542 



Royal Society : — Mr. G. Gore oti the 



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 quickly occurred, generally without fracture 

 of the tube, and the substances operated upon could in nearly all 

 cases be readily extracted for examination without suffering injury 

 by coming into contact with the saline contents of the tube. Pow- 

 dered substances, however, were frequently lost during the discharge, 

 owing to the sudden expansion of the gas in their pores expelling 

 them from the small glass cup. The great degree of pressure (probably 

 about 700 pounds per square inch and upwards) to which the various 

 substances were subjected, frequently made them very hard. 



Fig. 1, 



Fig. 2. 



The chief inconvenience met with in these experiments arose 

 from the action of the liquefied acid upon the upper gutta-percha 

 stopper, causing the acid to become dark red-brown and opaque, 

 and preventing accurate observation of the substances — also, on 

 discharge of the tube, causing the glass cup and its contents to 

 become coated with a tenacious film of gutta percha. To obviate 

 this inconvenience as much as possible, the inner end of the upper 

 stopper was carefully coated with melted paraffin. 



During the early part of each experiment, the liquefied acid 

 was repeatedly poured back, and redistilled by the application of 

 ether, in order to free it from colour imparted to it by the stopper, 

 and also to make its solvent or other action upon the immersed body 

 more rapid. The action of the liquid acid upon the bodies was only 



