Capillary Action of Fissures, 1 93^ 



produced by the action of fire upon the natural carbonate. 

 The happy consequence which he has drawn from his nu- 

 merous experiments, that Roman cement njay be made in 

 ahnost every place where limestone is found, appears to me 

 beyond all doubt. — Idem. 



27 Electricity. — It has been announced to the French 

 Academy that M. Becquerel has demonstrated that there is a 

 sensible developement of electricity during the ascent of li- 

 quids in capillary tubes. — Idem, November 182,3. 



28. Capillary action of fssnres. — M. Dobereiner, having 

 filled several air jars with hydrogen and placed • ttiem 

 over water, found that in one of them the water had risen so 

 as to fill one third of its volume. No other reason could bq 

 assigned than an extremely small crack in (he side of the 

 vessel. Upon further trial he found that hydrogen would es- 

 cape from vessels with extremely small fissures, and that if 

 the same vessels were covered with a bell glass or filled with 

 atmospheric air, oxygen, or azote, no change could be ob- 

 served in the volume of the gas. This he considers as a 

 proof that the atoms of hydrogen are smaller than those of 

 other gases, though surrounded with a larger atmosphere of 

 heat. He considers it desirable that some one should treat 

 this phenomenon mathematically, and calculate the volume of 

 of an atom of hydrogen from experiment. There are prob- 

 ably fissures which will allow azote to pass, but not oxygen ; 

 others which will admit the escape of oxygen but not of car- 

 bonic acid, &£c. 



Another experiment was favourable to this hypothesis. 

 Wishing to fill the bulb of a thermometer, through a capilla- 

 ry opening in the stem, by heating the ball, and plunging the 

 fine point in the liquid, he found the alcohol did not enter 

 as the ball cooled. On heating the ball again, fresh bubbles 

 of air were disengaged, but the liquid refused again to enter 

 on cooling. On taking the stem out of the alcohol, the air 

 rushed in with a hissing sound. He ascribes the efTect to 

 the fineness of the opening — too small for the atoms of alco- 

 hol, but large enough for those of the air which it contains. 

 An explanation is thus offered of a fact discovered by Mr. 

 Faraday, viz. that alcohol becomes concentrated by leav- 



Vol. IX. —No. 1. 25 



