474 Miscellaneous Intelligence, 



are carried on in close vessels, when the gas acquires a sufficient 

 elastic force, the chemical action will stop ; it is suspended until the 

 moment when freedom is given to the compressed gas, the force 

 of which in some sort makes an equilibrium to the chemical 

 action which tends to disengage it." It is this elastic force 

 which M. Babinet proposes to use as a measure of the action of 

 different substances at various temperatures. 



In 1818, a copper shell closed by a stop-cock was filled with 

 zinc, water, and sulphuric acid, and being left on the snow it did 

 not burst. In 1819 a copper tube was filled with the same 

 substances, but it again was strong enough to resist the efforts of 

 the gas to burst it. A vessel was tiien prepared and supfdied 

 with a gauge, in which the height of the mercury was to "give the 

 elasticity of the gas at the moment when the equilibrium was 

 established and the chemical action counterbalanced." At 25° 

 C. (77° F.) the hydrogen disengaged frpm water, zinc, and 

 sulphuric acid surpassed 33 atmospheres. 



Another experiment was niade by attaching a small copper 

 globe to the apparatus, allowing communication between the 

 two, then removing the globe and ascertaining how much gas it 

 contained at 10° C. (50° F.) The globe, removed from the pre- 

 ceding chemical re-action, was found to contain thirteen times as 

 much gas as under the ordinary pressure of the atmosphere ; 

 *' the disengagement was therefore arrested here with a force 

 of thirteen atmospheres." 



At 0° (32'^ F.) M. Babinet supposes the force of hydrogen gas 

 would be much feebler, and, employing iron instead of zinc, still 

 more feeble. At ordinary temperatures, chlorine from muriatic 

 acid and oxide of manganese has an elasticity not much more than 

 two atmospheres. — i4wn. de Chimie, xxxvii. 183. 



We are uncertain what is M. Babinet's real meaning, though 

 we quote his words accurately. That the chemical action is not 

 arrested by the pressure from the evolved gases, or even influenced, 

 except in the destruction of that mechanical action, which, when 

 gases are evolved, is so active in mixing the ingredients con- 

 cerned together, has been sufficiently shown in Mr. Faraday's ex- 

 periments upon the liquefaction of gases. When carbonate of 

 ammonia and sulphuric acid are put together and sealed up her- 

 metically in a tube, although the evolution of carbonic acid gas 

 ceases in a few hours or a day or two, still the chemical action 

 goes on, and the evolution of liquid carbonic acid continues until 

 no more of the carbonate remains to be decomposed. The same 

 is the case with muriate of ammonia and sulphuric acid, and with 

 many other mixtures. M. Babinet's process might give the 

 elastic force of the gases or vapours of the substances produced, 

 and be so far a measure of the mechanical effects of some che- 

 mical actions, but nothing else. — Ed. 



3. On the formation of Fulgorites^ or Lightning Sand Tubes. — Some 



