183 Miscellanies. 



would not have found a residue of calcium, uncombined with the ele- 

 ments of the glass. That the spangles obtained' by Dr. Hare from 

 lime, were calcium, was ascertained by their solution in aqua regia, and 

 the successive subsequent addition of ammonia and oxalic acid ; the 

 resulting precipitate being ignited, then, redissolved and again precip- 

 itated as at first. No precipitate ensued from the addition of ammo- 

 nia prior to that of the oxalic acid. Sulphydric acid produced a slight 

 discoloration, but gave no precipitate. That the substances, resulting 

 from the ignition of the carbonate with sugar, and washing with ace- 

 tic acid, contained calcium in the metallic state, combined with carbon, 

 was evident from their being insoluble in acetic or chlorohydric acid ; 

 from the deposition of carbon, and giving a precipitate of oxalate of 

 lime on being subjected to aqua regia, ammonia, and oxalic acid ; from 

 their metallic brilliancy, when burnished, and from their being excel- 

 lent conductors of the voltaic fluid. By the ignition of the carbonates 

 of baryta and strontia severally with sugar, Dr. Hare had attained 

 analogous results to those above mentioned in the case of the similar 

 ignition of carbonate of lime. 



The extreme avidity of calcium for iron was quite striking ; since, 

 when a crucible was inclosed in a clean iron case without a cover, the 

 mass, swelling up so as to reach the iron, became slightly imbued with 

 it. By intensely igniting the carburet of calcium, obtained from the 

 carbonate and sugar, with an equal weight of dry tanno-gallate of iron, 

 the whole of the aggregate became so magnetic that every particle was 

 transferred from one vessel to another by means of a magnet. The 

 mass was filled with minute metallic globules, which yielded only par- 

 tially to chlorohydric acid, and which, when dissolved in aqua regia, 

 gave, after adding ammonia and filtration a precipitate with oxalic acid. 



Dr. Hare was aware that it did not seem consistent that spangles of 

 calcium, burnished upon porcelain, should retain their lustre ; as, under 

 other circumstances, and especially when amalgamated, that metal 

 was found to oxidize as soon as exposed to the air. He had, however, 

 through the kindness of Mr. Booth, a pupil of Wohler, procured a 

 specimen of magnesium evolved by that celebrated chemist. This 

 specimen yielded, under the burnisher, spangles of a lustre as enduring 

 as that observed by Dr. Hare in the case of calcium. It should be 

 recollected that slight causes may affect the oxidability of substan- 

 ces, as has been lately seen in the case of the reaction of iron with ni- 

 tric acid ; and it is well known that silicon, boron, and some other 

 substances have two distinct states, in one of which there is a greater 

 susceptibility of combination with other bodies than in the other. 



April 5, 1839. — The Committee to whom was referred a paper, en- 

 titled " Contributions to the Geology of the Tertiary Formations of 



