1865.] Liquefied Hydrochloric Acid Gas. 205 



I described a mode of manipulation whereby various solid substances were 

 introduced into that liquefied gas whilst under very great pressures (vary- 

 ing from 500 to 1100 pounds per square inch), and the action of the 

 liquid upon them observed. 



The experiments described in the present paper were made in a similar 

 manner, but with some improvements in safety of manipulation, and in 

 the mode of discharging the tubes, so as to recover the immersed solids in 

 a satisfactory state. 



The glass tubes in which the gas was condensed were about y^ths of an 

 inch internal diameter, and fully -f ths of an inch external diameter. Each 

 tube was, before bending, 11^ inches long; it was bent, at 1^ inch and 

 6\ inches respectively from one end, to the form already described in the 

 paper referred to, thus giving 5 inches in length for the salt, 5 inches for 

 the acid, and 1^- inch for the liquefied gas. These distances are essen- 

 tial ; for if the quantities of acid and salt are not properly proportioned to 

 each other, and to the remaining space in the tube, the liquefied product 

 will be very small. The curve in the tube between the acid and the salt 

 should be very gradual, and the other bend much less so. The end of the 

 tube containing the salt should be constructed open, with a flange, and be 

 closed securely by a plug of gutta percha in the same manner as the 

 upper end. 



The materials used were strong sulphuric acid and fragments of sal- 

 ammoniac. Each tube was placed in a deal frame or box 10 inches high, 

 8 inches wide, and 4 inches from front to back, open at the back, and 

 with a front or door of wire gauze. The tube was supported by a cork 

 fitting into a hole in the side of the frame, and was secured within a notch 

 in the cork by a ligature of wire. By means of this arrangement the acid 

 and salt were brought into mutual contact by turning the box itself, with- 

 out incurring the danger of putting one's hand inside the box and turning 

 the tube alone, as in the former experiments. 



The annexed figures (1 & 2) represent the position of the box, 1st, when 

 charged and ready for the decomposition of the sal-ammoniac ; and 2nd, 

 after the decomposition is completed. The arrows indicate the direction 

 in which the box is turned. 



The action at first should be very slow ; otherwise the bubbles of gas 

 will convey the sulphuric acid into the short end of the tube, and endanger 

 the purity of the liquefied hydrochloric acid. The action of the acid was 

 less violent than when generating carbonic acid, and the process was less 

 frequently stopped by clogging of the tube. The liquefied gas was condensed 

 in contact with the various solid bodies by application (from behind) of 

 cotton wool, wetted with ether, to the short end of the tube, as in the 

 former experiments. 



Each tube was discharged of its contents by taking hold of it with an 

 ordinary wooden screw clamp support, and immersing its lower end in a 

 vessel of nearly boiling water behind a protecting screen. The explosion 



R2 



