REPORT ON THE COMPOSITION OF OCEAN-WATER. 
21 
1. Elimination of free and loosely combined carbonic acid by distillation with chloride 
of barium in a current of pure air ; subsequent redistillation after addition of a little 
hydrochloric acid, and determination of the carbonic acid thus liberated by Pettenkofer’s 
method. Results, partly * owing to my having to work on a very small scale, highly 
indefinite. 
2. Distillation of 100 c.c. of the sea- water, after addition of a small weighed quantity 
of perfectly neutral sulphate of ammonia, in an evacuated apparatus constructed on the 
principle of the cryophorus. Determination of ammonia in distillate, correction by blank 
experiments executed with an artificial sea-water made of absolutely neutral salts, checked 
by experiments with the same sea-water, rendered alkaline by addition of a measured 
volume of standard lime-water, subsequently neutralised by carbonic acid gas. Results 
not very constant, but clearly showing that sea- water, cceteris paribus, eliminates more 
ammonia than the corresponding neutral-salt mixture does. 
I shall recur to this subject in the chapter on “ The Carbonic Acid in Sea- 
Water.” 
After this digression let me now go back to the analyses proper. The serious 
constant error inherent in the method adoDted for the determination of the lime, which 
was referred to on p. 10, was detected only after the first series of 21 analyses had 
been reported on. But as I had always rigorously adhered to the mode of operating 
once laid down, I was able to correct the consequent inaccuracies by subsequent 
calculation. Taking l 0 and n 0 as signifying the true weights of lime and soda per kilo- 
gram of water analysed, and l and n as the corresponding incorrect values originally 
reported, it is clear from what was said on p. 11, that Z 0 = 0*91 l very nearly, and from 
the method used for the determination of the soda (pp. 17 to 19), it follows that 
the correct value of sulphate of soda = the reported + 0 '09 times the reported sulphate 
of lime. Now r ^ a |^ -, = Q'4366 and = 2*4286. Hence 
[Na 2 S0 4 ] [CaOJ 
n. 
— 71 + Ir, 
(- 
0-09 x 04366 x 2*4286\ 
091 ) 
or 
11 ^ — 11 + 0T0487 l 0 , 
or 
1=- -f 0*10487^ . 
n 0 n 0 
But 
n 0 
according to the sum total of my correct analyses is practically constant, and 
equal to very nearly 0*04102 ; hence, without appreciable error 
n 0 = 1*0043 x n. 
The amounts of magnesia and potash are independent of the determinations of lime ; 
* Compare chapter on carbonic acid. 
