Experiment 

 Extension 



SCIENTIFIC SIDE-LIGHTS 



236 



1149. EXPERIMENT REFUTES AN- 

 CIENT THEORY Scholastic Dictum Shattered 

 at Leaning Tower of Pisa. The notion of 

 the attractive force of the earth, unchecked 

 by any right conception of the action of 

 force in producing motion, led the ancients 

 into a very strange error. As the " weight " 

 of a body is the expression of the downward 

 " pull " which the earth exerts upon it, it 

 seemed natural to suppose that the rate of 

 the fall of any heavy body to the ground 

 would increase in proportion to that weight, 

 so that a body weighing ten pounds would 

 fall ten times as fast as a body weighing one 

 pound. And this was formulated as a 

 " law " by Aristotle, and accepted by " edu- 

 cated " mankind as such for nearly two 

 thousand years. . . . Galileo . . . 

 saw that it must be erroneous, as taking no 

 account of the very obvious consideration 

 that while the " pull " of the earth on the 

 weight of ten pounds is ten times as great as 

 it is upon the weight of one pound, it has to 

 give motion to ten times the mass ; so that 

 the rates of fall of the two bodies would be 

 the same. His teaching on this subject being 

 opposed by his colleagues, Galileo, in the 

 presence of the whole university, ascended 

 the Leaning Tower, and, dropping from its 

 summit bodies of different weights, tie 

 showed that (with an inconsiderable differ- 

 ence, due to the resistance of the air) they 

 reached the bottom in the same times. As 

 the monument of an experiment which gave 

 the death-blow to the unscientific legislation 

 of Aristotle, and prepared the way for the 

 scientific legislation of Newton, the Lean- 

 ing Tower of Pisa, beautiful in itself as an 

 architectural work, has a far grander inter- 

 est for all who can appreciate this great 

 step in the emancipation of thought. 

 CARPENTER Nature and Man, p. 371. (A., 

 1889.) 



1150. EXPERIMENT SUPERIOR TO 

 ORDINARY OBSERVATION Electricity and 

 Thunder-storm. When the scientific inves- 

 tigator is inquiring into the causes of a 

 phenomenon, he does not confine himself to 

 the investigation of things as they are given 

 in ordinary perception. That would never 

 take him to his goal, -tho he had at his com- 

 mand the experiences of all time. Thunder- 

 storms have been recorded, indeed carefully 

 described, since the first beginnings of his- 

 tory; but what a storm was could not be 

 explained until the phenomena of electricity 

 had become familiar, until electrical ma- 

 chines had been constructed and experiments 

 made with them. Then the matter was 

 easy. For when once the effects of a storm 

 had been observed and compared with the 

 effect of an electric spark, the inference was 

 plain that the discharge of the machine was 

 simply a storm in miniature. What the ob- 

 servation of a thousand years had left un- 

 explained was understood in the light of a 

 single experiment. WTJNDT Psychology, 

 lect. 1, p. 0. (Son. & Co., 1896.) 



1151. EXPERIMENT THOUGHT DE- 

 GRADING An aged and learned professor 

 of therapeutics, who occupied himself much 

 with the reorganization of the universities, 

 was urgent with me to divide physiology, in 

 order to restore the good old time; that I 

 myself should lecture on the really intellec- 

 tual part, and should hand over the lower 

 experimental part to a colleague whom he 

 regarded as good enough for the purpose. 

 He quite gave me up when I said that I 

 myself considered experiments to be the 

 true basis of science. HELMHOLTZ Popular 

 Lectures, lect. 5, p. 219. (L. G. & Co., 

 1898.) 



1152. EXPERIMENTER DIFFERS 

 FROM OBSERVER I do not question his 

 [Pouchet's] ability as an observer, but the 

 inquiry needed a disciplined experimenter. 

 This latter implies not mere ability to 

 look at things as Nature offers them to our 

 inspection, but to force her to show herself 

 under conditions prescribed by the experi- 

 menter himself. TYNDALL Floating Matter 

 of the Air, p. 284. (A., 1895.) 



1153. EXPERIMENTS CUMULATIVE 



Demonstrations of Science Pasteur 

 Traces Fermentation to Living Organisms. 

 As in all the conclusions arrived at by Pas- 

 teur, so in those relating to fermentation, 

 there were a number of different experi- 

 ments which were performed by him to eluci- 

 date the same point. We will choose one of 

 many in relation to fermentation. Jf a 

 sugary solution of carbonate of lime is left 

 to itself, after a time it begins to effervesce, 

 carbonic acid is evolved, and lactic acid is 

 formed; and this latter decomposes the car- 

 bonate of lime to form lactate of lime. This 

 lactic acid is formed, so to speak, at the 

 expense of the sugar, which little by little 

 disappears. Pasteur demonstrated the cause 

 of this transformation of suga'r into lactic 

 acid to be a thin layer of organic matter con- 

 sisting of extremely small moving organ- 

 isms. If these be withheld or destroyed in 

 the fermenting fluid, fermentation will 

 cease. If a trace of this gray material be 

 introduced into sterile milk or sterile solu- 

 tion of sugar, the same process is set up, 

 and lactic acid fermentation occurs. NEW- 

 MAN Bacteria, ch. 4, p. 112. (G. P. P., 

 1899.) 



1154. EXPERT, INTUITION OF Ac- 

 cumulated Associations from Long Experi- 

 ence. Saturated with experience of a par- 

 ticular class of materials, an expert intui- 

 tively feels whether a newly reported fact is 

 probable or not, whether a proposed hypoth- 

 esis is worthless or the reverse. He in- 

 stinctively knows that, in a novel case, this 

 and not that will be the promising course of 

 action. The well-known story of the old 

 judge advising the new one never to give 

 reasons for his decisions "the decisions will 

 probably be right, the reasons will surely be 

 wrong" illustrates this. The doctor will 



