EEPOET ON THE COMPOSITION OE OCEAN-WATEE. 
217 
Adding to the remaining 13 cases the 2 corresponding ones out of the set of 27 
previously considered, we see that out of all the 195 waters only 15 probably contained 
free carbonic acid. But Mr. Buchanan’s method, as appears from my critical experiments 
(see memoir, pages 110, et seq.), is liable to give low results; so we had perhaps better 
group our 13 together with all the 9 out of the set of 27 which exhibited no carbonic acid 
deficit, and say that out of Mr. Buchanan’s 195 waters 22 contained their surplus base 
in the form of at least fully, if not more than fully, saturated bicarbonate. 
Of these 22 waters— 
Six came from the surface ; 
Nine from the bottom, the depth varying from 1260 to 3875 fathoms.* 
Of the waters not bottom ivaters, 
Four came from depths varying from 25 to 100 fathoms ; 
One from a depth of 400 fathoms ; 
Two from depths greater than 1000 fathoms. 
The 6 surface waters, and the 4 from depths not exceeding 100 fathoms, are 
traced to their Stations in the following table, which gives also the dates of collection 
and the temperature of the water. 
The Six Surface Waters. 
No. 
When 
Collected. 
Tempera- 
ture of 
W ater. 
Free Car- 
bonic Acid. 
Milligrams. 
f265 
1873. 
October 
1 
22°-8 
1 "9 1 
380 
1874. 
February 
12 
r-i 
10 
382 
February 
13 
0°-7 
10 
386 . 
February 
16 
- 0°-7 
1 
515 
July 
23 
24°-5 
6 
532 
August 
17 
25°T 
41 
South Atlantic, 8° east of Eio Janeiro. 
J* South Indian Ocean at latitudes south of 60° S. 
South Pacific, lat. 20° S. 
Do. lat. 17° S. 
* In 8 out of the 9 cases. One of the waters, collected in Magellans Strait, or one of the passages leading thereto, 
came from a depth of only 245 fathoms. 
t Calculated from ascertained alkalinity. 
(PHYS. CHEJI. CHALL. EXP. — PART I. 1884.) A 28 
