210 



SCIENCE. 



[N. S. Vol. XV]I. No. 423 



history, its habits and its needs, that now 

 constitute so large a part of our study, and 

 is an acknowledged factor in practical 

 agriculture. 



American horticulture, still more ob- 

 viously a branch of applied ecology, has 

 already reached a stage of development in 

 which it is hardly an exaggeration to say 

 that desired forms are actually made to 

 order, and some of the men who are con- 

 tributing to this end are leading promoters 

 of ecological investigations. They are the 

 men we summon when we want to know 

 the real basis of Mendel's laws and the 

 ones who are teaching us from their own 

 studies the course of contemporaneous evo- 

 lution. 



I have already referred to forestry as 

 illustrating the extent &-a,d definiteness of 

 application of ecological principles in a 

 great practical industry. It is highly im- 

 portant, particularly in the United States, 

 that this relation should be well under- 

 stood. We are confronted in many of our 

 states with peculiarly difficult problems of 

 reforestation. Land that has been the 

 greatest source of wealth to the state is 

 now a wilderness, practically worthless 

 until it is clothed again with forests. How 

 this is to be accomplished is one of the 

 serious economic problems that the present 

 generation is called upon to solve. We 

 are gaining the data in part through the 

 suggestions of professional foresters, but 

 there is imperative need of all the light 

 that can be gained by critical and extended 

 istudy of the natural succession of plant 

 societies. It is fortunate that such studies 

 lave already attracted earnest and capable 

 students, and it is fair to say that those 

 who desire to render the state a permanent 

 economic service can hardly find a better 

 field, providing they are fitted for the task. 



I make no apology for thus emphasizing 

 the practical value of this branch of scien- 



tific work. Service, first wrung from the 

 unwilling slave, then the free-will offering 

 of the citizen and patriot, is now the 

 honorable goal of the worker in science, 

 and there is no higher end to be attained. 

 Speaking for botanists, I have taken 

 into account only one side of ecological 

 study, that which relates to the habits and 

 adaptations of plants. The habits of ani- 

 mals can not be less interesting and im- 

 portant, and it is a matter of congratula- 

 tion that zoologists are entering this field 

 with enthusiasm and well-defined aims. 

 We extend to them our hearty greetings 

 for the new year and the new era of bio- 

 logical work. V. M. Spalding. 



THE AMERICAN ASSOCIATION FOB THE 

 ADVANCEMENT OF SCIENCE. 



SECTION D, MECHANICAL SCIENCE AND 



ENGINEERING. 



TUESDAY MORNING, DECEMBER 30- 



Electrical Engineering : J. Burkitt Webb, 

 Stevens Institute, Hoboken, N. J. 

 Electrical engineering is a branch of en- 

 gineering which more than any other joins 

 the scientific with the practical, and. bases 

 the latter more immediately on theoretical 

 considerations and mathematical calcula- 

 tions. It differs widely in this respect 

 from some other branches of engineering, 

 and for this reason papers which might 

 otherwise come to this section are easily in- 

 cluded under the head of physics, just as 

 formerly all papers of scientific affinities 

 went together into one section. Now, since 

 Section D has been in existence, a paper, 

 say, on thermodynamics, has been consid- 

 ered suitable for it, for although its matter 

 was really a branch of physics, its engi- 

 neering connections would naturally bring 

 it to us. Now, Section B is overloaded 

 with papers and I would suggest that some 

 effort be made to get into this section such 

 papers as may properly be claimed under 



