[ ^33 ] 



contadl with it, the condenfation may be repeated feveral times. 

 It appears ufeful in order to expel the bubble of common air 

 left in the vefTel for the convenience of agitation, after two or 

 three condenfations to open the flop cock and fiifFer it to be ex- 

 pelled, and then to renew the charge of the carbonic acid gas. 

 In a very few minutes water may thus be acidulated to any 

 degree (provided the apparatus is fufficiently ftrong and clofe) 

 fo as even to foam out of the glafs veHel like liquors highly in 

 bottle as foon as the ftop cock is opened. 



As the carbonic acid gas may be quickly generated or pre- 

 ferved for any time in bottles clofely flopped, artificial mineral 

 waters in great perfedion may by this apparatus be prepared as 

 foon as any other medical prefcription. 



The apparatus I have conftrudled is of brafs, and however 

 carefully cleaned perceivably imparts a tafte of the metal to the 

 water. It is advifeable therefore to make it of fome metal which 

 either may not poflibly impart any fenfible tafte to the 

 water, or which may not be confidered injurious even if diffolved 

 in it in very fmall portions ; filver or tin appear beft adapted for 

 tliis purpofe, but as the former may be too expenfive for general 

 ufe, and as the latter is too foft to bear well the frequent fcrewing 

 and unfcrewing neceffary in the ufe of the apparatus, the 

 channels through which the gas pafles may be well coated with 

 filver or tin, which may anfwer the purpofe ; the pipes, and 

 cocks may have a thick filver wire foldered in the centre which 



may 



