THE ARTIFICIAL PRODUCTION OF DIAMOND. 



105 



EXPERIMENT. 



Carbon crucible containing sand, sulphur and iron, heated under 1 mm., 



and coal gas admitted during slow cooling. 

 Iron sulphide, carborundum and magnesia, heated in carbon crucible . . 



Reduced iron and carborundum, heated in carbon crucible 



Calcium and carborundum, heated in carbon crucible 



Iron, carbon and garnet, heated in carbon crucible 



Iron, carbon, olivine and iron sulphide, heated carbon in crucible . 

 Carborundum, heated white hot in carbon crucible and carbon bisulphide 



admitted through tap to top of crucible. 

 Reduced iron and lampblack, heated in carbon crucible, sand and sulphur 



round. 

 Ferrous oxalate, boric acid, sugar carbon and iron, heated in carbon 



crucible. 

 Sodium carbonate, carborundum and iron, heated for 20 minutes ;it 



bright red in iron crucible. 

 Carbon and iron placed in carbon crucible, carborundum grit on i.op, 



moderate heat. 

 Carbon and iron chips placed in carbon crucible, massive iron lid with 



hole bored in it, filled with No. G grit, temperature of crucible bright 



orange, temperature of lid and grit not exceeding dull red heat. 



Carbon with reduced iron and rouge in small crucible, same as previous 

 experiment, heated ten minutes bright red. 



Carbon, iron and carborundum, heated to bright red 50 minutes . . . 



Calcium and carborundum, heated for 15 minutes to bright red, carbo- 

 rundum No. 6 grit in tube on top. 



Carborundum, iron and rouge heated 20 minutes to bright red .... 



Iron, carbon and lime heated 20 minutes to bright red 



Ferro-vanadium, carborundum, lampblack and iron heated 15 minutes 

 bright orange. 



Iron pole arcing on iron in crucible rod carborundum on top 



Carbon pole arcing on iron rod placed in crucible containing iron filings 

 at bottom and carborundum on top. 



Carbon pole arcing on iron and magnesium, carborundum on top . 



Nickel and carbon heated to orange for 15 minutes, carbon crucible con- 

 taining No. 6 grit on top. 



Heated ferrous chloride and carborundum to bright red for 20 minutes, 

 No. 6 grit in tube on top. 



Gases from heated iron filings in steel bottle passed through silica tube 

 containing carborundum No. 6 grit heated to a bright red. 



Repeat with same filings gave nothing. To test if due to exhaustion of 



filings made following experiment : 



Passed CO over the previously used iron filings, 30 minutes, placed 

 filings in crucible, and heated in vacuum dull red, 20 minutes, 

 carborundum No. 6 grit in hole in massive iron lid on top. 



RESULT. 

 Nil. 



Nil. 

 Nil. 



Carborundum decomposed 



. to coke-like mass. 



Nil. 



Nil. 



Carborundum decom posed . 



Nil. 

 Nil. 

 Nil. 

 Nil. 



Several crystal plates from 

 top of tube which resem- 

 bled diamond and burnt 

 in oxygen. 



Nil. 



Nil. 



Nil. 



Doubtful. 

 Nil. 



Nil. 



Nil. 



Several crystal plates very 

 like diamond. 

 Nil. 



Nil. 



Nil. 

 Several plates as before. 



A few plates. 



