(222 oN THE QUANTITY OF CARBON IN CARBONIC ACID. 



the whole quantity of gas by 480, and multiplied the quotient 

 by the degrees of difference under GO°. 



It being- of great consequence in these experiments to 

 Sp. grav. of ox- know the exact weight of a given quantity of oxigen and car- 

 mc^arid "asses Domc llCK ^ gasses, we resolved to examine for ourselves, 

 determined. whether the statements aheady given were quite correct, and 

 accordingly made carbonic acid over mercury from Carrara 

 marble and diluted sulphuric acid, which, being tried with 

 lime water in Pepys's eudiometer, was all absorbed in 3 mi- 

 nutes, except 1 part in 100. We used two charges of lime 

 water, though one would have been sufficient. 

 Carbonic acid A glass globe, being exhausted by an excellent airpump, 

 was exactly balanced on a beam sensible to a minute portion 

 of a grain : then being screwed upon one of the glass receivers 

 of the mercurial gasometer previously filled with carbonic 

 acid gas, 21 cubic inches entered. The globe was now in- 

 creased in weight by 10'2 grains, In order to be certain, 

 We repeated the experiment, with exactly the same results* 

 The 21 cubic inches were to be brought to the mean tem- 

 perature and pressure, as the thermometer stood at 44° Fah- 

 renheit, the barometer *29 '30'. 



21 480) 2 1-00(0-043 G0° 



-6$ add for temp. 16 44 



21-68 0-6S8 add for temp. 16 diff. 



Correction for pressure. 

 30: 29*86:: 21-68 : 21'58 



The volume therefore at mean temperature and pressure 

 would have been 2 1*58, cubic inches. 



21-58 : 10*2:: 100:47*26 



100 cub. inches Consequently 100 cubic inches of carbonic acid gas at mean 



weigh 47-^0 temperature and pressure weigh 47*26 grains. 



g ' s " We next tried oxigen eas from the hyperoxigenised mu- 



Oxigon gas. . „ .. , b i i • i i xi ■ i- 



riate of potash made over mercury, and which by the eudi- 



- ometer left only a residuum of 2 parts in 100. The glasi 



globe, exhausted as before, and weighed, was screwed on to 



the glass receiver of the mercurial gasometer containing 



oxigen, and 21 cubic inches entered,, by which it increased 



in 



