INVENTION OF THE BALANCE SPRING. 36.5 



scholar, and brought with him a number of mechanical nick- 

 nacks which he had made at home. His mechanical genius 

 soon made him known to the members of the invisible society- 

 there, who employed him to work for them, making appara- 

 tus- for their experiments. Dr. Ward, afterwards Bishop of 

 Salisbury, took a hking to him, and instructed him in mathe- 

 raatics and astronomy. He urged him to try his mechanical 

 genius in contriving a 'scapement pendulum. It would appear 

 that they found the 'scapement for a balance, which had 

 long been in use, did not answer, probably because it required 

 very wide vibrations, which were found not so equable ; and 

 Mr. Hooke invented this sometime before February l656 ; for 

 there are observations of a solar eclipse made in that month, at 

 Oxford, by a pendulum clock. 



JMr. Hooke got RiccioU's book from Dr. Ward, where men- Attends to 

 tjon is made of the proposal of Gemma Frisius to discover the*^''"''^^*^^'-*'*'' 

 longitude by a timekeeper ; this he immediately proposed to 

 do by a pendulum clock. But it is- very remarkable, that 

 Hooke had mathematics enough to see that even the smallest 

 vibrations were not isochronous unless of equal width, althougli 

 Galileo had asserted that no difference would be observed. " 

 Another remarkable instance of his great genius is, that though 

 then only twenty-one years of age, he saw that every branch 

 of human knowledge had a system of its own, and a set of 

 principles on which it was regularly founded ; and he said it was 

 only by studying even shoemaking in this way, that one could 

 be certain of improving it. He had aheady begun to form 

 systems on the different subjects which had interested him. 

 He called them algebras, because they enabled the possessor His svstems for 



to invent and discover new things in their own line by rule, indentions cail- 

 j . , . . ■' ed bv him alge- 



and witli certamty of succeeding. Mechanics always was his bras^ 



Favourite; and his mechanical algebra, or method of me- 

 chanic invention, he always considered as his greatest trea- 

 sure. He says that no problem could be proposed to him in 

 mechanics, but his algebra would immediately tell whether it 

 was possible, and would put him and keep him in the right 

 road for solving it. He told Dr. Ward that his algebra 

 plainly showed him, that the only thing that could make equal 

 vibrations, was an accelerating force proportional to the dis- He shows the 

 tance from the place of rest, and this was not true even of the lawofisochion. 

 smallest arches of a pendulum. But he had not mathematics ^ *' '^ "^"^' 



enough 



