134 



Presents. 



[Jan. 9, 



A consideration of the various phenomena connected with the occur- 

 rence of this and other apparently similar springs which have at different 

 times been discovered in the district, would seem to lead to the inference 

 that they all have some more or less direct communication with the sea, 

 and that they are either the result of infiltration of sea-water through 

 faults, or are true and independent sources which, before being tapped 

 below the sea-level, had found their way to the ocean through faults or 

 channels. 



The following would appear, in the present state of our knowledge, a 

 not improbable explanation of the origin of the Huel Seton spring. 



The cross course is believed to extend through both granite and clay- 

 slate to the sea. From the close contact of its surfaces, the presence of 

 clay, and from other causes, this fault may be supposed not to be 

 uniformly permeable by water, which can only follow a circuitous passage. 

 In this way it penetrates to depths where reactions take place, which, 

 although not entirely in accordance with the results of daily experience 

 in our laboratories, can, after the investigations of M. Daubree, M. de 

 Senarmont, and others, be readily understood. 



By the action of sea-water on silicates o f calcium, silicates of sodium and 

 chloride of calcium may be produced. The sulphate of sodium of the sea- 

 water will be decomposed by this chloride of calcium, with the production 

 of sulphate of calcium and chloride of sodium. The decomposition of 

 clayey matter by common salt may produce chloride of aluminium and 

 silicates of sodium, while the magnesium of the chloride of magnesium may 

 be replaced by calcium • lastly, a portion of the potassium in the sea-water 

 appears to have been replaced by the lithium of the granite. 



Presents received January 9, 1873. 



Transactions. 



Amsterdam : — Koninklijke Akademie van Wetenschappen. Verhande- 

 lingen. Afdeeling Letterkunde. Deel 7. 4to. 1872. Verslagen en 

 Mededeehngen. Afdeeling Natuurkunde. Tweede Keeks. Deel 6. 

 Afd. Letterkunde. Tweede Eeeks. Deel 2. 8vo. 1872. Jaarboek 

 voor 1871. 8vo. Processen-Verbaal van de gew T one Yergade- 

 ringen der Afdeeling JNatuurkunde, 1871-72. 8vo. Ad Juvenem 

 Satira Petri Esseiva. 8vo. Amst. 1872. C. Leemans Bathmensche 

 Muurschilderingen. 4to. Amst. 1872. The Academy. 



obtained by addition of constituents, is doubtless in a great measure due to the partial 

 decomposition of aluminium and magnesium chlorides at the temperature (180° C.) at 

 which the drying of the residue was effected. 



