APPENDIX. 607 



bronze ; and for this reason, that, although the ores may contain a 

 sufficient proportion of tin, yet, as they also contain other metallic 

 ingredients, it would, I think, be impossible to get rid of all such 

 ingredients without at the same time getting rid of the tin also. 

 I have, however, directed our assay er to make some experiments 



with reference to this subject. 



I am, respectfully, thy friend, 



C. Seymour Grenfell, ALFRED JENKIN. 



Copper Office, 

 27, Upper Thames Street, London, E.G. 



In a subsequent letter, Mr. Jenkin states that the experiments 

 made by the assay er confirmed him in the opinion above expressed. 



MY DEAR LUBBOCK, September 21, 1875. 



I have no hesitation in saying that it is most improbable, 

 I would almost say impossible, that the bronze of any early age 

 could have been made from the direct fusion of ores containing 



o 



copper and tin. I make this assertion on the following grounds : 



1st. It would be extremely difficult to devise any method of 

 smelting which would reduce both these metals at once into a 

 metallic state ; and if they were so reduced they would be impure, 

 so that a refining would be necessary, during which the tin would 

 inevitably pass into the slag. No doubt, if both metals existed in 

 an ore in an oxidized condition, and free from earthy matter (which 

 is almost inconceivable, to any extent at least), they might be re- 

 duced into their metallic conditions by the action of a blast-furnace, 

 or in a closed vessel with carbon : if much earthy matter were 

 present, the loss in slags would be excessive, anything up to the 

 whole metallic contents, dependent on the relative proportions ; but 

 it is almost idle to argue on such a supposition, because I am not 

 aware that any such ore has ever existed. Then, again, it would be 

 possible if the ore were a sulphide, or, what is more probable, an 

 arsenical sulphide, to reduce it first to a regulus, or speiss, then to 

 calcine "dead," and to reduce the resulting oxides to a metallic 

 condition ; but the ancient smelters were, I am quite convinced, 

 unable to calcine dead, even if they burnt their regulus in heaps, 

 which I much doubt : if they burnt in heaps, the calcining would 

 be very imperfect, and the tin in the subsequent smelting would 

 for the most part pass into the slag. We have pretty good 



