206 



Mr. G. Gore on the Properties of 



[May 4, 



quickly occurred, generally without fracture of the tube, and the sub- 

 stances 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. Powdered 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. 

 Kg. 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 continued a few days ; and in 

 many cases the acid was not in a liquid state the whole of the time, but 

 only at intervals ; in all cases, however, the period of immersion was 

 abundantly sufficient for the liquefied acid to produce its full effect. 



The effects in nearly all cases were of so distinct a character, and the 

 conditions under which they were produced so definite, as not to require 

 repetitions of the experiments ; but those which were in any respect 

 uncertain were repeated, and those also which were of an important or 

 striking character were likewise repeated, in order to remove the least 

 shadow of a doubt that might be raised respecting them. 



