,,the ,,art ,,of ,,inventing    ,,by    
,,edwin ,j4 ,,prindle1 ,m4,e41          
,l4,l4,m41 of the ,new ,york ,bar4      
,a paper read at the #bc;d ,annual      
,convention of the ,american ,institute 
of    ,electrical ,engineers1           
,milwaukee1 ,wis41 ,may #bh-ca1 #aijf4  
,a paper presented at the #bc;d ,annual 
,convention of the ,american            
,institute of ,electrical ,engineers1   
,milwaukee1 ,wis41 ,may #bh-ca1 #aijf4  
,copyright #aijf4 ,by ,a4 ,i4 ,e4 ,e4   
,,the ,,art ,,of ,,inventing4    ,,by   
,,edwin ,j4 ,,prindle4      ,there are  
many kinds of invention4 ,the poet1 the 
artist1 the  playwright1 the novelist   
all exercise or may exercise invention  
in the  production of their works4 ,the 
merchant may exercise invention in the  
devising of a new method of selling     
goods4 ,the department store was an     
invention of this class4    ,the subject
 of my paper is1 however1 the art of    
making technical  inventions1 and       
particularly patentable inventions4     

,and1 first1 of  its commercial         
importance2 for the engineer is         
concerned with things  having a         
commercial value4 ,by the art of        
inventing1 wealth is created  absolutely
 out of ideas alone4 ,it usually takes  
capital to develop an  invention and    
make it productive1 but not always4 ,a  
notable recent  example is ,professor   
,pupin's loaded telephone line4 ,he     
received a  very large sum of money1 and
 his expenditures1 as ,i understand1    
were  comparatively trivial4    ,the    
certificate of ownership of an invention
 is a patent1 and the  importance of the
 art of invention will be made apparent 
from a brief  consideration of what     
rights a patent confers and of the part 
that  patents play in the industries4   
,a patent is the most perfect form of   
monopoly recognized by the law4 ,as  was
 said in a recent decision3             
,within his domain1 the patentee is     
czar4 ,the people must      take the    
invention on the terms he dictates or   

let it alone      for seventeen years4  
,this is a necessity from the nature of 
the grant4 ,cries of restraint of trade 
and impairment of the      freedom of   
sales are unavailing1 because for the   
promotion of      the useful arts the   
constitution and statutes authorize this
      very monopoly4    ,there is an    
enormous amount of wealth in this       
country that is based  upon patents4 ,as
 an instance1 might be mentioned the    
fact that the  ,united ,shoe ,machinery 
,company is1 by means of patents1 able  
to control  the sewing machines upon    
which ninety per cent4 of the welt shoes
  in the ,united ,states are sewed4 ,the
 ,bell ,telephone ,company1 and the     
,westinghouse ,air ,brake ,company and  
many other corporations of the first    
importance built themselves up on       
patents4 ,patents have become so well   
recognized a factor in commerce that1 in
 many lines of manufacture1  concerns do
 not depend simply upon cheapness of    
manufacture1 or  quality of product1 to 

maintain their trade1 but they count on 
always  having a product which is at    
least slightly better than that of their
  competitors1 and which is covered by  
patents1 so that they do not have  to   
compete with an article of equal merit4 
,and they keep a corps of  inventors at 
work in a constant effort to improve the
 product1 so that1  when the patents now
 giving protection have expired1 they   
will have a  better article to offer1   
which shall also be protected by        
patents4    ,inventing has become almost
 a recognized profession4 ,many large   
concerns constantly employ a large corps
 of inventors1 at liberal  salaries4    
,besides the inventors employed by large
 corporations1 there  are many inventors
 who have maintained their independence1
 and are free  lances1 so to speak4     
,some inventors have become wealthy     
almost solely  by their inventions1 such
 as ,edison1 ,bell1 ,westinghouse1      
,marconi1  ,pupin1 ,tesla1 and ,sprague4
 ,a considerable number of the smaller  

manufacturing concerns are built largely
 or wholly upon the inventions  of their
 principal owners4    ,aside from the   
question of financial returns from      
inventing1 the  inventor has the        
satisfaction of knowing that he is a    
producer of  the most fundamental kind4 
,all material progress has involved the 
production of inventions4 ,inventors are
 universally conceded to be  among the  
greatest benefactors of the human race4 
,the art of invention is therefore one  
of great commercial and  economical     
importance1 and it becomes a matter of  
much interest to know  how inventions   
are produced4 ,it is my object to       
attempt an explanation  of the manner of
 their production4    ,if it be inquired
 on what grounds ,i offer an explanation
 of this  apparently most difficult     
subject1 ,i reply that1 in the practice 
of  patent law1 ,i have often had       
occasion and opportunity to inquire into
  the mental processes of inventors1 and
 that the subject is one to which  ,i   

have given considerable attention4      
,it seems to be popularly believed that 
the inventor must be born to his  work1 
and that such people are born only      
occasionally4 ,this is true1  to a      
certain extent1 but ,i am convinced     
there are many people who1  without     
suspecting it1 have latent inventive    
abilities1 which could be  put to work  
if they only knew how to go about it4   
,the large percentage  of inventors in  
this country compared with all other    
countries1 shows  that the inventive    
faculty is one which can be cultivated  
to some  extent4 ,the difference in     
ingenuity is not wholly a matter of     
race1  for substantially the same blood 
exists in some other countries1 but  it 
is the encouragement of our patent laws 
that has stimulated the  cultivation of 
this faculty4    ,the popular idea seems
 to be that an invention is produced by 
its  inventor at a single effort of the 
imagination and complete1 as ,minerva   
sprang full grown and fully armed from  

the mind of ,jove4    ,it is1           
undoubtedly1 true that every inventor   
must have some imagination  or creative 
faculty1 but1 as ,i shall seek to show1 
this faculty may  be greatly assisted by
 method4 ,while reasoning does not      
constitute  the whole of an inventive   
act1 it can1 so to speak1 clear the way 
and  render the inventive act easier of 
accomplishment4    ,invention has been  
defined as ,in the nature of a guess2   
the mind  leaps across a logical chasm4 
,instead of working out a conclusion1 it
  imagines it4 ,the courts have         
repeatedly held that that which could be
  produced purely by the process of     
reasoning or inference1 on the part  of 
one ordinarily skilled in the art is not
 patentable1 but that the  imaginative  
or creative faculty must somewhere be   
used in the process4  ,the mind must    
somewhere leap from the known to the    
unknown by means of  the imagination1   
and not by mere inference in making the 
invention4 ,but  the inventor1          

consciously or unconsciously1 by proper 
method1 reduces  the length of this leap
 to much more moderate proportions than 
is  popularly supposed4    ,that        
reasoning and research frequently enter 
very largely into the  inventive act in 
aid of the creative faculty is the      
opinion of ,dr4  ,trowbridge1 of        
,columbia ,university who said3         
,important inventions leading to        
widespread improvements      in the arts
 or to new industries do not come by    
chance1 or      as sudden inspiration1  
but are in almost every instance        
the result of long and exhaustive       
researches by men whose      thorough   
familiarity with their subjects enables 
them to see      clearly the way to     
improvements4 ,almost all important and 
successful inventions which have found  
their way into general      use and     
acceptance have been the products of    
well-balanced and      thoughtful minds1
 capable of patient laborious           
investigation4    ,judge ,drummond1 in a

 decision many years ago1 said3         
,most inventions are the result of      
experiment1 trial1 and      effort1 and 
few of them are worked out by mere will4
    ,most inventions are an evolution   
from some previously invented form4 ,it 
has been said3        ,we know exactly  
how the human mind works4 ,the          
unknown--or      unknowable--it always  
conceives in terms of the known4        
,even the imagination conceives in terms
 of what is already known2 that  is1 the
 product of the imagination is a        
transformation of material  already     
possessed4 ,imagination is the          
association in new relations of  ideas  
already possessed by the mind4 ,it is   
impossible to imagine that1  the        
elements of which are not already known 
to us4 ,we cannot conceive  of a color  
which does not consist of a blending of 
one or more colors  with which we are   
already familiar4 ,this evolution of an 
invention is  more or less logical1 and 
is often worked out by logical processes

 to  such an extent that the steps or   
efforts of imagination are greatly      
reduced as compared with the effort of  
producing the invention solely  by the  
imagination4    ,edison is quoted as    
having said that any man can become an  
inventor  if he has imagination and     
pertinacity1 that invention is not so   
much  inspiration as perspiration4      
,there are four classes of protectable  
inventions4 ,these are        ,arts1    
,machines1      ,manufactures1 and      
,compositions of matter4    ,in popular 
language an art may be said to be any   
process or series of  steps or          
operations for accomplishing a physical 
or chemical result4  ,examples are1 the 
art of telephoning by causing           
undulations of the  electric current    
corresponding to the sound waves of the 
spoken voice4  ,the art of casting car  
wheels1 which consists in directing the 
metal  into the mold in a stream running
 tangentially instead of radially1  so  
that the metal in the mold is given a   

rotary movement1 and the  heavy1 sound  
metal flows out to the rim of the wheel1
 while the light  and defective metal is
 displaced toward the centre1 where it  
is not  subjected to wear4    ,the term 
machine hardly needs any explanation4   
,it may be said to be an  assemblage of 
two or more mechanical elements1 having 
a law of action  of its own4    ,a      
manufacture is anything made by the hand
 of man1 which is neither a  machine nor
 a composition of matter2 such as1 a    
chisel1 a match1 or a  pencil4    ,the  
term composition of matter covers all   
combinations of two or more  substances1
 whether by mechanical mixture or       
chemical union1 and  whether they be    
gases1 fluids1 powders or solids2 such  
as1 a new cement  or paint4    ,these   
definitions are not legally exact1 but  
serve to illustrate the  meaning4    ,in
 the making of all inventions which do  
not consist in the discovery  of the    
adaptability of some means to an end not
 intentionally being  sought after1 the 

first step is the selection of a        
problem4 ,the  inventor should first    
make certain that the problem is based  
upon a  real need4 ,much time and money 
is sometimes spent in an effort to      
invent something that is not really     
needed4 ,what already exists is good    
enough or is so good that no additional 
cost or complication would  justify     
anything better4 ,the new invention     
might be objectionable  because it would
 involve counter disadvantages more     
important than its  own advantages1 so  
that a really desirable object is the   
first thing to  be sure of4    ,having  
selected a problem1 the next step should
 be a thorough analysis  of the old     
situation1 getting at the reasons for   
the faults which  exist1 and in fact    
discovering the presence of faults which
 are not  obvious to others1 because of 
the tendency to believe that whatever   
is1  is right4    ,then the qualities of
 the material1 and the laws of action   
under which  one must operate should be 

exhaustively considered4 ,it should be  
considered whether these laws are really
 or only apparently inflexible4  ,it    
should be carefully considered whether  
further improvement is  possible in the 
same direction1 and such consideration  
will often  suggest the direction in    
which further improvement must go1 if a 
change  of direction is necessary4      
,sometimes the only possible improvement
  is in an opposite direction4 ,a glance
 at the accounts of how ,james  ,watt   
invented the condensing steam-engine    
will show what a large part  profound   
study of the old engine and of the laws 
of steam played in  his invention1 and  
how strongly they suggested the         
directions of the  solutions of his     
difficulties4    ,we now come to the    
constructive part of inventing1 in order
 to  illustrate which1 ,i will seek to  
explain how several inventions were1  or
 could have been1 produced4    ,the way 
in which the first automatic steam      
engine was produced was  undoubtedly    

this--and it shows how comparatively    
easily a really great  invention may    
sometimes be made4 ,it was the duty of  
,humphrey ,potter1  a boy1 to turn a    
stop-cock to let the steam into the     
cylinder and  one to let in water to    
condense it at certain periods of each  
stroke  of the engine1 and if this were 
not done at the right time1 the engine  
would stop4 ,he noticed that these      
movements of the stop-cock handles  took
 place in unison with the movements of  
certain portions of the beam  of the    
engine4 ,he simply connected the valve  
handles with the proper  portions of the
 beam by strings1 and the engine became 
automatic--a  most eventful result4     
,as one example of the evolution of an  
invention1 ,i will take an  instrument  
for measuring and recording a period of 
time1 known as the  calculograph1       
because it lends itself with facility1  
to an explanation  from a platform and  
because my duties as a lawyer have      
necessitated  my becoming very familiar 

with the invention1 and have caused me  
to  consider how it was probably        
produced4    ,and first the problem3    
,there was much occasion to determine   
and record  the values of periods of    
elapsed time2 such as1 the length of    
time of  a telephone conversation2 as   
the revenue of the telephone companies  
depended upon the accuracy of the       
determination4 ,all the previous        
methods involved the recording in hours 
and minutes the times of day  marking   
the initial and the final limits of the 
period to be measured1  and then the    
subtraction of the one time of day from 
the other4 ,this  subtraction was found 
to be very unreliable as well as        
expensive4 ,the  problem then was to    
devise some way by which the value of   
the period  could be arrived at directly
 and without subtraction and also by    
which  such value could be mechanically 
recorded4    ,the prior machine from    
which the calculograph was evolved is   
the  time-stamp1 a printing machine     

having a stationary die like a clock    
dial and having a rotating die like the 
hand of the clock1 as in  ,fig4 #a4 ,the
 small triangle outside the dial is the 
hour hand1 it being  placed outside the 
dial because it is necessary that the   
two hands  shall be at the level of the 
face of the dial and yet be able to pass
  each other4 ,the hour hand may be     
disregarded here1 as the records  needed
 are almost never an hour long4 ,the    
manner of using the time  stamp to      
determine the value of an interval was  
to stamp the time of  day at the        
beginning of the period1 and then to    
stamp the time of day  at the close of  
the period at another place on the      
paper1 as shown in  ,fig4 #b1 and       
finally mentally to subtract the one    
time of day from the  other to get the  
value of the period4    ,illustration3  
,,fig4 #a4    ,time ,stamp ,record4     
,the inventor of the new machine        
conceived the idea that1 if the         
time-stamp were provided with guides or 

gauges so that the card could  be placed
 both times in the same position1 and   
the two records of the  time stamp thus 
be superimposed concentrically 7as      
illustrated in ,fig4  #c71 the value of 
the period would be represented by the  
arc marked off  by the initial and final
 imprints of the minute hand1 so that1  
instead  of subtracting one record from 
another1 he had only to find the value  
of the arc marked off by counting the   
corresponding number of minutes  along  
the dial4    ,the inventor had thus     
gotten rid of the subtraction1 but there
 were  several desirable qualities not  
yet obtained4 ,first1 he could not tell 
from the record alone1 whether it was   
the longer or the shorter arc  marked   
off that was the measure of the period4 
,for instance1 he could  not tell       
whether the period was #g or #ec        
minutes4 ,this was because the  two hand
 or pointer imprints were exactly alike 
except in position4  ,so he conceived   
the idea of making the pointer imprints 

different in  appearance1 by providing  
the pointer die with a mark in line with
 the  pointer1 as illustrated in ,fig4  
#d4    ,the mark and pointer revolve    
together and either the dies or the     
platen  are so arranged that the mark   
can be printed without the pointer at   
the  initial imprint and the pointer at 
the final imprint as in ,fig4 #e1 the   
mark being printed or not at the final  
imprint1 as desired4 ,this could  be    
done either by allowing the pointer die 
or the corresponding portion  of the    
platen to remain retracted from the     
paper during the first  printing4       
,illustration3                #i3bc     
,,fig4 #b4           #aj3ae    ,initial 
,time ,stamp ,record4         ,final    
,time ,stamp ,record4                   
,elapsed ,time3 #aj3ae-i3bc  #eb        
minutes4    ,to read this record1 hours 
and minutes must be subtracted from     
hours  and minutes1 an operation liable 
to much error4    ,it could thus be told
 with certainty from the record alone   

whether  the longer or the shorter arc  
is the measure of the period1 because   
the beginning of the arc is that        
indicated by the imprint of the mark    
without the pointer4    ,there was still
 something to be desired4 ,the counting 
of the minutes  along the measuring arc 
was a waste of time1 if the value of the
 arc  could in some way be directly     
indicated4 ,if the hand were set back   
to #ab o'clock for the initial imprint1 
the final imprint would show  the hand  
pointing directly at the minute whose   
number on the dial is  the value of the 
period1 and it would not even be        
necessary to count4  ,but the setting of
 the hand back to zero would prevent its
 making  the final imprint of any       
previously begun record1 so that the    
machine  could only be used for one     
record at a time4 ,it was desirable to  
have  a machine that would record any   
number of overlapping intervals at  the 
same time1 so that one machine would    
record the intervals of all  the        

telephone conversations under the       
control of a single operator1  or rather
 of two operators1 because both of them 
could reach the  same machine4 ,so it   
wouldn't do to set the hand back to     
zero1 as the  hand must rotate          
constantly and uniformly4 ,then why not 
set the zero  up to the hand at each    
initial imprint8 ,this meant making the 
dial  rotatable1 as well as the hand4   
,it gave an initial record like that    
shown in ,fig4 #f4    ,illustration3    
,,fig4 #c4    ,subtraction eliminated   
but counting still required and         
uncertainty  whether elapsed period is  
#g or #ec minutes4    ,illustration3    
,,fig4 #d4    ,hand and zero mark       
revolving within stationary dial4       
,the inventor then thought of securing  
the dial to the pointer die so  that    
they would revolve together1 the zero of
 the dial being in line  with the       
pointer1 as illustrated in ,fig4 #g4    
,this would obviate the  necessity of   
setting the zero of the dial up to the  

pointer at the  initial imprint4        
,illustration3 ,,fig4 #e4    ,initial   
imprint of zero mark alone and final    
imprint of hand 7and  zero74 ,elapsed   
time1 #h minutes4 ,no subtraction and no
 uncertainty as to  which imprint first1
 but counting still required4    ,but   
again the improvement involved a        
difficulty4 ,as the dial rotated1  its  
final impressions would never register  
with its initial impressions  and would 
therefore always destroy them4 ,as the  
first imprint of the  dial was the only 
useful one1 and as the second imprint   
only made  trouble1 the inventor        
conceived the idea of not making any    
imprint of  the dial at the close of the
 period1 and this he accomplished by    
making  the annular portion of the      
platen covering the dial so that it     
could  be advanced to print or not as   
desired4 ,as the zero of the dial always
  marked the beginning of the measuring 
arc1 it served the same purpose  as the 
mark in line with the pointer1 and the  

latter could now be  omitted4    ,the   
final machine then consists simply of a 
revolving die which1 as  shown in ,fig4 
#h1 consists of a graduated and         
progressively numbered  dial1 having a  
pointer revolving in line with the zero1
 and the machine  has a platen          
consisting of an inner circular portion 
over the pointer  and an annular portion
 over the dial1 each portion being      
operated by a  separate handle so that  
the dial can be printed at the beginning
 of the  period and the pointer alone1  
at its close4    ,the final record has  
an initial imprint of the dial1 ,fig4   
#i;a1 the  zero of the dial showing the 
position of the pointer at the beginning
  of the period1 and a final imprint of 
the pointer alone1 as shown  in ,fig4   
#i;b1 the complete final record1 ,fig4  
#i;c1 consisting of the  superimposition
 of these two records1 and showing the  
pointer in line  with that graduation   
whose number is the value of the period4
 ,here is  a record not only involving  

no subtraction and no uncertainty but   
not  even1 counting in its record1 and1 
as it was made without disturbing  the  
motions either of the pointer or dial1  
any number of records of  other periods 
could have been begun or finished while 
the machine was  measuring the period in
 question4    ,illustration3 ,,fig4 #f4 
,dial moved up to initial position of   
zero mark4 ,elapsed time1 #aa  minutes4 
,no subtraction1 no counting1 no        
uncertainty2 but only one  record       
possible at a time4    ,hiding all the  
intermediate steps in the evolution of  
this invention1  it seems the result of 
spontaneous creation1 but considering   
the  steps in their successive order1 it
 will be seen that the invention  is an 
evolution from the time-stamp2 that     
logic rendered the effort  of the       
imagination at any one step small by    
comparison1 and that the  individual    
steps might be well within the capacity 
of a person to  whom the spontaneous    
creation of the final invention might be

 utterly  impossible4    ,a most        
interesting example of the evolution of 
an invention is that of  the            
cord-knotter of the self-binding        
harvester4 ,the problem here was to     
devise a mechanism which would take     
place of the human hands in tying a     
knot in a cord whose ends had           
mechanically been brought together      
around  a bundle of grain4              
,illustration3 ,,fig4 #g4    ,dial with 
pointer at zero revolving together4     
,the first step was to select the knot  
which could be tied by the  simplest    
motions4 ,the knot which the inventor   
selected is that shown in  ,fig4 #aj1   
and is a form of bow-knot4              
,illustration3 ,,fig4 #h4    ,dial with 
pointer at zero revolving together1 zero
 mark on pointer  being replaced by zero
 of dial4    ,the problem was to find   
how this knot could be tied with the    
smallest  number of fingers1 making the 
smallest number of simple movements4 ,as
  anyone would ordinarily tie even this 

simple knot1 the movements would  be so 
numerous and complex as to seem         
impossible of performance by  mechanism4
 ,the inventor1 by study of his problem1
 found that this knot  could be tied by 
the use of only two fingers of one hand1
 and by very  simple movements4 ,the    
knot will best be understood by         
following the  motions of these fingers 
in tying the knot4 ,using the first and 
second  fingers of the right hand1 they 
are first swept outward and backward  in
 a circular path against the two strands
 of the cord to be tied1 as  shown in   
,fig4 #aa4    ,illustration3 ,,fig4     
#i;a4    ,initial ,imprint4             
,illustration3 ,,fig4 #i;b4    ,final   
,imprint4    ,illustration3 ,,fig4 #i;c4
    ,complete ,record4    ,simple1      
direct-reading record4 ,no subtraction1 
no counting1 no  uncertainty4 ,any      
number of overlapping periods recorded  
on one  machine4    ,the fingers        
continue in their circular motion       
backward1 so that the  strands of the   

cord are wrapped around these fingers1  
as shown in ,fig4  #ab4                 
,illustration3 ,,fig4 #aj4              
,continuing their circular motion1 the  
fingers approach the strands of  the    
cord between the twisted portion and a  
part of the machine which  holds the    
ends of the cord1 and the fingers spread
 apart as shown  in ,fig4 #ac1 so that  
they can pass over and grasp the strands
 thus  approached1 as shown in ,fig4    
#ad4    ,the fingers then draw back     
through the loop which has been formed  
about  them1 the fingers holding the    
grasped portion of the strands1 as shown
  in ,fig4 #ae4    ,the knot is finished
 by the completion of the retracting    
movement of  the fingers through the    
loop1 thus forming the bow of the knot  
as shown  in ,fig4 #af4                 
,illustration3 ,,fig4 #aa4    ,the      
inventor found that one finger could    
have a purely rotary movement1  as if it
 were fixed on the arm and unable to    
move independently of the  arm1 and the 

movement being as if the arm rotated    
like a shaft1 but  the second finger    
must be further capable of moving toward
 and from  the first finger to perform  
the opening movement of ,fig4 #ac1 and  
the  closing movement of ,fig4 #ad by   
which it grasps the cord4 ,the inventor 
accordingly1 from his exhaustive        
analysis of his problem1 and his        
invention or discovery of the proper    
finger motions1 had further only  to    
devise the very simple mechanical device
 illustrated in ,fig4 #ag to  replace   
his fingers4    ,the index finger of the
 hand is represented by the finger ,s1  
which  is integral with the shaft ,v4   
,the second finger of the hand is       
represented by the finger ,u1 which is  
pivoted to the first finger by  the pin 
s4 ,the grasping movement of the finger 
,u is accomplished  by a spring ,v'     
bearing on the shank ,u'1 and its       
opening movement  is caused by the      
travel of an anti-friction roll ,u1 on  
the rear end  of the pivoted finger1    

over a cam ,v1 on the bearing of the    
shaft4  ,the shaft is rotated by the    
turning of a bevel pinion ,w on the     
shaft  through the action of an         
intermittent gear4 ,the necessity of    
drawing  the fingers backward to        
accomplish the movement between ,figs4  
#ad and #af  was avoided by causing the 
tied bundle to have a motion away from  
the  fingers as it is expelled from the 
machine1 the relative motion between    
the fingers and the knot being the same 
as if the fingers drew back4            
,illustration3 ,,fig4 #ab4    ,thus the 
accomplishment of a seemingly almost    
impossible function was  rendered       
mechanically simple by an evolution from
 the human hand1 after  an exhaustive   
and ingenious analysis of the conditions
 involved4    ,it will be seen from the 
examples ,i have given that the         
constructive  part of inventing consists
 of evolution1 and it is the association
 of  previously known elements in new   
relations 7using the term elements  in  

its broadest sense74 ,the results of    
such new association may1  themselves1  
be treated as elements of the next stage
 of development1  but in the last       
analysis nothing is invented or created 
absolutely out  of nothing4             
,illustration3 ,,fig4 #ac4    ,it must  
also be apparent1 that pure reason and  
method1 while not taking  the place of  
the inventive faculty1 can clear the way
 for the exercise  of that faculty and  
very greatly reduce the demands upon it4
    ,where it is desired to make a      
broadly new invention on fundamentally  
different lines from those              
before--having first studied the art to 
find  the results needed1 the qualities 
of the material or other absolutely     
controlling conditions should be        
exhaustively considered2 but at the     
time of making the inventive effort1 the
 details should be dismissed  from the  
mind of how results already obtained in 
the art were gotten4  ,one should       
endeavor to conceive how he would       

accomplish the desired  result if he    
were attempting the problem before any  
one else had ever  solved it4 ,in other 
words1 he should endeavor to provide    
himself with  the idea elements on which
 the imagination will operate1 but to   
dismiss  from his mind as much as       
possible the old ways in which these    
elements  have been associated1 and thus
 leave his imagination free to associate
  them in original and1 as to be hoped1 
better relations than before4  ,he      
should invent all the means he can      
possibly invent to accomplish  the      
desired result1 and should then1 before 
experimenting1 go to the  art to see    
whether or not these means have before  
been invented4 ,he  would probably find 
that some of the elements1 at least1    
have been  better worked out than he has
 worked them out4 ,of course1 mechanical
  dictionaries1 and other sources of    
mechanical elements and movements  will 
be found useful in arriving at means for
 accomplishing certain of  the motions1 

if the invention be a machine4 ,many    
important inventions  have been made by 
persons whose occupation is wholly      
disconnected  with the art in which they
 are inventing1 because their minds were
  not prejudiced by what had already    
been done4 ,while such an effort is     
likely to possess more originality than 
that on the part of a person in  the    
art1 there is1 of course1 less          
probability of its being thoroughly     
practical4 ,the mind well stored with   
the old ways of solving the  problem    
will1 of course1 be less likely to      
repeat any of the mistakes  of the      
earlier inventors1 but it will also not 
be as apt to strike  out on distinctly  
original lines4 ,it is so full1 already1
 of the old  forms of association of the
 elements as to be less likely to think 
of  associating them in broadly new     
relations4    ,illustration3 ,,fig4 #ad4
    ,illustration3 ,,fig4 #ae4          
,illustration3 ,,fig4 #af4    ,nothing  
should be considered impossible until it

 has been conclusively  worked out or   
tried by experiments which leave no room
 for doubt4  ,it is no sufficient reason
 for believing a thing won't work       
because  immemorial tradition1 or those 
skilled in the art1 say it will  not    
work4 ,many an important improvement has
 been condemned as  impracticable1 by   
those in the art1 before it has been    
tried4    ,a conception which an        
inventor has been striving for          
unsuccessfully  will sometimes come to  
him at a time of unaccustomed mental    
stimulation4 ,the slight stimulation of 
the movement of a train of cars1  and   
the sound of music1 have been known to  
produce this effect4 ,the  sub-conscious
 mind1 after having been prepared by a  
full consideration  of the problem to be
 solved1 will sometimes solve the       
problem without  conscious effort1 on   
the part of the inventor4               
,illustration3 ,,fig4 #ag4    ,the      
essential parts of the cord-knotter4    
,in inventing a machine to operate upon 

any given material1 the logical  way is 
to work from the tool to the power4 ,the
 tool or tools should  first be         
invented1 and the motions determined    
which are to be given  to them4 ,the    
proper gearing or parts to produce from 
the power each  motion for each tool    
should then be invented4 ,it should then
 be  considered if parts of each train  
of gearing cannot be combined1 so  as to
 make one part do the work of a part in 
each train2 in short1  to reduce the    
machine to its lowest terms4            
,occasionally a mechanism  will be      
invented which is exceedingly ingenious1
 but which it is  afterwards seen how to
 simplify1 greatly at the expense of its
 apparent  ingenuity4 ,this             
simplification will be at the sacrifice 
of the pride  of the inventor1 but such 
considerations as cheapness1 durability 
and  certainty of action leave no choice
 in the matter4 ,it will sometimes  be  
found that a single part can be made to 
actuate several parts1 by  the          

interposition of elements which reverse 
the motion taken from such  part1 or    
which take only a component of the      
motion of such part1 or  the resultant  
of the motion of such part and some     
other part4 ,where a  machine involves  
the conjoint action of several forces1  
it can be more  thoroughly studied1 if  
it is found there are positions of the  
machine  in which one force or motion   
only is in operation1 the effect of the 
others in such position being           
eliminated1 and thus the elements making
  up the resultant effect can be        
intelligently controlled4    ,the       
drawing board can be made a great source
 of economy in producing  inventions4   
,if the three principal views of all the
 essentially  different positions of the
 parts of a machine are drawn1 it will  
often be found that defects will be     
brought to light which would not        
otherwise have been observed until the  
machine was put into the metal4    ,it  
is desirable to see the whole invention 

clearly in the mind before  beginning to
 draw1 but if that cannot be done1 it is
 often of great  assistance to draw what
 can be seen1 and the clearer perception
 given  by the study of the parts       
already drawn1 assists the mind in the  
conception of the remaining parts4      
,if the improvement which it is sought  
to make is a process1 it should  first  
be considered whether any radically     
different process can be  conceived of1 
and if so1 whether or not it is better  
than the old  process1 and the reason   
for its defects1 and whether it is      
possible  to cure those defects4 ,if the
 old process appears to be in the right 
general direction1 it should be         
considered whether one of the old steps 
cannot with advantage be replaced by a  
new one1 or whether the order of        
performing the steps cannot be changed  
to advantage4 ,i have in mind one       
process in which a reversal of the order
 of steps resulted in giving  the       
product certain desirable qualities     

which had before been sought  for1 but  
could not be obtained4    ,it is        
sometimes desirable not only to invent a
 good process of  producing a product1  
but to control all feasible processes of
 producing  the product4 ,such a case   
occurred where the product itself had   
been  patented1 and it was desirable to 
extend the monopoly beyond the time     
when the patent on the product should   
expire4 ,there were two steps or        
operations which were essential to the  
production of the product1 and  the     
inventor1 by reference to permutations1 
saw that there were but  three orders in
 which those steps could be performed2  
first1 the order  ,a-,b1 then the order 
,b-,a1 and then both steps together4    
,the order ,a-,b  was the old order1    
which did not produce an article having 
the desired  qualities4 ,the inventor   
therefore1 proceeded to invent ways by  
which  the steps could be performed     
together1 and then by which they could  
be  performed in the reverse order1 and 

the patenting such two processes  would 
cover generically all possible ways of  
making the article and  secure the      
desired result of putting himself in    
position to control the  monopoly after 
the patent on the article had expired1  
because no one  could make the article  
without using one of his two processes4 
,in inventing compositions of matter    
there is one inventor who1 if he  is    
seeking for a certain result1 will take 
a chemical dictionary and  make every   
possible combination of every substance 
that could by any  possibility be an    
ingredient of that which he desires to  
produce4 ,it is  as if he were seeking  
to locate a vein of mineral in a given  
territory1  and1 instead of observing   
the geographical and geological         
formation1  and thus seeking to arrive  
at the most probable location of the    
vein1  he should dig up every foot of   
earth throughout the whole territory1   
in order finally to locate the vein4    
,this method is exceedingly  exhaustive1

 but does not appeal to one as involving
 much exercise of  the inventive        
faculties4    ,inventing has become so  
much of a science1 that if one is       
willing  to spend sufficient time and   
money to enable a competent corps of    
inventors to go at the matter           
exhaustively1 almost any possible       
invention involving but a reasonable    
advance in the art can be  perfected4   
,transciber's ,notes3    ,punctuation   
errors repaired4    ,the second         
copyright notice before the text begins 
has been changed  from #aijc to #aijf to
 match the first notice on the title    
page4