THE VOYAGE OF H.M.S. CHALLENGER. 
20 
T> i . *m } •. i r tli< results with Porch hammer’s, we must adopt Ins mode of stating 
them, that is with reference to 100 parts of chlorine. We then obtain: — 
Dittmar. 
Forchhaminer. 
Chlorine, ...... 
100 
100 
Oxygen equivalent of the chlorine, 
(22-561) 
Sulphuric acid, ..... 
11-576 
11-88 
Lime, ...... 
3 053 
293 
Magnesia, ...... 
11-212 
11-03 
Potash, ...... 
2-405 
1-93 
Soda, ...... 
74-760 
not determined. 
“Total salts,”* ..... 
180-445 
181-1 
It is |" rhaps as well to state that both with Forchhammer and myself “chlorine” 
i in- “ i«>t nl halogen calculated as chlorine ; ” the only difference being that lie weighed 
; ii.ilo-j.-u i' haloid of silver, and from the weight calculated the “ chlorine ” as if the 
pr ■ pit ate had been pure chloride — using, as it seems from his paper, the ordinary 
i mil • i A_ 108, Cl 35f>, whereas I determined the total halogen by titration with 
iver olution, using Stas’s values, and multiplied the number of equivalents of halogen 
thu ' it ctly ascertained by Stas’s Cl = 35'4G. I may also state on this occasion that 
I ib'i ■' jueiitly found reason to correct my values for the lime and the soda and for the 
. ■ i ii </'"i n d chlorine. My final numbers will be found at the end of the chapter on 
Alkalinity. 
I. • n-j ~;dr tin* potash, for whose determination Forchhammer used an unsatisfactory 
ni' t!i"d. hi- n -ult- and mine show a fair degree of agreement, although Forchhammer’s 
i ■ II i • lrr to surface waters, while the majority of my 77 samples came from more 
or lens considerable depths. 
\\ h'-n w. compare the percentages of the several components with the respective 
! • ii . W' fr-quently meet with differences which lie decidedly beyond the probable 
! u t- of the analytical errors; hence, the variations must be owing partly to natural 
. I ii fort unately, whatever these causes may be, they must in their effect on the 
• r L. presumed to be, to a certain extent, of the nature of observational errors, and, 
‘ ' ■ stent they are in our reports inseparably entangled with the analytical errors. But 
1 .-» tangible surplus, and I thought I should not leave this part of my subject 
- h iving at h i-t made an attempt to represent the several numerical items of my 
• functions of either the geographical position or of the depth from which the 
r. -j-.riv. w;it»T- wen- talo-tL Being more hopeful in the former direction, I began by 
’ i>‘\ 1 1 d \ ■ a< ' "iding to certain districts of the ocean, and averaging the per- 
** • : • hh’riic dplmric acid, &<•., for each group; but I did not arrive at satisfactory 
t' • r ' ' ' in- •:.» total nnd l>w« li< re r<- j*ort« <1 ; in Forclihaiutner’a the name phut his “Silica, &c.’’ 
(mm 
