186 Intelligence, and Miscellanies. 



■t> 



air, exhibiting a voluminous yellow flame. The reason why, 

 in common cases, it appears nearly uninflammable, is, that 

 it is used in very small quantities, and in narrow vessels, in- 

 to which the common aircan,atthe moment,scarcely enter, 

 and the gas is not sufiiciently inflammable to burn (like 

 pure hydrogen,) merely at the surface of contact, at the 

 mouth of the vessel. But if it rise through the air suddenly, 

 in large volumes, and in its ascent, strike the flame of a 

 candle, it is then sufliciently inflammable to be seen through 

 a large room, and forms a handsome experiment. — Editor. 



9. Crystalization of Sulphuric Acid. 



It is very well known to every chemist, that sulphuric 

 acid, diluted to about 1780. water being 1000. readily con- 

 geals and crystalizes with a moderate cold, it is also well 

 known that this crystalization, when the acid is not fully 

 concentrated, often happens spontaneously, and it is said, 

 that even carboys of sulphuric acid have been broken by 

 the expansion, resulting from the crystalization. 



Having occasion, recently, to clean out a neglected car- 

 boy, which had been nearly emptied of its sulphuric acid, 

 we found a few cubic inches of liquid in the bottom of the 

 carboy, and on shaking it, to wash out the adhering sulphat of 

 lead,(alwaysfoundin thebottom ofthesevessels)we weresur- 

 prised by the rattling, produced by thirty or forty distinct crys- 

 tals of great size and firmness. On being withdrawn from the 

 vessel, they proved to he isolated crt/stals of sulphuric acid; 

 some of them were two inches in the greatest diameter; 

 they appeared as firm as crystals of alum — were white and 

 transparent, and their form, which, on account of their cor- 

 rosiveness and their rapid deliquescence, it was difficult to 

 examine, appeared to be that of very obtuse and flat rhom- 

 boids, like the lenticular crystals of calc spar — the tete de 

 clou of the French. 



It is evident, in this case, that the little acid remaining in 

 the open carboy, had attracted water enough from the air, 

 to bring it to the degree of dilution, which makes it crystal- 

 ize most readily, and that the moderate cold which it ex- 

 perienced in a garret, in a mild night in November, had 

 been sufficient to produce that result in the manner above 

 stated. — Editor. 



