74 Scientijic Notices-^Miscellaneous, [Julv, 



ticity sufficient to counteract the tendency to assume the 

 gaseous form of the remaining liquid carbonic acid. If the 

 solution be freely exposed to the air, the whole of the carbonic 

 acid will in a short time assume the gaseous form, from the 

 impossibihty of forming such an atmosphere. But if the solu- 

 tion be exposed to a limited quantity of any foreign gas, the 

 carbonic acid will cease to evaporate, when the elasticity of the 

 gaseous portion can counteract the volatility of the liquefied 

 part. The greater the quantity of the foreign gas with which 

 the solution is in free communication, the less carbonic acid 

 will be detained, or would be taken up, were the absorption but 

 commencing. Hence the influence of the gaseous residue, as it 

 is called. 



To the partial displacement of one gas absorbed by a liquid, 

 by another gas, parallel cases may be adduced from the mixture 

 01 liquids. Thus, if alcohol holding a volatile oil in solution 

 be poured into water, the greatest part of the oil separates, 

 while the alcohol unites with the water. — ^The simultaneous 

 absorption of several gases by a liquid belongs to this class of 

 appearances. From Mr. Dalton's theory it follows that two 

 gases absorbed into a liquid should really occupy always the 

 same room as they would occupy, if each of them had been 

 absorbed singly, at the degree of density which it has in the 

 mixture. This law is inconsistent with the explanation given 

 here ; but it has been fully disproved by the subsequent expe- 

 riments of Saussure. 



It may be stated in conclusion, that all that is insisted upon 

 in the foregoing sketch is, that when gases appear to be ab- 

 sorbed by liquids, they are simply reduced into that liquid 

 inelastic form, which otherwise (by cold or pressure) they mi^ht 

 be compelled to assume. That their detention in the absorbmg 

 liquid is owing to that mutual affinity between liquids, which is 

 so common. An affinity which occasions the raiscibility of 

 liquids, affects the bulk or density of the mixture, and fre- 

 quently impairs the volatility of the more easily vaporized liquid 

 in the mixture. In this way, the phenomena of the absorption 

 of gases are brought into the same class, as those of the mis- 

 cibility of liquids. — (Scots Mechanic's Magazine.) 



Miscellaneous. 

 2. Lieutenant Drummond's Station-Light, 

 We are enabled to furnish some additional particulars to the 

 account of this interesting and useful invention, given in the 

 last number of the Annals, p. 451. 



Among the applications of the Station-light suggested by the 

 inventor, in his paper on the subject, is the adaptmg of it to the 

 very important purpose of illuminating light-houses ; which he 

 recommends especially with regard to those light-houses first 



