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XXII.—_ON THE OXIDATION OF IRON IN THE PRESENCE 
OF VARTRY WATER. By RICHARD J. MOSS, F.C.S. 
[Read December 16, 1878.] 
Ir is alleged* that the nitrates and nitrites contained in the 
water of the River Vartry, with which Dublin is supplied, are 
decomposed in the presence of iron, at a temperature correspond- 
ing with that of a steam boiler showing a pressure of 30 lbs. to 
the square inch, and that the corrosion of the steam boilers in 
which this water is used is mainly due to this reaction. Theore- 
tically, such a reduction of nitrogen salts appears most improbable, 
and for this reason J have considered it desirable to further in- 
vestigate the matter. 
It was shown many years ago by Wetzlart that in a saturated 
solution of potassium nitrate iron rusts more slowly than in pure 
water, pure water being a better solvent for atmospheric oxygen 
than the potassium nitrate solution. It would appear then that 
in the absence of free oxygen, and at ordinary temperatures, 
potassium nitrate in solution is without action oniron. This, I 
found, to be the case, by placing bright iron in water containing 
various quantities of the salt, in hermetically sealed flasks, the 
air and dissolved gases being expelled by ebullition. Ina similar 
manner, it was found that iron did not rust in potassium nitrite 
solution. In the course of these experiments I observed that, 
unless the solutions were boiled for at least thirty mimuies before 
the iron was introduced, and for a few minutes after it was intro- 
duced, the iron soon tarnished, and in some cases a considerable 
quantity of rust was produced. Also, that when bright iron is 
placed in cold distilled water containing the normal quantity of 
dissolved atmospheric gases, and the water then slowly heated, the 
iron becomes highly tarnished before the water has reached the 
boiling point. 
I next proceeded to examine the behaviour of iron with potas- 
sium nitrate and nitrite in solution, at higher temperatures, for 
which purpose the following experiments were made :— 
1. A solution of potassium nitrate, thoroughly boiled, was 
* Chemical News, vol. xxxviii., p. 191, + Gmelin’s Handbook, vol. y., p. 185. 
