28 Mr. J. A. Phillips on the Composition and Origin of 





Grammes per litre. 



Grains per gallon. 



I. 



II. 



T. 



II. 



Calcium carbonate 



•0921 



•0045 



trace 



0303 

 minute trace 

 6-7697 



1712 



•9003 



•0919 



trace 

 5-8442 



•4888 



trace 



•0693 



trace 



trace 



1011 

 •0047 

 trace 



0301 



minute trace 



6-7934 



1686 

 •9013 

 •0900 

 trace 

 5-8210 

 •4820 

 trace 

 •0719 

 trace 

 trace 



6-45 



•31 



trace 



212 



minute trace 



473-88 



11-98 



63-02 



6-43 



trace 



409 09 



34-22 



trace 



4-85 



trace 



trace 



708 



•33 



trace 



211 



minute trace 



475-54 



11 80 



6309 



6-30 



trace 



407-47 



33-74 



trace 



5 03 



trace 



trace 



Ferrous carbonate 



Manganous carbonate 



Calcium sulphate 



Cupric chloride 





Magnesium chloride 







Caesium chloride 



Sodium chloride 





Potassium bromide 



Potassium silicate (K 2 SiO 3 ). 

 Ammonia 



Nitric acid 





Total found by addition ... 



Total found directly* 



Free carbonic acid 



14-4623 



14-3658 



0373 



14-4641 

 0323 



1012-35 



1005-61 



2-61 



1012-49 

 2-26 





The nature and amount of the various substances in solution 

 in the saline waters having been determined, it was considered 

 desirable to ascertain by analysis the composition of the principal 

 rocks occurring in the neighbourhood of the spring. It was 

 hoped that in this way information might be obtained respecting 

 the sources from which some of the substances taken up by the 

 water had been derived. It was further thought that, by com- 

 paring the composition of the rock in the immediate vicinity of 

 the cross-course through which the heated waters issue with that 

 of the clay-slate further removed from its influences, it might be 

 possible to ascertain some of the effects produced by their action. 

 In the case of each of the rocks analyzed, numerous thin sec- 

 tions were cut and subjected to careful microscopical examination. 



" Elvan," sp. gr. = 2*64. — The rock constituting the dyke 

 G H, fig. 1, is exceedingly hard and compact, presenting the 

 appearance of a crystalline greyish matrix, enclosing numerous 

 well-defined crystals of flesh-coloured orthoclase ; a specimen of 

 this rock afforded by analysis the following results : — 



* The difference between the amount of total solid contents found directly 

 and that obtained by the addition of constituents, is doubtless partly due 

 to the partial decomposition of aluminium and magnesium chlorides at the 

 temperature (160° C.) at which the drying of the residue was effected. 



