IS 
THE VOYAGE OF H.M.S. CHALLENGER. 
\ : . 1 1 1. >ri . ■ ciil with the steam. The base thus liberated should certainly con- 
sist partly of lime, and this lime might have combined with the free carbonic acid of 
r f the atmosphere. The question, I thought, and still think, is answered in 
the affirmative, as * it is proved that, in sea-water, the number of equivalents 
- givater than the number of equivalents of sulphuric and muriatic 
ther. Supposing the existence of an excess of base to be proved, that 
- mint • • nsi.-t of carhoiiatrs, and these must include carbonate of lime. A more 
direct solution of the problem is simply impossible in the present state of science. 
11 thing 1 felt convinced of from the first, namely, that the routine method adopted 
in mineral salt anal} .. the elimination of the lime and magnesia, and subsequent joint 
* I' el -»f soda and potash as sulphates or muriates, would never give sufficiently 
u Hut I thought 1 might attain my object by an exact determination of the 
' ‘ - dt< (in* aniug the sum total of S0 8 , Cl 2 , Na 2 0, K 2 0, CaO, MgO, minus Oxygen- 
equi ’• • of the chlorine), and caused Mr. .Johnston to try a number of methods which 
1 I worked out for the purpose. Unfortunately the total salts in sea- water cannot be 
determined by mere evaporation to dryness and weighing of the dried residue, on 
unit of the instability of tin* chloride of magnesium in the presence of water at high 
*• mj» r.»tur< -. To prevent this dissociation — or as one might call it “loss of anhydrous 
muriatic acid " (C1 S H 2 — H 2 0 = C1 2 — 0) — we tried successively, with synthetically prepared 
solutions, the addition of weighed quantities of normal chromate of potash, tri-sodic 
1’ ; • • * 1 1 • , nd oxide of mercury ; hut we never succeeded in obtaining sufficiently 
m • nt r Milt-. As a last resource, and for obtaining at least an apology for the 
we att* mpted a determination of the total bases as sulphates, and, without 
■ " "bt lined Mirprisingly constant results. The modus operand! adopted was as 
follows : — 
^ fax mixed with rather less than the calculated volume 
’■ - -t nidanl -olution of sulphuric acid, and next evaporated to dryness, first on a 
water-hat h, then on an air-bath, in a platinum basin pro- 
vided with a perforated lid; the perforation being more 
than shielded by a circular platinum plate welded on to 
the under side of the lid, as shown by the figure (fig. 1). 
After the last trace of acid had been expelled at a dull 
red heat, over a naked flame and with the help of an 
rM. I. — Sactioa of PUUaui flsrfn 1 
auxiliary flame playing on a piece of platinum foil laid 
the r« -idm was weighed. A lit tip more vitriol was then added, and 
* * ; I the appearance of heavy sulphuric acid vapours, and sub- 
v of the weight after repeated exposure to dull redness, proved 
** '1 f - < 1. .in. ily n ; tint in the lout series increased it to 20 c.c. I do not 
lW>k UmI ifc* ' Lug* add'-l much to tbe precision. . 
