Dr. Schafhaeutl oji 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. 



Tlie acid whose action 1 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*169 to 1*17. 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 



