4o6 
THE VOYAGE OF H.M.S. CHALLENGER. 
53-29 
3-84 
7-08 
14-86 
9-31 
7-81 
0 - 31 
2-57 
1 - 69 
100-76 
82. Basic Volcanic Glass. — Station 285. 
Lat. 32“ 36' S., long. 137° 43' W., 2375 fathoms (Sipdcz). 
I. 1-0841 gnus, of substance, fused with the carbonates of soda and potash, gave 0-5417 grm. of silica, 0-1543 
grm. of ferric oxide, 0-1267 grm. of alumina, 0-1215 gi-m. of lime, 0-3864 grm. of pyrophosphate of 
magnesia = 0-1392 grm. of magnesia, and 0-0056 grm. of pyrophosphate of magnesia = 0-0036 grm. of 
phosphoric acid, and trace of manganese. 
II. 0-5185 grm. of substance, treated with hydrofluoric and sulphuric acids, required for oxidation 9-4 c.c. 
permanganate of potash solution (1 c.c. permanganate of potash solution = 0-0058463 grm. of ferrous 
oxide), corresponding to 0-05495 grm. of ferrous oxide. 
III. L0448 grms. of substance, treated with hydrofluoric and sulphuric acids, gave 00357 grm. of the 
chlorides of soda and potash, 0'0137 grm. of chloroplatinate of potash. The finely pulverised scoria, 
l)a.ssed through fuming hydrochloric acid, was but incompletely decomposed. 
Silica, 
Alumina, . 
Ferric oxide. 
Ferrous oxide 
•Manganous oxide, 
Lime, 
Magnesia, 
Potash, . 
.Soda, 
Phosphoric acid, . 
100-92 
11-68 
2-45 
10-60 
trace 
11-20 
12-84 
0 - 25 
1 - 60 
0-33 
Silica, 
Ferric oxide. 
Ferrous oxide. 
Alumina, 
Lime, 
Magnesia, 
Potash, 
Soda, 
AVater, 
83. Palaqonite. — Station 276. 
Lat. 13° 28' S., long. 149° 30' \V., 2350 fathoms (Dittmar). 
.\ brown, apparently amorphous, substance, some of it powdery, some in lumps, which when broken exhibited 
.a dirty-white fracture. The microscope showed white and yellow crystalline parts, and here and there 
black globule.s, also a few metallic-looking particles. Having been led to understand (by Mr Murray) that 
there were good grounds for looking ui)on this substance as disintegrated “ pumice,” and knowing that 
pumice is in a very high degree proof against the action of even strong acids, it struck me that the 
pro|)cr mode of investigating this substance was to extract from it all that could be rendered soluble by 
successive treatment with a (a) hot hydrochloric acid, (6) boiling carbonate of soda solution, (c) semi-con- 
centrated Ixiiling vitriol, (tl) boiling carbonate of soda solution ; to analyse the ultimate residue, and coin- 
jmre the results with reliable published nnalyses of pumice or obsidians. This lino of research was 
accordingly adojited ; but not wishing to rely altogether on second-hand information in this respect, an 
undoubted specimen of pumice from the Challenger collection was examined in precisely the same 
manner. 
