/ 



134 Mr. D. Forbes's Researches on the 



case did not appear to confirm this view. The tin which was 

 used for the pumps, when brought such a distance, was quite 

 dear enough to cause the proprietors not to be prodigal of it ; 

 and the quantity found in the washings appeared to be too great 

 to attribute it to this cause, especially as all the pieces found in 

 the washing-apparatus were infinitely larger than could arise 

 from the mere abrasion of the pump-beads. Added to this, it 

 must be remembered not only that the ground in which the pieces 

 were found was virgin, but that the tin itself came from the gold 

 stratum, fully 30 feet below the surface. In order to judge 

 better, I resolved to examine the coarser and heavier particles of 

 mineral left behind in the lavadero at the conclusion of the 

 operation of washing the gold, and in consequence obtained 

 about four or five pounds' weight of this residue. After sepa- 

 rating a number of pieces of steel and iron, which from their 

 shape could easily be recognized as fragments of the work-tools, 

 I found numbers of nuggets and irregular shots of metallic tin, 

 one piece being above one ounce in weight, and, to my astonish- 

 ment, along with these an abundance of Cassiterite, which 

 formed nearly the whole of the residue, although its existence 

 had not before been even suspected. 



Passing the whole quantity through a sieve with fifty holes to 

 the square inch, I separated it into two parts : the finer, weigh- 

 ing about 2 lbs., consisted chiefly of Cassiterite, and amongst it 

 many shots and grains of metallic tin ; but the larger, weighing 

 15,109 grs., was sufficiently coarse to enable me to pick out 

 its separate constituents and weigh them separately, resulting in 

 the following mechanical analysis : — 



Cassiterite, more or less pure . . . 11,115 grains. 



Red hsematite, in polished nodules . . 1,368 „ 



Pseudomorphic F 2 O 3 after iron pyrites . 110 „ 



Black tourmaline, in fragments . . . 214 „ 



Garnet, red, in crystals 113 „ 



Andalusite (or topaz ?) 112 „ 



Metallic tin 1655 „ 



Undeterminate rock 422 „ 



Total 15,109 *> 



The largest piece of tin found weighed 505 grs. The rela- 

 tive proportion of the tin present seemed so large, that I had 

 the curiosity to weigh the fragments of iron work-tools found 

 along with the mass, and found them in all to weigh only 1069 

 grs., although two of the pieces exceeded in size the largest 

 piece of tin; and from this circumstance one can but infer the 

 improbability of the tin having been derived from the pumps 

 as I had so determinedly endeavoured to prove, notwithstanding 



