February 8, 1895.] 



SCIENCE. 



143 



and to measure and how to work out the 

 numerical relations of things ; and it is a sin- 

 gular fact, that in an age when fancy ran riot 

 and when men were able to put together 

 fine phrases without troublmg themselves 

 much with the ideas which ought to accom- 

 pany their words, tliat Archimedes should 

 have concenti-ated his attention on such un- 

 poetic things as the principle of the hand- 

 spike and the crowbar, and the laws of hy- 

 drostatics. His appreciation of the doctrine 

 of the handspike and crowliar, or of the 

 lever as it is technically called, was worthy 

 of its far-reaching consequences ; and the 

 saying attriltutcd to hira — '' Give me a ful- 

 crum on which to rest and I will move the 

 earth " — is a favorite though commonly 

 ill-undei-stood popular expression of his 

 most important contribution to mechanical 

 science. 



For whatever purpose we read history, 

 we are continually reminded that the ab- 

 sorbing occupation of liumauity has lieen 

 fighting one another. The thirst for blood 

 and butchery has always been, and we fear 

 still is, greater than the thirst for knowledge. 

 Thus it was in the days of Archimedes : and 

 although devoted to those abstract studies 

 which engender no malice toward men, he 

 served his king and country by building 

 engines of destruction, and perished finally 

 at the hands of a Roman soldier in the mas- 

 sacre which followed the fall of Syracuse. 



The slowness of the growth of ideas and 

 the blight upon scientific thought which fol- 

 lowed the decay of the Grecian and Roman 

 civilizations are forcibly l>rought to mind by 

 the fa<'t that scarcely an increment to me- 

 chanical .science was attained during the 

 eigliteeu hundred years which elapsed be- 

 tween the epoch of Archimedes and the 

 epoch of Cialileo. But, as if in compensa- 

 tion for this long period of darkness, the 

 torch of science relighted by Galileo has 

 burned on with increasing intensity until 

 now its radiance illumes almost everv 



thought and action of our daily life. The 

 fame of Galileo in the popular mind rests 

 chieHy on his invention of the telescoije and 

 on his battle with the Church in the field of 

 astronomy. But he was able to see things 

 at short as well as at long range ; and his 

 obsei-vations on the vil)rating chandelier in 

 the cathedral at Pisa and on the laws of 

 falling bodies must be rated as of much 

 higher value than his discoveiy of the satel- 

 lites of Jupiter. The peculiar merit of those 

 observations lay in the fi\ct that they led 

 him to correct notions of the properties of 

 moving masses, and of the behavior of mat- 

 ter under the action of force. Archimedes 

 had dealt with matter in a state of relative 

 rest, or with statics only. Galileo rose to 

 the higher concept of matter in motion, and 

 founded that branch of mechanics now 

 known as dynamics. 



It seems strange at first thought when we 

 look back through the light of modern an- 

 alysis on these advances that they should 

 hav'e been so slowly achieved and still more 

 slowly accepted and utilized. "We must re- 

 member, however, that the elaboration of 

 the principles which Galileo added to our 

 science involved the removal of much scho- 

 lastic rubbisli. It was essential first of all 

 to establish the validity of precise and 

 correct observation. He had to recognize 

 that in .studying the laws of falling bodies 

 the most important ([uestion was not ivhtj 

 they fall but hoic they fall. In doing this 

 he set an example which has ever since 

 been followed with success in the investi- 

 gation of the phenomena of nature. Con- 

 sidering the times in which he lived, the 

 amount of work he accomplished is little 

 short of prodigious. For besides his capital 

 contributions to mechanics and astronomy, 

 he was the founder of our modem engineer- 

 ing science of tlie strength and resistance of 

 materials, a science which has recently 

 grown into a great department of mechanics 

 under the title of the mathematical theorv of 



