* 7 ^ Messrs . Allen and Pepys on the 
Experiment with Charcoal from Box-wood. 
The thermometer being at 42°Fahrenheit, barometer at 30,2, 
we kept some box-wood charcoal red hot fora considerable time 
under sand, and weighed 4 grains as expeditiously as possible ; 
this being put into the platina tray, was pushed to the middle of 
the platina tube ; the oxygene ( made from hyperoxygenised 
muriate of potash over mercury) was contained in gasometer 
No. 1 ; No. 2 was empty. Every thing being adjusted and found 
perfectly air-tight, the communication with the small receiver 
R was closed, and the common air contained in the tubes and 
sockets, amounting only to 2,84 cubic inches, was driven out 
b y a pressure of oxygene from gasometer No. 1 : when several 
cubic inches had passed into gasometer No. 2 , the gas was let 
out by opening the cock atthe top of its glass receiver, and pres- 
sing it down ; the cock being then closed, the gasometer 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common air having been previously withdrawn from the small 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 purity of our oxygene by the eudiome- 
ter in the manner before described, and found a residuum of 
3 parts in 100 : we then disengaged as much gas as reduced 
the quantity to 47 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 oxygene employed 49,84 
cubic inches. 
Correction for Temperature. 
49,84 480)49,84(0,103 6o° 
1,85 for temp. 18 42 
1 ,854 add for temp. 1 8 diff. 
