]30 EXPERIMENTS ON SULPHURIC ACID* 



by the addition latter (thofe made by directly combining lime with fulpburic 

 of oxalic and ac id) we had the proportion of real acid, contained in calcined 

 acid. fulphate of lime. Confequently, by knowing the ratio, that 



fulphate of barytes bears to fulphate of lime, with regard to 

 the acid in each, we fhall arrive at the knowledge of the 

 quantity of fulphur, contained in real fulphuric acid. For 

 this purpofe, I attempted to diflblve, in water, 100 parts of 

 fulphate of lime. But finding, in this method of proceeding, 

 a confiderable inconvenience arifing from the great quantity of 

 liquor, neceffary to effect the folution of that fait, I had re- 

 courfe to the following expedient. Upon 100 grains of cal- 

 cined fulphate of lime, I poured fome oxalic acid, which at- 

 tracts the bafis with an affinity fuperior to that exercifed by 

 fulphuric acid. Oxalate of lime was here formed ; but oxa- 

 late of lime is foluble in a very fmali excefs of any acid. A 

 little muriatic acid operated a complete folution ; and thus a 

 great quantity of fulphate of lime required but little water to 

 muriate of ba- diflblve it. Into this liquor, muriate of barytes was poured, 

 added Threw anc * Offered to remain fome time, gently heated. By thefe 

 down the acid in means, any oxalate of barytes, that might have been formed, 



futph. of barytes was reta j ne£ i - m f I u tion, by the original excefs of acid; and 

 weighing 1X3. 'jo 



This acid was the entire quantity of fulphate of barytes was deposited. Of 

 known to be 43 t h e exadnefs of all thefe methods, which I ufed, as the in- 

 struments by which I afcertained thefe remits, I convinced 

 myfelf by various preliminary experiments. After the ufual 

 filtration, warning and drying at the gentle heat of a fand- 

 bath, I obtained in one experiment 185, in another 183, and > 

 laftly, in another 180. This difference does not exceed the 

 limits of what all perfons, converfant in analytic chymiftry, 

 will allow to experiments of this nature. We may therefore 

 take 1 83 as the mean proportion ; confequently, we fhall fay, 

 that 183 of fulphate of Barytes contain the fame quantity of 

 fulphuric acid, as 100 of fulphate of lime; and 183 : 43 :: 

 The proportion 100 : 23.5. Therefore 23.5 is the proportion of acid in 100 

 r n tes°is therefore of ful P hate of barytes. But we have before feen, that 14.5 

 23.5 acid, and of fulphur, acidified by nitric acid, form that portion of ful- 

 the fulphur in pb ur i c add, contained in 100 of fulphate of barytes : viz. 



this, by the firft r * „ r J . 



exp. was 14.5. 23.5. We mutt now fay, that 23.5 : 14.5 : : 100: 61.5, and 

 Real fulph. acid the fourth term will be the proportion of fulphur = 61.5, 

 Uiph^andt the which combined with 38.5 of oxygen will form 100 of real 



reft = 9 o oxi- fulphuric acid. 



gen : or 6i£ to T n 



38i=lOO. • m 



