238 STEEAM TIN DEPOSITS OF PEEA^. 



or rather in the strata from which the granite is formed. I am of 

 opinion that it has been very finely, nay almost infinitesimally, 

 divided through the rocks just as gold and silver is in the sea at 

 the present day. Many people are not aware that these metals 

 exist in solution in sea-water, but in so small a quantity, that 

 tons of water must be evaporated before any appreciable quantity 

 can be extracted. Now, it is quite certain that the precious metal 

 is being deposited in the rocks forming on the sea-shore or at the 

 sea-bottom at the present day. No doubt, immense quantities of 

 this deposit would have to be reduced before even a trace of gold 

 would be seen, yet the quantity is absolutely if not relatively great. 



But what is not possible to man's chemistry is easily effected 

 in the great laboratory of nature. If the present shore and sea 

 deposits were subjected to such an action as that which reduced 

 the ranges here to granite, we should have the gold in rich veins 

 and shoots just as it is in the quartz veins in Australia. Tou may 

 be inclined to say that the gold in Australia has been much more 

 abundant than in the case I am supposing, but this is not so. It is 

 estimated that more than five tons of quartz or vein-stuff has been 

 operated upon for every ounce of gold extracted, which is consi- 

 derably below the truth. This, however, be it less or more, is only 

 a mere fraction of the rock metamorphosed from which this gold 

 has been derived. 



The whole process depends upon a peculiarity in the chemistry 

 of minerals which is only imperfectly understood. This is a ten- 

 dency to what we call segregation. Similar minerals seek each 

 other out and run together. In the heavier metals when they are 

 melted, one can understand it, but this occurs when the rocks or 

 metals are not melted at all, where they are not particularly heavy, 

 and where they take directions quite independent of the force of 

 gravity. You will find veins of quartz and veins of felspar running 

 through stratified rocks, you find lines of flints in chalk and sep- 

 tarian nodules in clay. If these things take place in solid rocks, 

 every facility occurs for their occurrence in granite. Thus, in 

 effect, we find in granite innumerable veins of quartz, felspar, 

 iron ores, tin from seams of considerable thickness to the merest 

 threads. They evidently do not depend upon cracks in the stone 

 and could not have been injected in a fluid state. They have 

 n imply segregated and come together in that strange movement 

 of particles to which the materials of the most solid rock are sub- 

 ject, by means of which they evidently travel long distance. 



]Sow, turning to the tin ore, we find it in the form of an oxide. 

 Pay attention to this. Tin is easily melted. If it had been sub- 



