WRITINGS OF JAMES SMITHSON. 69 



From several considerations, it appeared to me to be be- 

 yond all doubt that the opinion of these fibres having been 

 produced by crystallization was perfectly inadmissible ; and 

 I was for a very long time totally unable to come to any 

 conjecture with respect to the mode in which they had 

 originated. 



Looking on one of these specimens this morning, an idea 

 struck me which is, I am convinced, the solution of this 

 knotty problem. 



It occurred to me that these fibres had been generated at 

 the instant of consolidation of the fused slag. That by its 

 shrinking at that moment, it had compressed drops of cop- 

 per, still in a fluid state, dispersed in its substance, and 

 squeezed a portion of it through the minute spaces between 

 its particles, under this fibrous form, into its cavities, or air- 

 holes. 



For this operation to take place, the concurrence of sev- 

 eral conditions is required. The slag must be so thick and 

 pasty as to retain metallic copper scattered through it. It 

 must have developed bubbles of some gas which have occa^ 

 sioned vacuities in it. It must be less fusible than the cop- 

 per, but in so very small a degree that the copper consoli- 

 dates as the fibres of it are formed. 



It is evident that on this supposition these fibres of copper 

 are produced by a process entirely the same as that employed 

 for the manufactory of macaroni and vermicelli ; and which 

 .are made by forcing paste through small apertures by the 

 pressure of a syringe. It is wire-drawing performed in- 

 versely by propulsion instead of traction. 



As soon as this hypothesis had presented itself to me, I 

 became anxious to ascertain whether I could give birth to 

 this fibrous copper at the blow-pipe. I melted a small 

 fragment of the slag ; and, on breaking it, I had the grati- 

 fication of finding its little cavities lined with minute fibres 

 of metallic copper as those of its greater prototype. 



I wished now to form the slag itself which was to afford 

 the copper fibres. As I had ascertained the slag of the 



