Nitric Acid On Tin

In a paper read Lore the London üheniical society by C. H. Walker on ;he action of nitric acid on tin, some of ;he prevalent ideas on that subject are shown to be singularly erroneous. Among these is the general supposition ;hat metallic tin dissolves in nitric acid with the production of both a stannous and stannic salt, according to the condi;ions of temperature and concentration of the acid. In these later experimenta - made to determine the amounts of stannous salts f ormed under various conditions of temperature, concentration of acid and mass of tin treaféu - it is shown that with dilute acids the increase of temperature has but little effect, but with more eoncentrated acids the effect is more marked, for the alteration of a few more degrees will reduce the amouiit of stannous salt to nothing, while increase of concentration, other things being equal, decreases the proportion of stannous salt. It is found that the yellowish white substance f ormed from concentrated solutions is a hydrated stannic nitrate of varying composition, depending on the time between production and analysis, also on the method of puriflcation adopted for eliminating the nitric