REPORT ON THE DEEP-SEA DEPOSITS. 
15 
examination. The smaller fragments, which could not thus be picked out and 
examined separately, were searched for under high powers, and the presence or relative 
abundance of Coccospheres, Coccoliths, Ehabdoliths, and amorphous and other particles 
was noted. ^ 
Under the heading Carbonate of Calcium in the Tables, Chapter II., the general 
character of these organisms is indicated in two columns. In the first of these the 
Foraminifera are named, beginning with the pelagic Foraminifera, which make up the 
greater part of the carbonate of lime present in most deep-sea deposits. These organisms 
live on the surface of the ocean in vast numbers, and the dead shells accumulate at the 
bottom, forming, when in great abundance, the well-known Globigerina Ooze ; the pro- 
portion which these make of the whole deposit is estimated after inspection, and the 
figures indicating this proportion are placed in brackets ( ). In like manner, the 
percentage of the shells of those Foraminifera which live at the bottom of the sea is 
estimated and placed beneath in the same column. In the second column the kind and 
percentage of other calcareous organisms present in the deposit are indicated in the 
same way. 
In front of the two columns giving the names and estimated quantities of the different 
carbonate of lime organisms, is another smaller column under the general 
heading Carbonate of Calcium, which gives the total percentage of 
carbonate of calcium present in the deposit. This is obtained by a quan- 
titative determination of the carbonic acid by attacking the sediment 
with dilute hydrochloric acid. What is considered as a fair representa- 
tive sample of the deposit is taken, finely ground, and dried thoroughly 
in an air or water oven at a temperature (in the case of the air-oven) 
of 100°-110° C., and transferred to a sample tube. A portion, about 
0‘5 to 1 gramme, is weighed directly but quickly, and transferred to the 
large bulb of the carbonic acid apparatus (see Fig. 18). 
This apparatus consists of a bulb (a) of about 3 ozs. (100 c.c.) 
capacity, an acid bulb (6), and a calcium chloride tube (c). The bulb is 18 .— Carbonic 
, . , . , Add Apparatus. 
provided with two openings, one as ordinarily is the case, and another 
smaller one blown in the side of the neck. Into the larger opening is fitted an india- 
rubber stopper, through which passes the limb or delivery-tube of the acid bulb. This 
acid bulb is fitted with a ground stop-cock, and holds about half an ounce of dilute 
hydrochloric acid, 1 in 3. Into the smaller opening is fitted another india-rubber 
stopper, into which is fixed an upwardly-inclined calcium chloride tube, filled with 
fragments of fused calcium chloride, to dry the evolved carbonic acid gas. The calcium 
1 The minute organisma and amorphous calcareous matters here referred to are not, of course, included in the term 
“ fine washings” (p, 23), which we use exclusively to indicate the finer portions of the deposit after the removal of the 
coA-bonate of lime. 
