with high degrees of Force. 269 



With the same apparatus Mr Perkins made experiments on 

 the compression of other fluids. The most remarkable result 

 he obtained was with concentrated acetic acid, which, after com- 

 pression with a force of 1100 atmospheres, was found to be beau- 

 tifully crystallized, with the exception of about one-tenth part 

 of fluid, which, when poured out, was only slightly acid. 



He next applied his apparatus to the compression of aeriform 

 fluids. For this purpose a gasometer was filled half full of water. 

 It was then inverted and placed in a receiving tube, and it was 

 found, under a pressure of 500 atmospheres, that the whole of 

 the air was taken up by the water, but none of it was given 

 out when the pressure was removed. 



As it might be supposed that even glass was pervious to water 

 by such a force, a small phial was made air-tight by fitting in- 

 to its neck a well ground glass stopper. It sustained a pressure 

 of 500 atmospheres without change, and was perfectly dry with- 

 in, although it remained fifteen minutes under that pressure. 

 When subjected to a pressure of 800 atmospheres it was crush- 

 ed to atoms. 



During these experiments Mr Perkins observed the curious 

 fact, that the air began to disappear at a pressure of 500 atmo- 

 spheres, a circumstance which he attributes to its partial lique- 

 faction- At an increased pressure of 600 atmospheres, the 

 quicksilver was suspended about one-eighth of the volume up 

 the tube or gasometer ; at 800 atmospheres, it remained about 

 one-third up the tube ; at 1000 atmospheres, two-thirds up the 

 tube, and small globules of liquids began to form about the 

 top of it; at 1200 atmospheres the quicksilver remained three- 

 fourths up the tube, and a beautiful transparent liquid was 

 seen on the surface of the quicksilver, in quantity about j^os 

 part of the column of air. 



The gasometer was now charged with carburetted hydrogen, 

 and placed in a mercury bulb with its mouth immersed in quick- 

 silver. It was subjected to different pressures, and it began to 

 liquefy at about 40 atmospheres, and at 1200 atmospheres the 

 whole was liquefied. 



Mr Perkins is now occupied with the construction of a suit- 

 able apparatus for ascertaining the law of condensation of ga- 

 seous fluids at high degrees of pressure. 



