January 1, 1904.] 



SCIENCE. 



forms. Heat and mechanical energy are 

 absolutely essential to man. The chief 

 source of the energy that comes into play is 

 fuel. We are primarily dependent upon 

 the coal supply for the continuation of the 

 activities of man. Without this, unless 

 something is to take its place, man is 

 doomed. Statistics in regard to the coal 

 supply and the rate at which it is being 

 used up have so frequently been presented 

 by those who have special knowledge of this 

 subject that I need not trouble you with 

 them now. The only object in referring to 

 it is to show that^ unless by means of scien- 

 tific investigation man is taught new 

 methods of rendering the world's store of 

 energy available for the production of heat 

 and of motion, the age of the human race is 

 measured by the extent of the supply of 

 coal and other forms of fuel. By other 

 forms of fuel I mean, of course, wood 

 and oil. Plainly, as the demand for land 

 for the production of foodstuffs increases, 

 the amount available for the production of 

 wood must decrease, so that wood need not 

 be taken into account for the future. In 

 regard to oil, our knowledge is not sufficient 

 to enable us to make predictions of any 

 value. If one of the theories now held in 

 regard to the source of petroleum should 

 prove to be correct, the world would find 

 much consolation in it. According to this 

 theory petroleum is not likely to be ex- 

 hausted, for it is constantly being formed 

 by the action of water upon carbides that 

 in all probability exist in practically un- 

 limited quantity in the interior of the earth. 

 If this be true, then the problem of supply- 

 ing energy may be reduced to one of trans- 

 portation of oil. But given a supply of 

 oil and, of course, the problem of trans- 

 portation is solved. 



What are the other practical sources of 

 energy? The most important is the fall of 

 water. This is being utilized more and 

 more year by year since the methods of pro- 



ducing electric currents by means of the 

 dynamo have been worked out. There is 

 plainly much to be learned before the 

 energy made available in the immediate 

 neighborhood of the waterfall can be trans- 

 ported long distances economically, but ad- 

 vances are being made in this line, and al- 

 ready factories that have hitherto been 

 dependent upon coal are making use of the 

 energy derived from waterfalls. The more 

 rapidly these advances take place the less 

 will be the demand for coal, and if there 

 were only enough waterfalls conveniently 

 situated, there would be no difficulty in 

 furnishing all the energy needed by man 

 for heat or for motion. 



It is a fortunate thing that, as the popu- 

 lation of the earth increases, man's tastes 

 become more complex. If only the simplest 

 tastes prevailed, only the simplest occupa- 

 tions would be called for. But let us not 

 lose time in idle speculations as to the way 

 this primitive condition of things would 

 affect man 's progress. As a matter of fact 

 his tastes are becoming more complex. 

 Things that are not dreamed of in one gen- 

 eration become the necessities of the next 

 generation. Many of these things are the 

 direct results of scientific investigation. No 

 end of examples will suggest themselves. 

 Let me content myself by reference to one 

 that has of late been the subject of much 

 discussion. The development of the arti- 

 ficial dye-stuff industries is extremely in- 

 structive in many ways. The development 

 has been the direct result of the scientific 

 investigation of things that seemed to have 

 little, if anything, to do with this world. 

 Many thousands of workmen are now eln- 

 ployed, and many millions of dollars are 

 invested, in the manufacture of dye-stuffs 

 that were unknown a few years ago. Here 

 plainly the fundamental fact is the esthetic 

 desire of man for colors. A colorless world 

 would be unbearable to him. Nature 

 accustoms him to color in a great variety of 



