Experiments upon Diamond, Anthracite and Plumbago. 349 



success. I have made various attempts, which have failed, 

 and after losing two diamonds, the fragments being .thrown 

 about with a strong decrepitation, I have desisted from the 

 attempt, having, as I conceive, a more feasible project in 

 view. 



I trust you will not consider the details of the preceding 

 pages, as being too minute, provided the subject appears to 

 you as interesting as it does to me. The fusion of charcoal 

 and of plumbago, is sufficiently remarkable, but the evident 

 approximation of the material of these bodies towards the 

 condition of diamond, from which they differ so remarkably 

 in their physical properties, affords if 1 mistake not, a strik- 

 ing confirmation of some of our leading chemical doctrines. 

 I remain as ever your faithful friend and servant, 



B. SILLIMAN. 



Art. XXI. — Experiments upon Diamond, Anthracite and 

 Plumbago ivith the compound Blow Pipe, in a letter ad- 

 dressed to Prof. Robert Hare, M. D. by the Editor. 



Yale College, April 15, 1823. ** 

 My Dear Sir, 



Having last year, caused to be constructed, an apparatus, 

 capable of containing fifty-two gallons of gas, for the supply 

 of your compound, or, oxy-hydrogen blow pipe, and capable 

 of receiving a strong impulse from pressure, 1 have been in- 

 tending as soon as practicable, to subject the diamond, and 

 the anthracite to its intense heat. Although their being non- 

 conductors, would be no impediment to the action of the 

 blow pipe flame on them, still, obvious considerations have 

 always made me consider the success of such experiments, 

 as very doubtful. I allude of course, to the combustibility 

 of these bodies, from which we might expect, that they 

 would be dissipated by a flame, sustained by oxygen gas. 



My first trials were made by placing small diamonds in a 

 cavity in charcoal, but the support was, in every instance, so 

 rapidly consumed, that the diamonds were speedily displa- 

 ced, by the current of gas. I next made a chink in a peice of 

 solid quick lime, and crowded the diamond into it ; this proved 

 a very good support, but the effulgence of light was so daz- 



