1820 .J Mr. SmithsoH on a fibrous Metallic Copper. 47 



for the manufactory of macaroni and vermicelli ; and which are 

 made by forcing paste through small apertures by the pressure 

 of a syrnige. It is wire-drawing performed inversely — by pro- 

 pulsion instead of traction. 



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

 became anxious to ascertain whether I coukl 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 gratification of finding 

 its little cavities lined with minuite fibres of metallic copper as 

 those of its greater prototype. 



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

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

 consist of sulphur, copper, and iran, I had recourse to the yellow 

 sulphuret of copper and iron. To produce the required portion 

 of metallic copper, I calcined some small fragments of this yel- 

 low ore at the tip of the exterior flame. Finding that I had 

 exceeded the proper point, and rendered them too infusible, I 

 added a little of the raw ore ; and after encountering a few diffi- 

 culties succeeded in producing a little mass of slag, whose 

 internal cavities presented me, on breaking it, with the fibres of 

 copper which were the object of my toil. 



A repetition of these experiments in a furnace, on a larger 

 scale, would undoubtedly have yet more successful results. 



It deserves to be noticed that the curved form which these 

 fibres of copper generally have is entirely favourable to the fore- 

 going theory of their formation, and equally contrary to the sup- 

 position of their being produced by crystaUization. 



The power to which has been ascribed the phenomenon which 

 forms the subject of these pages has hitherto been overlooked. 

 It has not been considered what the effects might be of the con- 

 traction of a melted mass at the moment of its congelation. It 

 is, however, a means of efiects which may have acted on many 

 occasions in the earth. Two matters of unequal fusibility, and 

 of no attraction to each other, are not unlikely to have occurred 

 blended in a state of fusion ; and then the most fusible to have 

 become pressed out from between the particles of the other when 

 it solidified. If some evolved vapour had opened cavities in the 

 mass, or rents had formed in it, the fluid matter will have 

 escaped from the pressure into these voids, as has happened 

 with the copper. If these receptacles for it have been wanting, 

 it must have flowed to the external surfaces, and may have 

 formed a crust there. The matter which lines or fills the cavities 

 of some lavas has, perhaps, been so introduced into them. 



A knowledge of the productions of art, and of its operations, 

 is indispensable to the geologist. Bold is the man who under- 

 takes to assign effects to agents with which he has no acquaint- 

 ance ; which he never has beheld in action ; to whose indisputable 

 results he is an utter stranger ; who engages in the fabrication of 

 a world alike unskilled in the forces and the materials which he 

 employs. 



