164 



THE ULTIMATE SOURCE 



The deposits referred to are found as follows ! on the 

 surface, sand, clay, porphyrinic and quartzite stones ; next, 

 a firmer layer of conglomerated gypsum and salt ; next, 

 sulphites mixed with potassic nitrate, sodic chloride, sodic 

 iodide, potassic sulphate and sodic sulphate ; lower still, pure 

 sodic chloride and clay, resting on porphyry and granite. 

 Whatever the mode of origin of these salts, it is at least curious 

 that they should be, with the exception of potassic nitrate, a 

 salt easily formed in nature just such as characterise marine 

 deposits. I am willing to. attribute the Shevaroy salt 

 lick to chemical action, seeing that it appears to be a very 

 limited source of salt ; but in the presence of large deposits 

 of gypsum, common and other marine salts, apparently in a 

 stratified condition, I would prefer to suspend judgment. 

 The question is unsettled and requires an attitude of reserve. 



J \s. J. L. Ratton. 



NOTE. 



It is important that I should explain fully the data from which I hare 

 calculated the amount of salt in the ocean. 



First, as regards the percentage of salt in the sea. The specific gravity 

 of the sea has been shown by careful weighments to vary from 1-0246 at 

 the poles to 1*028 in the {Southern Ocean. 



I have, with a view to making a liberal allowance for the comparatively 

 fresh water about the poles and in the Black Sea, Caspian, and Sea of 

 Azof — in case the two latter should be included in KrummePs calculation — 

 adopted an average specific gravity for the entire ocean of 1*024, or a little 

 less than that found by Dr. Moss near the pole during the Arctic Expedition 

 of 1875-76. 



Taking the average specific gravity at 1*024, I next find the percentage of 

 salt as follows : The specific gravity of the Channel is 1*027. It contains 

 3*522 per cent, by weight soluble salts. Sodic chloride forms 2*706 parts of 

 the 3*522, or 76 per cent. I take this 76 per cent, as being the normal or 

 average percentage of sodic chloride to total contained salts throughout the 

 sea, although I am aware that the proportion between sulphates and chlorides 

 is disturbed about the north pole. Next, to find the total salts in the ocean 

 having a mean specific gravity of 1*024, I make a sum of proportion with 

 the specific gravity of the Channel and its known salts, and the specific 

 gravity of the sea — 27 : 24 : : 3*522— and find that the total salts amount to 

 3*130 per cent., of which common salt forms 2*378 at 76 per cent, of 3*130, 

 I think that so far there is no exaggeration. 



