02Q IMPROVEMENT OF WOULPE's APPARATUS. 



point at which the two bottles {hall be on a level ; and this, 

 difficulty is increafed ft ill more when a feries of bottles are to 

 be joined in this manner. The difficulty is indeed lb great; 

 that an apparatus of'rhis kind perfectly air tight, though it 

 would be of the greateft advantage in many chemical opera- 

 tions, has perhaps fcarcely ever been procured, and the at- 

 tempt to have it made was relinquished even by Lavoilier. 

 Luting is moft Various attempts have been made to obviate this inconve- 

 commonly «fed. nienc( ^ but whh fo Hule f ucce f s> that the or i g ; na l apparatus 



in which the joinings are clofed by a lute, is ftill the one em- 

 ployed by chemifts. Of the improvements that have been 

 Dr. Hamilton's propofed, I may remark that that by Dr. Hamilton, of which 

 excellent appa- a defcription is given in his tranflation of Berthollet on Dye- 

 ing, and which does not feem to be fufficiently known to che- 

 mifts, is by far the raoft convenient. It may be Amplified by 

 having the bent tubes to iffue from the receivers inilead of 

 being fitted to them by grinding, and for many purpofes it 

 anfwers exceedingly well. Its principal deficiency is, that no. 

 great degree of prelfure can be obtained in it, proportioned to 

 the quantity of water put into the receivers. 

 Cit. Girard's Cit. Girard has lately propofed another improvement, of 



improvement* w y c h an account has been given in the 4th Vol. of your 

 very exj;enhve, , ■ i • iir 



and why: Journal (p. 41.) On ordering his apparatus at the glais ma- 



nufaclory, I found that it could -not be made but at a very 

 great expence. This was Hated to be owing partly to the 

 trouble which would attend the bending the long tube at- 

 tached to the bottle, but ftill more to the difficulty of giving 

 this tube the fame curvature, as the larger tube fixed in the 

 bottle, into which the former is to be introduced. The exe- 

 cution of this by the mode Cit. Girard defcribed, would not 

 be fo eafy as he appears to have fuppofed it ; and a number of 

 bottles would probably have required to have been made, to 

 obtain a feries of three or four adapted to each other. 

 Thi« d* ftcultv ^ fometime afterwards occurred to me, that every difficulty 

 obviated by the might be obviated by a more fimple method, which I have 

 author, fince found is extremely eafy in the execution. The appara- 



tus conftrucled on this method is repreiented in the annexed 

 drawing. Plate XIII. 

 Defer' tion. A is an adopter ground into the bottle B, and connecting a 



The contrivance retort with it. C is a iiraight tube ground into an opening 



'tS'^tSi in the ridc ot B ' and int0 a fimilar °P e a in g in the flde °f the 

 P * peiFn *" bottle 



