844 



SCIENCE. 



[N. S. Vol. II. No. 51. 



and is still effecting further gains. The 

 methods adopted involved extensive utiliza- 

 tion of exhaust steam and a limited appli- 

 cation of electric power distribution. This 

 was the most striking and suggestive paper 

 of the week. The same writer discussed 

 ' Comparative tests of Steam Boilers with 

 different kinds of Coal;' showing that much 

 uncertainty still exists in regard to the ex- 

 act calorific value of the various elements 

 of the fuels, and their mutual influence as 

 burned in the fire-box of the steam boiler, 

 and also in regard to the relation between 

 the results of test in that manner and those 

 obtained by the use of the various ' calori- 

 meters,' bomb and other. The earlier work 

 of Mr. Kent was the basis of the discussion 

 largely. 



Prof. Kingsbury's account of his experi- 

 ments upon the friction of screws, by use of 

 an ingenious and well-designed automatic 

 apparatus of his own construction, interested 

 the convention and gave rise to considerable 

 discussion. Carrying pressures up to 10,- 

 000 and to 14,000 pounds on the square 

 inch, he found coefiBcients ranging from 

 three to twenty-five per cent., but showed 

 that moderate values could be secured by 

 the combination of proper metals in well- 

 proportioned and accui'ately-formed jour- 

 nals and bearings. He proved that the 

 heavy mineral oils, and especially those to 

 which a small amount of graphite had been 

 added, were best. "With the latter a co- 

 efl&cient as low as three per cent, had been 

 obtained. The testing apparatus was a 

 modification of Prof. Thurston's oil-testing 

 machine, in which the tremendous pres- 

 sures on the square-threaded screws em- 

 ployed were carried in such manner as not 

 to cause appreciable inaccuracy. 



Prof. Goss described tests of the DeLaval 

 Steam-Turbine, giving the horse-power 

 hour on about fifty pounds of steam, a 

 figure far above that usually claimed for 

 that class of machine, and three times as 



high as the reported best record. Prof. 

 Bissell described an ingenious recording de- 

 vice for testing machines and Prof. Car- 

 penter discussed Siblej" College experiments 

 on the effects of heat upon strength of iron 

 and steel; effects which were stated, in the 

 course of the discussion, to have been also 

 shown in the course of the more extended 

 experiments of German investigators. 



Prof. Barr's paper on the proportions of 

 high-speed engine summarized his work in 

 comparison of the proportions adopted by 

 the principal builders, and showed that 

 their practice covered a wide range, but 

 that the best grouped themselves about the 

 mean rather closely. Constants were thus 

 introduced into the rational formulas of 

 strength of materials hy the author of the 

 paper, which were representative of the ex- 

 tremes of practice and of the mean, which 

 latter are presumed to serve as a good 

 guide in general practice. This paper at- 

 tracted much attention as being a first step 

 in the direction of reduction of the vagaries 

 of ancient practice to a reasonable and 

 economical basis. Its author announced 

 that he had already commenced a similar 

 analj'sis of current practice, in the propor- 

 tioning of the ' low-speed ' engine. 



Many other papers and discussions, 

 which cannot be here noticed, contributed 

 greatly to the instruction and profit de- 

 rived from the convention. All will ap- 

 pear in the next volume of the transactions. 

 The attendance was large, about one fourth 

 the total membership. The Society, orga- 

 nized in 1880, now numbers about 1750 

 members and includes substantially all of 

 the leading members of the profession. A 

 novel and important feature of the conven- 

 tion was the appointment, at the request of 

 the Superintendent of Buildings, of a com- 

 mittee to cooperate with architects and 

 representatives of the building trades in the 

 revision and improvement of the building 

 laws. The newly elected President is the 



