334 



SCIENCE. 



[N. S. Vol. XVI. No. 400. 



Mendeleeff, when he saw the law of the peri- 

 cdic arxangement of the elements, knew that 

 elements exist which would fill the gaps ; 

 but it took many years of work by many 

 men to find a part of them; and during 

 the past few years a half dozen or more of 

 the vacant places have been occupied. 

 Each geologist, each scientist, now as in 

 the past, is just as right as he should be. 

 The scientific seers will ever go far in ad- 

 vance and guide others, even as did the 

 spiritual seers of old. 



The scope of these observations doubtless 

 extends beyond geology. ]\Iuch of what has 

 been said is true of knowledge as a whole, 

 not restricted to one subject. But I shall 

 have accomplished my purpose if what I 

 have said be true of geolog}^ ; for if my con- 

 clusions be well founded, they furnish the 

 basis upon which courses leading to degrees 

 in professional geology should be laid out, 

 and to methods of good geological work in 

 the field and in the office. 



C. R. Van Hise. 



Universitt of WiscoNSiiir. 



SECTION D, 31ECHANICAL SCIENCE AND 

 ENGINEERING. 



Papers were presented as follows : 



The Trend of Progress of the Prime 

 Movers: Pkofessor R. H. Thurston, 

 Cornell University. 



1. The great prime movers have been 

 known in type and in some cases, in specific 

 forms, still familiar, since the days of Hero 

 of Alexandria and probably may have been 

 in some forms known to prehistoric Greeks 

 and Asiatics. The sources of power— heat, 

 falling M'aters, the winds— all were well 

 known when the earliest scientific writings 

 were produced, and the famous Alexan- 

 drian ' Museum ' contained illustrations and 

 examples of even some of our simpler fa- 

 miliar types of steam-engine and steam- 

 boiler. 



2. The prime movers made little progress 

 toward their present perfection until the 

 commencement of the eighteenth century, 

 when the steam-engine of Savery and 

 Worcester, the old steam fountain of Hero 

 the Younger, was displaced by the modern 

 steam-engine, a real train of mechanism, 

 devised by Newcomer, the inventor of the 

 modern type of machine, about 1707. 

 Meantime, water-wheels and windmills were 

 taking form and the prime movers thus 

 were preparing to do their part in the 

 world. Improved by Watt, the steam-en- 

 gine assumed the largest part of the load, 

 but the water-wheels and windmills have 

 always done a large amount of work in the 

 aggregate. The industrial world came after 

 a time to be moved as a whole by the prime 

 mover of Watt, and steam power has of 

 late performed vastly more work than could 

 the whole population of the world, unaided. 



3. The gas-engine has a history of about 

 the same length as the steam-engine in its 

 form of a prime mover for mills. It was 

 introduced about a century ago and has 

 progressed meantime less rapidly than its 

 rival, but since the middle of the nineteenth 

 century its advance has been steady, both 

 in construction and in employment. To- 

 day this motor has assumed a perfection 

 of design and construction and has attained 

 an excellence of economical performance 

 which is rapidly bringing it into use in a 

 great variety of fields and is, in fact, mak- 

 ing it a promising competitor with the old- 

 er motor. 



4. The other motors have been meantime 

 greatly improved. The modern hydraulic 

 turbine has attained an efficiency of eighty 

 per cent, and upward and the contemporary 

 windmill is a scientifically designed, skill- 

 fully made apparatus of but little if any less 

 perfection, for its purpose, or efficiency in 

 utilizing its form of energy. All the com- 

 mon forms of prime movers have now, 

 thanks to advances in sciences related to 



