1 62 Proceedings. 



From Mr. Jones, of Liverpool- street, was received a silver coin (date 1711) of 

 Spanisli America. 



Extracts were read of the following letter from Dr. Knight to Sir William 

 Denison, on the native gold of New Zealand. According to Dr. Knight's re- 

 searches, it consists of pure gold 7'4275, and silver 2-06, with quartz as a matrix, 

 and he estimates its value at £3 8s. lOcZ. per ounce ; Tasmanian gold being worth 

 £3 19s., and that of Victoria from £4 to £4 2s., in the London market. 



"Auckland, \2tli January, 1854. 

 I had an opportunity, a few days, since of perusing for the first time Your Excel- 

 lency's interesting paper on the value of gold, read before the Eoyal Society of 

 Van Diemen's Land, on the 22nd June, 1852. 



My attention was directed to the same subject early in 1853, in reference to the 

 value of gold obtained in tliis disti-ict. Although my investigations were limited 

 to gold in a quartz matrix, it appears to me that they are of sufficient interest to 

 excuse my taking the Hberty of addressing Your Excellency on the subject. 



The New Zealand gold is mostly found in a quartz matrix or mixed with iron- 

 sand, (specular iron). 



It appeared to me that the quantity of gold in the quartz matrix could be 

 determined with facihty by taking the weight of the specimen in air and in water. 

 We shoijd then have the following known quantities: — 



Weightof specimen in air..... = a 



Ditto in water =e 



Specific gravity of gold = 6 



Ditto of quartz = c 



From which the quantity of quartz = {y) could be readily determined, that of 

 gold being («—?/) 



For (^—1) Ja^-y) weight of gold in water 



also \ fi 1) y =: weight of quartz in water 

 c 



. • . i ) y^'-'—y) i_ (c 1) y — weight of specimen in water 



c 



, . . y (eb -\- a ba) c ^ convenient expression for the quantity of 



c—b 

 quartz without fii-st computing the specific gi-avity. 



I may mention here that the absence of sUver had been (as it was thought), 

 satisfactorily shown by the analysis pubUshed in the Wellington Government 

 Gazette. 



Havmg determined by the above method the value of two or three specimens of 

 gold in a matrix of quartz, I was surprised to learn that when the ore was rim 

 out in Sydney, the value was declared to be much higher than my estimate; 

 suspecting this discrepancy to arise from the presence of silver, I imdertook the 



