Lavoifer't Apparatus for producing Water. 303 



comparing the rhombafes in queuioa with thofe marked by 

 the fame letters \f.g. 57;. 



The cryftals ot chis variety are fubject to a change of 

 dimenfiotis, which is, that the faces pGtcdeZffabnklih, and 

 their oppofites, which are at right angles to each other, are 

 ftretched out, in the direction of their breadth, in fuch a 

 manner that they exhibit the appearance of a quadrilateral 

 rectangular piifm, the fummits of which would be formed 

 by the faces fnuated towards the ridges PN, Y t. 



This variety is found in opake cryftals, and of a whitifhj 

 yellowifh, and fometimes reddifh colour, iri the granites of 

 Auvergne, and of different countries. There are fome of 

 them in groups and fome fingle, but the latter are uncom- 

 mon. 



[To be concluded in the tiext Number. - ] 



XII. Description of the Apparatus employed by LAVOISIER 

 to produce Water from its component Parts, Oxygen and 

 Hydrogen. 



A H E difepvery made by Mr. Cavendifli of the competi- 

 tion of water having effe&ed a complete revolution in the 

 theory of chemiftry, it will no doubt gratify many of our 

 readers to fee fome account of the principal apparatufes 

 which have been contrived to exhibit this phenomenon. 



Fig. 1, Plate X. is that ufed by Mr. Lavoifier. A is a 

 balloon holding about 30 pints, having a large opening, to 

 which is cemented the plate of copper B pierced with four 

 holes, in which four tubes terminate. The fir ft tube lih is 

 intended to be adapted to an air-pump, by which the balloon 

 may be cxhaufted of its air. The fecond tube gg communi- 

 cates by its extremity MM with a refervoir of oxygen gas, 

 from which the balloon is to be filled. The thud tube dDd 

 communicates by its extremity dKN with a refervoir of 

 hydrogen gas. The extremity d of this tube terminates in a 

 capillary opening, through which the hydrogen gas contained 



ia 



