228 GOLD IN SCIENCE AND IN INDUSTRY. 



Accordino; to Professor Liversidge, sea water contains on the 

 average about 1 grain of gold per ton. If this is the case, then tlie 

 above figures for the dihite cyanide soUition apply with only a 

 slight modification to sea water. No drop, however small it ma}^ be, 

 can be removed from the ocean which will not contain many millions 

 of gold molecules, and no point of its surface can be touched which 

 is not thickly strewn with these. From this molecular point of view 

 we must realize that our ships literally float on a gilded ocean ! 



From time to time adventurers arise who attempt to launch upon 

 this gilded ocean unseaworthy ships freighted with the savings of the 

 trusting investor. In order that nothing which has been said here 

 may tempt anyone to contribute to the freighting of these shi'ps, let 

 me hasten to point out that the weakest of the cyanide solutions here 

 referred to is richer in gold than sea water is reported to be. The 

 practical conclusion from this comparison is sufficiently obvious. If 

 the cyaniding expert, whose business it is to extract gold from dilute 

 solutions, finds that it does not pay to carry this extraction beyond a 

 concentration of 2 or 3 grains })er ton, even when the solution is 

 already in his hand, and when, therefore, the costs of treatment are 

 at tlieii- minimum, how can it possibly pay to begin the work of ex- 

 traction on sea water, a solution of one-half the richness, which would 

 have to impounded and treated by methods which could not fail to be 

 more costly in labor and materials than the simple j^rocess of zinc-box 

 precipitation ? It is generally misafe to prophesy, but in this case I 

 am rash enough to risk the prediction that if ever the gold mines of 

 the Transvaal are shut up it will not be owing to the competition of 

 the gold resources of the ocean. 



In these calculations with reference to the dilute cyanide solutions 

 it is assumed that the gold molecules are uniformly distributed — that 

 they are practically e(|uidistant from each other. There appears to 

 me to be considerable doubt whether we have any right to make this 

 assumption. Leaving out of account for the moment the action of the 

 water molecules, it would appear that as long as the gold molecules 

 are so numerous that a uniform distribution would bring them within 

 the range of each other's attraction, we can imagine that all sub- 

 merged molecules would be in equilibrium so far as the attractions of 

 their own kind are concerned, being subjected to a uniform pull in all 

 directions. This condition would certainly make for uniform dis- 

 tribution. But when the distance between them exceeds the range of 

 the molecular forces, it is evident that an entirely new condition is 

 introduced, and it seems not improbable that the widely distributed 

 molecides would tend to drift into clouds in which they are brought 

 back within the range of these forces. The range of the cohesive 

 forces in water and aqueous liquids is usually taken from 50 to 100 

 luicromillimeters, and I am disposed to think that ten times this 



