THE VOYAGE OF H.M.S. CHALLENGER. 
, ... i*l i, *n;it * - and free carbonic acid, which, as we shall see, are by no means 
'•.l'-.pi n.ii<- i . >ihjm iin nts ; also as part ol the organic matter. 
Silicon : in silicates. 
/, : , tlv detectable ; found also in the ashes of Zostera maritima and Fucus 
miculosus. 
Siltrr: found by Malaguti in the copper bottoms of ocean-going ships. Forch- 
h ,, m . r f.. ind 1 .1,000, 000th in a coral called Pocillopora alcicornis. 
I. I,- ii., .r- abundant than silver; the coral just named gave to Forchhammer 
eight parts of lead to one of silver. 
found in the ash of Fucus vesiculosus, and of other sea-weeds. The 
. /' - - contains 1 500,000th, the coral Ileteropora 1-350, 000th, of the metal. 
/ prov, d to be present only indirectly by the analysis of the ashes of sea-plants. 
• Z i'll maritima contains ‘035 per cent, of ZnO. 
i Wf >m<l Sickel : found in the ash of sea-plants. 
Iron : easily detected directly. 
1/ ; r- id v detected in the residue left on re-dissolving sea-water solids in 
■a i-- r 5 <> p : - - of dry Zostera maritima gave, to Forchhammer, 81‘4 of an ash which 
contained about 4 jmt cent, of manganese. 
. I : in .duminu, which can be detected by the ordinary methods. 
/ 1 s aiou, i i n I.,- detected directly, and besides have been found in the 
• i h • - of ni irim plants and in oceanic boiler-crusts. 
Arsenic: detected by Daubre. 
I < !*\ I’, zb, in the water of the Adriatic, by spectrum analysis. 
. uid Hold : discovered by Sonstadt. C. Schmidt succeeded in 
d' t. miming the rubnlmm even quantitatively. 
> I "i i ' ii ■ r, who analysed a large number of samples of water from a 
i : 1 ■ , < M tun -water contains, on an average, in 1000 parts by 
. • •• • ( •' t It:-, including 0‘07 to 0‘1 ]»art of insoluble “ residue ” left on 
r> •• ' "btaiiK-d by * vaporation, with pure water. This value, 0 ‘07 to 0T 
- i i -i ii,, .</,/, total of all the minor components. The principal 
: ' : ■ : in, authority, stand to one another on the average in the 
rate** expn-*,**d by the following numbers : — 
Sulphuric Acid. Lime. Magnesia. Potash. 
1 1 ‘8H 2-93 11 03 L93* 
' tb- ■ ratio- are, in passing from one part of the ocean to 
it \ ir it ion . if w< omit (as was done in the calculation of 
* •' 1 * tb' M- dit< rranean, the Black Sea, the Red Sea, the 
u i >, ■ in. tic l! Itic, and coast waters generally. It must be 
* Kmm iiulrvi of North Atlantic waters only. 
