and on the Nature of the Diamond. 223 



green sulphate, merely by its water of solution, absorbed it 

 very readily. 



It may be proper to notice here, that though we repeated- 

 ly tried the oxygen procured from hyperoxygenised mu- 

 riate of potash by the eudiometer and lime-water, it never 

 gave the least trace of carbonic acid. 



Experiment vuth Charcoal from Box'tvood. 

 The thermometer behig at 42" Fa'nrenheit, barometer at 

 SO' 2, we kept some box-wood charcoal red hot for a con- 

 siderable time muier sand, and weighed four grams as expe- 

 ditiously as possible ; this being put into ihe platina tray, 

 was pushed to the middle of the platina tube ; the oxygen 

 (made from hyperoxygenised muriate of potash over mer- 

 cury) was contained in gasometer No. I ; No. 2 was empty. 

 Every thing being axljusted and found perfectly air-light, 

 the communication with the small receiver R was closed, 

 and the common air contained in the tubes and sockets, 

 amounting only to 2'S4 cubic inches, was driven out by a 

 pressure of oxvgen from gasometer No. 1 : when several 

 cubic inches had passed into gasometer No. 2, the gas was 

 let out by opening the cock at the top of its glass receiver, 

 and pressing it down ; the cock being then closed, the gaso- 

 meter No. 2, was completely empty, and the whole of the 

 gas from No. 1, was driven through the tubes into No. 2, 

 and back again. The common air having been previously 

 withdrawn from the small receiver R, we tried the puritv of 

 our oxygen by the eudiometer in the manner before de- 

 scribed, and found a residuum of 3 parts in 100 : we then 

 disengaged as much gas as reduced the quantity to 4 7 cubic 

 inches by the register or scale ; to this must be added the 

 contents of the tubes and sockets 2*84 cubic inches, making 

 the total quantity of oxygen employed 49'84 cubic inches. 



Correction for temperature. 

 4 9-54 4 SO) 4 9- 84 (01 03 60** 



l-S^ for temp. 18 42 



51-09 1 '8.54 add for temp. iSdiiT. 



Cor- 



