Scientific Intelligence. Chemistry. 195 



Academic des Sciences of Paris." I have the honour of now- 

 announcing to the Academy that I have just finished a second 

 memoir upon liquid carbonic acid, in which, after having suc- 

 cessfully examined the different parts of this body, its specific 

 gravity, which is so variable that, from 32 to 86 Fahr., it suc- 

 cessively runs through the whole scale of densities from water to 

 that of ethers ; its dilatability, which is four times greater than 

 that of air itself ; its pressure and the weight of its vapour ; its 

 capillarity, and especially its compressibility, which is a thou- 

 sand-fold greater than that of water, I have succeeded in deter- 

 mining in the most exact manner, the uniform and constant law 

 which regulates all these phenomena, which at first view appear 

 altogether independent of each other. The Academy will without 

 doubt learn with interest, that, by means of a very simple appara- 

 tus, I have succeeded in instantly producing, and economically, 

 masses of solid carbonic acid weighing an ounce and an ounce 

 and a quarter, and which the experimental chemist may benefi- 

 cially employ. My first experiments on cold, which I have al- 

 ready presented to the Academy, were made by directing a 

 stream of liquid carbonic acid upon the bulb of a thermometer, 

 or on tubes which enclosed the different substances upon which 

 the action of the cold was tried. This method had the serious 

 inconvenience of wasting a great quantity of the liquid, and of 

 leaving some uncertainty upon the maximum of the cold pro- 

 duced. The facility and abundance with which I now ob- 

 tain the solid carbonic acid has supplied me with a method of 

 experimenting which is infinitely preferable. The bulb of the 

 thermometer having been introduced into the centre of a small 

 mass of solid carbonic acid, at the end of one or two minutes the 

 thermometer became stationary and stood at 194 Fahr. Some 

 drops of ether and of alcohol poured upon the solid mass did not 

 produce any appreciable difference less or more on the tempera- 

 ture. Ether forms a mixture which is half liquid, and of the 

 consistence of melting snow ; but alcohol, in combining with so- 

 lid carbonic acid, congeals, and produces a hard, brilliant, and 

 semi-transparent ice. This freezing of anhydrous alcohol only 

 takes place in the act of mixture ; when isolated, as in a silver 

 tube, in the midst of a mass of solid carbonic acid, the alcohol 

 undergoes no change whatever. The mixture of alcohol and 



