THE ARTIFICIAL PRODUCTION OF DIAMOND. 
99 
Experiment. Result. 
lUinch tempered steel die; gum arabic and phosphoric oxide, GO tons Nil. 
pressure, heated by gas for 1 hour to 250° C., black eindery deposit 
produced. 
li-iiich tempered steel die; lead peroxide and carborundum grit mixed Nil. 
with lead fluoride, 50 tons pressure, heated by gas for 1 hour, red 
leaflets of lead produced. 
H-inch tempered steel die; sodium peroxide, carborundum No. 6 grit Nil. 
and sodium chloride heated 45 minutes to 200° C., 50 tons pressure. 
H-inch tempered steel die; sodium peroxide, carborundum and artificial Nil. 
pyrope, heated by gas | hour to 200 ° C. at 50 tons pressure. 
H-inch tempered steel die; calcium carbide and glass bulbs filled with Nil. 
water, pressure 50 tons, time 30 minutes. 
Ditto plus a small amount of sodium. Nil. 
DUCK-GUN EXPERIMENTS. 
(See figs. 4 and 5.) 
Experiments. Result. 
Fired piston on to charge of graphite and cotton wool placed at end of Nil. 
barrel which contained air at atmospheric pressure; propellant, 
20 grains black powder. 
Same as above, but barrel filled with oxygen ; propellant, 40 grains Iflack Nil. 
powder. 
Same as above, but barrel filled with oxygen and acetylene, and pro- Small crystals in skin of 
pellant 57 grains of black powder. piston and end plug, 
probably Moissan effect. 
Calculation of the Temperature Reached on the Compression of Acetylene and Oxygen 
Experiment. 
By Stanley S. Cook. 
The temperature reached may be estimated from the final pressure, which the observed deformation of 
the block and plug indicates to have been in the neighbourhood of 100 tons per sq. inch. But it must be 
remembered that there is a change of molecular volume as a result of combustion. Thus the mixture 
which, as C 2 H 2 and 5 ( 0 ), has 3 | molecular volume, would on combustion to 2 CO 2 and H 2 O have only 
3 molecular volumes. The final temperature deduced from the pressure will therefore depend upon the 
extent to which chemical combination has taken place. 
The original mixture being at atmospheric pressure and a temperature of 290 C. absolute, a pressure 
of 100 tons per sq. inch after compression to 3 ^ of its original volume would indicate a temperature of 
15,250° C. If, however, complete combustion has taken place, this same pressure would correspond to a 
temperature greater in ratio of 3 ^ to 3, viz., to 17,700° C. The actual temperature must therefore have 
been something between these two values. 
XOL. CCXX.-A. 
P 
