Dr. Schafhaeutl on the Different Species of Iron, 45 
end of the tube is then drawn out over the lamp into a short 
capillary tube, the tube is afterwards bent about five inches 
from its closed end into a siphon-like figure, the capillary tube 
is immersed in a test glass until it nearly touches the bottom, 
holding not more diluted chlorohydric acid than sufficient to 
fill the drawn-out leg of the syphon to the height of three 
inches, whilst the other end is gradually heated over a spirit- 
lamp. The azote forming with hydrogen ammonia is driven 
out in a very small stream into the acid, and when the de- 
composition of the iron is completed, the heat is gradually di- 
minished, and the acid ascends in the same ratio into the end 
of the siphon. As soon as all the acid of the test tube is ab- 
sorbed, air is streaming through the capillary tube and the 
acid into the siphon, thus establishing the equilibrium between 
the interior and exterior of the tube. The heat is afterwards 
again raised, till the absorbed acid is driven out again into 
the test glass, and after this operation all the ammonia will be 
found to be absorbed by the acid. The larger end of the 
siphon is then cut off and well washed with distilled water, 
and the quantity of ammonia ascertained by means of a so- 
lution of chloride of platinum, added in excess, the liquor of 
course being evaporated nearly to dryness in the water-bath, 
and treated and washed with absolute alcohol. The com- 
pound of muriate of ammonia and chloride of platinum, in- 
soluble in alcohol, remains, from which the quantity of am- 
monia is calculated very easily. 
The action of acids upon iron and the products afterwards 
are highly curious and interesting. The products formed by 
the action of acids upon iron depend first, on the chemical 
constitution of the iron itself; secondly, on the greater or less 
division of the mass ; thirdly, on the chemical constitution of 
the acids ; fourthly, on the greater or less concentration of 
the acids ; fifthly, on the temperature ; and sixthly, on the 
presence or exclusion of the atmosphere. 
The acid whose action I have most studied is the hydro- 
chloric acid, and in some respects nitric acid. I therefore con- 
fine my observations to those two only. The specific gravity of 
the hydrochloric acid used by me was 1 * 1 69 to 1 * 1 7. The iron 
was in fragments from the size of a nut to that of a lentil. For 
the sake of illustrating the action of hydrochloric acid upon 
iron, I select first a fragment of a steel bar of the highest con- 
version of the Dannemora iron. A drop of already melted 
steel adhered with a very broad base on one side. The frag- 
ment about the size of a walnut in a temperature of 48 F., 
was treated in an open wine-glass with chlorohydric acid. The 
action of the acid was very rapid, but the outside of the bar 
