SClElCTIPiC NEW8. J^g 



posed for an hour to a strong heat, in a wind furnace. To 



ensure the complete decomposition of the flnor, the mass 



was reduced ta powder, and treated a second time in the 



»ame manner with {mother ounce of sulphuric acid. The save 15^ 6 of 



residue, which was white with a sli<^ht shade of red, proved s"lp^ateof 



on examination, to be pure sulphate of lime. It weighed ' 



156-6 t4rain>. 



No*v, it has been ascertained by the most careful experi- consequemly 

 ments, that sulphate of lime, thus violently heated, con- contained 

 tains 43 per cent of lime. Of consequence, the whole 67 34 grs of 

 quantity of lime in 156-6 grains of sulphate is 67*34 grains. ^*''"^^> 

 This is obviously the whole lime contained in 100 grains of 

 fluor spar ; and since that mineral contains no sensible por- 

 tion of water, the remainder of the 100 must be fluoric 

 acid. Hence flnate of lime is composed of. 



Lime .' 67-34 aud 32-65 fta- 



Fluoric acid 3 2-66 ont acid. 



100-00 

 This result differs very materially from the analysis al- 

 luded to in the beginning of this paper, which makes the 

 amount of the acid in the same weight of spar, only l6 

 grains, and the lime 57 grains; the remaining 27 grains 

 being considered as water. Bat from the care with which 

 my experiment was conducted, I flatter myfelf, that the 

 result which it exhibits is verv near the truth*. 



SCIENTIFIC NEWS 

 Mrw George Singer's course of Lectures on Electricity History and 

 and Electrochemistry will commence on the 7th of Febru- practice uf 

 ary, at the Scientific Ir^stitution, Prince's Street, Cavendish eiecUicity, 

 Square. They embrace not only all that has formerly been 

 done, but the most recent discoveries of Mr. Davy, and 

 Mr. De Luc's analysis of the Voltaic pile, an account of 

 which has appeared in the present and two preceding vo- 

 lumes of our Journal. ^ 



St. Thomas's and Guy\ Hospitals, 

 The Sj)ring Courses of Lectures at these adjoining Hos- Medical Lc<v 

 pitals will commence the bei;inning of February, as u^ual. tare*. 



TO CORRESPONDENTS. 



Mr. Moore's and Mr. Gsegor's communications were loo 

 late for the prcstnt number, but will appear in our next ; as 

 will Mrs. Ibbetson'son the corollas of flowers. 



* Since the precedinjj paper was read, 1 h^ve seen an analysis of fiaor" The resnh 

 spar by K.laproth, iu the 4lh volume of his Beifrago, conducted in u very r.^rees viih 

 diffoent maimer from mine, but leading to alnibst ihe very same re' Klaproti^. 

 suit. He found fluate of lime composed of 67t Hmr, and S'-J j aciJ — 

 quantities '«hich coincide with miiia, wiitiin less «hari 1 per ten'..— — 

 Nov 18U9: 



