THE AETIFICIAL PRODUCTION OF DIAMOND. 



99 



EXPERIMENT. 

 l-inch tempered steel die ; gum arabic and phosphoric oxide, 60 tons 



pressure, heated by gas for 1 hour to 250 C., black cindery deposit 



produced. 

 1 J-inch tempered steel die ; lead peroxide and carborundum grit mixed 



with lead fluoride, 50 tons pressure, heated by gas for 1 hour, red 



leaflets of lead produced. 

 1^-inch tempered steel die ; sodium peroxide, carborundum No. 6 grit 



and sodium chloride heated 45 minutes to 200 C., 50 tons pressure. 

 IJ-inch tempered steel die; sodium peroxide, carborundum and artificial 



pyrope, heated by gas J hour to 200 C. at 5O tons pressure. 

 1^-inch tempered steel die ; calcium carbide and glass bulbs filled with 



water, pressure 50 tons, time 30 minutes. 

 Ditto plus a small amount of sodium 



RESULT. 

 Nil. 



Nil. 



Nil. 



Nil. 

 Nil. 

 Nil. 



DUCK-GUN EXPERIMENTS. 



(See figs. 4 and 5.) 



EXPERIMENTS. 



Fired piston on to charge of graphite and cotton wool placed at end of 

 barrel which contained air at atmospheric pressure ; propellant, 

 20 grains black powder. 



Same as above, but barrel filled with oxygen ; propellant, 40 grains black 

 powder. 



Same as above, but barrel filled with oxygen and acetylene, and pro- 

 pellant 57 grains of black powder. 



RESULT. 

 Nil. 



Nil. 



Small crystals in skin of 

 piston and end plug, 

 probably Moissun 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 CsH 2 and 5 (O), has 3 molecular volume, would on combustion to 2COa and H 2 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 ^| 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, vi5., to 17,700 C. The actual temperature must therefore have 

 been something between these two values. 



VOL. CCXX. A. P 



