1044 
THE VOYAGE OF H.M.S. CHALLENGER 
The residue left undissolved by the acetic acid was exhausted with hot hydrochloric 
acid of 20 per cent., the solution filtered, evaporated to dryness, to eliminate the dissolved 
silica, the silica filtered off and weighed. It amounted to 073 grms., i.e., 073 per 
cent, of the original substance. The de-silicated solution was made up to 400 c.c., and 
aliquot portions used for the following experiments. One portion served for a thorough 
qualitative analysis, the results of which are included in the statement of quantitative 
determinations to be given below; but it is perhaps as well to state explicitly that 
lithium, beryllium, and the metals of the arsenic group, although very specially sought 
for, could not be detected. A second portion (25 grms. of original substance) was 
devoted to the quantitative determination of the cobalt, nickel, copper, and lead. A third 
portion was used for the determination of the alkalies. 
The residue left undissolved by the hydrochloric acid amounted to 26 - 3 grms. (dried 
at 100°, but not completely); Of these 26 '3 grms. of matter separate portions were used 
for determining the following components : — (a) the water volatile on ignition ; ( b ) the 
silica which had been rendered soluble by the treatment with hydrochloric acid — it was 
extracted by means of boiling carbonate of soda solution and separated out and weighed 
as usual ; ( c ) the part disintegrable by the method customarily used for the analysis of 
clays, viz., by treatment in the heat with concentrated sulphuric acid, and evaporation of 
the acid from the substance — the silica and alumina thus rendered soluble being deter- 
mined by the usuaL methods. 
Found in the 26 '3 grms. of matter insoluble in hydrochloric acid — 
Water (H 2 0), ...... 
Silica (Si0 2 ), set free by hydrochloric acid, 
Alumina (A1 2 0 3 ),* rendered soluble by sulphuric acid, 
Silica (Si0 2 ), rendered soluble by sulphuric acid, . 
Ultimate residue, ...... 
1-99 
6-74 
1-62 
0-83 
14-91 
Loss, ....... 
26-09 
0-21 
26-30 
As the hydrochloric acid solution had been nearly all used in the numerous qualitative 
trials made,- and the quantitative determinations reported, a special portion of “ original 
substance” (identical with the 100 grms. used for making that solution) was employed 
for determining the alumina, ferric oxide, manganese, lime, and magnesia extractable by 
hot hydrochloric acid. Other portions served for the direct determination of the total 
water and of the total carbonic acid. 
The results are included in the following : — 
* Includes a little oxide of iron. 
