288 



THE POPULAR SCIENCE MONTHLY. 



of coal per hor?c-power. The Persia, built 

 in 1850, had side-lever engines, indicating 

 3,600 horse power, and consumed 3 ?ci pounds 

 of coal per horse-power. The Gallia, built 

 in 1879, was fitted with compound engines 

 of 5,000 horse-power, and sailed with a 

 speed of 15^ knots an hour. The Persia 

 burned (S\ tons of coal for every ton of car- 

 go it carried ; while the Gallia burned less 

 than half a ton, although it carried the car- 

 go 2^ knots an hour faster than the Persia. 

 The Arizona, with 6,000 horse-power, con- 

 sumed If pound of coal per indicated horse- 

 power, and carried 3,400 tons of cargo at an 

 average speed of 16^ knots, burning less 

 than four hundred-weight per ton of cargo at 

 a speed across the Atlantic faster than any 

 previously recorded. 



Dr. Hiram A. Cutting, of Vermont, has 

 made a series of examinations into the dura- 

 bility under heat of different kinds of gran- 

 ite, sandstone, limestone, marble, conglom- 

 erate, slate, soapstone, and artificial stone. 

 Granite began to yield at a temperature of 

 between 700 and 800 ; it became cracked 

 between 800 and 900 ; generally cracked 

 between 800 and 950 ; and was made 

 worthless by or before reaching a tempera- 

 ture of 1,000. Sandstones showed a great- 

 er power of endurance, massive limestones 

 still greater, and marbles the greatest, while 

 conglomerates seem to have been among the 

 weakest stones. The least absorbent and 

 the most absorbent of the granites were 

 equally the granites most destructible by 

 heat. 



The annual meeting of the Society for 

 the Promotion of Agricultural Science will 

 be held at Cincinnati, August 16th, the day 

 before the meeting of the American As- 

 sociation for the Advancement of Science. 

 Papers will be presented by Professor W. J. 

 Beal, on " Testing Seeds "; by Professor R. C. 

 Kcdzie, on "The Ripening of Wheat" ; and 

 other essays, the subjects of which have not 

 been announced, will be read by Professor 

 S. W, Johnson, Patrick Barry, Professors J. 

 il. Comstock, E. W. Ililgard, and A. J. Cook, 

 Messrs. J. J. Thomas, L. B. Arnold, and E. 

 Lewis Sturtevant, M. D. 



The meeting of the French Association 

 for the Advancement of Science at Al<riers 

 was successful in point of numbers, at least, 

 notwithstanding the troubles with Tunis. A 

 great many members had arrived on the 11th 

 of April, fresh ones were coming in every 

 boat, and it was thought that the attendance 

 would exceed a thousand. 



Professor James Tennant, F. G. S., a 

 "well-known mineralogist, has recently died 

 in London, at the age of seventy-three years. 

 He was the possessor of one of the largest 

 and most valuable collections of minerals, 

 was for many years Professor of Geology and 

 Mineralogy, afterward Professor of Mineral- 



ogy in King's College, London ; he held the 

 office of "Mineralogist to the Queen," and 

 was consulted by the Government, as one of 

 the best authorities on gems, with respect to 

 the cutting of the Koh-i-noor diamond. He 

 did useful work in preparing collections of 

 minerals and fossils suitable for educational 

 purposes and as a lecturer, and was author, 

 in connection w'ith the late Professor Ansted 

 and the Rev. W. 0. Mitchell, of the treatise 

 on " Geology, Mineralogy, and Crystallogra- 

 phy " in Orr's " Circle of the Sciences." 



The death is reported of Mr. F. A. Xo- 

 bert, the celebrated producer of test-plates 

 for miscroscopists. He had been engaged 

 for many years in ruling micrometers and 

 diffraction plates, and produced one set of 

 lines his nineteenth band equivalent to 

 about 112,000 lines to the inch, which he 

 believed could never be seen resolved in the 

 microscope. Dr. Woodward eventually pro- 

 duced photographs of the finest of these 

 lines ; when Mr. Nobert ruled a new plate, 

 the finest band of which the twentieth 

 was of a fineness equivalent to about 224,- 

 000 lines to the inch. 



The New York Electrical Society was 

 formed in this city on the 8th of February 

 last, with the purpose of bringing persons 

 engaged in operations connected with elec- 

 tricity into closer connection and association 

 with each other for improvement in knowl- 

 edge of electric art and science, and for so- 

 cial intercourse. The first regular meeting 

 of the society was held on the 2d of March, 

 when the organization was completed. Its 

 real work was begun at the meeting of 

 March 16th, when a paper was read by Mr. 

 F. W. Gushing on the " Harmonic Telegraph " 

 of Professor Elisha Gray. The preliminary 

 meeting was participated in by between 

 thirty and forty electricians and telegra- 

 phists : more than two hundred members 

 had been enrolled at the meeting of March 

 16th. 



Sir Philip Egerton, Bart., M. P., one of 

 the Vice-Presidents of the Geological Socie- 

 ty, died in London, April 5th, in the seventy- 

 fifth year of his age. He was chosen a 

 Fellow of the Geological Society in 1829, 

 and a Fellow of the Royal Society in 1831, 

 and was also a Fellow of the Society of An- 

 ticiuaries, antiquary to the Royal Academy, 

 trustee of the British Museum, and one of the 

 senate of London University. He was the 

 author of fifty-one scientific papers, chiefly 

 devoted to studies of fossil fishes, and gen- 

 erally published in the journal of the Geo- 

 logical Society, besides several papers in 

 which he was joint author with other per- 

 sons. He was owner of a collection of fos- 

 sil fishes of remarkable value, it being but 

 little inferior to that of the Earl of Ennis- 

 killen, which is, perhaps, the finest in the 

 world. 



