ihe Comhujiion of the Diamond^ jor 



eludes, that praftlcal confequences will, no doubt, be deduced for the reduction of metals ; 

 the cementation of fteel, which probably takes up only the oxide of carbone, fince it is 

 feparated in this ftate*; for the incineration of the coaly refidues of our analyfes; for the car- 

 bonization of wood, pit-coal, and turf; and iaftly, for the ufeful application of mineral coals, 

 which, though difficult to be burned, are capable of affording a ftrong and lafting heat when 

 mixed with a due proportion of other materials which burn more readily. 



The general recapitulation of fails and inferences, in the words of the author, are as 

 follow : 



1. It is not merely by its colour, weight, hardnefs, tranfparency, and other fenfible qua- 

 lities, that the diamond differs from charcoal, as has hitherto been thought. 



2. Neither does the conftitution of the diamond depend fimply on its ftate of aggregation. 



3. Nor do the diftinclive properties of charcoal depend on the two hundredth part of 

 refidue, which it leaves in the form of afhes, nor the fmall quantity of hydrogen which it 

 contains. 



4. But the moft effential difference confifts in the chemical properties. 



5. The diamond is the pure combuftible fubftance of this genus. 



6. The produdt of its combuftion, or combination with oxygen, carried to the point of 

 faturation, is carbonic acid without refidue. 



7. Charcoal burns at a temperature which may be eftimated at 188° of»the centigrade 

 thermometer f. The diamond does not burn but about pirometric degrees, which, in the 

 fyftem of Wedgwood's fcale, affords a difference between 188 and 2765. 



8. Charcoal fet on fire in oxygen gas, does itfelf maintain the temperature neceffary for its 

 combuftion ; but the combuftion of the diamond ceafes, as foon as it is no longer maintained 

 by the heat of the furnace, or the concentration of the folar rays. 



9. The diamond requires, for its complete combuftion, a much greater quantity of oxygen 

 than charcoal does, and likewife produces more carbonic acid. For one part of charcoal ab- 

 forbs 2,527 of oxygen, and produces 3,575 of carbonic acid. But one part ofdiamond ab- 

 forbs fomewhat more than four of oxygen, and really produces five of carbonic acid. 



10. There are fubftances which exift in an intermediate ftate of compofition between the 

 diamond and charcoal. Thefe are plumbago, or native carburet of iron; the incombuftible 

 foffil coal; the carburet of alumine of Dolamieu; the anthracolite of Werner; the black 

 matter united to iron in the ftate of caft-iron and fteel ; the coaly refidues of difficult inci- 

 neration ; and charcoal itfelf unburned by the aftion of a ftrong heat, without the contact 

 of air. 



11. Thefe fubftances, mixed or weakly combined with three or four hundred parts of 



• It is a ftrong faft in favour of this theory, that the charcoal which has been ufed for the cementing pro- 

 cefs is rendered incapable of being again ufed for the fame purpofe. See Duhamel, in the Encyclopedic 

 Methodique, art. Acier. — N. 



t Diftionnaire ile Chimie de I'Encyclopedie, method. I. 714. 



R r 2 their 



