,a                                      
,,course                                
,,of               ,mechanical1         
,magnetical1 ,optical1 ,hydrostatical1  
,,and                                   
,pneumatical ,,experiments4    ,to be   
perform'd by ,,francis ,,hauksbee2 and  
the ,explanatory ,lectures read by      
,,william ,,whiston1 ,m4 ,a4            
,,mechanicks4    #ast ,day4 ,,sir       
,,isaac ,,newton's ,three ,laws of      
,motion1 or ,nature1  demonstrated by   
,experiments4    ,that the ,velocity of 
,falling ,bodies is as the ,times of    
,falling1 and the  ,lines of ,descent in
 the ,duplicate ,proportion of those    
,times4    ,an ,instrument to measure   
the ,force of ,falling ,bodies4         
,experiments concerning the ,sliding1   
,rolling1 and ,falling of ,bodies4      
,that ,bodies will ascend as high1 as   
whence they fall by the last ,velocity  
impress'd1 when all ,obstacles are      
removed4    ,that ,bodies by a compound 
,force move in a ,diagonal ,line4       

#b;d--,the ,balance and ,stilyard1 with 
all their ,properties and ,uses shewn   
and  explain'd4    ,the ,method of      
estimating the ,momentum1 or ,quantity  
of ,motion in any  given ,body4    ,the 
general ,principle of ,mechanicks       
established upon this ,method4          
,experiments to demonstrate the         
different ,effects of the same ,weight  
of  ,power acting in different          
,directions at the same ,point of any   
,engine4    ,the ,resolution of ,forces 
into those of other ,directions4    ,all
 the various ,kinds of ,levers          
explain'd4    #c;d--,all the ,phnomena  
of ,pulleys1 both single and in all     
their possible  ,combinations explain'd4
    ,the ,power of the ,wheel or ,axis  
in ,peritrochio explain'd4    ,the      
,wedge1 with the ,method of comparing   
its ,force1 deduced from  ,experiments4 
,the ,screw1 with the manner of         
computing its ,force4    ,a ,compound   
,engine4    #dth--,an ,experiment of    
,lifting a ,weight by a ,chain of       

,inflated ,bladders1  with its          
,application to ,muscular ,motion4      
,galilo's ,demonstration concerning the 
,strength of the ,bones1 ,timber1  c4   
reduced to ,experiment4    ,the ,method 
of computing the ,force of the ,air on  
the ,sails of ,windmills1  and of       
,ships2 and of ,water on ,water-,wheels1
 and on the ,rudder of a ,ship4         
,experiments to shew the proportional   
,advantages of large and small ,wheels1 
in all ,sorts of ,carriages1 as         
,couches1 ,waggons1 ,carts1 c4          
#eth--,an ,experiment to shew1 that the 
lateral ,motion compounded with the     
perpendicular ,projection1 does not     
alter the ,line of ,ascent or ,descent  
in  the projected ,body4    ,the most   
considerable ,objections against the    
,motion of the ,earth1 answered  from   
this ,experiment4    ,that the ,line    
described by a ,projectile is a         
,parabola4    ,the ,experiments upon    
which the ,art of ,gunnery does depend1 
most exactly  perform'd4                

#fth--,experiments concerning           
,pendulums4    ,the ,description and    
chief ,properties of the ,cycloid1 and  
the ,application  of ,cycloidal ,cheeks 
for regulating the ,vibrations of       
,pendulums4    ,an ,experiment to shew  
the ,analogy between the ,swings of a   
,pendulum and the  ,waves of the ,sea4  
,experiments concerning the ,expansion  
of ,metals by ,heat4    #gth--,the ,laws
 of ,motion in the ,collision of ,hard  
and ,elastick ,bodies4    ,experiments  
concerning the ,centrifugal and         
,centripetal ,forces of ,solid and      
,fluid ,bodies in ,motion4              
,experiments in order to estimate the   
,centrifugal ,forces of ,solid ,bodies4 
,,magneticks4    #hth ,day4 ,attractive 
and ,directive ,powers of ,loadstones4  
,the ,form or ,position of ,filings of  
,iron at the ,poles and ,equator of a   
,loadstone4    ,magnetick ,power acts   
thro' all ,bodies but ,iron4    ,the    
,attraction of different1 and ,repulse  
of corresponding ,poles4    ,the manner 

of touching and untouching of ,needles4 
,the ,law of ,magnetick ,attraction     
discover'd4    #ith--,the ,phnomena of  
,terrella1 or ,spherical ,loadstones4   
,the ,direction of ,magnetick ,needles  
on the ,surfaces of ,terrella nearly    
towards the ,poles4    ,their ,variation
 ,east and ,west4    ,the ,inclinatory  
or ,dipping-,needle1 with the ,law of   
the ,alteration of that  ,inclination on
 the ,surface of a ,terrella4    ,the   
,terrestrial ,magnetism consider'd4     
,the ,application of the                
,dipping-,needle to the ,discovery of   
the ,longitude  and ,latitude of ,places
 by ,land and ,sea4                     
,,opticks4    #ajth ,day4 ,experiments  
to demonstrate1 that in the ,rays of    
,light the ,angle  of ,incidence is     
equal to the ,angle of ,reflection in   
all ,sorts of ,surfaces4    ,the ,method
 of tracing the reflected ,rays of      
,light from ,plain1 ,convex1  ,concave1 
and ,cylindrical ,superficies1 with all 
their wonderful ,properties  and ,uses1 

shew'd and explain'd4    #aath--,sir    
,is4 ,newton's ,reflecting ,telescope   
exhibited1 and its  ,construction       
explained2 together with some ,specimens
 of its ,uses in  observing the ,planets
 and ,fixed ,stars4                     
#abth--,experiments to shew the ,manner 
of ,refraction4    ,the ,sines of the   
,angles of ,incidence and ,refraction1  
shewn to be 7at all  ,degrees of        
,incidence7 in a constant ,proportion to
 each other4    ,an ,instrument to      
measure the ,refraction of ,fluids4     
,the ,method of tracing the ,refracted  
,rays of ,light thro' ,plain1 ,convex1  
and  ,concave ,superficies4             
#acth--,an artificial ,eye1 in which all
 the ,coats and ,humours are curiously  
represented4    ,the ,dissection of the 
,eye4    ,the ,explication of ,vision by
 the naked ,eye1 deduced from           
,experiments4    #adth--,all the        
,effects1 ,properties1 and ,uses of     
,plain1 ,convex1 and ,concave  ,glasses1
 both single and combin'd in ,telescopes

 and ,microscopes1 shew'd  and          
explain'd4    ,several ,kinds of        
,microscopes and ,telescopes1 with the  
,manner of applying  them to their      
respective ,objects2 together with a    
,specimen of the ,uses of  such         
,microscopes and ,telescopes4    ,a     
,multiplying ,glass4    ,the ,magick    
,lanthorn4    #aeth--,a particular      
,apparatus to manifest and measure the  
,refraction of  ,air4    ,the ,camera   
,obscura4    ,the ,theory of ,light and 
,colours1 as delivered by ,sir ,isaac   
,newton1  demonstrated by several of his
 principal ,experiments4    ,the        
,archbishop of ,spalato's ,experiment1  
which discovered the ,cause of  the     
,rainbow4    ,monsieur ,hugen's         
,experiments1 which discover the ,causes
 of ,halo's1 of  the ,mock ,suns and    
,moons1 and of inverted ,rainbows4      
,experiments concerning the blending and
 ,production of ,colours by ,motion4    
,,hydrostaticks4    #afth ,day4 ,that   
,fluids gravitate in proprio loco1 the  

upper ,parts  continually pressing upon 
the lower3 ,that this ,pressure is not  
only  propagated ,downwards1 but even   
,upwards1 and ,sideways1 according to   
all  possible ,directions2 ,that a      
lighter ,fluid may gravitate upon a     
heavier1  and an heavier upon a lighter2
 ,that a ,fluid may sustain a ,body     
heavier in  ,specie than it self1 and   
even raise it up2 ,that a ,fluid may    
detain a ,body  lighter in ,specie than 
it self1 and even depress it4 ,a general
  ,experiment to prove1 that a competent
 ,pressure of a ,fluid may produce the  
remarkable ,phnomena of the             
,torricellian ,tube1 the ,pump1         
,syringe1 ,syphon1  polished ,plates1   
and other ,effects of the like ,nature4 
#agth--,that ,fluids press according to 
their perpendicular ,altitudes1         
whatever be their ,quantities1 or       
however the containing ,vessels be      
figured4 ,the exact ,estimate of all    
manner of ,pressures4 ,that the         
,velocity  and ,quantity of ,fluids     

running out at a given ,hole1 is in the 
subduplicate  ,proportion of their      
perpendicular ,altitudes4 ,several      
,sorts of ,pumps4 ,of  the sinking and  
floating of ,bodies immers'd in ,fluids2
 their relative  ,gravities and         
,levities2 their ,situations and        
,positions4 ,the ,phnomena of  ,glass   
,bubbles and ,images accounted for4     
#ahth--,an ,instrument to find out the  
,specifick ,gravity of all ,liquors4    
,the  ,hydrostatical ,balance explain'd1
 with the ,methods of determining the   
,specifick ,gravities of all ,sorts of  
,bodies1 whether ,solid or ,fluid1      
thereby4 ,the ,praxis of the            
,hydrostatical ,balance1 whereby the    
,specifick  ,gravities of several       
particular ,bodies are actually found   
out4 ,some  ,account of the various     
,uses of such ,enquiries4               
,,pneumaticks illustrated by            
,experiments for the most part ,tubular1
  being such as were wont to be made    
before the ,air-,pump was invented4     

#aith ,day4 ,the several ,phnomena of   
the ,torricellian ,experiment exhibited 
and explained4 ,other ,experiments of   
the like ,nature1 with ,fluids variously
  combin'd4 ,several ,sorts of          
,barometers1 ,thermometers1 and         
,hygroscopes4 ,the  ,pressure of the    
,air shewn by ,experiment to be         
different at different  ,altitudes from 
the ,surface of the ,earth4             
#bjth--,the ,density and ,spring of the 
,air proved by several ways to be as the
  ,force which compresses it1 and       
reciprocally as the ,spaces into which  
it is  compress'd4 ,from hence an       
,enquiry is made into the ,limits and   
,state of the  ,atmosphere4             
#bast--,the ,effects of the ,weight and 
,spring of the ,air in ,syringes1       
,pumps1  ,siphons1 polished ,plates1    
,cupping-,glasses1 ,suction3            
,respiration explained  by artificial   
,lungs2 ,that the ,air may be so        
disorder'd by a violent  ,impulse1 as to
 require ,time to recover its ,strength 

and ,elasticity again4      ,the more   
known ,properties of the ,air           
established by the ,air-,pump1 and      
other ,engines4    #bb;d ,day4 ,the     
,air-,pump2 the ,instruments for        
,condensing and ,transferring of  ,air2 
their ,fabrick1 ,operation1 and ,gages  
explained4    #bc;d--,a ,parcel of ,air 
weighed in the ,balance2 its ,specifick 
,gravity to that  of ,water determined  
thereby2 an artificial ,storm1 shewing  
that high ,winds  may make the          
,barometer sink much and suddenly4      
#bdth--,the ,weight1 ,pressure1 and     
,spring of the ,air prov'd several ways2
 by  the ,sense of ,feeling2 by breaking
 ,glass ,vials2 the ,phnomena of        
,bladders1  ,glass-bubbles1 ,fountains2 
the ,gardiner's ,watering-,pot2 the     
,diving-,bell1  c4    #beth--,the       
,torricellian ,tube in ,vacuo2          
,quicksilver raised to the usual        
,height of the ,weather-,glass1 by the  
bare ,spring of a little included ,air2 
,otto ,gerick's ,hemispheres2 and that  

dense ,air has the same ,advantage  over
 common ,air1 as that has over a        
,vacuum4    ,the ,ebullition of ,liquors
 in ,vacuo2 the ,quantity of ,air       
contain'd in  them2 the ,sustentation of
 ,fumes and ,vapours2 the ,descent of   
,bodies in  ,vacuo4      ,the more      
hidden ,properties of the ,air          
consider'd by the help of the like      
,engines4    #bfth ,day4 ,the ,influence
 of the ,air examin'd as to the ,causes 
of ,magnetism2  the ,elasticity of      
,springs2 the ,cohsion of the ,parts of 
,matter2 the  ,sphericity of the ,drops 
of ,fluids2 the ,ascent of ,liquors in  
capillary  ,tubes1 and between          
,glass-,planes in the ,curve of the     
,hyperbola1 both by the  ,attractive and
 ,repulsive ,power of the ,glass4       
#bgth--,the ,influence of the ,air1 as  
to ,sounds1 ,fire1 and ,flame2 the      
,consumption of ,fuel2 the firing of    
,gunpowder2 the ,effects of rarified1   
condensed1 and burnt ,air upon the ,life
 of ,animals4    #bhth--,a ,piece of    

,phosphorus in ,vacuo2 new ,experiments 
concerning the  ,mercurial ,phosphori2  
,experiments concerning the ,electricity
 of ,bodies4                            
----------------------------------------
----------------------------------      
,every ,,subscriber is to pay ,three    
,guineas2 ,one ,guinea at the ,time of  
,subscription1 and the ,remainder1 the  
,first ,day of the ,course4             
,,subscriptions are taken in at ,mr4    
,whiston's1 in ,great ,russel-,street2  
and   at ,mr4 ,hauksbee's1 in           
,crane-,court in ,fleetstreet2 where the
 ,course is to                          
be perform'd4                           
,advertisement4      ,air-,pumps1 or    
,engines for ,exhausting the ,air from  
proper ,vessels1 with all  their        
,appurtenances2 whereby the various     
,properties and ,uses of that ,fluid    
are discover'd and demonstrated by      
undeniable ,experiments4 ,engines for   
the  ,compression of the ,air3          
,fountains1 in which the ,water1 or     

other ,liquor1 is  made to ascend by the
 ,force of the ,air's ,spring4 ,syringes
 and ,blow-,pipes1  with ,valves for    
,anatomical ,injections4 ,hydrostatical 
,balances1 for  determining the         
,specifick ,gravity of ,fluids and      
,solids4 ,the ,engine and  ,glasses for 
the ,new ,way of ,cupping without ,fire4
 ,scarificators1 which at  once make    
either #aj1 #ac1 or #af ,incisions4     
,weather-,glasses of all ,sorts1 as     
,barometers1 ,thermometers1 c4          
,reflecting ,telescopes1 by which in so 
short a ,length as ,six ,feet1 all that 
has hitherto been discovered in the     
,heavens 7by the longest ,telescopes of 
the common ,construction7 may be        
observed4    ,all the above-mention'd   
,instruments1 according to their ,latest
 and ,best  ,improvements1 are made and 
sold by ,,francis ,,hauksbee1 in        
,crane-,court in  ,fleetstreet1 ,london4
                       ,mechanicks      
,plate ,i4  ,sutton ,nicholls sculp3    
#a                                      

,,mechanicks4                        ,an
 ,explication of the ,first ,,plate4    
,figure4 #a4 ,this belongs to ,galilo's 
famous ,demonstration of the            
,velocities and ,times of ,bodies       
descending by an uniform ,force1 such is
  that of ,gravity here below3 ,and     
shews that they will ever fall in equal 
,times1 #a1 #b1 #c1 #d1 c4 according to 
the odd ,numbers1 #a1 #c1 #e1 #g1 c4  or
 the ,trapezia ,b ,c ,d ,e1 ,d ,e ,f ,g1
 ,f ,g ,h ,i1 c4 and by consequence1    
that  their ,velocity will increase     
uniformly in ,proportion to the ,lines  
,b ,c1  ,d ,e1 ,f ,g1 ,h ,i1 c4 or to   
the ,times of ,descent4 ,and that the   
entire ,lines  of their ,descent will be
 as the ,triangles ,a ,b ,c1 ,a ,d ,e1  
,a ,f ,g1 ,a ,h ,i1  c4 or as the       
,squares of those ,times1 #a1 #d1 #i1   
#af1 c4    ,fig4 #b4 ,this is a strong  
,balance for an ,experiment to prove the
 former  ,proposition1 by shewing that  
any ,bullet or ,ball1 when it falls from
 four  ,times the ,height1 has twice1   

from nine ,times the ,height has thrice 
its  former ,velocity or ,force2 and    
will accordingly raise a double or      
triple  ,weight in the opposite ,scale1 
to the same ,height1 and no more2 and so
 for  ever4    ,fig4 #c4 ,this shews how
 ,bodies upon an inclin'd ,plane will   
slide1 if  the ,perpendicular through   
the ,center of their ,gravity falls     
within2 and  will rowl1 if that         
,perpendicular fall without their common
 ,section4    ,fig4 #d4 ,this shews that
 an oblique ,body will stand1 if the    
,perpendicular  through its ,center of  
,gravity cut the ,base2 and that it will
 fall1 if it  cut not the ,base3 ,as    
accordingly we stand when the           
,perpendicular through  the ,center of  
,gravity of our ,bodies falls within the
 ,base of our ,feet2 and  we are ready  
to tumble when it falls without the     
same4    ,fig4 #e4 ,this is a ,conick   
,rhombus1 or two right ,cones1 with a   
common  ,base1 rowling upwards to       
,appearance1 or from ,e towards ,f and  

,g3 ,which  ,points are set higher by   
,screws than the ,point ,e4 ,but so that
 the  ,declivity from ,c towards ,a and 
,b is greater than the ,aclivity from ,e
  towards ,f and ,g4 ,whence it is      
plain1 that the ,axis and ,center of    
,gravity  do really descend all the     
,way4    ,fig4 #f4 ,is a ,balance1 in an
 horizontal ,posture1 with weights at   
,distances from the ,center reciprocally
 proportional to themselves2 and        
thereby in quilibrio4    ,fig4 #g4 and  
#h4 ,are two other ,balances in an      
horizontal ,posture1 with  several      
,weights on each ,side1 so adjusted1    
that the ,sum of the ,motion on  one    
,side1 made by multiplying each ,weight 
by its ,velocity1 or ,distance  from the
 ,center1 and so added together1 is     
equal to that on the other3 ,and  so all
 still in quilibrio4    ,fig4 #i4       
,belongs to the ,laws of ,motion1 in the
 ,collision of ,bodies to be  tried with
 ,pendulums1 or otherwise1 both as to   
,elastical ,bodies1 and to  those which 

are not ,elastical4    ,fig4 #aj4       
,belongs to that ,famous and            
,fundamental ,law of ,motion1 that if a 
,body be impell'd by two distinct       
,forces in an ,proportion1 it will in   
the  same ,time move along the ,diagonal
 of that ,parallelogram1 whose ,sides   
would  have been describ'd by those     
distinct ,forces2 and that accordingly  
all  ,lines1 in which ,bodies move1 be  
consider'd as ,diagonals of             
,parallelograms2  and so may be resolved
 into those two ,forces1 which would    
have been  necessary for the distinct   
,motions along their two ,sides         
respectively3  ,which grand ,law        
includes the ,composition and           
,resolution of all ,motions  whatsoever1
 and is of the greatest ,use in         
,mechanical and ,natural  ,philosophy4  
,fig4 #aa4 ,are two polite ,plains      
inclined to one another1 to shew that   
the  ,descent down one ,plain will      
elevate a ,ball almost to an equal      
,height on  the other4                  

,plate ,,ii4  ,sutton ,nicholls sculp3  
,,mechanicks4 #b                        
,an ,explication of the ,second ,,plate4
      ,figure #a4 ,is the deceitful     
,balance2 which yet is in quilibrio     
because  the ,weights #bc and #bd are   
reciprocally proportional to their      
,distances  from the ,center of ,motion4
 ,now this ,cheat is easily discover'd  
by changing  the ,position of the       
,weights1 and putting each of them into 
the other  ,scale1 which will then be   
very unequal1 or nearly as #aa to #ab4  
,fig4 #b4 ,is that sort of ,balance     
which is called a ,stiliard1 and of     
frequent ,use among us4 ,it is only a   
,common ,balance1 with ,weights at      
,distances from the ,center of ,motion  
reciprocally ,proportionable to         
themselves3 ,only here the ,length of   
,part of the ,beam is compensated by a  
large ,ball or ,weight ,b1 fixed to the 
shorter ,beam2 and one ,weight as w     
removed along equal ,divisions is made  
use of to weigh several others1 as  #f  

w4 c4    ,fig4 #c4 ,is design'd to shew 
how any ,force is diminish'd by its     
,obliquity2 and that a ,weight hung     
obliquely at #c1 #b1 #a1 in the         
,circumference of a ,circle or ,wheel1  
is of no more ,efficacy1 as to the      
turning of the ,wheel round1 than if it 
were hung perpendicularly at the        
corresponding ,points #c1 #b1 #a1 in the
 ,semidiameter of the same ,circle4     
,fig4 #d4 ,is the ,demonstration of the 
former ,case1 by shewing that in  those 
,circumstances the ,force ,p ,b is      
resolved into two ,b ,f and ,b ,g1 of   
which ,b ,f pulls directly from the     
,center1 and is of no ,use to the       
turning  the ,wheel round3 ,and so all  
the remaining ,force is represented by  
the  perpendicular ,force ,b ,g1 which  
is wholly spent in turning it round4 ,so
  that as ,b ,p is to ,b ,g1 so is the  
whole oblique ,force1 to the real or    
direct ,force3 ,or so1 in the similar   
,triangle ,b ,e ,c1 is ,b ,c the whole  
oblique ,radius1 to ,c ,e the           

,perpendicular3 ,or so in the foregoing 
,figure is  ,o #a1 ,o #b1 ,o #c1 the    
common ,hypotenuse or entire ,radius1 to
 ,o #a1 ,o #b1 ,o #c1  the ,bases or    
shorter ,radij1 where the ,string cuts  
the entire ,radius  perpendicularly4    
,fig4 #e4 ,is the first ,sort of ,lever1
 where ,c the ,prop is between the      
,resistance to be overcome1 or ,weight  
to be moved #e w1 and w #a the ,power or
  ,weight to move the other by3 ,and is 
so like the ,case of the ,balance or    
,stiliard1 that it needs no particular  
,explication4 ,a ,crow of ,iron is of   
this ,sort4    ,fig4 #f4 ,is the second 
,sort of ,lever1 where the ,resistance  
to be  overcome1 or ,weight to be moved 
w #c1 is between the ,prop ,c and the   
,point  ,a1 to which by the means of the
 ,pulley ,p1 the ,power or ,weight to   
move the  other by1 is applied4 ,bakers 
,knives for cutting ,bread are commonly 
of this  ,sort4    ,fig4 #g4 ,is the    
third ,sort of ,lever1 where the        
,resistance to be overcome1  or ,weight 

to be moved1 w #b is at one ,end1 the   
,prop at the other1 and the  ,power or  
,weight w #c between them4 ,a ,ladder   
lifted up by the ,middle1 in  order to  
be rear'd1 where one ,end is fixed1 is  
of this ,sort4 ,only the  ,force being  
in this ,case nearer the ,prop than the 
,resistance to be  overcome1 or ,weight 
to be moved1 this ,sort of ,lever       
diminishes ,force  instead of increasing
 it1 and is therefore of little ,use4   
,fig4 #h4 ,is a common ,lever of the    
first ,sort1 with its ,prop and equal   
,divisions1 fit to be used as the       
,stiliard4    ,fig4 #i4 ,is a compound  
,lever of the first ,sort1 as long as   
the single one  just above it1 where a  
,weight at ,g1 by being doubled three   
several ,times1  will raise eight ,times
 its own ,weight at ,a1 as well as the  
other does it  at once4 ,this last is   
therefore of the same ,force as the     
former1 and no  more2 and by being      
compounded1 is less considerable than   
the other4    ,n4 ,b4 ,had the          

,proportion in the ,compound ,lever1    
,fig4 #i4 been  otherwise1 as suppose   
the ,part ,b ,c on one ,side of the     
,prop ,b three ,times  the ,length of ,a
 ,b on the other ,side1 and the same in 
the other two ,levers  ,c ,e and ,e ,g2 
then the ,weight ,g being but the #bgth 
,part of the ,weight at ,a1  will be in 
quilibrio with it4    ,fig4 #aj4 ,is a  
bended ,lever of the first ,sort1 where 
,c the ,prop is at an  ,angle1 and the  
,force is increas'd with ,c ,h1 the     
,distance of the ,weight  w #a1 which by
 the means of the ,pulley ,p1 is applied
 to the longer ,part of  the ,lever2 and
 in this ,lever1 the ,power is to the   
,resistance reciprocally  as their      
,distances4 ,an ,hammer drawing out a   
,nail is such a bended ,lever4    ,fig4 
#aa1 #ab4 ,shew that ,levers or         
,balances that are even when horizontal1
  may be uneven in other ,positions2    
that is1 too light when the ,center of  
,gravity of one ,weight is fix'd to the 
,lever or ,balance above1 and it is     

elevated2 or below1 and depress'd3      
,because the ,perpendicular cuts the    
horizontal ,line too near the ,center in
 these ,cases4                          
,plate ,,iii4  ,sutton ,nicholls sculp3 
,,mechanicks4 #c                        
,an ,explication of the ,third ,,plate4 
,figure #a4 ,is a ,sort of ,compound    
,lever of the second ,kind1 where the   
,weight  ,h #f is unequally born by the 
,weights ,f #d and ,g #b1 which are     
reciprocally  proportional to the       
,distances ,c ,b and ,c ,a2 and are     
accordingly in  quilibrio4 ,whence we   
see how two ,men may bear unequal ,parts
 of the same  ,weight1 in ,proportion to
 their ,nearness thereto4    ,fig4 #b4  
,is another ,engine of the same ,nature 
with the former2 where the  ,lines ,d   
,c1 ,a ,e1 ,b ,f1 and the ,lever ,a ,b1 
are parallel to the ,horizon2 but  the  
,lines on which the ,weights hang ,d w  
#g1 ,e w #e1 ,f w #b1 are perpendicular 
thereto2 and here a ,force or ,weight   
pulling at the ,point ,c sustains the   

unequal ,weights w #e and w #b in       
quilibrio3 ,provided the ,distances ,c  
,b  and ,c ,a be reciprocally           
proportional to those ,weights4 ,whence 
we learn1  how ,horses of unequal       
,strength may be duly fitted to preserve
 equally in  their ,labour2 viz4 by     
taking care that the ,beam by which they
 both draw  a ,weight or ,waggon1 may be
 divided at the ,point of ,traction as  
,c1 in  reciprocal ,proportion to such  
their ,strength4    ,fig4 #c4 ,a ,b is  
an upper ,pulley1 of no direct          
,advantage1 but for  ,readiness of the  
,motion1 as increasing not the ,power at
 all2 equal ,weights  being ever        
required to raise others4    ,fig4 #d4  
,is an upper and an under ,pulley       
connected together2 where the  upper    
being of no ,efficacy1 the lower does   
however double the ,force1 as is  ever  
the ,case in such ,pulleys4    ,fig4 #e4
 ,is a ,compound ,pulley of three upper 
and three under ,pulleys1 all           
communicating together2 where therefore 

the whole ,weight is divided among  #f  
,strings2 and so #a ,pound balances #f  
,pound4 ,the last ,string ,b ,m #a1 as  
passing beyond the last upper ,pulley1  
not being here to be reckon'd of any    
,consequence4    ,fig4 #f4 and #g4      
,these are ,boxes of the same ,number of
 upper and under  ,pulleys with the     
former2 only in other ,positions1 and   
depend on the same  ,principle entirely4
                            ,plate ,,iv4
  ,sutton ,nicholls sculp3              
,,mechanicks4 #d                        
,an ,explication of the ,fourth ,,plate4
      ,figure #a4 ,is a ,system of      
,pulleys connected together1 whereby the
 ,force is  increased by ,addition in   
,proportion to the ,number of ,cords2 so
 that one  ,pound1 w #a1 sustains five  
,pounds1 w #e1 as must happen from the  
,equality of  the stretching of the     
whole ,cord1 and the consequent         
,division of the whole  ,weight into    
five equal ,parts1 as equally supported 
by them all4    ,fig4 #b4 ,is a ,system 

of ,pulleys not connected together1     
whereby the ,force  is increas'd1 for   
every lower ,pulley2 according to the   
,numbers1 #b1 #d1 #h1  in a double      
,proportion2 because every lower ,pulley
 doubles the ,force of  the former2 as  
is evident at the first ,sight2 since   
the ,velocity of ,ascent  or ,descent of
 the greater ,weight is every ,time but 
half so great as  before4    ,fig4 #c4  
,is the ,axis in ,peritrochio2 or       
,wheel1 with its ,axel2 where any       
,weight or ,force applied round ,e ,f1  
or ,c ,d1 or ,a ,b1 has just so much    
greater ,power to move the ,wheel1 or   
entire ,machine about the ,axis1 as the 
,velocity or ,distance from the         
,geometrical ,axis it self is greater4  
,nor is  there any farther ,difficulty  
in this plain ,engine4    ,fig4 #d4     
,this is only a ,train of ,wheel-work2  
which by ,composition of  ,wheels vastly
 increases the ,force4 ,thus suppose the
 ,diameter of the ,barrel  ,e ,f1 be ten
 times the ,diameter of the ,pinion ,g3 

,and the ,diameter1 or  ,number of equal
 ,teeth in ,g1 be one tenth of the      
,diameter1 or ,number of  equal ,teeth  
in ,h ,i3 ,and the ,diameter and        
,velocity of the ,teeth in ,h ,i1 be    
ten times the ,diameter and ,velocity of
 the ,pinion ,k2 and the ,diameter or   
,number of equal ,teeth in ,k1 be one   
tenth of the ,diameter1 or ,number of   
equal ,teeth in ,l ,m2 ,and that the    
,barrel ,n ,o1 be of the same ,diameter 
with  the ,wheel ,l ,m4 ,then a ,weight 
on the ,barrel ,e ,f will balance a     
,weight one  hundred times as heavy upon
 the ,barrel ,n ,o2 which is done by its
 moving an  hundred ,times as swift as  
the other4 ,for the ,velocity in the    
first ,barrel  ,e ,f1 to that of its    
,pinion ,g1 is as ten to one2 and that  
in the ,wheel ,h ,i1  to that in its    
,pinion ,k1 is also as ten to one4      
,while the ,velocities at  each ,wheel1 
and its corresponding ,pinion in the    
other ,wheel1 as well as at  the ,wheel 
,l ,m1 and its ,barrel ,n ,o1 are equal4

    ,fig4 #e4 ,is a compound ,engine1 to
 prove that in a ,wedge1 as ,e ,m ,g1   
depress'd by a ,weight w1 or by its own 
,weight1 or by a ,stroke1 the ,force  is
 diminished in ,proportion to the ,sine 
of its ,aperture1 compar'd with the     
,line of its ,depth3 ,so that when the  
former ,sine is double or triple1 c4    
the ,force is diminished one half1 or   
one third1 c4 ,this is here prov'd  by  
the ,wedges separating two ,cylinders1  
which are drawn together by other       
,weights1 in the ,scales ,r and ,s      
beneath1 when its ,sides are screw'd    
nearer  or farther off1 to adjust their 
,distance to those ,weights perpetually4
    ,fig4 #f4 ,is a ,wedge by it self1  
where the ,force is increas'd in the    
,proportion of the ,sines of the ,angles
 of ,aperture1 ,d ,f and ,d ,e1 to the  
,radius ,d ,b2 or is resolv'd into two  
,forces1 the one perpendicular1 and the 
other parallel to the ,plain of the     
,tree or ,timber it is to reeve3 ,and   
this  because the ,velocity downward is 

ever to the ,velocity side-ways in the  
,proportion of ,d ,b to ,d ,f and ,d ,e1
 or to #b ,d ,f4 i4 e4 by the           
,similitude  of ,triangles1 as ,a ,b or 
,c ,b to ,a ,c4    ,fig4 #g4 ,is a      
,paper ,wedge1 ,h ,f ,g coil'd round a  
,cylinder1 and so  representing a       
,screw2 and shews that its ,force must  
be increas'd in  ,proportion to the     
,progress along its ,cylinder1 when it  
is compar'd with  the ,circumferences on
 the same ,cylindrical ,surface1 or as  
,h ,f to ,h ,g4    ,fig4 #h4 ,is a      
compound ,engine to explain and measure 
the ,power of the  ,screw3 from whence  
it appears1 that the ,force of ,screws  
is reciprocally  proportional to the    
,distance of the ,helix's or ,threads   
which compose  them4                    
,plate ,v4  ,sutton ,nicholls del4      
sculp3                                  
,,mechanicks4 #e                        
,an ,explication of the ,fifth ,,plate4 
,figure #a4 ,is a ,compound ,engine in  
which all the several ,mechanical       

,powers  are combin'd3 as the ,wheel and
 ,axle ,g ,h3 ,the ,balance or ,lever ,i
 ,k3 the  ,screw ,f2 which includes the 
,wedge3 and the ,pulley ,l ,m4 ,the     
entire ,force of  this ,engine is to be 
computed by compounding the separate    
,forces together4    ,fig4 #b4 ,is a    
,windmill2 whose ,force is here         
represented1 by its raising a  ,weight  
on a ,barrel4 ,the ,wind is supposed to 
blow parallel to the ,axis1  from ,e    
towards ,d2 its several ,sails have     
their ,plains nearly #de ,degrees       
oblique to the ,plain through the middle
 of those ,sails3 ,two of them          
inclining1 and two reclining4 ,by this  
,means the ,wind falling at about #de   
,degrees obliquity on the ,plain of each
 ,sail2 the ,breadth of each ,sail is a 
,diagonal of a square1 one of whose     
,sides is parallel to the ,direction of 
the circular ,motion1 and has its full  
,force2 and the other is  perpendicular 
thereto1 and so has no ,effect as to    
that circular ,motion at  all4 ,and as  

much as the ,side of a ,square is lesser
 than the ,diagonal1 so  much of the    
whole ,quantity of the ,wind is lost on 
every single ,sail4 ,but  then each     
,pair along the same ,line1 by the      
different ,situation of those  ,sails1  
agreeing in the same ,motion1 the whole 
united ,quantity is more than  the      
single ,quantity upon one equal ,sail   
directly expos'd to the same ,wind1  as 
much as two ,sides of a ,square are     
greater than the ,diagonal4 ,but this   
without the ,consideration of the       
weakning of the ,force of the ,wind by  
the  ,obliquity of ,incidence2 which    
alters the former ,proportion3 for this 
also  diminishing the ,force in the same
 ,proportion with the former ,diminution
 of  the ,quantity of the ,wind1 the    
whole ,diminution will ever be as the   
,squares  of that ,quantity2 or as the  
,squares of the ,sines of the ,angles of
  ,incidence3 wherefore in this ,case of
 ,four oblique ,sails of #de ,degrees   
will  be equivalent to ,two direct ones4

    ,fig4 #c4 ,is the elastical spiral  
,spring of a ,watch1 out of its ,box1   
and  unwinding it self more weakly1 as  
it is less restrained4    ,fig4 #d4 ,is 
the same ,spring in its ,barrel ,a ,b   
join'd by a ,chain to its  ,fusee ,c ,d1
 or spiral ,line about a ,cone1 which   
,cone has the ,semidiameter or          
,distance from its ,axis in the very    
same ,proportion1 greater as the ,spring
  is weaker1 and lesser as the ,spring  
is stronger3 that so the absolute       
,force on the ,wheels of the ,watch may 
be ever the same1 for the exact         
,equality of their ,motion in all       
,cases4    ,fig4 #e4 ,is an ,imitation  
of a ,waggon or ,coach1 with its fore   
,wheels ,e ,f1  either equal 7as here17 
or else lesser1 or greater1 than the    
hinder ,g ,h2  to be drawn by a ,weight 
w in the ,scale1 either upon an         
,horizontal1 or upon  an ,inclined      
,plain ,a ,b1 and to get over any       
,obstacle as ,c ,d3 ,the ,quadrant  ,m1 
and ,bullet ,n1 are to shew the         

,quantity of the ,elevation of that     
,plain1  for the ,tryal of ,experiments 
relating to all such ,sort of ,vehicles4
    ,fig4 #f4 ,is a strong ,machine1    
with a ,wheel ,o ,p1 and its ,winch ,r1 
and  ,string ,o ,p ,l ,k1 its lesser    
,barrel ,k ,l1 circular ,table ,a ,b1   
,scale with a  ,weight w1 suspended by a
 ,string that comes through the hollow  
,axis ,c ,d1  and oblique ,tube ,g ,c1  
in which ,mercury or a ,bullet is       
included2 its ,screw  ,h2 its ,balls ,i 
and ,b1 and their ,strings2 ,to shew    
that ,motion once begun  always         
continues1 till some other ,cause stops 
it3 ,that absolute and  respective      
,motion are entirely different3 ,and to 
shew withal the ,endeavour  of ,bodies  
that move circularly to recede from the 
,center of their ,motion1  on inclined1 
as well as horizontal ,plains1 and that 
in the same ,circle in  a duplicate     
,proportion to their ,velocity4         
,plate ,,vi4  ,sutton ,nicholls sculp3  
,,mechanicks4 #f                        

,an ,explication of the ,sixth ,,plate4 
,figure #a4 ,is an ,instrument to shew  
the various ,parabola's that are made by
  ,projectils1 and particularly the     
,truth of the several ,rules in the ,art
 of  ,gunnery4 ,wherein ,a ,b is a      
,tunnel full of ,quicksilver1 ,d ,k is a
 ,glass ,tube1  let into a ,groove or   
,frame of ,wood for its ,support1 and at
 ,k is a fine  ,stem1 accommodated to   
the ,arch of a ,quadrant ,l ,m1 and     
turning upon its  ,center1 to direct the
 projected ,quicksilver to any ,angle2  
while the ,tube's  perpendicular        
,altitude1 or the ,force that produces  
the ,projection1 is  either the same1 or
 altered by a different ,inclination at 
,pleasure1  according to the ,nature of 
the several ,experiments4    ,fig4 #b4  
,is a ,cycloid with its equal ,sides ,a 
,b1 ,a ,c1 and pendulous ,body  ,e1     
oscillating therein4 ,and1 ,note1 ,that 
by the ,make of the ,figure1 the  ,line 
,b ,c is equal to the ,circumference of 
the ,circle ,d ,g ,f1 by which it  was  

describ'd2 that the ,length of the      
,cycloid it self is four times that     
,circle's ,diameter2 that every ,part of
 it from ,f the ,vertex is still  double
 to the ,chord of the ,correspondent    
circular ,arch ,g ,f2 that its  included
 ,area ,b ,d ,c ,f1 is ,three times the 
,area of the former ,circle2 that  the  
,force upon the ,pendulum at any ,point 
,e1 is exactly proportional to the      
,distance along the ,cycloid of the     
,point from the ,vertex1 as ,e ,f2 and  
that therefore the ,time of every       
,oscillation1 in all ,angles whatsoever1
 is  always equal4    ,fig4 #c4 ,a ,c ,b
 is a ,syphon with ,quicksilver from ,a 
to ,c1 and a ,pendulum  of half that    
,length2 to shew here also that the     
,force is as the ,line to be  describ'd1
 and that by ,consequence the           
,vibrations in the ,syphon are all      
equal3 as also to shew that they are    
equal to those of a ,pendulum1 of half  
the same ,length3 ,as is plain from the 
former ,case of the ,cycloid1 where  the

 ,length of the ,pendulum is half that  
of the ,cycloid in which the ,body      
moves4    ,fig4 #d4 ,a ,b are two       
,spheres1 to denote the several ,laws of
 ,motion in the  ,collision of ,bodies1 
whether ,elastical or not ,elastical1 to
 be tried in  the ,cycloid1 or in a     
,circle1 with proper ,corrections3      
,which ,experiments  yet are most of    
them too difficult for such a ,course as
 this is4    ,fig4 #e4 ,is an           
,instrument to explain muscular ,motion2
 supposing the  ,muscles to be some way 
like a ,string of ,bladders2 by shewing 
that a  smaller ,quantity of an         
elastical ,fluid may equally raise equal
 ,weights  with a larger2 and to shew   
exactly what ,quantity is necessary for 
any  particular ,effect4 ,for thus will 
the lesser ,quantity of ,air1 7measured 
in  both ,cases by the ,gage ,c ,a ,k1  
as condens'd by the ,syringe ,h ,a7     
equally  raise an equal ,weight to the  
same ,height by the lesser three        
,bladders1  that the greater ,quantity  

raises the same by the one larger       
,bladder4    ,fig4 #f4 ,are several     
,pendulums of several ,sorts of ,matter1
 heavy and  light2 where the ,centers of
 ,suspension and ,oscillation are       
equally  distant1 and the ,times of     
those ,oscillations are all equal4 ,this
 also  hints the other remarkable       
,phnomena of ,pendulums2 viz4 that the  
,semicircular and ,cycloidal ,times of  
,oscillation are to each other as #cd to
  #bi3 ,that in both the ,length of the 
,strings of ,pendulums are in a         
duplicate  ,proportion to their ,times  
of ,oscillation2 and that the ,heights  
of ,roofs1  c4 may be found from the    
,times of the ,oscillations of          
,pendulous ,bodies  fixed to them1 on   
the known ,hypothesis that a ,pendulum  
of #ci4b ,inches  vibrates in one       
,second of ,time4    ,fig4 #g4 ,is a    
,fountain running on ,wheels1 and made  
by ,air condens'd on  the ,surface of   
,quicksilver1 and so forcing the        
,quicksilver to ascend  through the     

,pipe ,g3 ,and is to shew that the      
,lines of ,projectils1 or other         
,bodies1 are not alter'd by the common  
,motion of the whole ,instrument or     
,floor on which they are plac'd2 and    
that all ,motions on the ,earth1 if it  
move1 will be the same as if it stand   
still4    ,fig4 #h4 ,is a ,parabola with
 the several ,lines belonging to it1 in 
order  to demonstrate the ,doctrine of  
,projectils2 and particularly the ,art  
of  ,gunnery4    ,fig4 #i4 ,is an       
,engine moving on ,wheels1 that lets a  
,ball fall down from a  ,groove through 
a ,hole1 as it is in ,motion2 to shew   
that it will then fall  on the same     
,point of the ,frame that it falls upon 
when it is at rest2 as  does a ,stone   
let fall from the ,top of the ,mast of a
 ,ship under ,sail3 and  that all       
respective ,motions on the ,earth must  
be the very same1 while it  self moves  
as if it were at rest4    ,fig4 #aj4 ,is
 a ,cylindrical ,iron ,a ,b1 swinging on
 a ,pin ,e ,f1 in the very  same time   

that a pendulous ,body ,d of two thirds 
of its ,length ,c ,d does2 to  shew that
 two thirds is the ,center of           
,oscillation or ,percussion in all  such
 prismatick or cylindrical ,bodies4     
,opticks ,plate ,i4  ,sutton ,nicholls  
sculp3                                  
#g                                      
,,opticks4                        ,an   
,explication of the ,first ,,plate4     
,figure #a4 ,represents the ,foundation 
of ,vision1 and of all ,opticks         
whatsoever1 by exhibiting to the ,eye a 
,specimen how the ,rays of ,light do  as
 well originally1 as after ,reflection  
or ,refraction1 spread themselves  in   
right ,lines from each ,point in every  
visible ,object1 as ,p1 to each  other  
,point1 as ,r1 ,r1 ,r1 ,r1 ,r1 every    
way1 to be receiv'd by the ,eye in any  
direct ,position whatsoever4    ,fig4   
#b4 ,represents the known ,law of       
,reflection2 that the ,angle of         
,incidence ,c ,p ,d1 is equal to that of
 ,reflection ,c ,p ,e1 or that the      

,angle  of ,inclination ,d ,p ,a is     
equal to the other ,e ,p ,b4    ,fig4   
#c4 ,shews the ,reason why a plain      
,looking-,glass1 as ,a ,e ,f ,b1        
exhibits  the ,object ,c ,d by the      
,image c d1 which is equal to ,c ,d1 and
 equidistant  from the ,glass ,a c  ,a  
,c3 ,and in an erect ,posture2 all      
depending only on  the ,equality of the 
,triangles1 whose ,vertices are ,c c 3  
,d d1 and have  their common ,bases     
below ,e and above ,f1 which ,glass by  
forming the same  ,image c d1 so to the 
,eye1 as if the real ,object ,c ,d was  
at c d1 must  needs shew that ,picture  
in the ,place assign'd1 without any     
,inequality of  ,distance or ,magnitude1
 or any ,inversion4    ,fig4 #d4 ,shews 
the ,reason why the same or equal       
,object1 as ,a ,b1 ,c ,d1 ,e ,f1        
appears larger when it is nearer1 and   
smaller when farther off3 viz4 on       
account of the ,inequality of the       
,angles ,a ,g ,b1 or ,m ,g ,n1 and ,c ,g
 ,d1 or  ,k ,g ,l1 and ,e ,g ,f or ,h ,g

 ,i1 and the consequent ,inequality of  
the ,pictures  made by the ,rays at the 
,bottom of the ,eye4    ,fig4 #e4 ,shews
 the ,reason why a ,convex              
,looking-,glass1 as ,a ,e ,f ,b1        
exhibits ,object ,c ,d by the ,image c  
d1 both nearer to the ,glass1 and       
lesser than it self2 but still in an    
erect ,posture4 ,all depending only on  
the different ,bend of the ,circle      
between ,e and its lower ,point1 between
 ,f  and its upper ,point2 which cannot 
make the ,angles of ,reflection or      
,inclination equal1 as they must needs  
be in all such ,reflections1 without    
making the ,vertices of the ,angles1 as 
c and d1 nearer the ,glass than ,c  and 
,d3 ,and so the apparent ,picture or    
,diameter c d lesser than that of  the  
,object ,c ,d1 though without any       
,inversion4    ,fig4 #f4 ,shews the     
,reason why a ,concave ,glass1 as ,a ,e 
,f ,b1 exhibits an  ,object plac'd      
nearer the ,glass than the ,center1 as  
,c ,d by the ,image c d1  remoter from  

the ,glass1 and larger than it self1    
viz4 for ,reasons just  contrary to     
those under the fifth ,figure foregoing4
    ,fig4 #g4 ,shews the ,reason why a  
,concave ,glass1 as ,c ,d ,e ,f1        
exhibits an  ,object1 if it be plac'd   
remoter than the ,center1 as ,a ,b1     
inverted1 and at  different ,distances  
between the ,eye and the ,glass2        
according to the ,length  or ,shortness 
of its own ,distance1 as ,b ,c or ,a ,d1
 viz4 ,because the ,rays  from the same 
,point still cross one another1 as at ,g
 and ,h1 before they  fall upon the     
,eye2 and so by forming an inverted     
,image make it impossible  for the ,eye 
to see the ,object in any other         
,position than that the ,image  has2    
which ,image indeed it self is the only 
proper ,object of the ,eye1 in  all such
 ,cases whatsoever4    ,fig4 #h4 ,is a  
,picture in ,confusion2 but rectified by
 a ,convex ,cylinder1  and thereby      
brought into exact ,order again4        
,fig4 #i4 ,represents an ,image in a    

,cylindrical ,concave ,surface1 when the
  ,eye is in a ,plain perpendicular to  
its ,axis2 so that lengthways it is as a
  ,plain1 and breadthways as a ,concave 
,speculum3 ,which therefore makes the   
,picture longer1 but not wider4 ,the    
contrary will happen in a ,convex       
,speculum1 which will make it shorter   
but not narrower1 for the like  ,reason4
                            ,plate ,,ii4
  ,sutton ,nicholls sculp4              
,,opticks4 #h                       ,an 
,explication of the ,second ,,plate4    
,figure #a4 ,shews that an ,object1 as  
,k1 seen through a plain ,glass1 whose  
,sides ,a ,b1 ,c ,d1 are parallel1 by   
the ,eye at ,g1 appears out of its true 
,place2 and this so much the more as the
 ,glass is thicker3 ,while at the  same 
time the two ,surfaces do exactly       
balance each other's ,refraction1 and   
make the two ,rays ,h ,k1 ,g ,f exactly 
parallel4    ,fig4 #b4 ,exhibits a plain
 ,method of measuring the ,refraction of
 ,fluids at  all ,angles1 and of proving

 thereby that it is always in one fixed 
,proportion of the ,sines1 as the next  
,figure will explain it4 ,for if the    
moveable ,rule ,k ,c ,l1 with its       
measuring ,circle ,a ,b ,d ,e fix'd by  
the ,prop  ,e1 to a heavy ,pedestal ,f  
,g1 in a large ,glass ,a ,h ,i ,d1 be so
 far immers'd  in the ,fluid1 that the  
,center ,c may be in the ,surface of the
 ,fluid1 and  one of its ,legs ,c ,l be 
so far bent from a rectilinear          
,position1 that the  ,refraction of the 
,fluid can just make it appear as if it 
were in a strait  ,line1 the ,angle ,b  
,c ,k1 or its equal ,m ,c ,e1 is the    
,angle of ,incidence3 ,and  ,l ,c ,e the
 ,angle of ,refraction3 ,and ,l ,c ,m   
the ,difference1 or the refracted       
,angle4    ,fig4 #c4 ,is for the        
,illustration of the former             
,proposition1 and shews the  ,sines     
afore-mentioned2 as ,a ,d or ,g ,n 7for 
they are suppos'd equal1 and the  ,line 
,a ,c ,n one strait ,line17 is the ,sine
 of the ,angle of ,incidence1 and  ,f ,e

 the ,sine of the ,angle of ,refraction1
 which ,sines do in the same ,fluid  at 
all ,angles bear one and the same       
,proportion to each other2 till at      
last1 if the ,refraction be out of a    
thick ,medium into a thin one1 and      
makes the second ,sine equal to the     
,radius1 that ,ray cannot emerge at all1
  but will be reflected back by the     
,surface into the same ,medium whence it
  came1 along the ,line ,c ,r4    ,fig4 
#d4 ,is a ,bason of ,water1 or other    
,fluid2 to shew the common  ,experiment 
of ,refraction2 where a ,shilling1 or   
other ,object at ,a1 7which  is so      
plac'd that it cannot be seen by the    
,eye at ,o1 the ,side of the ,bason  ,c 
interposing7 is readily seen there1 as  
soon as the ,water or other ,fluid  is  
put in to the same ,bason1 and appears  
to be remov'd to the ,point ,b4    ,fig4
 #e4 ,is the ,alteration of a round     
white ,object ,d1 as seen through a     
,triangular ,glass ,prism ,a ,b ,c1 by  
the ,eye at ,g1 where the double        

,refraction  of the ,glass at ,e and ,f 
makes the ,object appear at d2 and that 
as an  oblong colour'd ,image2 wherein  
the upper ,part is made by the violet   
,rays1  which are most refrangible2 and 
the lower by the red ,rays1 which are   
least  so2 and the intermediate ,parts  
by those that are refrangible in a mean 
,degree2 after the ,order of the        
,colours of the ,rainbow4    ,fig4 #f4  
,shews the ,nature of a multiplying     
,glass ,a ,d1 and its ,plains ,a ,b1  ,b
 ,c1 ,c ,d1 c4 and the ,reason why the  
different ,refraction of every  oblique 
,plain1 as ,a ,b1 ,c ,d1 c4 exhibits the
 same ,object ,k as a  different ,object
 k1 k1 c4 according to the ,number of   
the oblique  ,plains3 ,while the direct 
,plain ,b ,c shews it still in its own  
,place3 ,and  while the ,convolution of 
the ,glass on the ,axis ,k ,l removes   
all the oblique  ,images1 but does not  
remove the direct one1 on ,account of   
the ,change of  the ,position of those  
oblique ,plains1 and of the unchanged   

,position of the  direct ,plain4        
,fig4 #g4 ,shews the ,effect of the     
,lens1 or double ,convex ,glass1 in     
gathering parallel ,rays1 as ,g ,l1 ,h  
,m1 ,a ,b1 ,i ,n1 ,k ,o1 c4 towards a   
,point1 as ,d2 because1 as in the ,case 
of the ,prism above1 the ,refraction  to
 the perpendicular in the ,entrance1 and
 from it in the ,exit of those  ,rays1  
do still1 by the different ,position of 
that ,perpendicular1 conspire  to unite 
the same ,rays4    ,fig4 #h4 ,shews the 
contrary ,effect of the double ,concave 
,glass1 in  scattering the parallel     
,rays2 and that exactly on the like     
,account2 and so  this needs no new     
,explication4    ,fig4 #i4 ,shews the   
,reason why a ,lens1 or double ,convex1 
shews a near  ,object at ,q1 as more    
remote at q1 because it refracts it so  
that the  ,rays from the same ,point    
meet more backward than before3 ,and why
 it shews  the same ,object larger also3
 ,which must needs be1 because every    
,point in  the ,object appearing so much

 more backward1 and yet in the same     
apparent  ,angle1 its ,length and       
,breadth must every where be            
proportionably enlarg'd4    ,fig4 #aj4  
,shews how such a ,lens inverts         
,objects1 as ,a1 ,b1 b a1 which it  does
 on ,account of the ,intersection of the
 ,rays from each ,point1 in or  near the
 ,lens it self3 ,which necessarily      
infers such an ,alteration3 just  as the
 ,images of all ,objects are in the ,eye
 in an inverted ,position1 on  the like 
,account4    ,fig4 #aa4 ,shews how a    
,lens does so refract the ,rays from    
every ,point of  an ,object1 that is in 
its ,focus ,c1 and ,b1 and ,a1 that the 
,rays from each  of those ,points do    
become parallel afterward2 and also how 
parallel ,rays  of different ,positions 
are gather'd in that ,focus4    ,fig4   
#ab4 ,is the ,nature of direct ,vision  
by the ,eye1 in some ,conformity  to the
 #ajth ,figure3 only in this ,case the  
,crystalline ,humour is the ,lens4      
,fig4 #ac4 ,is the ,case of a           

,concavo-convex ,glass1 with its        
parallel  ,surfaces1 as in ,fig4 #a4    
,plate ,,iii4  ,sutton ,nicholls sculp3 
,,opticks4 #i                        ,an
 ,explication of the ,third ,,plate4    
,figure #a4 ,is a ,telescope1 with two  
,convex ,glasses1 the one towards the   
,object and the ,segments of a great    
,sphere1 the other near the ,eye1 the   
,segments of a small ,sphere g h i1 and 
they are to be so placed that the       
distinct ,base or ,image may1 by the    
,collection of the ,rays1 be in the     
common ,focus of both the ,glasses f e  
d4 ,by these two ,glasses the  parallel 
,rays1 or those nearly so1 as proceeding
 from the same ,point of  the ,object ,a
 ,b ,c1 7which is to be suppos'd        
considerably remote7 are made  to meet  
in the intermediate ,image f e d1 at f1 
and e1 and d2 and  again at the ,bottom 
of the ,eye1 at r1 and s1 and t2 but in 
an erect  ,position2 and therefore so as
 to shew the ,object inverted4    ,fig4 
#b4 ,is a ,telescope with four ,convex  

,glasses1 the one towards the  ,object1 
and three nearer the ,eye3 ,whose       
,images are made in the common  ,focus  
of two ,glasses1 as before4 ,this is    
like the former2 but only that  two of  
the ,eye ,glasses serve merely to       
reinvert1 or to erect the ,image1  that 
so it may be inverted at the ,bottom of 
the ,eye2 and therefore may  shew the   
,object in its true or erect ,position4 
,fig4 #c4 ,is a ,telescope1 with a      
,convex ,object ,glass1 and a ,concave  
,eye  ,glass2 which last1 by scattering 
the ,rays1 as if they came from a nearer
  ,point1 makes the ,image inverted in  
the ,bottom of the ,eye1 and therefore  
shews the ,object in its true or erect  
,position4 ,only this takes in but a    
small ,part of an ,object1 an so is less
 used than the two former  ,telescopes4 
,fig4 #d4 ,is a ,telescope with a       
,triangular ,prism ,d ,b in its ,axis2  
and that  ,prism's ,gage ,f ,g for the  
,demonstration of the ,refraction out of
 ,vacuum  into ,air1 and out of thinner 

,air into thicker2 and both by the      
,means of an  ,object seen through the  
,prism1 as well when the ,air is        
condensed1 as when  it is exhausted4    
,where in the first ,case the ,object is
 seen higher1 and in  the other lower   
than in its natural ,situation2 as the  
two following  ,figures demonstrate4    
,fig4 #e4 ,shews how the ,object or     
,circle which was low at first1 is to   
,appearance rais'd as it passes through 
condens'd ,air2 by being refracted      
towards the perpendicular1 in its       
,ingress into a ,glass ,prism1 and from 
it  in its ,egress into the common ,air 
again4    ,fig4 #f4 ,shews how the same 
,object or ,circle1 which was high at   
first1 is  to ,appearance depress'd1 as 
it passes through the ,vacuum2 by being 
refracted from the ,perpendicular1 in   
its ,ingress into the ,prism1 and       
towards it1 in its ,egress into the     
common ,air again4    ,fig4 #g4 ,is a   
,triangular ,glass ,prism1 fitted to    
receive all sorts of  ,fluids1 and when 

rightly apply'd to the ,semi-circle of  
the next ,figure1  does exactly measure 
the refractive ,power of all those      
,fluids4 ,where the  vertical ,angle ,g 
,d ,h is #de ,degrees2 and by           
consequence the half ,angles  ,c ,d ,h1 
,c ,d ,g1 ,c ,h ,g1 are #bb #cj1 and    
where all is to be so contriv'd1  that  
the ,rays within the ,glass may be      
parallel to ,g ,h1 and perpendicular  to
 ,c ,d1 and may fall on each side ,plain
 of the ,glass ,prism in an ,angle of   
#bb #cj from their ,perpendiculars2 that
 so the ,refractions at the ,ingress    
and ,egress may be equal1 and the       
,computations easy4    ,fig4 #h4 ,is the
 ,semicircle1 with the ,glass ,prism    
full of its ,liquor  rightly apply'd    
thereto2 and both ,arms of the ,index ,e
 ,d1 ,f ,d1 equally  elevated above the 
horizontal ,line ,a ,c4 ,this shews the 
,proportion of the  ,sine of the ,angle 
of ,incidence to that of ,refraction1 in
 this ,incidence of  #bb #cj2 which     
,proportion of ,sines being the same in 

all other ,angles1 we  hence learn that 
,proportion accurately and universally4 
,plate ,,iiii4  ,sutton ,nicholls sculp3
                                        
,,opticks4 #aj                       ,an
 ,explication of the ,fourth ,,plate4   
,figure #a4 ,is the ,apparatus for      
,microscopes3 ,containing ,a ,c a       
,cylinder of  ,brass or ,ivory2 to      
which1 near the ,eye at ,k1 the         
,microscope it self1 or  very small     
,sphere of ,glass set ,ivory1 is        
apply'd2 ,g ,h a small ,slice of        
,ivory1 and its ,muscovy ,glass         
,circles1 with the fine ,objects upon   
them1  inserted in their true ,place2 ,e
 ,f a ,convex ,glass1 screwed into the  
former  ,cylinder1 and at a due         
,distance casting ,light on the         
,objects2 with ,i ,l1  the ,handle of   
the ,microscope4    ,fig4 #b4 ,is only  
one of the ,slices of ,ivory ,a ,b1 like
 ,g ,h  before-mentioned1 set by it     
self2 with the double ,circles of       
,muscovy  ,glass1 and kept down by      

circular ,wire2 between which1 on one of
 those  ,glasses1 the small ,objects are
 commonly plac'd4    ,fig4 #c4 ,is a    
,scheme to demonstrate how the double   
,microscope comes to  magnify so much4  
,where ,g is the small ,object2 which1  
if there be ,light  sufficient1 may by  
the small ,microscope ,glass ,e ,f1     
placed very near the  ,object1 be cast  
into a larger ,image ,h ,i3 ,which by   
the ,means of the two ,eye  ,glasses1   
are reduc'd into a ,compass fit to enter
 into the ,eye4 ,and here by  the way it
 is to be noted that die small ,glasses1
 whereby single  ,microscope do magnify 
so much1 and whereby the ,magnitude is  
in ,part  increas'd in this double      
,microscope1 is only a very small       
spherical ,glass1  or ,segment of it1   
which does so suddenly reduce distant   
,rays to  ,parallelism1 or nearly to it1
 that a small ,object1 which by its     
great  ,nearness could not be otherwise 
seen1 is hereby made visible4    ,fig4  
#d4 ,is the double ,microscope1 with all

 its ,apparatus and  ,contrivances1 as  
to the ,position of the ,object1 the    
,light to be thrown  upon it1 and the   
,elevation and ,depression of the       
,instrument it self1 as  the ,case      
requires1 c4 all which the ,figure does 
plainly shew to the  ,eye4    ,fig #e4  
,is a circular ,plate of ,ivory1 with a 
small ,sphere of ,glass in its  ,center1
 and a ,screw round the ,center1 to be  
put upon the first ,figure at  ,b ,c1 as
 a single ,microscope4    ,fig4 #f4 ,is 
a small ,fish1 represented in a         
,cylindrical hollow ,glass1 so  as it is
 to be placed when the ,circulation of  
,blood in its ,tail is to be  seen by   
the single ,microscope4    ,fig4 #g4 ,is
 the ,magick ,lanthorn1 with its        
,pedestal ,t3 its ,lamp ,w2 its  double 
,convex ,glass ,x ,y2 its ,pictures     
inverted upon the ,plate ,e ,f2 and its 
large or gygantick ,images at ,b ,a     
projected upon the white ,wall1 to the  
,surprize of the ,spectators4    ,fig4  
#h4 ,is the ,demonstration of the       

,camera obscura1 or dark ,chamber2      
which will shew the ,object as ,a ,b    
erect4 ,where ,c ,d is the double       
,convex  ,glass1 ready to form an       
inverted ,picture b a3 ,which by the    
,reflection of  the plain ,speculum ,e  
,f1 plac'd obliquely in an ,angle of #d1
 is formed in  an erect ,position at a  
b1 for the ,view of the ,spectator4     
,plate ,v4  ,sutton ,nicholls sculp3    
,,opticks4 #aa                          
,an ,explication of the ,fifth ,,plate4 
,figure #a4 ,is one of ,sir ,isaac      
,newton's ,experiments1 to shew the     
different ,refrangibility of the ,rays  
of ,light1 of the different ,colours1   
,red1 ,orange1 ,yellow1 ,green1 ,blue1  
,indigo1 ,violet4 ,where ,d ,e is a     
,parallelogram of ,pastboard1 having the
 one half ,d ,g blue1 and the other     
half ,f ,e red2 both strongly           
illuminated by the same ,candle3 and    
having  black ,silk wrapped several     
times round it4 ,m ,n is a ,lens or     
double ,convex  ,glass interpos'd1 which

 gathers upon white ,paper the blue     
,rays sooner at  h i than the ,red at ,h
 ,i3 ,as appears by the ,distinctness of
 the ,colours  and of the ,silk at those
 and only those ,distances4 ,where also 
at somewhat  above #ab ,feet from the   
,colours to the ,images1 the ,distance  
between h i  and ,h ,i is no less than  
an ,inch and half4    ,fig4 #b4 ,is     
another of ,sir ,isaac's ,experiments to
 the same ,purpose3  ,where ,x ,y       
represents the ,sun3 ,e ,g1 a ,window1  
with a small round ,hole at ,f3  within 
which is a ,triangular ,glass ,prism ,a 
,b ,c1 by which the ,rays of the  ,sun  
are differently refracted upon a white  
,wall or ,paper ,m ,n2 and become  an   
,oblong ,image ,p ,t2 the ,violet seen  
at ,p as most refracted2 and the ,red   
at ,t1 as least refracted3 ,and the     
intermediate ,colours seen in           
intermediate ,places1 according to the  
different ,degrees of their             
,refraction4    ,fig4 #c4 ,is another of
 his ,experiments1 to shew that ,white  

is a ,mixture  of all ,sorts of colour'd
 ,rays2 where ,d ,c is a ,hole in the   
,window1 which  admits the ,sun's ,rays4
 ,e ,f ,g a ,prism1 casting its oblong  
colour'd ,image  upon a ,lens1 or double
 ,convex ,glass2 which collects all     
those ,rays into  its ,focus4 ,in which 
,case1 the ,point of ,concourse exhibits
 a perfect ,white  ,colour2 tho' upon   
their ,separation again1 the oblong     
colour'd ,image  appears again1 only in 
an inverted ,position3 as the crossing  
of the ,rays  in the ,focus must of     
,necessity occasion4    ,fig4 #d4 ,is   
the last ,experiment improv'd2 by       
shewing that the ,white ,light  made by 
the ,mixture of all the ,colours is but 
imperfectly so1 when any of  the several
 ,colours are intercepted in their      
,passage to their ,focus1 or  ,place of 
,mixture4    ,fig4 #e4 ,is the          
,experimentum ,crucis1 or determining   
,experiment4 ,where  ,b ,f is the ,hole 
that lets in a large ,ray of ,light3    
whose middle ,part1  after it has pass'd

 through the ,prism ,a ,b ,c1 is let    
through a lesser ,hole  at ,g1 and forms
 an oblong colour'd ,image at d e3 where
 another small  ,hole lets thro' one    
,colour only2 which passing through the 
,second ,prism  a b c it is refracted   
again1 and cast upon ,n ,m4 ,and here it
 is most  remarkable1 that the two      
,holes and second ,prism are kept       
immoveable2 and  so the ,rays ,g g fall 
upon the second ,prism in the very same 
,angle1  whatever ,colour they are of1  
and that by the ,motion of the first    
,prism1  all the ,colours may           
successfully pass through the same      
,holes4 ,yet is the  ,refraction by the 
second ,prism never then able to produce
 any ,variety of  ,colours2 but exhibits
 the ,image always of that ,colour      
alone1 which falls  upon it before the  
second ,refraction4    ,fig4 #f4 ,is a  
,figure for the ,explication of the     
several ,refractions and  ,reflections  
of ,light1 which cause the ,phnomena of 
the ,rainbow4 ,thus if  the greatest    

,crowd of ,rays enter in ,parallel to ,b
 ,q along or near to ,a ,n1  the round  
,drop of ,water ,l ,b ,g ,q will refract
 ,part of those ,rays to ,f1  whence    
,part of them will be reflected to ,g3  
,and going there out of the  ,drop1 will
 be thereby refracted to ,r1 which      
double ,refraction will so  separate the
 several ,colours1 and make them go out 
in ,angles so sensibly  different1 that 
as the ,eye is placed a little higher or
 lower1 it will see  a different        
,colour2 and that in ,angles as ,a ,x   
,r1 of about #da ,degrees2 and  this is 
the ,case of the primary ,rainbow1 which
 appears in about that ,angle  from the 
,axis ,b ,q1 or its ,parallel ,a ,x4    
,thus also1 if the same ,line ,a ,n be  
now suppos'd to represent another ,drop1
 and that some of the ,rays at ,g are   
reflected a second time1 and so pass out
 at ,h1 and are there refracted to  ,s2 
here will be a weaker ,impression1 but a
 like ,refraction and ,separation  of   
the ,colours as before2 and the ,eye    

placed a little higher or lower will    
also see different ,colours1 tho' in a  
contrary ,order to the former2 and  that
 in an ,angle1 as ,a ,y ,s1 of about #eb
 ,degrees and a half2 which is the      
,case of the secondary ,rainbow4        
,fig4 #g4 ,are the two ,rainbows        
themselves1 r presented as they appear  
in  ,nature4 ,where ,a ,e ,b ,f         
represents the ,air full of spherical   
,drops of ,rain1  in such ,parts as the 
,angles ,e ,o ,p1 ,f ,o ,p are about #da
 ,degrees from the  ,axis ,o ,p1 which  
,axis is the ,line from the ,sun's      
,center1 through the ,eye of  the       
,spectator1 to the ,center of the       
,rainbow3 ,and where ,c ,g ,d ,h        
represents  the same ,air1 full of the  
like ,drops1 in such ,parts where the   
,angles  ,g ,o ,p1 ,h ,o ,p are about   
#eb ,degr4 and a half4 ,where also the  
,rays ,s ,e1 ,s ,f1  ,s ,g1 ,s ,h1      
coming from the ,sun's ,center1 are     
represented as parallel1 by  reason of  
its vast ,distance4 ,these ,rays1 when  

they fall upon the higher  ,quadrant of 
the ,drop1 as at ,s ,e1 ,s ,f1 come to  
the ,eye at ,o in about an  ,angle of   
#da ,degrees1 after two ,refractions1   
and one ,reflection2 and so  cause the  
primary ,rainbow3 the ,red is without1  
by the least refrangible  ,rays at ,f3  
and the blue within1 by the more        
refrangible ,rays at ,e4 ,but  when they
 fall upon the lower ,quadrant of the   
,drop1 as at ,s ,g1 ,s ,h1 they  come to
 the same ,eye at ,o1 but in an ,angle  
of about #eb ,degrees and a half1  after
 two ,refractions1 and two ,reflections1
 and so cause the secondary  ,rainbow4  
,which is ,blue without1 by the more    
refrangible ,rays at ,h2 and ,red       
within by the least at ,g4 ,where note1 
that because the ,angles ,f ,o ,p1  ,e  
,o ,p1 as well as those ,h ,o ,p1 ,g ,o 
,p1 are ever the same1 the same ,colours
  must still be circular1 or appear in  
the ,surface of a right ,cone1 whose    
,axis is ,o ,p1 and whose ,sides are the
 ,lines turned round thereon1 as ,o ,e  

,o ,f1 and ,o ,g ,o ,h4                 
,hydrostaticks ,plate ,i4  ,i4 ,senex   
sculp4t                                 
#ab                                     
,,hydrostaticks4                        
,an ,explication of the ,first ,,plate4 
,figure #a4 ,is a ,balance1 to weigh    
,water in its own ,element1 and in the  
,air2  and to prove that its ,weight is 
the very same in the former ,case as in 
the  latter4 ,for when the ,glass       
,bottle ,f is exhausted of ,air1 it will
 indeed  require much more ,weight to   
counterpoise it in the ,air1 than in the
 ,water2  by ,reason of the much greater
 ,weight of the ,water thrust out by it1
 than  of the ,air2 yet when upon the   
,admission of ,water within1 you weigh  
it  again in the ,air1 and then in the  
,water1 the additional ,counterpoise now
  necessary is the very same2 and shews 
that the real ,weight of the ,water     
admitted1 is the same in both ,elements4
 ,this ,figure does also shew how       
,trials may be made to shew the         

respective ,weight of those ,bodies in  
,fluids  that sink in them4    ,fig4 #b4
 ,is an inverted ,syphon1 to shew why   
,fluids ever press according  to        
perpendicular ,altitude1 and not        
according to ,quantity of ,matter3 ,as  
the  small ,quantity of ,water in the   
smaller ,tube is a ,balance for the     
great  ,quantity in the greater1 and    
stands upon the same ,level ,c ,d ,e ,g2
 because  in all possible ,motions and  
,vibrations of the ,fluid1 the ,velocity
 in the  smaller must1 by the ,make of  
the ,syphon1 compensate the ,quantity in
 the  larger2 the one ascending or      
descending as far as ,b ,d1 while the   
other  ascends only as far as ,e ,h1 and
 so the ,force is equal on both ,sides1 
as is  the known ,case in the ,stiliard 
also4    ,fig4 #c4 ,is to shew the same 
equal perpendicular ,height or ,level in
 a  common ,syphon inverted4    ,fig4   
#d4 ,is a ,number of hollow ,tubes1 of  
all ,shapes and ,directions1 to  shew   
that if their lower ,orifices be put    

under tinged ,water1 and ,oil be  poured
 on the ,surface of that ,water1 from ,g
 ,h to ,e ,f1 the tinged ,water  will   
equally be pressed upwards through all  
the ,tubes1 according to all            
,directions2 and will stand upon a      
common ,level2 tho' somewhat under the  
,surface of the ,oil1 because ,oil is   
lighter than ,water4    ,fig4 #e4 ,is   
for the same ,experiment with ,water on 
the ,surface of  ,quicksilver2 into     
which ,quicksilver a hollow ,tube is    
inserted before the  pourings in of the 
,water4 ,for the ,water will press upon 
the ,quicksilver1  and raise it in the  
small ,tube1 till it bears the same     
,proportion to the  ,height of the      
,water1 that the ,specifick ,gravity of 
,water bears to that of  ,quicksilver1  
or about a fourteenth ,part so high4    
,which1 by the by1 is one  ready ,way   
also of finding the ,specifick ,gravity 
of ,quicksilver to ,water1  by measuring
 their several ,altitudes4    ,fig4 #f4 
,is to shew how ,water in a very small  

,tube may elevate  ,quicksilver it self1
 when it is thrust more below the       
,surface of the  ,water1 than the       
,difference of their ,specifick ,gravity
 requires2 and that  it will rise or    
fall as you thrust it lower1 or raise it
 higher2 and will  at last fall out at  
the ,bottom1 if you raise it too high4  
,fig4 #g4 ,is to shew that ,fluids of   
different ,specifick ,gravities1 as     
,water ,a ,b1 and ,oil ,a ,c1 will stand
 at unequal perpendicular ,altitudes1 in
  ,proportion to their ,quantities1 and 
,difference of ,specifick ,gravities4   
,fig4 #h4 ,is a ,part of a ,compound    
,balance1 to be joined to that of  ,fig4
 #a4 for the weighing of ,levity1 or of 
the ,power of ,ascent in a ,body1  as   
,f1 lighter than the ,fluid wherein it  
is2 and will shew that that ,levity  is 
the ,difference of the ,weight of that  
,body1 and of an equal ,bulk of the     
,fluid3 ,which is also the respective   
,gravity of those ,bodies which are     
heavier than their ,fluids1 as may be   

tried by the same ,balance of  ,fig4 #a4
 alone4                                 
,plate ,,ii4  ,i4 ,senex sculp4t        
,,hydrostaticks4 #ac                    
,an ,explication of the ,second ,,plate4
      ,figure #a4 ,is a large ,glass    
,vessel ,a ,d full of ,water as high as 
,e ,f4 ,within  this is a lesser ,glass 
,vessel ,p ,h1 open at both ,ends1 but  
somewhat  narrower at the ,bottom4      
,through the middle of this goes a      
strong ,wire ,m ,n1  to which is fixed  
at the lower ,end a ,plate of ,lead ,g  
,h1 with wet ,leather  to its upper     
,surface1 to be applied to the large    
lower ,orifice of the  lesser ,glass ,i 
,k1 to keep out the ,water from entring 
into the same any  otherwise than by a  
slow ,insinuation4 ,this is to shew that
 a ,plate of  ,lead1 or other ,metal1   
may be supported by ,water1 and not sink
 in it1 where  the ,water is kept from  
pressing on its upper ,surface1 so long 
as its ,depth  under the ,water is      
greater than its ,specifick ,gravity    

requires2 and that  by ,consequence     
while ,water is gradually admitted over 
it1 it will not sink  till the          
perpendicular ,height of the ,column of 
,air between ,e ,f and ,r ,s  bears no  
greater ,proportion to the ,thickness of
 the metalline ,plate 7with  what is    
annexed to it7 than the ,specifick      
,gravity of the ,metal bears to  ,water4
    ,fig4 #b4 ,is a cylindrical ,vial or
 ,glass ,a ,d1 with a small ,cylinder of
  ,wood below ,g ,h fixed to its        
,bottom1 and made very smooth at ,top2  
and  another like ,cylinder of ,wood    
above ,g ,h1 made equally smooth on the 
lower  ,side1 that it may as exactly as 
possible fit the other2 with a strong   
,pin  ,i1 fixed in its ,axis4 ,upon     
these ,two1 when laid close1 is pour'd  
,quicksilver1 till it covers them both  
as far as ,e ,f4 ,this is to shew1 that 
there is no such thing as positive      
,levity2 but that ,wood is so far from  
rising in ,quicksilver of it self1 that 
till a sufficient ,force pulls it  up1  

and permits the ,quicksilver to         
insinuate between the two ,plates1 the  
upper is fastned to the lower by that   
,quicksilver3 ,tho' upon the first      
,insinuation of the same it immediately 
and violently emerges of it self3  ,as  
,dr4 ,moor's ,famous ,trencher did in   
his ,bucket1 to his great ,surprize2    
till he was forc'd to solve it by the   
,introduction of his ,spirit of         
,nature4    ,fig4 #c1 and #d4 ,are      
,vessels of equal ,altitude1 but unequal
 ,bases1 and  of the same ,quantity of  
,water2 to shew that ,fluids ever press 
according to  their ,bases1 if their    
perpendicular ,height be equal2 and     
according to  their perpendicular       
,height1 if their ,bases be equal1      
whatever ,figure they  are of4    ,fig4 
#e4 ,is a cubical ,vessel full of       
,water1 in order to compute the  entire 
,quantity of the ,pressure its ,sides   
and ,bottom sustain4 ,and that the      
,bottom alone sustains the whole ,weight
 of the ,water2 as is most evident4     

,fig4 #f4 ,is to shew that each ,side of
 the same ,vessel sustains a ,pressure  
equal to half the ,weight of the same   
,water4 ,for since the ,pressure at     
every point1 as ,l1 ,m1 ,n1 ,c1 is equal
 to the ,altitude of the ,water above   
it1 ,a ,l1 ,a ,m1 ,a ,n1 ,a ,c1 by      
erecting equal ,perpendiculars ,l ,o1 ,m
 ,p1 ,n ,q1  ,c ,d1 and so at all the   
intermediate ,points1 and summing them  
up1 we shall  have the ,triangle ,a ,c  
,d as the ,sum of all the ,pressures2   
which being half  the ,square ,a ,c ,d  
,b1 made by as many ,perpendiculars     
equal to the longest  ,c ,d1 and bearing
 the whole ,weight of the ,square over  
it ,a ,c ,d ,b1 shews  that the         
,pressure on every physical ,line1 as ,a
 ,c of a triangular ,prism1  and so on  
the whole ,side represented by it1 is   
one half of the whole  ,water4 ,so that 
since each of the four ,sides sustain   
half1 and the ,bottom  the whole ,weight
 notwithstanding1 the entire ,pressure  
is three times the  ,weight4    ,fig4   

#g4 ,is a like ,method of ,computation  
for an inclined ,plain's  ,pressure1 and
 how to estimate it2 viz4 by the ,weight
 of ,water equal to  the ,prism         
represented by the ,triangle ,a ,r ,c1  
where the ,lines ,l ,o1 ,m ,p1  ,n ,q1  
,c ,r1 are erected perpendicular to ,a  
,c1 and equal to ,l ,g1 ,m ,t1 ,n ,v1   
,c ,x1 respectively4    ,fig4 #h4 ,is to
 determine the ,center of ,pressure ,z  
against such a ,plain2  at which if an  
equal ,weight ,w directly pulls along ,z
 ,p over the ,pulley ,p1  it will just  
balance the ,water1 and evenly sustain  
its ,pressure4    ,fig4 #i4 ,is to shew 
that this ,center of ,pressure is no    
other than the  ,center of ,percussion  
or ,oscillation about an ,axis1 as ,d4  
,for the ,pressures  being as the       
,perpendiculars ,e ,a1 ,f ,b1 ,g ,c2 and
 the ,percussions1 as ,d ,a1  ,d ,b1 ,d 
,c1 the ,radij of the ,circles of       
,motion2 and ,e ,a being to ,f ,b1 as ,d
 ,a  to ,d ,b2 and ,f ,b to ,g ,c1 as ,d
 ,b to ,d ,c3 ,the ,percussions are     

still as the  ,pressures2 and so the    
,center of ,percussion1 the same with   
the ,center of  ,pressure4    ,fig4 #aj4
 ,is for the ,computation of the        
,quantity and ,center of the  ,pressure 
on any erect ,rectangle under ,water2   
according to that ,rule1 that  the      
,depth of any ,bodies or ,surfaces      
,center of ,gravity is to be taken for  
the perpendicular ,altitude of all the  
,pressures1 as a ,mean between them4    
,fig4 #aa4 ,is a large ,glass ,vessel ,a
 ,d1 containing ,water near the ,bottom2
  with another smaller ,vessel ,f ,k    
with ,water almost to its ,top4 ,there  
is  also a ,syphon ,b ,h ,k1 with an    
hollow ,stem ,g ,h1 communicating with  
both its  ,legs4 ,to shew that if you   
stop the ,top of the ,stem of the       
,syphon while you  pour ,oil into both  
,vessels1 a considerable ,height above  
the ,bend of the  ,syphon1 and then     
unstop it1 the ,oil will press upon the 
,water in both  ,vessels1 and force it  
to ascend in each ,leg2 till meeting at 

the ,bend1 it  run down the longer ,leg1
 out of the higher ,water into the      
lower4 ,this is  to shew how the ,air   
pressing upon ,water may raise it up1   
and cause the  known ,effects of        
,syphon1 ,pumps1 ,syringes1 c4 ,which   
used to be ascribed  to ,nature's       
,abhorrence of a ,vacuum4    ,fig4 #ab4 
,is a ,cube at different ,depths of the 
same ,water2 to shew how it  must have  
the same ,weight in one ,place that it  
has in another1 because the  ,water and 
,cube have ever the same ,proportion of 
,bulk and ,gravity to one  another4     
,fig4 #ac4 ,is a ,bucket under ,water2  
to shew it can have there no  respective
 ,gravity1 or cannot preponderate2 tho' 
it has ever the same  absolute ,gravity4
    ,fig4 #ad4 ,are a ,bubble and       
,images of the same ,nature1 made of    
,glass1 ,air1  and ,water2 all so nicely
 pois'd1 that by the ,pressure or       
,relaxation of the  ,air included1 which
 is done at the ,bladder ,a ,d1 the     
,bubble and ,images rise  and fall after

 a surprizing ,manner4                  
,plate ,,iii4  ,sutton ,nicholls sculp4 
,,hydrostaticks4 #ad                    
,an ,explication of the ,third ,,plate4 
,figure #a4 ,is a ,tube full of ,water1 
with ,two ,holes ,e1 ,f1 for the ,water 
to  run out at1 the one ,f four times as
 much below the ,surface of the ,water  
,a ,b as the other2 7the ,vessel to be  
still kept equally full all along37 to  
shew that the ,velocity and ,quantity of
 ,fluids that run out1 are in only a    
subduplicate ,proportion of the         
,altitude of the ,fluids1 or twice so   
much in  a ,fourfold ,altitude4 ,not can
 it be otherwise3 ,for twice the        
,quantity  running out1 with twice the  
,velocity1 implies the ,force or        
,pressure to be  ,fourfold1 as the      
,fourfold ,altitude requires2 and so for
 ever4    ,fig4 #b4 ,is a ,pump2 where  
,g ,m is a hollow ,cylinder1 reaching to
 the ,water  below1 with a ,valve ,g1   
which will be lift up by the ascending  
,water1 and  permit its ,entrance into  

the ,body of the ,pump2 but will not    
permit its  ,return when it is          
attempting to descend4 ,d is the        
,sucker1 with its hollow  ,cylinder1 and
 a like ,valve3 which ,sucker is pulled 
upward or thrust  downward by the       
,handle ,i ,l ,k4 ,when it is pulled    
upward1 it leaves the ,body  of the     
,pump a ,vacuum3 whence the ,air's      
,pressure on the ,water's ,surface      
below raises it up into that ,space1 and
 fills it2 and when it is thrust  down1 
the ,water1 which is stopp'd by the     
lower ,valve from going back1 is  forc'd
 through the ,valve in the ,sucker ,d1  
into the ,cistern above2 whence  by its 
own ,gravity it runs out at the ,canal  
,a ,c4    ,fig4 #c4 ,is a ,forcing      
,pump1 in the main made like the other1 
only without  a ,cistern2 and the ,exit 
is out of the ,side through a ,hole1    
with a ,valve  opening outward1 but     
shutting inward1 in which the ,sucker   
when thrust  downwards forces the ,water
 out sideways with great ,violence4     

,fig4 #d4 ,is ,archimedes's ,spiral     
,pump ,c ,d1 made of only a ,cylinder1  
with  a hollow ,spiral ,tube wreath'd   
about it2 where the ,fluid partly       
descending1  and partly ascending1 all  
the way1 makes its flowing along the    
more easy1  till upon its ,arrival at   
the ,top it runs out at ,c4    ,fig4 #e4
 ,is the whole ,apparatus of the        
,hydrostatical ,balance4 ,the ,glass    
,bubble ,g is heavier than all ,fluids  
but ,quicksilver1 and is to be put into 
all those ,fluids3 ,the ,bulk of ,water 
in ours is #hcj ,grains ,troy4 ,if when 
pois'd in ,water it sink more by any    
,number of ,grains1 that ,number of     
,grains substracted from2 if less1 added
 to those #hcj1 do by their  ,proportion
 to #hcj give the ,specifick ,gravity of
 all such ,fluids to ,water4  ,i ,k is  
the ,glass ,bucket1 which in ,air is in 
quilibrio with the ,scale ,e3  ,and     
because when it is let into ,water1 it  
will be no longer an ,equipoise  to the 
opposite ,scale1 but lighter2 the ,scale

 ,r is to be added to the ,part  ,h1 by 
which the ,bucket is suspended1 and that
 will restore the quilibrium  in ,water4
 ,by this ,solids and ,quicksilver are  
weighed first in ,air1 and  then in     
,water3 ,the ,difference of which       
,weights being the ,weight of an  equal 
,bulk of ,water1 by its ,proportion to  
the first ,weight in ,air1 gives  the   
,specifick ,gravity of the ,solid       
compared with ,water3 ,and if that      
,difference still divide the ,weight in 
,air1 for all sort of ,bodies1 we may   
have a ,table of the ,specifick         
,gravities of the ,solids2 as by        
dividing #hcj  by the ,sum or           
,difference of the other ,fluids1 we may
 have a like ,table of  the ,specifick  
,gravity of ,fluids1 such an one as here
 presented the ,reader4                 
,,hydrostaticks4      ,a ,,table of the 
,specifick ,gravities of several ,solid 
and ,fluid ,bodies4          ,fine ,gold
               #ai1fdj   ,calculus      
,humanus         #a1gjj      ,standard  

,gold           #ah1hhh   ,oyl of       
,vitriol           #a1gjj               
,quicksilver             #ad1jjj   ,oyl 
of ,tartar            #a1eej      ,lead 
#aa1cbe   ,bezoar                       
#a1ejj      ,fine ,silver               
#aa1jia   ,honey                        
#a1dej      ,standard ,silver           
#aj1ece   ,gum ,arabick                 
#a1cge      ,bismuth                    
#i1gjj   ,spirit of ,nitre              
#a1cae      ,copper                     
#i1jjj   ,aqua ,fortis                  
#a1cjj      ,cast ,brass                
#h1jjj   ,serum of ,human ,blood        
#a1aij      ,steel     ,soft            
#g1gch   ,pitch                         
#a1aej      the same  ,hard             
#g1gjd   ,spirit of ,salt               
#a1acj      ,piece     ,spring ,temper  
#g1hji   ,spirit of ,urine              
#a1abj      ,iron                       
#g1fde   ,human ,blood                  
#a1jdj      ,tin                        
#g1cbj   ,amber                         

#a1jdj      ,glass of ,antimony         
#e1bhj   ,milk                          
#a1jcj      ,a ,pseudo ,topaz           
#d1bgj   ,urine                         
#a1jcj      ,a ,diamond                 
#c1djj   ,dry ,box-,wood                
#a1jcj      ,clear ,crystal ,glass      
#c1aej   ,sea-,water                    
#a1jcj      ,iceland ,crystal           
#b1gbj   ,common ,water                 
#a1jjj      ,fine ,marble               
#b1gjj   ,camphire                      
#j1iif      ,rock ,crystal              
#b1fej   ,bees-,wax                     
#j1iee      ,common ,green ,glass       
#b1fbj   ,lynseed ,oyl                  
#j1icb      ,stone of a mean ,gravity   
#b1ejj   ,dry ,oak                      
#j1ibe      ,sal ,gemm                  
#b1adc   ,oyl ,olive                    
#j1iac      ,brick                      
#b1jjj   ,spirit of ,turpentine         
#j1hgd      ,nitre                      
#a1ijj   ,rectified ,spirit of ,wine    
#j1hff      ,alabaster                  

#a1hge   ,dry ,ash                      
#j1hjj      ,dry ,ivory                 
#a1hbe   ,dry ,maple                    
#j1gee      ,brimstone                  
#a1hjj   ,dry ,elm                      
#j1fjj      ,dantzick ,vitriol          
#a1gae   ,dry ,firr                     
#j1eej      ,allom                      
#a1gad   ,cork                          
#j1bdj      ,borax                      
#a1gad   ,air                           
#j1jja                                  
,plate ,i4 ,pneumaticks                 
#ae                                     
,,pneumaticks4                          
,an ,explication of the ,first ,,plate4 
,figure #a4 ,are several ,torricellian  
,tubes or ,barometers of different      
,shapes1 ,bores1 and ,positions2 but    
where the perpendicular ,altitude of the
  ,quicksilver in the ,tubes1 above the 
,level of the ,surface of that in the   
,bason1 is ever the same1 or between #bh
 and #ca inches high2 which is the      
known ,counterpoise between #cb and #cf 

,feet of ,water2 and to the entire      
,atmosphere in its several ,states and  
,elevations1 where the ,bases or the    
several ,tubes are supposed equal4      
,fig4 #b4 ,is a ,diagonal ,barometer1   
where the ,alteration of the            
,perpendicular ,altitude of #c ,inches1 
by the ,obliquity of that ,part ,b ,c of
  the ,tube ,a ,b ,c1 7as a ,diagonal is
 oblique to the ,sides of its           
,parallelogram17 is increas'd to #bj or 
#cj ,inches ,sideways1 for more ,nicety 
of ,observation4    ,fig4 #c4 ,is a     
,wheel ,barometer1 where by two ,weights
 ,g and ,h on a ,pulley1  by which a    
,hand is turned1 the one of which plays 
freely in the ,air1 and  the other rises
 and falls with the ,quicksilver in the 
,tube1 the ,divisions  are larger and   
more obvious than in the ordinary       
,barometer3 as they are in  the         
,diagonal one2 for the like greater     
,nicety of ,observation4    ,fig4 #d4   
,is a common ,thermometer1 to determine 
the ,quantity of the ,heat  of the ,air1

 or of any ,liquor1 by the ,rarefraction
 of ,spirit of ,wine  contain'd in the  
hollow ,ball at the ,bottom1 and its    
consequent ascending  to the several    
,divisions on the small ,tube4    ,fig4 
#e1 and #ab4 ,are to shew that the      
,air's ,density is as its  ,compression1
 the former upon a greater ,compression1
 and the latter upon a  greater         
,rarefraction2 and that accordingly1 in 
the first ,case1 ,b ,d the  ,standard   
,altitude1 or about #bi ,inches1 and ,l 
,m the ,additional ,altitude of         
,quicksilver pour'd in higher than the  
,level ,h1 taken together1 is to ,b ,d  
the ,standard ,altitude alone1 as ,i ,g 
the inverted ,part of the ,tube when    
full of common ,air1 to ,h ,g the ,part 
full of condens'd ,air3 ,and in the     
,second ,case1 ,b ,d the ,standard      
,altitude1 is to ,d ,c the ,depression  
by the  ,air1 as ,e ,c the ,part of the 
,tube full of the expanded ,air1 to ,e  
,f the ,part  at first left full of     
common ,air4    ,fig4 #f4 ,is ,monsieur 

,azout's noble ,experiment1 to          
determine1 that 'tis  certainly the     
,air's ,pressure that raises the        
,quicksilver in the ,barometer4  ,the   
,instrument is nothing but a double     
,barometer communicating together1  by  
the ,means of a small hollow ,pipe in   
the ,middle3 ,its lower ,tube is        
stopp'd at the ,bottom with a ,bladder2 
and when the entire ,cavities are  full 
of ,quicksilver1 the ,bladder is prick'd
 or cut1 and the ,quicksilver  runs out3
 ,hereupon the upper ,barometer's ,tube1
 and ,part of its ,bason1  becomes      
empty2 while the lower is yet full3 ,but
 upon the unscrewing a  ,screw1 and     
letting ,air in above the upper ,bason1 
that ,air presses on the  ,quicksilver's
 ,surface1 and raises it into its ,tube2
 while the same ,air  pressing down the 
upper ,part of the under ,tube1         
depresses the ,quicksilver  therein at  
the same time4    ,fig4 #g4 ,is a       
,hygrometer1 or ,cord1 with a ,needle or
 ,index in a ,circle1 to  measure the   

,air's ,moisture by its shrinking up1   
and consequent ,revolution  one way2 and
 the ,air's ,dryness1 by its ,extension 
down1 and consequent  ,revolution the   
contrary way2 and both measured by the  
,degrees of the  ,bottom ,circle4       
,fig4 #h4 ,is a ,syphon above #bi       
,inches high1 along where no ,suction   
nor  ,art can make the ,quicksilver run1
 as it uses to do when it is of any less
  ,altitude4    ,fig4 #i4 ,is the new   
,sort of ,cupping-,glass1 whence the    
,air is suck'd out  by a ,syringe1 and  
where by a ,valve it is hindred from    
returning4    ,fig4 #aj4 ,is an ,example
 of ,suction2 and will shew that        
,quicksilver can  thereby never be      
rais'd to #bi ,inches4    ,fig4 #aa4 ,is
 an ,example of a ,weight raised by a   
,syringe1 as ,water uses to  be2 and    
still shews1 that all is proportionable 
to the ,power of the ,air's  ,pressure1 
and is limited thereby4                 
,plate ,,ii4  ,i4 ,senex sculp4t        
,,pneumaticks4 #af                      

,an ,explication of the ,second ,,plate4
      ,figure #a4 ,is the ,air-,pump1   
with its ,receiver and ,gage1 as ready  
for ,use2  a a1 a a are two strong      
hollow ,cylindrical ,barrels1 in which  
are  suppos'd to be ,suckers1 with their
 ,handles c c1 c c notched2 into  which 
,notches a ,cog-wheel falls1 which      
,cog-wheel moves upon the ,axis f1  when
 the ,engine is put into ,motion by the 
,winch b b4 g g1 g g are  two ,cylinders
 of ,wood1 fixed to the ,frame of the   
,air-,pump1 with ,screws at  the ,top1  
on which the ,nuts e1 e e do run1 and   
press down the upper  ,piece f f upon   
the ,tops of the ,brass ,barrels1 to fix
 them both at ,top  and ,bottom4 h h is 
a ,swan-neck'd1 or small bended hollow  
,brass ,pipe1  leading from the         
,top-,plate i i i i1 or rather from the 
,brass hollow  ,piece above n n1 which  
communicates through that ,top-,plate   
with the  ,cavity of the ,receiver4     
,this ,pipe is screwed to a bottom      
,brass ,piece1  included in the ,box d  

d2 which is perforated not only         
lengthways1 but  also upwards1 in three 
,places3 ,the ,middle one for a         
,communication with  this ,swan-neck'd  
,pipe1 and at the two ,ends through     
small ,cylinders2  inserted into the two
 ,brass ,barrels a a a a2 and 'tis by   
this ,threefold  ,communication1 that   
the ,air is pump'd out of the ,receiver4
 l l l is the  ,gage2 which is no other 
than a common ,barometer1 or            
,weather-,glass2 with  its ,bason of    
,mercury m m1 fix'd to the ,engine by a 
particular  ,contrivance1 and its ,index
 or ,boxen ,receptacle1 with ,inches1   
and its ,cork  to support that ,index   
upon the ,surface of the ,mercury1 and  
to rise and  fall with it2 for the      
,exactness of measuring the ,height of  
the ,mercury  from that ,surface4 ,only 
this ,barometer is open at the ,top1 and
  communicates1 as does the ,swan-neck'd
 ,pipe1 with the ,cavity of the         
,receiver4 n n is a ,stop-cock1 that    
communicates also with the ,cavity of   

the ,receiver1 and either excludes or   
readmits the ,air1 as you see           
convenient4 k is the ,bottom of the     
,receiver1 ground true to fit the       
,brass ,circle below it2 to which it is 
affixed by the ,hand at first1 and      
afterward by the ,pressure of the ,air1 
with wet ,leather instead of ,cement4   
,fig4 #b4 ,is a ,barometer ,tube1 open  
at the ,top ,h1 and included in such a  
,receiver ,g ,b1 as gives room for it to
 stand upright1 and yet permits the     
,air to go backward or forward on its   
,surface1 according as you pump the     
same out of or readmit the same into    
that ,receiver4 ,and this is done so1   
that the included ,air ,c ,d1 which     
supports the ,mercury1 by pressing on   
the  ,surface of that in its ,bason ,e  
,d1 is confin'd within4 ,this small     
,quantity  of ,air1 on the ,extraction  
of that in the ,receiver1 will1 by its  
,elasticity1 raise the ,mercury almost  
as high as the usual ,standard3 ,and    
thereby shews1 that the ,spring of any  

small ,part of common ,air presses      
equally with the whole correspondent    
,column of the ,atmosphere4    ,fig4 #c4
 ,is a ,contrivance to make an          
,explosion of ,gunpowder in ,vacuo3     
,where ,h ,d is a red hot ,iron1        
standing on its ,pedestal ,e1 within a  
,receiver  ,g ,c2 and ,f is a ,cock made
 above like a ,dish1 to contain the     
,gunpowder2  which by the pulling up and
 thrusting down a strong ,wire1 with a  
,hole like  the ,eye of a ,needle1 is in
 a certain ,quantity let fall every time
 upon the  hot ,iron2 and on the        
,explosion produces ,flame1 and         
fictitious ,air2 but  very little       
,sound1 by reason of the ,absence of the
 ,air that should convey  it4    ,fig4  
#d4 ,is a ,syringe1 which will suck up  
the ,water in the ,glass ,c ,d1  when it
 is in the open ,air2 but will not do   
the same under the ,exhausted  ,receiver
 ,e ,f1 unless for so small an ,altitude
 as the remaining ,air can  sustain4    
,plate ,,iii4  ,i4 ,senex sculp4t       

,,pneumaticks4 #ag                      
,an ,explication of the ,third ,,plate4 
,figure #a4 ,is a large strong ,glass   
,receiver1 or ,condenser1 ,arm'd with   
,brass  ,circles at both ,ends1 and fit 
to receive and bear the ,pressure of    
,air  considerably condens'd1 when      
crouded into it by a ,syringe fitted for
 that  ,purpose4 ,it has also annexed to
 it a ,gage ,c ,d1 to determine the     
,quantity  of the condens'd ,air within4
 ,this ,gage consists of a hollow ,tube1
  ,hermetically seal'd at ,d1 with      
another smaller included1 open towards  
,d1  and ,hermetically seal'd at the    
other ,end4 ,in this smaller ,tube is   
left a  little ,quicksilver3 ,this      
,quicksilver is by the ,air at ,d in the
 larger  ,tube1 which communicates with 
the condens'd ,air in the ,receiver it  
self1  and so is of the same ,density   
with it1 crouded inwards towards ,c     
every  time of the ,admission of new    
,air2 and by its whole ,length from the 
,end  near ,d1 compar'd with its        

,distance from the ,end near ,c1 it     
determines the  ,proportion of the      
,density of the included ,air to that of
 the common ,air4  ,note1 ,that the     
,syringe to be made use of with the     
,receiver1 is the same  with that       
represented in the next ,figure1 as     
joined to the condensing  ,engine it    
self2 and acts by pulling up the ,sucker
 above the ,hole ,h1 for  the ,admission
 of a full ,cylinder of common ,air1 and
 then crouding it down  into the        
,receiver2 at the ,bottom of this       
,syringe is a ,valve1 that hinders  what
 is once crouded in from returning back 
again1 as is necessary on all  such     
,occasions4    ,fig4 #b4 ,is the usual  
,brass ,condenser it self1 with a       
,stop-cock ,e ,f near  it2 to be        
interposed between the ,syringe and the 
,receiver upon ,occasion4  ,the         
,instrument1 besides the ,frame1 is     
composed of a ,recipient of ,brass1     
made of ,two ,hemispheres1 or what is   
equivalent to them1 closed together by  

a ,ring of wet ,leather1 to keep in the 
,air2 and because in this ,case the     
dense ,air within endeavours forcibly to
 disjoin these ,hemispheres1 they  are  
confin'd down close by a strong ,piece  
of ,iron1 and ,screws belonging         
thereto4 ,the ,syringe already          
describ'd1 is represented as join'd to  
it  after the same manner that it is    
when the ,air is thereby intruded4 ,this
  ,brass ,recipient will bear ,air very 
much denser than the foregoing ,glass   
one1 tho' it being not transparent as   
the other is1 cannot be so pleasant1    
nor so well shew the ,mutations that    
happen to ,animals or other ,bodies in  
condens'd ,air as the former4    ,fig4  
#c4 ,is the ,logarithmick ,curve ,a ,c  
c1 with its ,ordinates ,a ,b1 ,c ,d1  c 
d1 ,k  representing ,absolute ,numbers1 
and its ,absciss1 ,c ,g or ,d ,b1  ,i c 
or ,b d and ,b 1 representing their     
,logarithms1 whose famous ,property  it 
is1 that one ,ordinate as ,a ,b1 is to  
another ,ordinate as ,c ,d1 or c d  or  

,k 1 as that unlimited ,space between   
the ,curve and ,asymptote above the     
one1 is to that above the other2 and    
whence is deduc'd the ,proportion of    
the ,air's ,rarity at all ,altitudes    
whatsoever2 that at #g ,miles high it is
 #d  times as rare2 at another #g1 or   
#ad ,miles1 it is #af times as rare1 and
 so  for ever1 in a ,geometrical        
,proportion of ,rarity1 compar'd with   
the  ,arithmetical ,proportion of its   
,altitude2 tho' all this is here upon   
the  ,hypothesis that the ,distances are
 not so great1 that the real ,gravity of
  the ,parts be sensibly diminished4    
,for in that ,case1    ,fig4 #d4 ,gives 
the ,scheme1 which is made use of to    
discover the ,air's  ,rareness1 even at 
such ,distances1 as imply a considerable
 ,alteration in  that ,gravity2 whence  
it will appear1 that the ,density of the
 ,air is  diminished in that ,case more 
than #d times for every #g ,miles of    
,altitude4                              
,plate ,,iiii4  ,i4 ,senex sculp4t      

,,pneumaticks4 #ah                      
,an ,explication of the ,fourth ,,plate4
      ,figure #a4 ,is a compound        
,instrument1 to shew1 why in a ,storm   
the ,mercury in  the ,barometer vibrates
 so much1 by a parallel ,case in an     
,imitation of such  a ,storm4 ,a ,a is a
 large hollow ,brass ,sphere1 into which
 by the means of  the ,syringe in ,fig4 
#b4 ,air is crouded till it is #h or #aj
 times as dense  as usual4 ,h ,f and ,l 
,k are ,two ,barometers1 with their     
,basons in the ,boxes  ,f ,f1 ,k ,k1    
which ,boxes communicate by a long      
hollow ,tube ,i ,i4 ,e ,e is a  ,brass  
hollow ,tube1 to convey the crowded ,air
 near the ,surface of one of  the       
,basons of ,quicksilver1 which ,air     
passes out of that into a larger  hollow
 ,pipe ,g ,g1 and so into the open ,air4
 ,upon the turning of the  ,stopcock ,c 
to give vent to the condensed ,air1 it  
rushes with great ,force  along the     
hollow ,pipes ,e ,e1 ,g ,g2 and as it   
passes not far off the ,surface  of the 

,bason of ,quicksilver ,f ,f1 it causes 
the ,mercury in both the  ,barometers ,h
 ,h1 and ,l ,l1 to descend and vibrate  
several ,inches1 as the  great ,storm   
made ,barometers descend and vibrate in 
,chambers at a distance  from it4       
,fig4 #c4 ,is a ,transferrer2 containing
 one common hollow ,stem ,i 7here       
represented as screw'd to a square      
,piece of ,wood1 and thereby held       
upright7 with its ,stopcock ,i1 and its 
,horizontal ,hollow ,g ,h with which it 
communicates4 ,upon this ,horizontal    
,piece two more hollow ,stems are       
erected1 and communicate therewith4     
,these also have ,stopcocks ,e and ,f1  
and  to these are screw'd ,two ,brass   
,plates ,a ,b and ,c ,d1 on which ,two  
,recipients  may be fix'd1 and may      
communicate with the rest4 ,by this     
means the whole  ,instrument may be     
apply'd to the ,air ,pump1 and one or   
more of its  ,recipients exhausted2 and 
afterward any ,factitious or ,natural   
,air may be  transferr'd from one       

,receiver to another1 as ,occasion      
requires3 ,of which  ,instrument ,mr4   
,boyle made great ,use in his ,second   
,continuation of  ,experiments4    ,fig4
 #d4 ,are very small or capillary ,glass
 ,tubes1 of different ,bores1 let  down 
into ,tinged ,water1 in ,vacuo1 to shew1
 that by the ,attraction of the  ,glass 
the ,water will be elevated1 contrary to
 the ordinary ,law of  ,hydrostaticks1  
and that to a considerable ,height2 and 
what is chiefly  remarkable1 is1 that   
the ,altitude of the ,liquid in the     
,tubes is the same  in ,vacuo as in the 
open ,air1 and is always in an exact    
reciprocal  ,proportion to the          
,diameters of their ,bases4    ,fig4 #e4
 ,is the noble ,improvement of the      
former ,experiment by ,mr4  ,hauksbee1  
,sen4 upon which the ,learned ,mr4      
,ditton has written a small  ,treatise4 
,it is done by two ,glass ,plains1 ,a ,c
 ,b1 ,a ,d ,b1 meeting in an ,axis  at  
,a ,b2 and being about a ,tenth of an   
,inch distant at the greatest  ,aperture

 ,d ,c4 ,these ,plains are ,erected in  
,spirit of ,wine1 and are like a        
,series of ,tubes of all different      
,diameters less than ,d ,c1 which must  
therefore elevate the ,fluid a little at
 ,d ,c1 and higher all the way to ,b1   
where the ,elevation ought to be        
,infinite2 the ,tops of the elevated    
,columns  will form an ,hyperbola1 ,e ,f
 ,g1 with its ,two ,asymptotes1 the     
,surface of the  ,fluid ,d ,c ,b1 and   
the ,line ,b ,a4 ,note1 ,that if the    
,angle at ,d ,c be  altered1 the        
,bigness of the ,hyperbola will be      
alter'd1 while its ,species  remains2   
but that if the ,angle ,a ,b ,c be      
alter'd1 the ,species of the  ,hyperbola
 will be alter'd also1 though it will   
still be a true ,hyperbola1  and that if
 the ,glass be clean1 to a surprizing   
,degree of ,exactness4                  
,plate ,v4  ,sutton ,nicholls sculp3    
,,pneumaticks4 #ai                      
,an ,explication of the ,fifth ,,plate4 
,figure #a4 ,are ,otto ,guerick's       

,hemispheres1 with their several ,screws
 and  ,apparatus at large1 set          
separately by themselves4 ,they are     
designed to  prove that the ,force of   
the outward ,air1 when the inward is    
extracted from  between them1 is equal  
to the ,weight of a ,column of          
,quicksilver of about  #bi ,inches and a
 half3 ,of ,water of about #cd ,feet3   
,and of ,air to the ,top of  the        
,atmosphere1 all pressing upon the same 
,base with the largest ,circles  of     
those ,hemispheres4    ,fig4 #b4 ,is the
 ,syringe1 with its ,hole2 to be screw'd
 on to the ,top of  the ,receiver of the
 next ,figure2 in order to thrust ,air  
into it1 for the  ,improvement of the   
former ,experiment2 or to shew that tho'
 common ,air be  left in the            
,hemispheres1 yet if that on their      
outward ,surface be made  twice or      
thrice as dense1 they will still sustain
 an equal1 or a double  ,weight         
respectively1 before they are separated4
    ,fig4 #c4 ,is that ,instrument      

included in such a ,receiver ,d ,b1 and 
that  ,receiver kept close to its ,basis
 by a cross ,piece and ,screws1 as in   
the  ,condenser before3 ,together with a
 newly contriv'd ,stiliard1 to which the
  upper ,hemisphere is hung2 with its   
fixed ,base1 and its ,gage1 to measure  
the ,degrees of ,condensation of the    
,air1 where by the ,proportion of ,s ,p 
to  ,p ,k1 the ,weight #ej w4 is        
equivalent to greater ,weights1 and     
shews how many  ,pounds are required to 
separate the ,hemispheres in all ,cases4
 ,if the  ,diameter be #c ,inches and a 
half1 they will sustain about #aej      
,pounds2 and  so in all other           
,proportions4    ,fig4 #d4 ,is the      
,plate which covers the upper ,part of  
the ,receiver4 ,and  through the ,hole  
,c the ,piece ,d ,e slides1 which takes 
hold on the upper  ,hemisphere4    ,fig4
 #e4 ,shews the ,gage of the same       
,instrument2 this is like that for the  
,glass ,condenser before describ'd1 and 
contains a bended ,tube1 whose open     

,end is in a small ,basin of ,mercury2  
and the other is ,hermetically seal'd3  
,for this ,mercury crowded by the       
condensed ,air in the ,receiver1 will   
croud  the ,air in the small ,tube      
closer in ,proportion to its ,density1  
and so will  afford us the ,knowledge of
 the ,quantity thereof4    ,fig4 #f4 ,is
 a like ,experiment of the ,cohesion of 
polished ,plates of  ,brass1 or of      
,marble2 when the ,air is excluded by a 
little ,oil1 and an  exact ,application4
 ,this ,cohesion may be weighed by the  
,stiliard1 as well  as that of the      
,hemispheres2 and is equal to the same1 
upon the same ,base2  provided a ,ring  
do prevent their side or sliding        
,motion2 and provided the  ,air can     
equally be excluded from between the    
,plates1 as between the  ,hemispheres4  
,which last yet is almost impossible to 
be done4    ,fig4 #g4 ,is a ,number of  
great ,weights1 kept steady one over    
another by an  ,iron ,rod passing       
through them1 and pressing upon a       

,bladder half blown1  plac'd below them3
 ,this ,bladder1 by the ,elasticity of  
its included ,air1  gradually elevates  
all those ,weights2 as soon as by the   
,extraction of the  other ,air out of   
the ,receiver1 wherein they are all     
included1 its  ,counterpoise is         
gradually taken away4    ,fig4 #h4 ,is a
 ,number of ,jet d',eaus1 or ,fountains1
 made by condens'd ,air1  in a large    
,copper ,vessel ,c ,d1 pressing on the  
,surface of ,water at the  ,bottom of   
the ,vessel2 into which ,water a hollow 
,brass ,pipe is immers'd4  ,for if there
 be then a ,stopcock at ,g1 to open or  
shut the hollow ,pipe at  ,pleasure2 and
 several smaller ,pipes at ,i ,k1       
communicating therewith1  turning upon  
,balls or ,joints1 and plac'd in ,order1
 we shall have a very  pleasant ,set of 
these ,jet d',eaus1 or ,fountains2 all  
whose ,water will be  caught by the     
,bason ,a ,b1 which ,water may be again 
let into the ,vessel ,c ,d1  by         
unscrewing the ,pillar in the ,center of

 the ,bason4                            
,plate ,,vi4  ,i4 ,senex sculp4t        
,,pneumaticks4 #bj                      
,an ,explication of the ,sixth ,,plate4 
,this ,plate is in ,reality but one     
compound ,instrument or ,apparatus1 for 
trying the ,electricity of ,glass1 and  
its ,luminousness1 when put into        
,motion1 and rubb'd upon to heat it4    
,wherein ,b ,c is a ,wheel1 with its    
,string ,a ,b ,c4 ,d ,e is a ,sphere of 
,glass1 whose ,air has been drawn out by
  the ,air-,pump3 ,this is turned round 
by the former ,wheel-string at ,a4 ,f is
 a  ,stopcock1 whereby the ,air is      
exhausted1 and may be readmitted at     
,discretion4    ,in ,fig4 #a4 ,k ,l ,m  
is an ,arch with ,threads of ,cruel or  
,yarn upon it1 as  they hang about the  
,glass ,d ,e1 7here represented by a    
smaller ,circle  within the ,arch7      
before it is turned round or heated by  
rubbing4    ,fig4 #b4 ,g ,h ,i is the   
same with the former2 only the ,threads 
are here  represented as they hang at   

the ,beginning of the turning round of  
the  ,globe1 before it be heated by     
,friction2 being plainly bent one way1  
by a  ,wind arising from that           
,convolution4    ,fig4 #c4 ,n ,p ,o is  
the same2 only with the ,threads        
pointing towards the  ,sphere1 or its   
,center1 when the ,arch is in an upright
 ,posture1 and some of  the ,threads    
hang partly downwards1 and this upon the
 ,spheres being heated  sufficiently4   
,fig4 #d4 ,q ,s ,r is the same1 with its
 ,threads pointing the same way1  though
 in a downward ,posture1 when some of   
the ,threads thereby are forc'd  to     
stand erect4    ,fig4 #e4 ,t ,u is a    
,circular ,arch1 in an horizontal       
,position1 when the  ,threads point     
towards the same ,center1 in the same   
horizontal ,plain4    ,fig4 #f4 ,is     
another ,sphere1 communicating with the 
,air1 and to be apply'd  to the same    
,wheel in the ,room of ,d ,e1 where-into
 is inserted an ,axis with  a ,circle   
affixed to it2 at the ,edges of which   

,circle the ,threads are  placed4 ,these
 upon the ,friction and ,heat of the    
,glass extend themselves  outward1 and  
point from the ,center to the           
,circumference1 contrary to the  former4
 ,in both ,cases the ,threads1 when     
under the ,influence of the             
,electricity1 will be moved by the      
,finger1 even without ,contact1 nay by  
the  ,finger and ,breath1 even through  
the ,glass it self2 so subtle are these 
,effluvia4 ,the ,light is made when the 
,air is exhausted1 and diminishes as    
you readmit it4 ,it spreads and branches
 it self inwardly like ,lightning1  when
 about half that ,air is readmitted4    
,the ,colour of that ,light is always   
,purple4 ,it spreads at some ,distance1 
and makes the ,edges of a ,cravat look  
a little like the milky ,way1 by the    
great ,number of ,sparkles it emits3    
,which may also be felt by the ,flesh1  
with a crackling ,noise that            
accompanies them4 ,if you also          
sufficiently rub and heat a large ,tube 

of  ,glass1 either solid or hollow1 it  
becomes strongly ,electrical1 even      
through ,glass it self2 tho' not so much
 through ,muslin4 ,other ,heat than     
that by ,friction signifies nothing4 ,it
 will attract and repel ,leaf ,gold1    
and the like small and light ,bodies1   
after a strange manner1 by turns2  when 
once they have been fully repell'd they 
cannot be made to touch them1  till they
 have been reflected from some other    
,body4 ,if they lye between  two ,pieces
 of ,wood1 laid pretty near1 the        
,electricity fails of its ,effect4      
,with other ,circumstances very         
surprizing and unaccountable4           
,,finis4                                
,transcription note3      ,the original 
punctuation and ortography of the book  
have been faithfully  preserved2 words  
which are spelled variantly1 or         
inconsistently  capitalized 7e4g41 ,axel
 vs4 ,axle1 crowded vs4 crouded1 blue1  
red  vs4 ,blue1 ,red1 etc47 have been   
left as such4    ,likewise1 the         

7mis7spelling of names like ,galilo1    
,azout1 ,hugen1 ,guerick1  has been     
retained4    ,the following             
typographical mistakes have been        
corrected1 taking into  account         
recurrences across the text3      99    
,page ,,iii1 #beth day3         99 ,the 
,ebullition of ,liquors in ,vacuo  ,the 
,ebullition of ,liquors           in    
,vacuo      99 ,mechanicks1 ,explication
 of the #bnd ,plate3         99 ,figure4
 #a4 ,is the deceitful ,balance2 which  
yet is in ,equilibrio                   
,figure #a4 ,is the deceitful ,balance2 
which yet is in quilibrio         99    
,fig4 #c  ,fig4 #c4         99 ,fig4    
#aj3 perpendiculary  perpendicularly    
99 between ,fig4 #i and #aj3 ,n4 ,b4    
,n4 ,b4         99 ,fig4 #aj3 and in    
this ,leaver  and in this ,lever      99
 ,mechanicks1 ,expl4 #eth ,plate1 ,fig4 
#c3         99 us it is less restrained4
  as it is less restrained4      99     
,opticks1 ,expl4 #ast ,plate1 ,fig4 #c3 
99 ,looking-glass  ,looking-,glass      

99 ,opticks1 ,expl4 #bnd ,plate3        
99 ,fig4 #h4 ,shows  ,fig4 #h4 ,shews   
99 ,fig4 #aj3 on the like ,acccount4  on
 the like ,account4      99             
,hydrostaticks1 ,expl4 #ast ,plate3     
99 ,fig4 #e3 specifick ,gravity of      
,water  ,specifick ,gravity of ,water   
99 ,hydrostaticks1 ,table of ,specifick 
,gravities3         99 ,spirit of ,nirre
  ,spirit of ,nitre      99             
,pneumaticks1 ,expl4 #bnd ,plate3       
99 ,fig4 #a3 'tis by this ,thteefold    
'tis by this ,threefold         99 ,fig4
 #b3 small ,part of ccmmon ,air  small  
,part of common ,air      99            
,pneumaticks1 ,expl4 #eth ,plate3       
99 ,fig4 #f3 as between the ,hemispheres
  as between the           ,hemispheres4
      99 ,pneumaticks1 ,expl4 #fth      
,plate3         99 ,fig4 #f3 througn    
,muslin  through ,muslin