418 
THE VOYAGE OF H.M.S. CHALLENGEK. 
hydrochloric acid extracts when volatilised in a powerful electric spark, with and without the use 
of a condenser, and also in the electric arc, failed to give conclusive evidence, and in many cases 
even any indication of the presence of elements which subsequent analysis proved to be present. 
The various products of the preliminary examination were of course examined spectroscopically, and 
by the accurate measurement of the various characteristic lines, positive proof was obtained of the 
presence of a number of elements, which were present in so small quantity that their identification 
at that stage by other analytical methods would have been very difficult if not impossible. 
Amongst these may be mentioned — Lithium, Potassium, Barium, Strontium, Zinc, Thallium, and 
Titanium. Throughout the course of the final analyses spectroscopic measurements were made when- 
ever practicable. The measurements were made with a Dewar and Liveing direct vision spectroscope, 
and in order to obtain the necessary data for the conversion into wave-lengths of the micrometer 
readings of this instrument, careful measurements were made of eighty bright lines characteristic of 
twenty different elements. 
Qualitative Analysis. 
150 grammes of the finely-powdei'ed nodules were boiled in a large new Berlin porcelain basin 
with specially-prepared perfectly pure hydrochloric acid. After prolonged treatment the whole was 
evaporated to dryness, in order to separate any silica which might have gone into solution. The 
dry mass was then moistened with strong hydrochloric acid, and subsequently digested with dilute 
hydrochloric acid, and the solution filtered from the insoluble residue (A), which was thoroughly 
washed, dried, bottled, and weighed. 
Through the solution a current of pure sulphuretted hydrogen gas was passed for two days, after 
which the small precipitate that had gradually formed was collected on a small filter, washed with 
water containing a little sulphuretted hydrogen, dried, bottled, and weighed (B). 
The filtrate from B was boiled to drive off the excess of sulphuretted hydrogen, and after cooling 
mixed with a little sulphuric acid and about one-third of its volume of alcohol. 
After standing for some days the small precipitate which had formed was collected on a small 
filter, washed, dried, bottled, and weighed (C). 
The alcohol in the filtrate from C was then boiled off, and excess of pure oxalic acid added. An 
extremely small precipitate separated out on prolonged standing. It was collected on a small filter, 
ignited. The ignited precipitate weighed little more than one milligramme (D). 
The filtrate from D was nearly neutralised with ammonia, whereupon a considerable precipitation 
took place, accompanied obviously by absorption of oxygen from the air. The precipitate (E) was 
collected on a filter, and washed with hot water. 
A further precipitate (F) was obtained by prolonged exposure of the solution to the air. The 
filtered solution was then acidified with hydrochloric acid, and the oxalic acid present destroyed by 
addition of pure recrystallised potassium permanganate. 
To the solution thus obtained ammonia and ammonium sulphide were added to precipitate the 
metals of the iron group. The bulky precipitate was collected on two large filters, and washed 
with water containing ammonium sulphide. The filtrate was evaporated to dryness in large 
platinum basins, and the residue gently ignited, in order to drive off ammoniacal salts. The residue 
was bottled (G). 
The iron group precipitate was treated in a closed flask with 5 jicr cent, hydrochloric acid, 
prepared by diluting 20 per cent, acid with sulphuretted hydrogen water. After standing two days 
the undissolved residue wa.s filtered off and washed with hot water containing a little sulphuretted 
hydrogen, dried, bottled, and weighed (H). 
