214 FurificatUn of Wattr.'-^Lamp Furnact, 



ments may be procured, it is fufficient to obferve, that by ufing an aqueous folution of 

 barytcs of which thefpecific gravity was no more than 1,0205, the quantity of 15 grammes 

 in weight (344' grains Englifli), or 0,1473 cubic metres (4,1 cubic inches Englifh), proved 

 fufficient completely to purify eleven decilitres (2y wine pints Ejiglilli) of water. Cotife- 

 quently one decilitre or part of the fame aqueous folution of barytes will ferve to afford 74)6a, 

 parts, or about 8 (French) pints of diftilled water. 



I muft add an obfervation, which is very proper -to fliew that the colledlion of r»in-water 

 is worth the trouble and care of procuring it in ihe circumftances moft favourable to its 

 purity. By a comparative operation on ratn-water, I found that river water acquired 60 

 grammes, .or four times the quantity of the fame folution of barytes. 



I have jio doubt but that the aqueous folution of barytes for the purification of water 

 will, in the courfe of time, be introduced into manufadories for dyeing. It will ferve, at a, 

 very moderate expence, to render the artifl; mafter of the fhades he means to produce, with- 

 out waiting for the feafon in which he confiders his water as moil pure. I gave this ad- 

 vice to a manufacturer wiiorrequefted me t« analyfe the water of a fmall ftream which fup- 

 plied his works. 



Thcfe obfervations may alfo probably be applied to another purpofe. It is known that 

 water faturated with fulphate of lime is much lefs putrefcible than purer water: would it 

 not be of advantage, in long voyages, to take a fupply of water exprefsly loaded with this 

 earthy fait, and, when it is wanted for ufe, to purify it three or four days before hand by a 

 fmall portion of the folution of barytes ? 



This folution would occupy little room, and be attended with inconfiderable expence. 

 If it were apprehended that a fmall portion of barytes might remain in folution, which would 

 not in fa£t be without danger, as this eartlv is perceptibly noxious, a proof might be madej 

 or, to fpeak more correftly, the depuration might be rendered abfolute by the addition of a 

 few drops of the folution of carbonate of foda. All thefe manipulations are among thofe 

 which may be very eafily praGifed by perfons of no chemical experience. 



Explanation cf the Figures of the Economical Labor atcryi Plate IX. 



Figure i. reprefents the whole apparatus ready mounted for diitillation, with the tube of 

 fafcty and a pneumatic receiver. 



A is the body or refervoir of the ufual lamp of Argand, with its fliadc and glafs chim- 

 ney. The lamp may be raifed or lowered at pleafure by means of the thumb fcrew B *, 

 and the wick rifes and falls by the motion of the fmall toothed wheel placed over the waftc 

 cup. This conftruction is moft convenient, becaufe it affords the facility of altering the 

 pofition of the flame with Tegard to the veffels, which remain fixed ; and the troublefome 

 management of bended wires above the flame for the fupport of the veffels is avoided, at the 

 fame time that the flame itfelf can be trought nearer to the matter on which it is intended 

 to aft. 



D, a fupport confifting of a round ftem of brafs, formed of two pieces which fcrew to- 

 gether at about two-thirds of its height. Upon this the circular ring E, the arm F, and the 

 nut G flide, and are fixable each by its refpeftive thumb-fcrew. The arm alfo carries a 



• Itt the lamps of this conftruftion made in London there is a fpring in the focket, fufficiently rigid to pre- 

 vent the lamp A from falling by its weight when B is unfcrcwcd, I fuppofe Citizen Guyton's lamp was pro- 

 vided .with the fame convenicace, bu< that by overfight it may jaot have been inention«d. N. 



moveable 



