the Waters of a Salt Spring in Huel Seton Mine. 33 



My friend, Mr. W. J. Henwood, has called my attention to 

 the fact that so long ago as 1827 waters rich in chloride of 

 sodium had been found in some of the Cornish mines by Mr. R. 

 W. Fox. This gentleman says*, " In some instances I have de- 

 tected common salt, particularly in the water from the bottom of the 

 United Mines, the Consolidated Minesf, Hue] Unity, and Poldice. 

 Out of the 92 grains of residuum from the latter J, 24 grains 

 proved to be the muriate of soda, 52 grains the muriates of lime 

 and magnesia, and the remainder muriatic acid with iron and 

 sulphate of lime. The water from another part of the same 

 mine contained 5^ grains of common salt. All these mines are 

 in ' killas ' or primitive slate, and several miles from the sea. 

 It may be inferred from such facts as these that the sea- 

 water must in some places penetrate into the fissures of the 

 earth/' 



Previously to discussing whether the water in question is or 

 is not the result of infiltrations from the sea, it will be instruc- 

 tive to compare, by calculation, its composition with that of sea- 

 water so diluted with distilled water as to contain the same 

 amount of fixed constituents as that found in the Huel Seton 

 spring §. Analyses of the waters of the German, Atlantic, and 

 Pacific oceans agree so closely with one another as to justify 

 the conclusion that the waters of the entire ocean have an essen- 

 tially similar composition ; but for the purpose of this compa- 

 rison, an analysis of the waters of the Irish Sea by Messrs. T. 

 E. Thorpe and E. H. Morton has been selected ||. This analysis 

 has been chosen, both from the circumstance of its recent date, 

 and also because, from the geographical position of the 

 locality whence the water was obtained, it may be regarded as 

 fairly representing the waters of the Atlantic Ocean which wash 

 this portion of the Cornish coast. 



* Transactions of the Royal Geological Societv of Cornwall, vol. iii. 

 (1827) p. 324. 



t Lately part of the Clifford Consolidated Mines. 



X From the evaporation of a pint of water. 



§ The error consequent on the assumption of the dilution being made 

 with distilled water is not great. Four deep-mine waters recently ana- 

 lyzed gave an average of *42 gramme of solid matter per litre, or less than 

 3 per cent, of the solid contents of the water in question. 



|| Ann. Chem. Pharm. clviii. pp. 122-131. 



Phil. Mag. S. 4. Vol. 46. No. 303. July 1873. D 



