.REPORT ON THE COMPOSITION OF OCEAN-WATER. 
193 
Column V. gives the value 1000 \n 2 ,i.e., the volume (in c.c. reduced to 0° and 760 mm.) 
of nitrogen, which 1 litre of sea-water, according to my experiments, absorbs when saturated 
with a very large volume of air at t degrees and 760 mm. dry-air pressure. For an exact 
comparison, the values in Column IV. ought to have been corrected for the deviation of 
the existing dry-air pressure from 760 mm., but I had not the necessary barometric 
observations, and therefore took the values (Column IV.) as they stand. In each group for a 
given temperature (t), the values (Column IV.) are arranged according to their magnitude. 
Diagram p. 194 is to Table XVIII. what diagram p. 190 is to Table XVI. Curve 
A, A, A, corresponds to the function from which the values \n 2 on Table IX. were calcu- 
lated; curve A, B, B, B, is an approximation to the function which the water gas-analyses 
tend to establish, the dots registering the individual observations. At 15° the observed 
values of nitrogen tend to be higher ; at 20°, 25°, 30° they are, on the whole, lower 
than the values corresponding to complete saturation by air. 
Gases from Waters not Surface- Waters. 
I treat the intermediate along with the bottom waters, because I have not been able 
to discover anything in the results which is characteristic of bottom-waters as such. The 
mode I adopted for manipulating these is founded upon the obvious proposition that 
water from any depth must have obtained its oxygen and nitrogen from the surface, and 
consequently, gasometrically speaking, may be viewed as a sea- water saturated completely 
with air under 760 mm. dry-air pressure at some temperature t x different in general 
from its temperature t 0 in situ. I accordingly calculated from the quantity of nitrogen 
(per litre) found (for t 0 ) the temperature t x at which that volume of nitrogen would have 
been absorbed under 760 mm. from air, and then, by means of my table of values of ~ 
calculated the volume of oxygen which, in the imaginary surface absorption, would have 
accompanied the nitrogen found. On Tables XII. and XIII. these calculated volumes 
of oxygen are entered as (0 2 ) 1 — in Column IX. and in Column VIII. respectively. 
The next column in either table gives the “ oxygen deficits ” — (0 2 ) 1 minus ( 0 2 ) found. 
In the following Table XIX., the oxygen deficits from both Tables XII. and 
XIII. are arranged according to their magnitudes in Column V. ; Column I. gives the 
number of the water (enclosed in brackets when it is a bottom -water) ; Column II. the 
Station whence it was obtained ; Column III. the depth $ at which the water was 
collected ; Column IV. its natural temperature t 0 . 
A glance at Tables XII. and XIII. shows that the calculated temperatures are in 
the overwhelming majority of cases higher than the observed temperatures t 0 . Table XIX. 
shows that small oxygen deficits occur more frequently in waters from small depths, and 
that these deficits in waters from great depths sometimes assume very considerable 
(PHYS. CHEM. CHALL. EXP. — PART I. — 1884.) A 25 
