1868.] 



Mr. W. Shanks on Euler's Constant, 



299 



which evidences are still to be found in the hot springs and recent metal- 

 liferous veins met with in various parts of the Pacific coast. 



d. From the variable temperatures at which the vacuities in their fluid- 

 cavities become filled, it may be inferred that they are the result of an in- 

 termittent action, and that the fissures were sometimes traversed by cur- 

 rents of hot water, whilst at others they gave off aqueous vapour or 

 gaseous exhalations. This is precisely what is now taking place at Steam- 

 boat springs, where the formation of a vein is in progress, and from which 

 currents of boiling water are often poured forth, whilst at other times the 

 fissures give off currents of steam and heated gases only. 



e. That gold may be deposited from the same solutions which give rise 

 to the formation of the enclosing quartz, appears evident from the presence 

 of that metal in pyrites enclosed in siliceous incrustations, as well as from 

 the fact of large quantities of gold having been found in the interior of the 

 stems of trees, which in deep diggings are often converted into pyrites. 



/. The constant presence of iron pyrites in auriferous veins, and when 

 so occurring its invariably containing a certain amount of gold, suggests the 

 probability of this sulphide being in some way necessarily connected with 

 the solvent by which the precious metal was held in solution. It has been 

 shown that finely divided gold is soluble in the sesquichloride of iron and, 

 more sparingly, in the sesquisulphate of that metal. It is also well known 

 that iron pyrites sometimes results from the action of reducing agents on 

 the sulphates of that metal. If therefore sulphate of iron, in a solution 

 containing gold, should become transformed by the action of a reducing 

 agent into pyrites, the gold, at the same time being reduced to the me- 

 tallic state, would probably be found enclosed in the resulting crystals of 

 that mineral. 



ff. The silica and other substances forming the cementing material of 

 the ancient auriferous river-beds have probably been slowly deposited at a 

 low temperature. 



The connexion existing between the decomposition of granite by the 

 agency of boiling springs, the existence of alkaline plains, and the for- 

 mation o f lakes containing various salts of soda and potash, is too ob- 

 vious to require comm^ent. 



IL "Third Supplementary Paper on the Calculation of the Nu- 

 merical Value of Euler^s Constant." By William Shanks. 

 Communicated by the Rev. B. Price. Received February 29, 

 1868. 



When n=5000, we have 



9-09450 88.529 84436 96726 12455 33393 43939 17829 

 87811 30384 14506 16283 86638 30530 78016 46808 

 46902 09226 85495 77084+ 



