224' Professor J. Joty—The Age of the Earth. 



Now as to the "fossil sea-water." In the first place we find very 

 conflicting evidence. Mr. Fisher, himself, quotes two observations — 

 one affording 0-042 per cent, of "chlorine calculated to sodium 

 chloride," the other affording a quantity too small for estimation. 

 Sterry Hunt quotes many analj^ses of deep-seated springs, some in 

 faulted beds, others in apparently undisturbed beds. The results 

 give the most widely varying amounts of sodium and other elements 

 in solution. Even in the case of wells ai'ising in the same rocks 

 and near together (as in the Trenton Limestone) the relative 

 proportions of dissolved salts vary even to 100 per cent. His 

 results did not lead him to the conclusion reached by Mr. Fisher 

 (that but little sodium had entered the sea since Silurian times), 

 but to the conclusion that the original ocean contained large amounts 

 of calcium chloride, and that alkaline carbonates (derived from 

 decomposing felspars) " which from the earliest times have been 

 flowing into the sea have gradually modified the composition of 

 its waters, separating the lime as carbonate and thus replacing the 

 chloride of lime with chloride of sodium." (" Chemistiy of Natural 

 Waters," § 24.) A conclusion essentially in accord with the theory 

 of oceanic supply which I have advocated. 



- Finally, if we refer to No. 148 Bulletin of U.S. Geological Survey, 

 containing Messrs. Clarke & Hillebrand's valuable collection of 

 rock analyses, we find among many very minute analyses of slates, 

 shales, and clay-slates the chlorine, in one case only, given at as much 

 as O'Ol per cent., and generally left blank or entered as " trace." 



But the part played by possible "fossil sea-water" is capable 

 of estimation and of having a true value assigned to its importance. 



Let us accept Mr. Fisher's first quoted observation, that most 

 favourable to his suggestion, without reserve. Assume the per- 

 centage of chloride of sodium derived from "fossil sea-water" to 

 be 0-042 in all slates and similar rocks, and that such rocks cover 

 one-half the land area of the globe. We will also take the figure 

 of one foot in 6,000 years (which Mr. Fisher favours) as the rate 

 of denudation ; and remarking that the sodium chloride supply 

 from this source, in order to be continuous, must keep pace with 

 the rate of denudation, we proceed to estimate the amount of 

 sodium set free by denudation, and express this as a percentage 

 of the quantity of the element contained in the river supply to 

 the ocean. The result, as I reckon, comes out as 09 per cent. 

 If, then, this amount of sodium chloride circulated, our conclusion 

 as to the duration of Geological Time would be falsified by about 

 this percentage, but the assumptions we made in obtaining even 

 this number are evidently entirely unwarranted. 



In point of fact, the conclusion which Mr, Fisher draws from 

 his experiments might indicate that the premises were somewhere 

 at fault — that " not much additional sodium can have accumulated 

 in it (the ocean) since Silurian times." Mr. Fisher elsewhere refers 

 to the setting free of the alkalies of the felspars of granites. 

 What, then, became of all the sodium contributed in this manner 

 to the ocean throughout the ages that have since passed away ? 



