152 TRANSACTIONS OF THE 



portant. The progress of scientific discovery is marked at every 

 milestone by the revelations of accidents, which the thoughtful 

 mind of the inventor did not apply to practical ends till long after- 

 wards, when the need had arisen. If it was an accident that led 

 Galileo to the discovery of the isochronous oscillation of the pen- 

 dulum, it was not till fifty years afterwards that this discovery was 

 applied to regulate the movement of a clock. The phenomena of 

 electricity that accident may have revealed to Galvani and Volta, 

 are the basis of inventions that the most active minds of this decade 

 are expending their best energies upon. It cannot be denied that 

 in discovery accident has played an important part ; but the more 

 this fact is considered, and the more we consider the true function 

 of discovery, the more strongly do we find the proposition con- 

 firmed that improvements in the arts are not the result of chance 

 but of intelligent efforts to supply conscious needs. Hence I shall 

 regard this proposition as conceded, and I pass to another. 



(4) Every human invention has sprung from some prior invention 

 or from some prior known expedient. Inventions do not, like their 

 protectress, Pallas Athene, spring forth full grown from the heads of 

 their authors. This suggestion needs no argument when made re- 

 garding any of the modern inventions. Every one of them is seen 

 by the most superficial observer to be built upon or elaborated out 

 of inventions and expedients previously in use. It is only when 

 we go back of these and study the expedients and appliances out of 

 which they have grown, and whose history is unrecorded, that the 

 proposition I contend for is not obvious. And yet there is not a 

 single one of them which does not when studied exhibit in itself 

 the evidences of a similar substructure. In the process of elimina- 

 tion we go back and back, and find no resting place till we reach 

 the rude set of expedients, the original endowment of men and 

 brutes alike. This is a truth which study more and more confirms, 

 and from it the proposition stated may be deduced as one of the 

 laws of invention. 



It may be deduced as a corollary to this proposition, but at the 

 same time a fact determinable by independent observation, that the 

 generation of one invention from another is not immediate but 

 always through one or more intermediate steps. The effect of every 

 invention fundamental in its character is first to generate wants be- 

 fore unknown or unfelt. The effort to supply these wants leads to 



