Sixth Meeting. 12th October, 1868. (Adjourned from 6th October.)
The Hon. W. B. D. Mantell, F.G.S., in the chair.
His Excellency the Grovernor, Sir Gr. F. Bowen, G.C.M.G., was present.
Letter read from His Lordship the Bishop of Wellington, resigning the office of Vice-President, on account of his being about to leave the colony.
Before proceeding to the papers for the evening, Dr. Hector exhibited some geological specimens, including two from "The Golden Claim," Thames District. First, vein rock, highly pyritous, which had been analyzed in the laboratory, and showed the following results:—First sample, pulverized very finely and roasted, yielded on extraction, with mercury, at the rate of 683 oz. 16 dwts. per ton. A second sample of the same rock, more pyritous than the first, yielded to mercury, when finely pulverized, but not roasted, proportionally as follows to the several amalgamations:—
| oz. | dwts. | grs. | ||||
| 1st | amalgamation | | 1,213 | 4 | 8 | |
| 2nd | {{{1}}}„ | 89 | 3 | 14 | ||
| 3rd | {{{1}}}„ | 33 | 4 | 0 | ||
| 4th | {{{1}}}„ | Traces. | ||||
| Total | = | 1,335 | 11 | 22 | per ton. | |
When at last only traces of gold could be extracted by mercury, the whole of the residue from these amalgamations was dried and well roasted, and the amalgamating process again repeated, when a very white alloy was obtained, consisting mostly of silver, in the proportion of 4 oz. 11 dwts. 9 grs. to the ton.
These results show plainly that all the gold is in a free state, and also that a portion of the silver present is in combination, and most probably with sulphur, the effect of roasting being to decompose, and so render the silver amenable to the affinities of mercury.
The second specimen was a felstone, a portion of the bed rock in which the above vein stone was found. It has not been hitherto valued by the miners, but analysis showed it to contain at the rate of 53 oz. 16 dwts. 6 grs. per ton. The proportion of silver in gold, on first amalgamation, was 29.60 per cent.
Several other geological specimens were laid on the table, including samples of siliceous deposit from the Waiotapu Springs, pyritous quartz, and part of the gold obtained by Mr. Groves when prospecting in this province.
1. "A further Notice of the Earthquake "Wave," by James Hector, M.D., F.R.S. (Transactions, p. 42.)
The author recapitulated some of the facts already explained at previous meetings, and added some interesting particulars received lately from other localities, his object being to place on record all the particulars obtainable of
