SUL

SUL

rated, but none of this was found,liquors in the apparatus were united, and nitratof barytes was added as long as any precipitateappeared, which was therefore fulphat of bary-tes, and amounted when dry to 69; grs. Twoother experiments gave nearly the fame refults,whence the author concludes the quantity offulphur in 100 parts of fulphat of barytes tobe 14..5 grs.

In the next place feme pure lime was pre-pared by faturating muriatic acid with whitemarble, precipitating the lime as a carbonat bycarbonated potafh, and fully calcining the car-bonat of lime in a platina crucible, in a violent'heat, till the weight no longer diminifhed. Ofthis lime, Jco grains were diflolved in dilutemuriatic acid in a platina crucible, and thenfufficient fuiphuric acid was added which pre-cipitated fulphat of lime. The whole contentsof the crucible were evaporated to drynels, then*raifed to fuch a temperature as would expel!every thing but the combined fuiphuric acid.The increafe of weight thus obtained was 7 6grs. whence the author concludes 176 parts ofdry fulphat of lime to contain 7 6 of real fui-phuric acid, fo that this fait will then confift of57 per cent, of lime and 43 of acid. Hence,by knowing the ratio that fulphat of barytesbears to fulphat of lime, the quantity of ful-phur in fuiphuric acid may be afcertained. Forthis purpofe 100 grs. of the fame dried fulphatof lime (at 43 per cent, of acid) were attemptedto be diffolved in water alone, but finding thatan inconvenient bulk of fluid would be re-quired in this way, Mr.C. fir ft adde.d fomeoxalic acid to the fulphat, and then a little mu-riatic acid, which effected a compleat folutionin a moderate quantity of fluid.

The folution therefore contained oxalat oflime, probably with a little fuper-fulphat, bothof which were diffolved in muriatic acid.

Into this liquor muriat of barytes was pouredas long as any precipitate fell down, and theliquor was heated for a fhort time to keep infolution any oxalat of barytes which would beformed, and which is eafily foluble in an excefsof acid. The weight of the fulphat of baryteswas (on the average of three experiments) 183grs. which therefore, contain as much acid as100 grs. of the fulphat of lime employed, or 43grs. and hence 100 parts of fulphat of baryteswill contain 23.5 of acid. But by the firftexperiment, 100 parts of fulphat of baryteswere formed by the acidification of 14.5 grs.of fulphur, and hence the 23.5 parts of ful-phuric acid are eftimated to be compofed of

14.5 of fulphur and 9. of oxygen, fo that 100parts of dry fuiphuric acid mull confift of 61.5of fulphur and 38.5 of oxygen. Alfo, if ful-phat of barytes contains only 23.5 per cent, ofacid, the whole of the remainder, or 76.5 muftbe barytes

To recapitulate the refults of thefe experi-rments —

Sulphuric acid is compofed of

61.5 Sulphur

38.5 Oxygen

100.0

Sulphat of lime, perfectly deficcated, iscompofed of

5-7.. Lime

43. Sulphuric acid

100.

Sulphat of barytes, perfectly deficcated, i*compofed'of

76.5 Barytes

Sulphur 14.5 \ Sulphuric acidOxygen 9.0 J J J r

100.0

100 parts of fulphat of lime contain the famequantity of acid as 183 parts of fulphat ofbarytes.

The difagreement between the experimentsof il/lr. Chenevix -and thofe of Klaproth , Wi-thering, and other chemifts already mentioned,is much too great to be accounted for fromflight variations in deficcation, &c. and w T emuft acknowledge they are unaccountable.Some obfervations may be made on this fub-jeft.

Firft, as to the proportion of barytes in thefulphat eftimated by Mr. C. This able chemiflinfers it from the quantity of acid produced,and attempts to account for the difference be-tween his and former calculations, by obferv-ing that “ at the time when the experiments“were made that determined the proportion of“33 per cent, of acid in fulphat of barytes it“ was not known that we had never obtained“ barytes pure, and that a confiderable portion“ of carbonic acid refilled the adlion of every“ degree of heat that had been applied to car-“ bonat of barytes,” &c.

But the experiments that determined the

above proportion of 33 per cent, were made

( 583 )All the