L. MECHANICS AND ENGINEERING. 473 



carbonic acid gas contained in the atmosphere at an altitude 

 of 24,000 feet. The experiment of the inhalation of oxygen, 

 after attaining a considerable altitude, was tried, to ascer- 

 tain its effects ; but at a height above 22,000 feet M. Tissan- 

 dier fainted. He was shortly afterward awakened by M. 

 Croce-Spinelli, who warned him to throw over some ballast, 

 which was done. He then fell asleep for about an hour, and 

 on awakening: found the balloon descending at a terrific rate. 

 No more ballast was to be thrown away, and his two friends 

 were suffocated. Their faces had turned black, and the 

 blood was flowing; from their mouths and noses. M. Tissan- 

 dier's only resource was to cut the grapnel rope a little be- 

 fore the instant when the car should strike the ground, and 

 the balloon was torn open to stop it. It was finally caught 

 on a hedg-e about 190 miles southwest of Paris. 



The temperature of minus 10 Centigrade was observed 

 at the height of 22,960 feet, but it was supposed the altitude 

 to which the balloon had ascended was considerably greater, 

 the indication of the self -registering barometer being 14,000 

 meters, or eight miles. 12 A, April 24, 1875, 495. 



CASING FOB STEAAt-PIPES, ETC. 



The following composition for casing steam-pipes, etc., is 

 recommended by a German association of engineers as equal 

 in effect to that of Leroy, while it is cheaper: Mix well 120 

 parts, by weight, of finely ground limestone, 350 of finely 

 ground stone-coal, 250 of finely ground clay, 300 of flue-dust 

 (from the boiler flues), 600 of water, 10 of sulphuric acid of 

 50 Baume, and 15 of hair. The place to be covered, warm- 

 ed if possible, is coated with this mass in layers, from half 

 an inch to \\ or 2 inches thick, and when finished may be 

 painted. 14 <7, CCXIII., 1874, 169. 



CONSUMPTION OP WOOD BY RAILWAYS. 



The National Car Builder reports that at the close of 

 1873 there were 71,564.9 miles of main lines, and 13,512 miles 

 of sidings and double tracks, making 85,076.9 miles of rail- 

 way within the United States. Upon these roads the larger 

 proportion of the locomotives consumed wood for their fuel. 

 The number of ties used varies from 2200 to 2800 per mile. 

 Taking 2500 as the mean, it appears that 212,692,500 pieces 



