A DICTIONAEY 



OF 



ARTS, MANUFACTURES, AND MINES. 



Omissions. 



Page 240 insert METEORIC STONES. See METEORITES. 



517 PAVEMENT. See BITUMEN. 



,, 628 ,, PREHNITE. A hydrous silicate of alumina aiid lime. See 

 Bristow's ' Glossary of Mineralogy.' 



i, PRESERVED MEATS. See PUTREFACTION : Curing of Pro- 

 visions. 



682 PYROMORPHXTE. A chlorophosphate of lead. See LEAD. 



Bread-fruit order. This is the Indian jaca, a native of Southern Asia. Its fibres are 

 employed for many purposes by the natives, and the wood is used for furniture. A 

 yellow dye, derived from the inner bark is employed in India for dyeing the robes of 

 the Buddhist prieste. 



JACXSO17XTE. A name applied by Whitney to a mineral from Keweenaw 

 Point, Lake Superior. It appears to be nothing more than ordinary prehnite. See 

 PREHNITE. 



T ACQUARD-XiOOM. A peculiar and most ingenious mechanism, invented by M. 

 Jacquart of Lyons, to be adapted to a silk and muslin loom for superseding the employ- 

 ment of draw-boys, in weaving figured goods. Independently of the ordinary play of 

 the warp threads for the formation of the ground of such a web, all those threads which 

 should rise simultaneously to produce the figure, have their appropriate healds, which 

 a child formerly raised by means of cords, that grouped them together into a system, 

 in the order, and at the time desired by the weaver. This plan evidently occasioned 

 no little complication in the machine, when the design was richly figured ; but the 

 apparatus of Jacquart, which subjects this manoeuvre to a regular mechanical operation, 

 and derives its motion from a simple pedal put in motion by the weaver's feet, was 

 generally adopted soon after its invention in 1800. Every common loom is susceptible 

 of receiving this beautiful appendage. It costs in France 200 francs or SI. sterling, 

 and a little more in this country. 



Fig. 1287 is a front elevation of this mechanism, supposed to be let down. Fig. 1288 

 is a cross section, shown in its highest position. Fig. 1289, the same section as the 

 preceding, but seen in its lower position. 



A is the fixed part of the frame, supposed to form a part of the ordinary loom ; 

 there are two uprights of wood, with two cross-bars uniting them at their upper ends, 

 and leaving an interval x y between them, to place and work the moveable frame 



VOL. III. B 



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