AND MODERN PHYSICS. 69 



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 illustra- 

 tive 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. The simpler the 

 materials of an illustrative experiment, and the more familiar 

 they are to the student, the more thoroughly is he likely to 

 acquire the idea which it is meant to illustrate. The educa- 

 tional value of such experiments is often inversely proportional 

 to the complexity of the apparatus. The student who uses 

 home-made apparatus, which is always going wrong, often 

 learns more than one who has the use of carefully adjusted 

 instruments, to which he is apt to trust, and which he dares 

 not take to pieces. 



" It is very necessary that those who are trying to learn from 

 books the facts of physical science should be enabled by the 

 help of a few illustrative experiments to recognise these facts 

 when they meet with them out of doors. Science appears to 

 us with a very different aspect after we have found out that it 

 is not in lecture-rooms only, and by means of the electric light 

 projected on a screen, that we may witness physical phenomena, 

 but that we may find illustrations of the highest doctrines of 

 science in games and gymnastics, in travelling by land and by 

 water, in storms of the air and of the sea, and wherever there 

 is matter in motion. 



" If, therefore, we desire, for our own advantage and for the 

 honour of our University, that the Devonshire Laboratory 

 should be successful, we must endeavour to maintain it in 

 living union with the other organs and faculties of our learned 

 body. We shall therefore first consider the relation in which 

 we stand to those mathematical studies which have so long 

 flourished among us, which deal with our own subjects, and 

 which differ from our experimental studies only in the mode in 

 which they are presented to the mind. 



