468 
THE VOYAGE OF H.M.S. CHALLENGER. 
105. Manganese Nodule (external portion). — Station 252. 
Lat. 37° 52' N., long. 160° 17' W., 2740 fathoms (Brazier). 
. 15-20 
. trace 
4-50 
. 16-92 
mere trace 
. 25-48 
0-58 
3-58 
2-27 
9-20 
2-10 
0-90 
0-65 
0-20 
. 18-42 
100-00 
106. Manganese Nodules. —Station 252. 
Lat. 37° 52' N., long. 160° 17' W., 2740 fathoms (Dittmar). 
The nodules had a brown or brownish black colour, and, in size and shape, were pretty much like potatoes. 
They were easily broken by the hammer, and were then seen to consist of a clay-like nucleus enclosed in con- 
centric layers of dark coloured matter, the degree of blackness increasing with the distance from the centre. 
In some cases, how-ever, the whole of a section was found to he almost uniformly black. My work was 
limited to exhaustively determining the elementary composition of the nodules, and to trying to ascertain, as 
far as possible by chemical methods, the state of combination of the several elements present. In the latter 
connection I proposed to direct my attention more particularly to the manganese, and to ascertain whether that 
metal is present altogether as binoxide, or partly, if not wholly, in the form of lower oxides. 
Portion 
soluble 
Acid 
in Hydrochloric ) 
= 62-53 I 
Portion insoluble in Hydrochloric \ _ 
Acid = 22 -27 J 
Loss on ignition after di-ying at 230° Fahr., 
Copper, 
Alumina, 
Ferric oxide. 
Calcium phosphate, 
Manganese oxide. 
Calcium sulphate, . 
Calcium carbonate. 
Magnesium carbonate. 
Silica, 
f Alumina, 
I Ferric oxide 
Lime, 
Magnesia, 
I Silica, 
Qualitative Analysis. 
To obtain a true average sample of the nodules, it would have been necessary to pound finely and 
thoroughly mix the entire stock, but I did not consider myself justified in taking this course ; I therefore satis- 
fied myself with selecting a few nodules and pounding these. The powder was well mixed and preserved 
as “ substance to be analysed.” A preliminary trial showed that the substance gave up to boiling water nothing 
but small quantities of chlorides and sulphates^ (which I thought might safely be put down as sea-water solids), 
and besides showed that the filtration of the aqueous infusion was a very tedious process. Hence, in pro 
ceefling to the actual analysis (which was executed with 100 grms. of substance), the turbid liquid obtained in 
extracting the small portion of substance soluble in water was simply poured away. The residue was next 
digested in the cold in acetic acid of 25 per cent, until the carbonates of lime and magnesia and substances of 
a similar nature could be assumed to be dissolved, and the residue collected on filters and washed with water. 
This ofieration was not attended with any visible evolution of gas, which, however, does not prove the absolute 
alienee of carbonates in the substance. The acetic acid extract was evaporated to dryness and the residue 
(5-23 grma) analysed. Qualitative teats showed the presence of considerable quantities of lime, magnesia, and 
soda, a little alumina, and traces of iron, copper, and chlorine. There was absolutely no manganese, which 
' The aqueous extract contained no lime salts, showing the absence of sulphate of lime. 
