a new Mineral Borate. 287 



" Franklandite," with the permission of the distinguished 

 chemist, whose researches on the organo-boron compounds 

 have contributed so materially to extend our knowledge of 

 those interesting bodies. 



Although the formulas given above for the two minerals are 

 not in any true sense "constitutional," they make one point 

 clear, namely that the substitution of one molecule of sodic 

 oxide (Na o 0) for three molecules of water is capable of con- 

 verting Ulexite into Franklandite, so far at least as composi- 

 tion is concerned. As a change of this kind can evidently be 

 effected by various indirect means, it is to be expected that 

 mixtures of the two borates in different proportions would be 

 found ; and the observed differences in the analytical results 

 afforded by some specimens of native sodio-calcic borates seem 

 to indicate that such mixtures are not uncommonly met with. 



No. 3. — On the Composition qfLievrite } as determined hy Mr. 

 Early's method. 

 Of the several methods which have been devised for the 

 analysis of ferroso-ferric silicates, that which has been pub- 

 lished by Mr. William Early*, Demonstrator of Chemistry in 

 this Laboratory, is probably the most easily managed. The 

 advantages attending its use are chiefly felt in analyzing sili- 

 cates, which are either insoluble in, or attacked with difficulty 

 by the ordinary acids ; but it can also be used with great con- 

 venience in the analysis of silicates easily acted upon by acids. 

 Lievrite is a silicate belonging to the latter class ; and as the 

 formula of the mineral is by no means definitely fixed, I re- 

 quested Mr. Early to analyze by his method a portion of a 

 particularly fine crystal which I obtained some time ago from 

 the well-known Elba locality, our chief aim being to deter- 

 mine with precision the relative amounts of ferrous and ferric 

 compounds present in the specimen. 



The analysis was conducted in the following manner : — 

 1*54 grin, of the finely and recently pow r dered mineral were 

 mixed with 20 cubic centims. of hydrofluoric acid (containing 

 20 per cent, of real acid) ; and the mixture was boiled for five 

 minutes in a deep platinum crucible with a rather loosely 

 fitting cover. 10 cubic centims. of diluted sulphuric acid 

 (1 part to 2 of water) were then added, and the boiling con- 

 tinued for a few minutes. The contents of the crucible were 

 then washed into a flask with air-free water, and the amount 

 of iron in the ferrous condition determined as rapidly as pos- 

 sible by standard potassic permanganate solution. Another 

 quantity of the mineral was acted upon by strong hydrochloric 

 acid ; perfect decomposition was effected and a gelatinous 

 * Chemical News, October 9, 1874. 



