Chemical Science, 175 



usual tests gave no indications of that metal ; arsenious acid, 

 however, being detected. On dissolving the sal-ammoniac in water, 

 a brownish residuum was left, which fused readily in a glass 

 tube, and gave an orange-coloured sublimate. On hot coals it 

 inflamed, evolving at first a mixed odour of sulphur and arsenic, 

 and then the offensive smell of selenium. By digestion in nitric 

 acid, till the orange colour disappeared, a solution was obtained, 

 which, with sulphite of potash, threw down much of a cinnabar- 

 coloured precipitate, possessing all the characters of selenium, 

 whilst the solution evaporated gave acicular crystals of selenic acid. 

 This discovery by M. Stromeyer of selenium amongst the vol- 

 canic products of the Lipari Islands, renders it probable that the 

 peculiar orange tint of the sulphur, found in those islands, proceeds 

 chiefly from selenium, and not, as hitherto supposed, from arsenic 

 combined with the sulphur. — Ann. Phil. N. S. x. 234. 



6. Natural Sources of Carbonic Acid Gas. — Bischoff and Nbg- 

 gerath, in Schweigger's Journal, mention a pit on the side of 

 the Lake of Laach, in which they found many dead animals, as 

 birds of different kinds, squirrels, bats, frogs, toads, and also 

 insects. On descending into the pit, and gradually sinking the 

 head, they experienced the same sensation as when held over a 

 vat in a state of fermentation. The quantity of gas evolved va- 

 ries at different times. This evolution of carbonic acid gas is 

 more striking in the volcanic Eifel. On the right bank of the 

 river Kyll, nearly opposite to Birresborn, there is a spring 

 named Brudelreis ; a provincial name for a boiling spring, and 

 applied to this because it is perpetually agitated by large 

 bubbles of gas, the agitation being so great as to produce a 

 noise heard four hundred yards off. In its vicinity numerous 

 dead birds are found, killed by the carbonic acid rising from the 

 water ; and persons who kneel to drink at the spring are driven 

 back by the gas. As MM. Bischoff and Nbggerath approached 

 this spring, they heard the noise of its ebullition at a consider- 

 able distance, and by approaching their faces to the surface of the 

 turf in the vicinity of the spring, found that it was covered with a 

 layer of carbonic acid gas. They did not observe any deleterious 

 effects produced on the surrounding trees or grass. On emptying 

 the basin no more water was collected, shewing that it was rain, 

 not spring water ; but the gas continued to rise through the fis- 

 sures of the rock in some places, with such force as to feel to the 

 hand like wind from a bellows. Lime-water poured into one of 

 the fissures became turbid, and caused the appearance of ebulli- 

 tion again, but it was not ascertained whether the gas was pure 

 carbonic acid or not. — Edin. Phil. Jour. xiii. 191. 



7. Process for the Detection of Phosphate of Lime.— A process 



