22 On a new Apparatus for preparing Muriatic Acid. 



the salt ; to the neck of the matrass immediately adapt the bent 

 tube, inserting it through a cork, which also contains a capil- 

 lary tube communicating with the matrass, (if the latter be not 

 tubulated.) and made air-tight with some soft wax. When the 

 wbite fumfs appear in the other extremity of the bent tube it 

 must be promptly inserted in the mouth of the receiver, which 

 should contain distilled water equal in weight to that of the 

 salt employed, but not occupying above half its capacity. The 

 mouth of the receiver must be slightly closed with a cork 

 through wliich the long limb of the bent tube passes. As soon 

 as the muriatic gas has begun to be disengaged, continue it 

 without interruption at the ordinary temperature and pressure 

 of the atmosphere, and, after a time, add fire to the apparatus 

 in the course of the process, in order to develop the gas with 

 greater rapidity. 



The solution of mnriate of barytes put into the curvature e 

 of the tube bb ascends during the passage of the gas into the 

 expanded part f, which is partly filled again ; and hence all the 

 acid gas is constrained to traverse it, and as it were wash itself, 

 previous to reaching the water in the receiver C. If in the 

 course of the process the solution of barylic salt put into the bent 

 tube decomposes and becomes turbid, it at the same time as- 

 sumes a dirty yellow colour. The acid gas which passes into 

 the receiver C is sometimes in such a cpiantity in the lower 

 part of the tube, that the water about it becomes very hot. For 

 this reason I have found it convenient to immerse the receiver 

 C in a larger vessel d containing cold water, or, what is still 

 better, water mixed with snow. Near the end of the process, 

 when the hvdrate of nmriatio acid (muriatic gas combined with 

 water) in the receiver C begins to ascend up by the tube b, 

 the capillary tube g in the matrass must be opened to allow 

 the apparatus to cool. The bent tube is afterwards v^ithdrawn, 

 and the mouth of the receiver C, containing the nmriatic acid, 

 immediately stopped. 



Distilled water at the mean temperature and pressure of the 

 atmosphere absorbs about 450 times its own volume of muriatic 

 gas, and increases aliout one-third its original bulk. The mu- 

 riatic acid obtained by this apparatus is found very strong, 

 fuming, transparent, of a yellowish colour, and entirely divested 

 of sulphuric acid. When tubulated matrasses are not at hand, we 

 may us°, as before observed, a capillary tube through the cork 

 which closes the untubulated matrass. 



In order that the process may be finished with safety and ease, 

 it is better to operate on a small quantity of salt, and repeat the 

 process oftcner ii required. Thus the matrass or retort may be 

 of small size, and serve for the same process many times. 



VII. An 



