226 ~ Chronieles of Science. [ April, 
be present, the strip of blue paper will be bleached when introduced 
into the air space of the bottle. The reaction in this case the 
_ author shows to be five times more delicate than the opposite one, 
when iodic acid and starch are used on the paper. To detect nitric 
oxides, Mr. Warington employs paper imbued with iodide of potas- 
sium and starch, which will be made blue by either of the oxides. 
Since, however, sulphurous acid destroys the blue iodide of starch, 
the presence of an excess of this gas will prevent the detection of 
the nitric oxides. But as these latter are without effect on the test 
paper employed for sulphurous acid, it is possible to obtain the 
reactions of both gases from the same oil of vitriol, if the sulphurous 
acid is not in excess. 
Another paper of great practical value is that by Mr. W. 
Valentin, “On the Estimation of Sulphur in Coal Gas.”* On 
few matters have greater discrepancies appeared in the reports of 
different experimenters than on this important question of the 
amount of sulphur in coal gas. Allowing that the quantity is very 
variable, these discrepancies admit of easy explanation. Still a 
process for its accurate determination is a great desideratum, and 
Mr. Valentin supplies one which has obvious recommendations. 
The gas, mixed with a proper proportion of atmospheric air, is 
passed through a porcelain tube, heated to redness by means of a 
combustion furnace. Within the porcelain tube is placed another 
tube made of fine platinum gauze, and filled with spongy platinum, 
and then a short platinum tube about four inches long, containing 
a few grammes of pure soda-lime. As the mixture of gas and air 
passes through the heated spongy platinum the sulphur compounds 
are completely oxidized, and the sulphuric acid (or the greater part 
of it) is fixed by the soda-lime as sulphate of sodium and calcium. 
The little that escapes may be fixed by causing the products of com- 
bustion to pass through a flask containing a solution of pure caustic 
soda. For the complete details respecting the operation, we must 
refer our readers to the place indicated below, with the remark that a 
process for estimating sulphur in gas is quite secondary in import- 
ance to one for removing sulphur before the gas reaches the consumer. 
Another paper worthy of notice, is one by Mr. J. Hargreaves, 
“On the Manufacture of Steel from Cast Iron by the use of Nitrates 
and other Oxidizing Agents.’t The subject of this paper, however, 
belongs properly to our Metallurgical Chronicle. 
In organic chemistry a vast number of papers have been published 
which only ;ossess interest for the advanced chemist. We may 
notice, however, the reported conversion by Siersch of methylic 
into ethylic alcohol{ as a novelty of general interest. 
The researches of Dr. Thudichum on the “ Colouring Matters 
* ‘Chemical News,’ vol. xvii., p. + Ibid., vol. xvii, p. 20. 
p. 89. 
t~ ‘Ann. der Chem. und Pharm.,’ Jan., 1868. 
