INTRODUCTORY LECTURE ON EXPERIMENTAL PHYSICS. 



to science, and we are daily receiving fresh proofs that the popularisation of 

 scientific doctrines is producing as great an alteration in the mental state of 

 society as the material applications of science are effecting in its outward lit',-. 

 Such indeed is the respect paid to science, that the most absurd opinions may 

 become current, provided they are expressed in language, the sound of which 

 recals some well-known scientific phrase. If society is thus prepared to receive 

 all kinds of scientific doctrines, it is our part to provide for the diffusion and 

 cultivation, not only of true scientific principles, but of a spirit of sound 

 criticism, founded on an examination of the evidences on which statements 

 apparently scientific depend. 



When we shall be able to employ in scientific education, not only the 

 trained attention of the student, and his familiarity with symbols, but the 

 keenness of his eye, the quickness of his ear, the delicacy of his touch, and 

 the adroitness of his fingers, we shall not only extend our influence over a 

 class of men who are not fond of cold abstractions, but, by opening at once 

 all the gateways of knowledge, we shall ensure the association of the doctrines 

 of science with those elementary sensations which form the obscure background 

 of all our conscious thoughts, and which lend a vividness and relief to ideas, 

 which, when presented as mere abstract terms, are apt to fade entirely from 

 the memory. 



In a course of Experimental Physics we may consider either the Physics 

 or the Experiments as the leading feature. We may either employ the experi- 

 ments to illustrate the phenomena of a particular branch of Physics, or we 

 may make some physical research in order to exemplify a particular experimental 

 method. In the order of time, we should begin, in the Lecture Room, with 

 a course of lectures on some branch of Physics aided by experiments of illus- 

 tration, and conclude, in the Laboratory, with a course of experiments of research. 



Let me say a few words on these two classes of experiments, Experiments 

 of Illustration and Experiments of Research. The aim of an experiment of 

 illustration is to throw light upon some scientific idea so that the student may 

 be enabled to grasp it. The circumstances of the experiment are so arranged 

 that the phenomenon which we wish to observe or to exhibit is brought into 

 prominence, instead of being obscured and entangled among other phenomena, as 

 it is when it occurs in the ordinary course of nature. To exhibit illustrative 

 experiments, to encourage others to make them, and to cultivate in every 

 way the ideas on which they throw light, forms an important part of our duty. 



