TEE PHYSICAL LABORATORY 107 



in the wooden shutter of his window in order to admit a narrow beam 

 of light which was to be dispersed into a spectrum by his prism. Even 

 as late as the middle of the nineteenth century the celebrated determi- 

 nation of the velocity of light was made by Foucault, who is said to have 

 been so poor that he was obliged to hire a pair of telescopes at an op- 

 tician's and to make the experiment in his own rooms. In fact, phys- 

 ical research had reached a very great extension before the provision of 

 special buildings in which to carry it on had been thought of, and these 

 were first provided in connection with instruction. It was not until 

 1874 that the celebrated Cavendish laboratory was completed at the 

 University of Cambridge, and it is worth remarking that this great lab- 

 oratory, out of which has proceeded a large number of the most re- 

 markable modern discoveries in physics, was built at a cost of little over 

 $40,000. It is interesting to know that the introduction of laboratory 

 studies at Cambridge was attended with much shaking of heads and it 

 seemed necessary to Maxwell, the first professor of experimental physics 

 there, to justify its introduction in his opening lecture. " But 

 what," he says, " will be the effect on the university, if men pursuing 

 that course of reading which has produced so many distinguished 

 wranglers turn aside to work experiments? Will not their attendance 

 at the laboratory count not merely as time withdrawn from their more 

 legitimate studies, but as the introduction of a disturbing element, 

 tainting their mathematical conceptions with material imagery and 

 sapping their faith in the formulas of the text-books ?" A more amusing 

 doubt was that expressed by Todhunter, himself a distinguished mathe- 

 matician and student of natural phenomena. "What is the use," said 

 he, " of a student's confirming a physical phenomenon by an observation 

 in the laboratory? If he will not believe the statement of his tutor, who 

 is presumably a gentleman of exemplary character in holy orders, what 

 use can there be in his repeating the experiment for himself?" It is 

 needless to say that this point of view has long since passed into ob- 

 livion and the strong point of the laboratory is that it enables the stu- 

 dent to himself verify the laws of nature quite independently of the 

 statements of any authority whatever, however respectable. 



The purposes of our laboratories then are twofold. First, in them 

 we teach our students the use and manipulation of instruments and the 

 methods for the precise verification of physical laws. In this way the 

 student becomes accustomed to habits of accuracy and the reporting of 

 what he actually sees without the aid of the varnish of imagination and 

 unaffected by any prejudices as to what result he expected to get. We 

 thus have an education in morals which is hard to equal in any other 

 part of education. As a simple example let us consider the method in 

 which the student studies the motion of the pendulum in the elemen- 

 tary laboratory. Instead of measuring the time of its swing by his 



