180 ANALYSIS OF SULPHATE OF BARYTES. 



Klaproth ; the former making it contain 57 parts of lime 

 and 43 acid in a hundred, and the latter 57 acid and 43 

 lime nearly. I at first imagined this was a typographical, 

 or perhaps an arithmetical errotir; but this is not the case: 

 100 parts of pure lime afforded Mr. Chenevix 176 grains 

 of calcined sulphate, which gives the proportions exactly as 

 stated in his memoir. Here then evidently hinges the dif- 

 ference in Mr. Chenevix's analysis of sulphate of barytes 

 These there- compared with mine and others ; it remained therefore to 

 gated. ascertain, which of the two analyses of sulphate of lime 



was to be relied on; that which makes the proportion of 

 acid 43 per cent, or that which makes it amount to 57. 

 u^rotiriat? 1 ^ *' f dissolved 10 ° grains of pure lime, prepared as Mr. 

 acid and pre- Chenevix has directed, in muriatic acid in a platina cruci- 

 sulphuric/ ^le; an ^' a ^ er P rec ipi tat i n g with sulphuric acid, evapo- 

 rated the mass slowly to dryness. The crucible was then 

 exposed during an hour to a white heat. The calcined sul- 

 phate of lime weighed 240 grains. 

 Carbonate of o. Fifty grains of pure carbonate of lime were dissolved in 

 inacetfc acid acet * c aci d> and sulphuric acid added in excess. The mass, 

 and precipi- after slow and careful evaporation to dryness, was exposed 



'huric 7 SUl * to a *' hlte heat near an hour ' and afforded 6 ?*3 grains of 

 sulphate of lime. 



Proportions The first experiment, in which 100 grains of pure lime 



according to afforded 240 of calcined sulphate, gives for the composition 

 menu* ' of the latter 58*34 acid, and 41 '66 lime. The second, if 

 we admit with Dr. Marcet, that carbonate of lime contains 

 44 per cent of carbonic acid, gives for the composition of 

 sulphate of lime, acid 59, lime 41, which are exactly the 

 proportions of Kirwan. I feel disposed however to place 

 greater confidence in the first result; the experiment was 

 several times repeated, and I think, if we state the pro- 

 portions in sulphate of lime as 58 acid and 42 lime, we shall 

 not be far from the truth. 



These confirm ]\ T 0V v Mr. Chenevix found, that 100. parts of calcined 



the analys s of 



Phil. Mag. vol. XI, p. 115, the proportions of acid and base, as given 

 by Mr. Chenevbc in his analysis of sulphate of lime, and thus restored 

 them to accuracy. . This errour has b«en copied into a woik of very infe- 

 rior merit, the " Chimie applicjuee aux Arts" of Chaptal. 



sulphate 



