240 
A. H. Church. 
organisms of the sea have been evolved in the first instance. The 
conclusion is not only warranted, but generally accepted, that 
living plasma, as the primitive source of what is termed biological 
life of land-organism, is evolved directly from sea-water itself, as a 
medium which is not known to have been markedly different in 
composition from what it is to-day, at any preceding epoch of the 
world’s history, so long as an aqueous envelope has existed on the 
crust of the earth. 
Sea water still covers more than three-quarters of the surface of 
the world, in quantity sufficient to submerge the levelled crust to a 
depth of over two miles (2000 fathoms). The actual quantity of the 
medium has been estimated at 1.3 x 10 18 tons ; though on a model of 
the globe a metre in diameter such an ocean might be indicated by 
sponging the surface to give a wet film of \ mm. It constitutes a 
watery solution containing very approximately 3.5% of dissolved salts 
by weight; 3.5%, ora salinity of 35 per thousand may be taken as 
accurate for the English Channel. The salt-content may be regarded 
as comprised essentially of 8 elementary ions :—4 electro positive 
(kations), Na', K', Mg", Ca”, and 4 electro-negative (anions) Br', Cl', 
S0 4 ", C0 3 ", with the possibility of at least 16 salts, as also with traces 
of such elements as Nitrogen, Phosphorus, Iodine, Iron, Manganese, 
Gold, Silver, etc., or 32 in all (Kriimmel). The general run of these 
elements follows the sequence of the Periodic Law from A.W. 12—40, 
in which A1 and F are conspicuously deficient, while Fe appears 
accessory, as if of meteoric origin. Such a solution of 3.5% salt- 
content presents a freezing-point of —1.910°C, and an osmotic value 
of 23.12 atmospheres (Kriimmel), From similar phj'sical data it would 
appear that the solutes are ionized to the extent of 90% (Kriimmel), 
and the excess salt-molecules are mainly NaCl; i.e, all minor consti¬ 
tuents (N, P, Si, compounds) must be regarded as fully ionized. The 
water itself is also ionized to an extent of approximately one part in 
ten million ; the ionization coefficient being taken as C H - x Con* =10'’ * 
The solution is very fairly neutral, i.e, balanced at 10 7 (H - ) x 10 7 
(OH') ; but many seas are distinctly alkaline, the latter effect being 
the expression of a predominance of OH' ions, as noted for Pacific 
water off the Californian coast, as opposed to water of the North 
Atlantic (Loebl. Alkalinity has been found to increase normally 
from Northern Seas towards the warmer Mediterranean ; possibly 
largely as the effect of plankton-photosynthesis in withdrawing 
CO, from the solution. The H’ ion concentration is given as 7.95 to 
8.35 x 10 7 for the Mediterranean (Palitzsch), while the high estimate 
of 22.4 xlO" 7 is recorded by Gaarder (1917) for Norwegian Fjords. 
Loeb and others have shown that such alkalinity is favourable for 
animal life: for practical demonstration “acid” water gives yellow 
to red coloration with Methyl Orange; “alkaline” water red with 
1 ’henolphthalein (Palitzsch, p. 243). 
