possible to bestow  
upon it  in that place4 ,with abstruse  
chemical formulae and complex chemical  
equations it is proposed to have as     
little as possible to do1 but even  the 
most unscientific treatment of the      
subject must occasionally  necessitate a
 scientific method of elucidation4      
,the dyeing industry has been radically 

changed during the last half  century by
 the introduction of what are known as  
the artificial dyes1  whilst the natural
 colouring matters which had previously 
been the sole  basis of the industry1   
and which had been obtained by very     
simple  chemical methods from some of   
the constituents of the animal kingdom1 
or  which were found in a natural state 
in the vegetable kingdom1 have very     
largely given place to those which have 
been obtained from coal-tar1 a  product 
of the mineralised vegetation of the    
carboniferous age4    ,the development  
and discovery of the aniline colouring  
matters were not1  of course1 possible  
until after the extensive adoption of   
house-gas for illuminating purposes1 and
 even then it was many years  before the
 waste products from the gas-works came 
to have an appreciable  value of their  
own4 ,this1 however1 came with the      
increased utilitarianism  of the        
commerce of the present century1 but    
although aniline was first  discovered  

in #ahbf by ,unverdorben1 in the        
materials produced by the dry           
distillation of indigo 7,portuguese1    
anil1 indigo71 it was not until  thirty 
years afterwards1 namely1 in #ahef1 that
 the discovery of the  method of        
manufacture of the first aniline dye1   
mauveine1 was announced1  the discovery 
being due to the persistent efforts of  
,perkin1 to whom1  together with other  
chemists working in the same field1 is  
due the great  advance which has been   
made in the chemical knowledge of the   
carbon1  hydrogen1 and oxygen compounds4
 ,scientists appeared to work along two 
planes2 there were those who discovered 
certain chemical compounds in the       
resulting products of reactions in the  
treatment of existing  vegetation1 and  
there were those who1 studying the      
wonderful constituents  in coal-tar1 the
 product of a past age1 immediately set 
to work to find  therein those compounds
 which their contemporaries had already 
discovered4 ,generally1 too1 with signal

 success4    ,the discovery of benzene  
in #ahbe by ,faraday was followed in the
 course of  a few years by its discovery
 in coal-tar by ,hofmann4 ,toluene1     
which was  discovered in #ahcg by       
,pelletier1 was recognised in the       
fractional  distillation of crude       
naphtha by ,mansfield in #ahdh4         
,although the method  of production of  
mauveine on a large scale was not       
accomplished until  #ahef1 yet it had   
been noticed in #ahcd1 the actual year  
of its recognition  as a constituent of 
coal-tar1 that1 when brought into       
contact with  chloride of lime1 it gave 
brilliant colours1 but it required a    
considerable cheapening of the process  
of aniline manufacture before the  dyes 
commenced to enter into competition with
 the old natural dyes4    ,the isolation
 of aniline from coal-tar is expensive1 
in consequence of  the small quantities 
in which it is there found1 but it was  
discovered by  ,mitscherlich that by    
acting upon benzene1 one of the early   

distillates of  coal-tar1 for the       
production of nitro-benzole1 a compound 
was produced  from which aniline could  
be obtained in large quantities4 ,there 
were thus  two methods of obtaining     
aniline from tar1 the experimental and  
the  practical4    ,in producing        
nitrobenzole 7nitrobenzene71 chemically 
represented as  7,c#f;,h#e,,no#b71 the  
nitric acid used as the reagent with    
benzene1 is  mixed with a quantity of   
sulphuric acid1 with the object of      
absorbing  water which is formed during 
the reaction1 as this would tend to     
dilute  the efficiency of the nitric    
acid4 ,the proportions are #ajj parts of
  purified benzene1 with a mixture of   
#aae parts of concentrated nitric acid  
7,,hno#c7 and #afj parts of concentrated
 sulphuric acid4 ,the mixture is        
gradually introduced into the large     
cast-iron cylinder into which the       
benzene has been poured4 ,the outside of
 the cylinder is supplied with an       
arrangement by which fine jets of water 

can be made to play upon it in  the     
early stages of the reaction which      
follows1 and at the end of from  eight  
to ten hours the contents are allowed to
 run off into a storage  reservoir4     
,here they arrange themselves into two  
layers1 the top of which  consists of   
the nitrobenzene which has been         
produced1 together with some  benzene   
which is still unacted upon4 ,the       
mixture is then freed from the  latter  
by treatment with a current of steam4   
,nitrobenzene presents itself  as a     
yellowish oily liquid1 with a peculiar  
taste as of bitter almonds4  ,it was    
formerly in great demand by perfumers1  
but its poisonous  properties render it 
a dangerous substance to deal with4 ,in 
practice a  given quantity of benzene   
will yield about #aej per cent of       
nitrobenzene4  ,stated chemically1 the  
reaction is shown by the following      
equation3--    ,c#f;,h#f        ,,hno#c 
,c#f;,h#e,,no#b1      ,h#b,o  7,benzene7
       7,nitric acid7                   

7,nitrobenzene7         7,water74       
,the water which is thus formed in the  
process1 by the freeing of one of  the  
atoms of hydrogen in the benzene1 is    
absorbed by the sulphuric acid  present1
 although the latter takes no actual    
part in the reaction4    ,from the      
nitrobenzene thus obtained1 the aniline 
which is now used so  extensively is    
prepared4 ,the component atoms of a     
molecule of aniline are  shown in the   
formula ,c#f;,h#e,,nh#b4 ,it is also    
known as phenylamine or  amido-benzole1 
or commercially as aniline oil4 ,there  
are various methods  of reducing        
nitrobenzene for aniline1 the object    
being to replace the  oxygen of the     
former by an equivalent number of atoms 
of hydrogen4 ,the  process generally    
used is that known as ,bchamp's1 with   
slight  modifications4 ,equal volumes of
 nitrobenzene and acetic acid1 together 
with a quantity of iron-filings rather  
in excess of the weight of the          
nitrobenzene1 are placed in a capacious 

retort4 ,a brisk effervescence  ensues1 
and to moderate the increase of         
temperature which is caused by  the     
reaction1 it is found necessary to cool 
the retort4 ,instead of acetic  acid    
hydrochloric acid has been a good deal  
used1 with1 it is said1  certain        
advantageous results4 ,from #fj to #fe  
per cent4 of aniline on the  quantity of
 nitrobenzene used1 is yielded by       
,bchamp's process4    ,stated in a few  
words1 the above is the process adopted 
on all hands for  the production of     
commercial aniline1 or aniline oil4 ,the
 details of the  distillation and       
rectification of the oil are1 however1  
as varied as they  can well be1 no two  
manufacturers adopting the same process4
 ,many of the  aniline dyes depend      
entirely for their superiority1 on the  
quality of the  oil used1 and for this  
reason it is subject to one or more     
processes of  rectification4 ,this is   
performed by distilling1 the distillates
 at the  various temperatures being     

separately collected4    ,when pure1    
aniline is a colourless oily liquid1 but
 on exposure rapidly  turns brown4 ,it  
has strong refracting powers and an     
agreeable aromatic  smell4 ,it is very  
poisonous when taken internally2 its    
sulphate is1  however1 sometimes used   
medicinally4 ,it is by the action upon  
aniline of  certain oxidising agents1   
that the various colouring matters so   
well  known as aniline dyes are         
obtained4    ,commercial aniline oil is 
not1 as we have seen1 the purest form of
  rectified aniline4 ,the aniline oils  
of commerce are very variable in        
character1 the principal constituents   
being pure aniline1 para- and           
meta-toluidine1 xylidines1 and          
cumidines4 ,they are best known to the  
colour manufacturer in four qualities-- 
7a7 ,aniline oil for blue and black4    
7b7 ,aniline oil for magenta4    7c7    
,aniline oil for safranine4    7d7      
,liquid toluidine4    ,from the first of
 these1 which is almost pure aniline1   

aniline black is  derived1 and a number 
of organic compounds which are further  
used for the  production of dyes4 ,the  
hydrochloride of aniline is important   
and is  known commercially as aniline   
salt4    ,the distillation and          
rectification of aniline oil is         
practised on a  similar principle to the
 fractional distillation which we have  
noticed as  being used for the          
distillation of the naphthas4 ,first1   
light aniline  oils pass over1 followed 
by others1 and finally by the heavy     
oils1 or  aniline-tailings4 ,it is a    
matter of great necessity to those      
engaged in  colour manufacture to apply 
that quality oil which is best for the  
production of the colour required4 ,this
 is not always an easy matter1 and      
there is great divergence of opinion and
 in practice on these points4    ,the   
so-called aniline colours are not all   
derived from aniline1 such  colouring   
matters being in some cases derived from
 other coal-tar  products1 such as      

benzene and toluene1 phenol1            
naphthalene1 and  anthracene1 and it is 
remarkable that although the earlier    
dyes were  produced from the lighter and
 more easily distilled products of      
coal-tar1 yet now some of the heaviest  
and most stubborn of the  distillates   
are brought under requisition for       
colouring matters1 those  which not many
 years ago were regarded as fit only to 
be used as  lubricants or to be regarded
 as waste4    ,it is scarcely necessary 
or advisable in a work of this kind to  
pursue  the many chemical reactions1    
which1 from the various acids and bases1
  result ultimately in the many shades  
and gradations of colour which are  to  
be seen in dress and other fabrics4     
,many of them1 beautiful in the         
extreme1 are the outcome of much careful
 and well-planned study1 and to  print  
here the complicated chemical formulae  
which show the great changes  taking    
place in compounds of complex molecules1
 or to mention even the  names of these 

many-syllabled compounds1 would be to   
destroy the purpose  of this little     
book4 ,the ,rosanilines1 the ,indulines1
 and ,safranines2 the  ,oxazines1 the   
,thionines3 the ,phenol and ,azo dyes   
are all substances which  are of greater
 interest to the chemical students and  
to the colour  manufacturer than to the 
ordinary reader4 ,many of the names of  
the bases  of various dyes are unknown  
outside the chemical dyeworks1 although 
each  and all have complicated2         
reactions of their own4 ,in the reds are
  rosanilines1 toluidine xylidine1 c42  
in the blues--phenyl-rosanilines1       
diphenylamine1 toluidine1 aldehyde1 c42 
violets--rosaniline1 mauve1  phenyl1    
ethyl1 methyl1 c42 greens--iodine1      
aniline1 leucaniline1  chrysotoluidine1 
aldehyde1 toluidine1 methyl-anilinine1  
c42 yellows and  orange--leucaniline1   
phenylamine1 c42                        
browns--chrysotoluidine1 c42            
blacks--aniline1 toluidine1 c4    ,to   
take the rosanilines as an instance of  

the rest4    ,aniline red1 magenta1     
azaleine1 rubine1 solferino1 fuchsine1  
chryaline1  roseine1 erythrobenzine1 and
 others1 are colouring matters in this  
group  which are salts of rosaniline1   
and which are all recognised in         
commerce4    ,the base rosaniline is    
known chemically by the formula         
,c#bj;,hl#i,n#c1  and is prepared by    
heating a mixture of magenta aniline1   
toluidine1 and  pseudotoluidine1 with   
arsenic acid and other oxidising agents4
 ,it is  important that water should be 
used in such quantities as to prevent   
the  solution of arsenic acid from      
depositing crystals on cooling4 ,unless 
carefully crystallised rosaniline will  
contain a slight proportion of the      
arseniate1 and when articles of clothing
 are dyed with the salt1 it is  likely  
to produce an inflammatory condition of 
skin1 when worn4 ,some  years ago there 
was a great outcry against hose and     
other articles dyed  with aniline dyes1 
owing to the bad effects which were     

produced1 and this  has no doubt proved 
very prejudicial to aniline dyes as a   
whole4    ,again1 the base known as     
mauve1 or mauveine1 has a composition   
shown by  the formula ,c#bg;,h#bd,n#d4  
,it is produced from the sulphate of    
aniline by mixing it with a cold        
saturated solution of bichromate of     
potash1 and allowing the mixture to     
stand for ten or twelve hours4 ,a       
blue-black precipitate is then formed1  
which1 after undergoing a process  of   
purification1 is dissolved in alcohol   
and evaporated to dryness4 ,a           
metallic-looking powder is then         
obtained1 which constitutes this        
all-important base4 ,mauve forms with   
acids a series of well-defined salts    
and is capable of expelling ammonia from
 its combinations4 ,mauve was the  first
 aniline dye which was produced on a    
large scale1 this being  accomplished by
 ,perkin in #ahef4    ,the substance    
known as carbolic acid is so useful a   
product of a piece of  coal that a      

description of the method of its        
production must necessarily  have a     
place here4 ,it is one of the most      
powerful antiseptic agents with  which  
we are acquainted1 and has strong       
anaesthetic qualities4 ,some  useful    
dyes are also obtained from it4 ,it is  
obtained in quantities from  coal-tar1  
that portion of the distillate known as 
the light oils being  its immediate     
source4 ,the tar oil is mixed with a    
solution of caustic  soda1 and the      
mixture is violently agitated4 ,this    
results in the caustic  soda dissolving 
out the carbolic acid1 whilst the       
undissolved oils  collect upon the      
surface1 allowing the alkaline solution 
to be drawn from  beneath4 ,the soda in 
the solution is then neutralised by the 
addition of  a suitable quantity of     
sulphuric acid1 and the salt so formed  
sinks while  the carbolic acid rises to 
the surface4    ,purification of the    
product is afterwards carried out by a  
process of  fractional distillation4    

,there are various other methods of     
preparing  carbolic acid4    ,carbolic  
acid is known chemically as             
,c#f;,h#e7;,,ho74 ,when pure it appears 
as colourless needle-like crystals1 and 
is exceedingly poisonous4 ,it has  been 
used with marked success in staying the 
course of disease1 such as  cholera and 
cattle plague4 ,it is of a very volatile
 nature1 and its  efficacy lies in its  
power of destroying germs as they float 
in the  atmosphere4 ,modern science     
tells us that all diseases have their   
origin  in certain germs which are      
everywhere present and which seek only a
  suitable nidus in which to propagate  
and flourish4 ,unlike mere  deodorisers 
which simply remove noxious gases or    
odours2 unlike  disinfectants which     
prevent the spread of infection1        
carbolic acid  strikes at the very root 
and origin of disease by oxidising and  
consuming  the germs which breed it4 ,so
 powerful is it that one part in five   
thousand parts of flour paste1 blood1   

c41 will for months prevent             
fermentation and putrefaction1 whilst a 
little of its vapour in the  atmosphere 
will preserve meat1 as well as prevent  
it from becoming  fly-blown4 ,although  
it has1 in certain impure states1 a     
slightly  disagreeable odour1 this is   
never such as to be in any way harmful1 
whilst on the other hand it is said to  
act as a tonic to those connected  with 
its preparation and use4    ,the new    
artificial colouring matters which are  
continually being brought  into the     
market1 testify to the fact that1 even  
with the many beautiful  tints and hues 
which have been discovered1 finality and
 perfection have  not yet been reached4 
,a good deal of popular prejudice has   
arisen against  certain aniline dyes on 
account of their inferiority to many of 
the old  dye-stuffs in respect to their 
fastness1 but in recent years the       
manufacture of many which were under    
this disadvantage of looseness of  dye1 
has entirely ceased1 whilst others have 

been introduced which are  quite as     
fast1 and sometimes even faster than the
 natural dyes4    ,it is convenient to  
express the constituents of coal-tar1   
and the  distillates of those           
constituents1 in the form of a          
genealogical chart1  and thus1 by way of
 conclusion1 summarise the results which
 we have  noticed4                      
,,coal4                                 
4---------------------------------------
-----------------4                      
,water   ,house-gas   ,coal-tar         
,ammoniacal  ,coke                      
liquor                                  
4----------------------------------4    
,sulphur                                
7sulphurreted        ,first     ,second 
,heavy  ,anthracene  ,pitch             
hydrogen3        light      light   oils
     7green                             
sulphurous        oils       oils       
7creosote   oils7                       
acid3 oil                 7crude   oils7
                             of vitriol7

     4--------4  naphtha7               
,anthracene                             
,ammoniacal ,benzene                    
,alizarin or            liquor          
toluene1          dyer's madder         
c4                                      
,sulphuric acid,carbonate               
of,hydrochloric                         
ammonia        acid                     
7smelling                               
salts7                                  
,lime,sulphate of   ,lime,chloride of   
ammonia            ammonia 7sal         
ammoniac7                               
4--------4         4--------4           
,ammonia  ,sulphate   ,ammonia          
,chloride                               
of lime             of lime4            
7,plaster of ,paris7                    
4-----------------4                     
,crude    ,carbolic  ,naphthalin        
,creosote   acid                        
4---------------------------------------
------4                                 
,benzene,nitric ,acid  ,toluene  ,nylene

  ,artificial   ,burning                
turpentine    oils    ,nitrobenzene     
,iron filings         oil 7solvent      
7,essence de   and acetic acid          
naphtha7     mirbane7                   
,aniline,various reagents               
,aniline dyes              ,,index4     
,a4    ,accidents1 causes of mining     
,age of ,acrogens  ,alethopteris        
,alizarin  ,american coal-fields        
,ammoniacal liquor  ,aniline  ,aniline  
dyes  ,aniline oil1 commercial  ,aniline
 salt  ,aniline tailings  ,anthracene   
,anthracite  ,artificial turpentine oil 
,asphalt  ,australian coals             
,aviculopecten    ,b4    ,bchamp's      
process  ,benzene  ,bind  ,bitumen in   
,trinidad  ,blower a  ,boghead coal     
,bog-oak  ,boring diamonds  ,borrowdale 
graphite mine  ,bovey ,tracey lignite   
,british coal-fields  ,british          
,north-,american coal-measures          
,briquettes    ,c4    ,calamites1       
extinct horsetails  ,carbolic acid      
,carboniferous formation1 the           

,cardiocarpum1 fossil fruit             
,carelessness of miners  ,causes of     
earth-movements  ,changes of level      
,charcoal as a disinfectant  ,chemistry 
of a gas-flame  ,chinese coals          
,clanny's safety-lamp  ,clayton's       
experiments with gas  ,clay1 regularity 
in deposition of  ,club-mosses1 great   
height of fossil  ,coal-dust1 danger    
from  ,coal formed in large lakes or    
closed seas  ,coal formation1 geological
 position of  ,coal formed by escape of 
gases  ,coal-mine1 the  ,coal not the   
result of drifted vegetation            
,coal-period1 climate of  ,coal-pipes   
,coal-plants1 classification of         
,coal-seam1 each1 a forest growth       
,coals of non-carboniferous age  ,coal1 
vegetable origin of  ,coke  ,cole       
,condensers  ,cones of ,lepidodendra    
,conifers in coal-measures              
,current-bedding in sandstone    ,d4    
,davy-lamp  ,dangers of benzene  ,darwin
 on the ,chonos ,archipelago  ,diamonds1
 how made artificially  ,disintegration 

of vegetable substances  ,disproportion 
in relative thickness of coal and       
coal-measures    ,e4    ,early use of   
coal  ,effects of an explosion          
,encrinital limestone  ,equiseta        
,essence de mirbane  ,european          
coal-fields  ,evelyn on the use of coal 
,experiments illustrating fossilisation 
,f4    ,filling retorts by machinery    
,firedamp  ,fire1 mines on  ,first light
 oils  ,first record of an explosion    
,flashing-point of oil  ,flooding of    
pits  ,fog and smoke  ,foraminifera     
,fossil ferns  ,fructification on       
fossil-ferns  ,furnace1 ventilating     
,g4    ,gas1 coal  ,gasholder1 the      
,gas1 house1  constituents  of          
,glossopteris  ,graphite  ,green ,grease
    ,h4    ,hannay1 of ,glasgow  ,heavy 
oils  ,humboldt's safety-lamp           
,hydraulic ,main    ,i4    ,impurities  
in house-gas  ,indian coals  ,insertion 
of rootlets of stigmaria  ,insufficiency
 of modern forest growths  ,ireland     
denuded of coal-beds  ,iron1 supplies of

    ,l4    ,lepidodendra  ,lepidostrobi 
,lignite  ,london lit by gas    ,m4     
,mammoth trees  ,marco ,polo  ,marsh gas
  ,medium oils  ,metamorphism of coal by
 igneous agency  ,methods of ventilation
  ,mountain limestone  ,murdock's use of
 gas  ,mussel beds    ,n4    ,napthalin 
,neuropteris  ,newcastle1 charters to   
,nitro-benzole    ,o4    ,objections to 
use of coal  ,oils from coal and lignite
  ,oil-wells of ,america  ,olefiant gas 
,orthoceras    ,p4    ,paraffins  ,peat 
,pecopteris  ,pennsylvanian anthracite  
,persian fire-worshippers  ,pitch       
,plumbago  ,polyzoa  ,prejudice against 
aniline dyes  ,prohibitions of the use  
of coal  ,proportions of explosive      
mixtures  ,psaronius  ,purifiers        
,pyrites in coal    ,q4    ,quantity of 
coal raised in ,great ,britain    ,r4   
,reptiles of the coal-era  ,resemblance 
of ,american and ,british coal-flora    
,retorts  ,roman use of coal            
,rosanilines1 the  ,royal ,commission of
 #ahff    ,s4    ,sandstone1 how formed 

,shales  ,sigillaria  ,south ,american  
coals  ,spores of lepidodrendron        
,spores1 resinous matter in  ,spores1   
inflammability of  ,steel-mill          
,sternbergia  ,stigmaria  ,subsidence   
throughout coal-era  ,surturbrand at    
,brighton  ,sussex iron-works    ,t4    
,tar  ,testing pits by the  candle      
,texas coal  ,toluene1 discovery of     
,torbanehill mineral  ,trappers    ,u4  
,underclays  ,uses to which coal is put 
,v4    ,vaseline  ,vegetation of the    
coal age  ,ventilation of coal-pits     
,w4    ,washers  ,waste of fuel         
,wealden lignite  ,westphalian          
coal-field    ,y4    ,young's ,paraffin 
,oil    ,z4    ,zoroastrians