254 Improved Chemical Apparatus 



of preferving all the gafecxis as well as liquid produfts evolved 

 from them during his experiments. The apparatus invented 

 by Woulfe, and which will immortalize his name, was the 

 lirft, and indeed may be faid to be the only one yet made 

 known, calculated at all to anfwer lb defirable an end : but 

 it had defe^ls ; and though fome of them have been removed 

 by fubfequent improvements, Itill it has its impcrfecSlions. 

 Every chemift will readily perceive that I have in my eye the 

 inconvenience experienced on changes of temperature : if ab- 

 forption take place between the retort and receiver, a portion 

 of liquid from the Hrft Woulfe's bottle rufhes into the re- 

 ceiver; or, if the tube of Welter is ufed, an undetermined 

 quantity of atmofpheri-c air finds admiffiou to fupply the va- 

 cuum thus formed. 



To obviate thcfe inconveniences, in a train of experiments, 

 in which I was engaged in the year 179B, on the oxymuri- 

 atic acid and its compounds, after thinkina; of different con- 

 trivances, itftruck me that I (houlJ be able to accomplifh 

 what I had in view, by procuring an adaptor, mounted with a 

 glafs valve (fimilar to that ufed in the improved Noolh's ap- 

 paratus), and, at the end furnlflied with the valve, ground 

 into a tubulated receiver ; and then, by means of a bent tube, 

 conncfting the upper opening of the adaptor with a feries of 

 Woulfe's bottles. J->v means of this apparatus, which was 

 executed agreeably to my inftrucliions by Mr. Blades, I was 

 enabled to form the purell oxymuriates without the fmalleft 

 rif'^ue of any accident trom abforption. 



Bv another modillcaiion of the apparatus, in which the 

 wouifes were difpenfcd with, T obtained fome of the fined 

 cryllals of oxvmuriate of potafli I have ever feen, without 

 the fmalleft portion of gas efcaping — a clrcumftance of no 

 fmall moment ; oxymuriatic gasy^as every one knows, being 

 extremely noxious. In this arrangement, two additional 

 adaptors were joined to the one ground into the receiver 

 and furniflu'd with the valve as alreadv mentioned ; and the 

 vppermoit adaptor was furniflied with a tube leading into a 

 pneumatic apparatus; or, when the redundant gas was not 

 to be preferved, into a chimney. By employing the appa- 

 ratus in this form, cverA- bubble of gas has to pafs through 

 the three adaptors, and experiences a confiderable agitation 

 alono- with the liquor employed in them ; the gas forcing the 

 liquid from the loweft into the fecond, and from that into 

 the uppermoft adaptor,' — till, a portion of it being taken up 

 bv the fluid, and the lower orifices of the upper adaptors 

 beinc at times left quite free, the liquid, following the eom- 

 nion law of gravity^ returns to occupy again the lower fta- 



tion. 



