112 
TIIE VOYAGE OF H.M.S. CHALLENGER. 
; by direct analysis to 57‘1G x (expressed in mgrms. per litre) 
:i. amount of carbonic acid required to produce bicarbonate = 2 x 57*16 = 
11 r:S2 mgrm.s. per litre. According to two direct determinations the carbonic acid 
amounted to only 1 1 0'5 and 111*2 mgrms. A portion of the liquor was therefore taken 
out. saturated with carbonic acid, and then re incorporated with the rest. The carbonic 
arid now was found to be 124*1 mgrms. per litre ; showing the presence of free carbonic 
acid 
The whole of the mixture, therefore, was Shaken three times, each time with 10 
volumes of fresh air. 
'I'lio carbonic acid in the resulting liquid was found to be 109'04 and 109’0 mgrms. 
per litre ; less than before I 
Three successive volumes of this water were boiled in my modification of Classen’s 
apparatus with excess of solid chloride of barium, the eliminated carbonic acid collected in 
standard baryta, and titrated as usual. 
N umber of Experiment. 
1 . 
2. 
3. 
Amount of water used, .... 
250 
250 
200 c.c. 
Hydrated barium chloride added, 
4 
4 
3*5 grms. 
Mgrms. of carbonic acid per litre of water, 
44*0 
39*0 
53*0. 
In th«- euso of (l ) and (2), the residues were mixed with excess of standard hydrochloric 
.. id, tie- boiling resumed, and the additional liberated carbonic acid collected in afresh 
supply of standard baryta. 
KxjN-riment (1.) (2.) 
Amount of hydrochloric acid added, 20 50 
mi of cart ■ id, per litre of water, 24 - 0 23 - 2 
Total carbonic acid extracted, mgrms. per litre, . . 68*0 62*2 
Looae carbonic acid in iii.r; , . j>« r 1 i t r. ■ nf waU r, • »l< ul.it od, 51*8 51*8 
Here* as before, the inconstancy of tie* results is very surprising ; in (1) about 88 
5) about 78 per cent, and in (3) a little more than 100 per cent, of the 
carbonic acid was recovered by chloride of barium. 
In the case of No. 2 the residue obtain <1 in the second boiling (with acid) was mixed 
wi*.i it- own volume of 20 per cent, hydrochloric acid, and again treated as before, 
i boryt water in the vacuum-flask remained perfectly clear, though strongly alkaline. 
■ ’• sting with nitrate of silver, only a mere trace of chlorine cuuhl be discovered in it, 
v * " ' *1 |; R the inverted condenser, even under these very unfavourable eon- 
rv . fli. c ni in condensing tlm volatilis'd hydrochloric acid. The 117 mgrms. 
• n • acid which must have been pn ent in the liquor operated upon, resisted the 
' v ' n 10 per cent* hydroc hloric acid. I his, however, is no more than a con- 
* r.i; ^**(<1 in multiple* «f '' u. • ’ll.- .•.*.:.*;. r-juin-l ar ( . : alinity determination was 
14 01 
