NEW METHOD OF ESTIMATING NITRIC ACID. 123 
British writers, who had done as much in this respect as 
the Germans; the latter, however, had great tact in taking 
hints from us, and, as the Methodists would say, "enlarging" 
upon them. One fact might be mentioned in reference to 
the action of diuretics in stimulating the kidneys in cases of 
poisoning, viz., that often the excitement in the circulation 
was so great that the secretion of urine was altogether ar- 
rested. We should, in consequence, fail in the exhibition 
of diuretics, unless we first got rid of the congested state of 
the kidneys by depletion and diluents. — Chem.from Royal 
Med. and Chir. Soc. 
ART. XL.— ON A NEW METHOD OF ESTIMATING NITRIC 
ACID. 
By M. Gossart. ' 
The examination of the oxidizing action of nitre under 
the influence of sulphuric acid has proved to me that, in a 
great number of cases, the products of this action may be 
rendered constant, and so furnish a large number of processes 
for the accurate estimation of nitric acid and the nitrates. 
In the following method I have been guided by the princi- 
ple applied by M. Pelouze to the estimation of copper. In 
analysing crude nitre I employ as reagents, — 1st, an acid 
solution of the protosulphate of iron ;* 2nd, a very dilute 
solution of the red ferrocyanide of potassium. 
I pour into a flask with a long neck 50 cubic centimetres 
of sulphuric acid of 1.704 spec, grav., and 25 of a solution 
*The solution of the protosulphate which I have usually employed 
was strongly acid and nearly saturated. 
