Tin and Iron with descriptions of some new Alloys. 465 



soluble in the hydric salt. Deville and Caron describe FeSn 

 as insoluble in hydric chloride and crystallizing in plates. 

 The alloys which I have obtained, giving these formulas, do 

 not agree with these descriptions. All writers on these allovs 

 agree in giving aqua regia as the solvent for them. I have 

 uniformly used hydric chloride and have found but a small 

 amount of any one of them insoluble in this agent, and the 

 portion insoluble in it was almost as insoluble in aqua regia. 

 The description of forms is also quite at variance. This may 

 be due to difference of interpretation of the forms, or it may 

 indicate that these alloys vary greatly, both in form and prop- 

 erties according to the conditions under which they are formed ; 

 my observations tend to establish the latter. The compounds 

 Fe 2 Sn 3 , Fe 3 Sn 4 , and Fe 4 Sn 5 vary in their property of being 

 magnetic, sometimes being almost or quite non-magnetic, and 

 it will require a more exhaustive study of their crystal form 

 to establish any distinctive difference between them in this 

 respect ; the habit of the crystals as obtained is, it is true, 

 somewhat different, but it is doubtful whether it is uniform 

 and persistent enough to be relied upon as distinctive. I have 

 recognized but one form with certainty, a rhombic prism, 

 which is the crystal form of the alloy FeSn 2 . Though some 

 crystals of this form were observed which have not been 

 proven to be this alloy and this form may be common to 

 several alloys. Furthermore certain rough six-sided imita- 

 tive forms have been observed, which are not characteristic 

 of any one of at least three alloys. These facts indicate as 

 already suggested, that the various observations may not be 

 contradictory because made on material which is not perfectly 

 comparable. 



The members of this series are all brittle, so much so 

 that in the form in which they were obtained, they can 

 be rubbed to a powder between the thumb and finger ; 

 they all burn, readily and quite brilliantly, when strewn into 

 the flame of a candle or alcohol lamp with the formation of a 

 dense smoke, and the emission of an intense odor of tin, best 

 observed a short distance above the flame. This odor was so 

 intense and similar to that of arsenic that it was with difficulty, 

 and only after repeated experiments, that I convinced myself 

 of the absence of this element. 



These alloys require so high a temperature to fuse them that 

 I was able to fuse only small portions of them before the 

 blowpipe, and that not very satisfactorily ; whether they suf- 

 fered decomposition thereby was not evident, but with soda 

 on charcoal they were decomposed with emission of sparks and 

 the separation of malleable tin. Concentrated hydric sulphate 

 acts upon them violently with copious evolution of sulphur 

 dioxide. 



