in anstscer to Prof. Vamixeni. 285 



or filing— was utterly devoid of attraction for the magnet — 

 was not acted upon by nitric acid — nor did muriatic acid, 

 which had been digested on it, yield any oxide of iron, or give 

 any other indication of that metal. 



These observations were made by my friend Mr. G.T. Bowen, 

 under my inspection. Mr. Bowen assisted Professor Silliman 

 at the time when he first made his observations on the fusion 

 of carbon. On perusing Mr. Vanuxem's memoir, Mr. Bowen 

 was no less convinced than myself that there had been a mis- 

 take, which, considered as the foundation of a broad and un- 

 reserved, though indirect, contradiction given to Professor 

 Silliman's representations, is really unfortunate. 



I do not feel authorised to decide whether the substance 

 analysed by Mr. Vanuxem was that which Dr. Macneven for- 

 warded. By oversight, one minute portion of matter may be 

 exchanged for another as easily as mistaken — but supposing 

 that the mistake originated with Dr. Macneven, it should be 

 recollected that he did not act under the idea of any serious 

 responsibility. He was writing to a friend, not controverting 

 the conclusions of a skilful chemist. 



It was in January last that Dr. Macneven first operated with 

 a deflagrator. I then sent him the first he ever had. Not- 

 withstanding his well-known accuracy, in cases where his op- 

 portunities of observation are duly great, it is not unaccount- 

 able that amid the hurry of his lectures and his practice he 

 should have mistaken a globule of iron for a specimen of fused 

 carbon. But considering Professor Silliman's great experience 

 and skill as a mineralogist and chemist, and his having ope- 

 rated with the deflagrator for nearly u year before his memoir 

 on the fusion of charcoal was published, it ought not to have 

 been so readily supposed that in scrutinizing the substances 

 which he had obtained, with a view to communicate the re- 

 sult to the public, any advantageous employment of the magnet, 

 the hanmier, the file, or the mineral acids, had been omitted*. 



It is true, as Mr. Vanuxem observes, that the incineration 

 of charcoal proves it to contain impurities— but those impuri- 



♦ It appears from Professor Silliman's memoir (vol. v. p. 363, American 

 Journal of Science), that he did employ boiling sulphuric and boiling nitric 

 acid ; and irioreover, it is ev ident that the products which he represented 

 as fused carbon could not have been iron, both on account of their habi- 

 tudes with these acids, and on account of their disap|)carance when sub- 

 jected to the solar focus in oxygen gas. Of course no " advantageous " ap- 

 plication of the magnet could have been made. In examining the globules 

 j)roduced upon plumbago, when ex|)osed to the deflagrator, it will be found 

 that Professor Silliman did resort to the n)agnet. Iron being a constituent 

 of plumbago, it was in that case rational to exjicct that the globules might 

 be magnetic. The magnet was also enii)loyed by him in testing the globules 

 procured from anthracite, by means of the deflagrator, 



ties 



