380 



SCIENCE. 



[Vol. II., No. 32. 



BNGINBEBING. 



Pressure on valves. — Professor S. W. Robinson 

 presented to the American society of mechanical 

 engineers, at its meeting in New Torlc, November, 

 1882, a paper on the theoretical and the experimental 

 determinations of the mean pressure on steam-valves 

 exposed to pressure both above and below. He finds 

 that a line can be determined, circumscribing an area 

 which he calls the equilibrium area of the valve. 

 This area being multiplied by the maximum pressure 

 gives the total mean pressure acting to hold the valve 

 to its seat. The extent of this area is determined by 

 experiment ; and a theory of the case is constructed, 

 which is given at length, with the practical formulas 

 derived by means of it for use in designing. — {Van 

 Nostrand's mag., July.) k. h. t. [216 



The performance of the "Worthington pump- 

 ing-engiae. — Messrs. Shedd and Ward present to 

 the water-commissioners of the city of Buffalo a re- 

 port upon the performance of a Worthington purap- 

 ing-engine, recently built for the city. The delivery 

 was 28.8% greater than was demanded under the 

 contract with the makers, amounting to above 19,- 

 000,000 gallons per day; and the 'duty' was some- 

 thing above 70,000,000 pounds of water raised one 

 foot high per thousand pounds of steam used. This 

 was above the duty demanded by the city. — {Ibid. ) 



B. H. T. [217 



CHEMISTRY. 



C Organic.) 

 Reconversion of nitro-glycerine into glycer- 

 ine. —Great difficulty having been experienced in 

 destroying the dynamite recently captured in Eng- 

 land, Prof. C. L; Bloxam has tried several methods for 

 decomposing its nitro-glycerine constituent. 1. Nitro- 

 glycerine was shaken with methylated alcohol, and 

 the solution was mixed with an alcoliolic solution of 

 KHS. Considerable rise in temperature resulted, 

 the liquid became red, a large quantity of sulphur sep- 

 arated, and the nitro-glycerine was entirely decom- 

 posed. 2. Nitro-glycerine was shaken with a strong 

 aqueous solution of commercial KjS. The same 

 changes were observed as in 1 ; but the rise in tem- 

 perature was not so great, and the liquid became 

 opaque very suddenly when the decomposition was 

 completed. 3. The ordinary yellow solution of ammo- 

 nium sulphide was mixed with the nitro-glycerine, 

 and the mixture evaporated to dryness on the steam- 

 bath, when bubbles of 'gas were evolved, due to the 

 decomposition of the ammonium nitrite. The pasty 

 mass was treated with alcohol to extract the glycer- 

 ine. 4. Calcium sulphide, made by boiling flowers 

 of sulphur with slaked lime, was used. Reduction 

 took place as above, but more slowly, and more agita- 

 tion was required. This last is the cheapest process. 

 — ( Chem. new.'i, April 13. ) 



The reducing action of alkaline sulpirides on nitro- 

 glycerine was pointed out some time shice, and 

 A. H. Elliott, F.C.S., showed in the School of mines 

 quarterly, Sept. 15, 1882, that the method admitted of 

 quantitative application. — c. E. m. [218 



METALLURGY. 



"Water-gas as a fuel. — Mr. W. A. Goodyear be- 

 lieves that the fuel of the future in cities, for all do- 

 mestic as well as for most manufacturing .and metal- 

 lurgical purposes, will be gas of some kind. The 

 ease and cheapness of its distribution, the cleanliness 

 and economy of its use, will, in his opinion, cause at 

 no distant day a revolution in the present use of 

 fuel. As a contribution to that end, he describes an 

 apparatus of his own devising for the manufacture 

 of water-gas, by means of which, he claims, this gas 

 can be made in any desired quantity; and, while 

 leaving a handsome profit to the manufacturers, it 

 can be supplied at a cost that will render its general 

 use more economical than that of any kind of solid 

 fuel. — {Trans. Amer. inst. min. eng., Boston meet- 

 inrj.) M. E. w. [219 



The recovery of the volatile constituents of 

 coal. — The attention at present paid to the utiliza- 

 tion of products heretofore wasted is well illustrated 

 in an account of the Jameson process of coking coal, 

 given before the London society of arts, April 26. 

 The coking-ovens of England are estimated to have 

 a capacity of some 20,000,000 tons a year; and only a 

 slight and inexpensive alteration in tlie plant would, 

 it is said, recpver oil and ammonia to the value 

 of $16,000,000, and good heating-gas to the value of 

 812,500,000. From the experiments of Sir J. B. 

 Lawes, it has been estimated, that, if all the ammonia 

 from all the raw coal burned in England were utilized 

 in agriculture, 250,000,000 dollars' wortli of bread- 

 stuff would be added to the yearly produce. The 

 use of raw coal is characterized as a relic of barbar- 

 ism. — {Iron, May 4.) b. h. b. [220 



GEOLOGY. 



Stratified drift in Delaware. — F. D. Chester 

 describes the relations of the gneissic rocks of Dela- 

 ware, with their rolling, hilly, and local soils, to the 

 unconfurmably overlying cretaceous clays extending 

 to the south-east, with stratified gravels derived from 

 the gneiss. These gravels and similarly derived 

 deposits extend even over the top of Polly Drum- 

 mond's hill, the highest land in the state, two hun- 

 dred and fifty feet above the cretaceous plain, and 

 three hundred and thirty feet above the sea. Large 

 dolerite bowlders of undetermined origin, sometimes 

 twenty-five feet in circumference, lie on this hill; 

 and a little farther south there are two hills of uu- 

 slratified detritus and bowlders, which are thought to 

 have been dropped from ice floating in the sea, that 

 deposited the stratified gravels during the submer- 

 gence of the Champlain period. As the highest point 

 in Delaware was then covered, this measure gives a 

 minimum value of three liundred and thirty feet 

 for the submergence. — {Amer.journ. sc, xxv. 1883, 

 436.) w. M. D. [221 



Meteorites. 



Concretions in meteoric iron. — Professor J. 

 Lawrence Smith gives a connected statement regard- 

 ing the concretions found from time to time in 

 the interior of various meteoric irons. Six kinds 



