352 "XPERIMENTS ON THE RELATION 
from the fire, and attend diligently to the application of the 
ether. Dry muriatic acid gas, and common air, do not affect 
iron in the cold, at least during a period equal to their joint 
application in the present case, as [have found by experiment ina 
graduated glass-tube over quicksilver ; and as the whole atmo- 
spheric air was expelled, before the application of heat, the ef- 
fect is solely due to the acid gas, as, indeed, its progressive in- 
crease, with the duration of the process, sufficiently attest. 
The oxygen of the atmosphere could have no influence on the 
result *. ' 
There was found within the tube, near the end farthest from 
the retort, on the verge of the ignited part, a white pulverulent 
matter, glistening like snow, and the adjoining laminz of iron, 
were encrusted with the same substance, in spangling crystal- . 
line plates. 
This powder dissolves readily in water. Into recently boil- 
ed water, when a little of it was put, and a small fragment of 
crystallised prussiate of potash was added, a greyish cloud ap- 
peared, speedily becoming blue. Tincture of galls dropped 
into a similar solution, gave the characteristic purple tinge of 
iron. Thirteen parts of it by weight, being ignited in a small 
platina tray, evolved copiously a dark-brown smoke, smelling 
of muriatic acid, and left 6 parts, which were red oxide of iron. 
But 13 of green muriate, by Dr Wot.asron’s scale, are equiva- 
lent to 8 of red oxide. Does the above muriate contain the 
atomic 
* M. Gay Lussac, in his Recherches Physico-chimiques, describes a similar 
experiment, but without the production of water. If the utmost precautions be 
not taken, to keep the condensing tube at a very low temperature, the expanded 
and heated acid gas will readily carry off the moisture, as I found in one experi- 
ment. The neglect of these precautions will account for the difference of 
M. Gay Lussac’s result. 
