420 Transactions. — Geology. 



of my solution resulted in the loss of an unknown amount ; and hence the 

 absence of exact data. The assays made from this leader varied consider- 

 ably, the lowest being at the rate of 1 oz. 5 dwts. 18 grs. to 10 oz. 6 dwts., 

 showing that it was very irregularly present in the stone. When the pecu- 

 liar characteristics of its presence are found it will be possible to isolate 

 sufficient of the group to show the quantity of the other members of the 

 platinum group which accompany it. 



In the continuation of this investigation I have found this metal present 

 in the large reef, both at the 540 feet and 600 feet levels, by assay, but in 

 very much smaller proportions, and have washed several packets of tailings 

 from the battery, the result of the crushing of this reef, and obtained the 

 metal in the shape of minute grains accompanying the escaped gold. These 

 grains viewed under the microscope are generally rounded, but a great 

 many take the octahedral shape, some being beautifully perfect crystals. 

 As it is intended to commence sinking immediately to the 670 feet level, I 

 shall have ample opportunity of continuing my examination of this subject 

 with a view to finding whether it is possible to note its presence in the 

 stone by any visible peculiarity. 



The rarity of this metal being found in situ may be gathered from Ure, 

 who remarks of a sample of ore containing platinum from Guadalcanal in 

 Spain, " This would be the only example of platinum existing in a rock 

 and in a vein." Since then, however, Edison in America and Eoscoe and 

 Schorlemmer have shown that it exists more largely than is generally 

 presumed, and I think it is highly probable that if it was looked for syste- 

 matically at the Thames, it would result in its being found much more 

 widely distributed in the network of reefs and leaders than is generally 

 supposed. 



