CHEMICAL SCIENCE. 211 



more frequent, and the colors more vivid, and the rapid and varied 

 motion in all the tubes forms a very beautiful spectacle. Each may 

 be considered a miniature representation of an explosion in a coal 

 mine. Mining Journal. 



PERNICIOUS EFFECTS OF CARBONIC OXIDE. 



PROF. DUMAS, at the British Association, alluded to the great, and, 

 indeed, almost unsuspected influence of carbonic oxide gas. The judi- 

 cial investigations in France have disclosed the fatal effects of this gas 

 as being much greater than carbonic acid gas. In the atmosphere 

 produced by the burning of charcoal, one two-hundredth part of car- 

 bonic oxide was fatal, while with one third the volume of carbonic 

 acid the animal was asphyxiated, but afterwards revived. 



ON THE DETECTION OF SULPHUR. 



DR. PLAYFAIR'S beautiful salt, the nitroprusside of soda, is justly 

 recommended by its discoverer as the most delicate of all tests for 

 alkaline sulphurets. Another application, which is very obvious, 

 although not alluded to by Dr. Playfair, is to employ it not only as a 

 direct test for alkaline sulphurets, but as an indirect one for sulphur in 

 any of its compounds. Any substance containing sulphur will yield 

 an alkaline sulphuret, if heated with carbonate of soda, either with or 

 without the addition of carbonaceous matter, according as a deoxidiz- 

 ing action is required, or not. The magnificent purple which is then 

 produced by the addition to the fused mass of a drop of the solution 

 of the nitroprusside, will at once prove the presence of sulphur. This 

 reaction is so easily obtained, and is so decisive, that the nitroprusside 

 of soda must take its place among the most useful adjuncts of the 

 blowpipe tests. By means of it the presence of sulphur in the smallest 

 particles of coagulated albunen, horn, nails, feathers, mustard seed, 

 &c., which can be conveniently supported on a platinum wire for 

 blowpipe experiments, may be most distinctly shown ; and I have repeat- 

 edly obtained the characteristic purple tint in operating upon a piece 

 of a single fibre of the human hair less than one inch in length. Prof. 

 J. W. Bailey, Sillimari's Journal. 



TEST FOR NITRIC ACID. 



THE following qualitative test for nitric acid is communicated to the 

 Chemical Gazette, by James Higgins, Esq. : 



The methods in ordinary use of detecting nitric acid do not show 

 very small quantities, and the liquid suspected to contain nitrates has 

 generally to be concentrated before the presence of nitric acid can 

 be ascertained. Being engaged lately in testing for nitrates in water, 

 I employed the following method with perfect success : It is founded 

 on the immediate liberation of iodine from hydriodic acid by nitric 

 acid, and its subsequent detection by starch. To insure accuracy, 

 certain minutice have to be attended to ; and, these observed, the 

 test becomes one of great delicacy. 1st. The solution of iodide of 

 potassium must be very dilute, or iodine is liberated by sulphuric 



