3i8 SCIENCE PROGRESS 



no relation to the experience of our daily lives. We teach a student elementary 

 principles of measurement when he wants to know the working of a telephone, we 

 explain to him all about specific and latent heat when he thinks that he knows 

 already something of how a locomotive works, and does not see why he should 

 have to go through all this drudgery. I do not wish to alter the present modes of 

 instruction. Teaching has a disciplinary value apart from the facts that are 

 taught. The concentration of thought on a definite problem ; the training in 

 accuracy and neatness in work ; the importance of mechanics as a foundation of 

 science — all these are necessary if the value of science teaching is not to be 

 impaired. But, simultaneously with this instruction and independently of it, I 

 think some time might be spent in stirring the imagination, improving the obser- 

 vational faculties, and bringing the different branches of science into proper 

 relationship with each other. While physics and chemistry must always receive 

 the first place in laying a firm foundation, observational sciences such as 

 astronomy, geology, and biology will furnish large opportunities to supply the 

 supplementary teaching with instructive examples. 



More intimately connected with the main object of my lecture is the moral 

 lesson that can be drawn from all science teaching. Nature works by fixed rules. 

 Constant changes are occurring in the position and the illumination of the objects 

 that surround you, or in the state of our inner consciousness. Each of these 

 changes is both preceded and followed by other changes which are not inde- 

 pendent, but connected with it, like the oscillation of the piston of an engine with 

 the rotation of the wheel it drives. Every one of your acts and every one of your 

 thoughts have traces which persist throughout time, and reach to the ends of the 

 universe. You may accidentally — but it never is accidentally — drop a sheet of paper; 

 you think nothing of it and lift it up again, and there, perhaps, to your mind, 

 the matter ends. But while the paper fell, the whole earth moved towards it, and 

 your casual act has affected every person that stands on it ; your carelessness has 

 increased the length of the day by an amount which you ought to be able to calcu- 

 late. By replacing the paper in its previous position, you can never quite undo all 

 that you have done ; some effect of your action will persist for ever. Or while out 

 on a walk on a clear day, you may be taken with a desire to smoke. You light 

 a match, which the wind blows out immediately. During the second the match 

 was burning it sent out waves of light. The waves will travel outwards, pass 

 through the atmosphere, and reach the sun in 8^ minutes of time ; but to the right 

 and the left of the sun they will pass onwards. In sixty years they will reach 

 stars whose distances may still be measured by direct means. But other methods 

 of estimating distance are now available, and we are able to point to small tele- 

 scopic bodies, and say that twenty thousand years hence the explosive compound 

 contained in your match will supply a minute fraction of its energy to their surface. 

 The consequences of your action will endure for ever. If this be true of your 

 most casual and irresponsible acts, it also holds for the thoughts and motives 

 which guide you in the serious tasks of your life. The consequences may be 

 more vital, but we cannot trace them so accurately in the intellectual domain as 

 we can in the material universe. Theology and philosophy may attempt to do so, 

 but scientific knowledge alone can enforce the lesson with unrelenting persistency 



