262 Mr. J. Napier on Copper Smelting. 



These numbers agree very well with the formula C® H^ O, or 

 Q40 JJ28 Q4^ taking the number of atoms of carbon at 40, the 

 number to which the composition of so many of the other resins, 

 both fossil and recent, seems to be referable. By calculation 

 from this formula the resin should contain in 100 parts, — 



Carbon .... 77-05 



Hydrogen . . . 8-99 



Oxygen .... 10-28 



Ash 3-68 



Thismineral approaches amber (as a single compound C'*''H^^O^) 

 in composition more nearly than any of the other fossil resins, 

 differing fi-om it by four atoms of hydrogen if the higher number 

 of equivalents of carbon be adopted for both, or only one atom 

 if we take the smallest numbers expressing their constitution. 



From the hardness of the mineral exceeding that usual in 

 others of the same class in a considerable degree, it might be 

 called Scleretinite {aK\,7jpd^'pr]TiV7]) in the absence of any more 

 appropriate term. 



XLII. On Copper Smelting . By James Napier, F.C.S.* 



[Continued from p. 201 .] 



On the Fuel suitable for Copper Smelting. 



IT has been remarked, that wherever iron ore abounds, coal 

 and lime as fuel and flux are contiguous. The opposite 

 relations with regard to the fuel is observable in the case of ores 

 of copper ; where these ores are abundant, coals are not found ; 

 it is therefore of great consequence that a coal district be sought 

 so contiguous that the cost of transit of either coal or ore should 

 not interfere with the full development of the mineral wealth of 

 either locality. Such is eminently the condition of the Swansea 

 coal district in relation to the Cornwall and Devonshire copper 

 mines. 



What first induced the old copper smelters to erect their 

 works in Swansea rather than Cornwall, we do not at present 

 know. The average per-centage of copper in the ore being 8, 

 and 20 tons of coal being required in the early period of smelting 

 to produce one ton of copper, it was cheaper to take 12|^ tons 

 of ore to Swansea than 20 tons of coal to Cornwall. And Corn- 

 wall requiring coal for domestic pm-poses and her tin smelting, 

 which by law must be smelted in the county, ensured a back 

 freight. These were no doubt some of the causes which deter- 



* Communicated by the Author, who reserves to himself the copyright, 

 anv infringement whereof will invoke legal proceedings. — Eds. 



