MECHANICS AND USEFUL ARTS. 73 



exposed to the direct action of (he sun's rays while in the most 

 active stage of decomposition. 



Tiie "New York Rendering Company" have located a vessel 

 on each side of the dock, wliich extends about 200 feet into the 

 river. On these vessels have been fitted up 9 sets of apparatus, 

 for the purpose of immediately suppressing this nuisance and 

 utilizing the material here deposited. The offal, brought to the 

 dock in butchers' carts, is dumped directly into iron tubs^ provided 

 for the purpose; these are hoisted over the vessel, and imme- 

 diately discharged into the tanks, which, as soon as filled, are her- 

 metically closed, so that no further odor escapes from them. Steam 

 heat is then applied by means of a steam-jacket surrounding the tank. 

 The vapors and obnoxious gases evolved during the process of 

 rendering are wholly conducted by an iron pipe into a coil, several 

 hundred feet in length, located in a separate furnace, where, being 

 superheated, they are brought into contact with the flame of the 

 furnace, and, united with certain proportions of atmospheric air, 

 which render them combustible, are entirely consumed. No offen- 

 sive odor could be detected, after repeated and critical observation, 

 during any stage of the process. Dead animals are disposed of in 

 the same way, the larger ones being cut up. When the contents of 

 the tanks are sufficiently cooked, the steam is shut off, and they are 

 allowed to cool down ; the grease is then taken out, and the greaves 

 or scrap, after being washed, is discharged from the bottom of the 

 tanks, drained, and removed upon sloops lying alongside, and the 

 remainder is transported beyond the city limits to be used for pur- 

 poses of fertilization. During the operations there are two periods 

 when an offensive odor escapes ; while emptying the contents of 

 the carts into the tanks, and during the evisceration of the large 

 animals ; but this is confined to the immediate vicinity of the boats, 

 and is not perceptible 50 feet therefrom. Thus, these poisonous 

 and destructive materials are, by this process, rapidly changed 

 into life-sustaining principles, and a fruitful source of disease 

 effectually suppressed. 



USE OF REFUSE LEATHER AND HIDE. 



In Capt. Brown's process for making compressed leather, the 

 cuttings and heretofore useless waste of shoemakers are first 

 cleansed from dirt and foreign matters ; the cuttings and refuse of 

 hides, unfit to tan, and usually sold to glue-makers, are also re- 

 duced to a fibrous mass. These are combined together with 

 water, to which is added 1 part of sulphuric acid to 100 parts of 

 water, until a plastic mass is formed, which may be pressed into 

 moulds of anj' size and thickness. When dried in a steam-heated 

 room, they are passed through heavy pulp rolls, glazed on one 

 side and rough on- the other, to represent the grain and flesh sides 

 of the leather. An addition of 5 to 20 per cent, of the raw fibre 

 may be added to the tanned filaments, the former giving a vitality 

 to the latter by agglutinating them and imparting the albumen 

 and gelatine which were' destroyed by the tannic acid. To render 

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