538 Scientific Proceedings, Royal Dublin Society. 
“Comparing the results by the number of successful days first, 
we may say, that for gold producing, the sub-metamorphic rocks are to 
the metamorphics as (100—13°6=)86-4 to (100—66=)34=2°5:1; 
comparing by daily average, the proportions become ‘49 :-16=q. p. 
3:1. We may therefore conclude that the sub-metamorphics are 
between two and half and three times as productive of gold as the meta- 
morphics, so that as the gold washers only find a subsistence from 
washing in the sub-metamorphie area, it is obvious that it would not pay 
them to work in the metamorphics. 
“The greatest amount found on one day was 2-2 grains, but the daily 
averages given above should not be taken as indicative of the amount of 
gold to be found by a regular system of working, where the washers 
would of course be set at favourable spots, and would not have to spend 
a considerable portion of their time daily, as was the case of the men I 
employed, in making marches before they reached the scene of their 
labours.* 
“‘ Various papers in the Asiatic Society’s Journal describe the methods 
of gold-washing practised in different parts of India. ‘The instruments 
used, though essentially the same in principle throughout, have local 
peculiarities of shape, &c., and the manner of manipulation also varies. 
At Hira Khund, in Sambalpur,t the same instrument and manipula- 
tion serve for the separation of both diamonds and gold. In fact the 
diamonds are found in the middle of the process, the iron sand with 
specks of gold being the final residue. In Manbhtim and Singbhim 
the instruments used are perhaps more simple than those used in any 
other place. The dish measures 28” by 18", it is hollowed somewhat 
eccentrically to a maximum depth of about 25 inches. A scraper 
formed of a flattened iron hook set in a handle, serves to collect the auri- 
ferous sand and gravel which accumulates in the angles of the rocks in 
the beds of streams. The dish when filled is placed in shallow water, 
and the operator working with his hands soon separates and throws 
aside all the coarser gravel and stones, while the agitation of the water 
serves to carry away all the mud and lighter portions. The dish is 
then balanced on the palm of the left hand and oscillated to and fro 
with the right; this serves to throw off the greater portion of the re-_ 
maining gravel, and the process is ‘completed by a circular motion, 
* It is conceivable that the fact of the greater quantity of gold being found in the 
superficial deposits within the sub-metamorphic area might be attributable to something 
in the configuration or elevation of the ground conducive to the greater accumulation of 
gold within that area. I could not, however, discover anything of this kind; the fall to 
south is gradual throughout both formations. The origin of the gold which is annually 
found in the rivers at present is, I believe, twofold. A portion being directly derived 
from the rocks, and the remainder resulting from the re-assortment of detritus which is 
the remnant of sub-aerial action. In both formations, the evidences of extensive sub- 
aerial action are numerous and prominent, and it is obvious that nature has been carrying 
on gold-washing operations in the valleys since denudation first commenced to scoop them 
out, leaving barriers of intervening ranges of hills formed of the hardest rocks between 
them. 
+ “Jour. Asiatic Soc., Bengal,” VIII., 1057, 1839. 
