THE 
VOYAGE OF H.M.S. CHALLENGER. 
PHYSICS AND CHEMISTRY. 
REPORT on Researches into the Composition of Ocean- Water collected by 
H.M.S. Challenger during the years 1873-76. By William Dittmar, 
F.R.SS. L. and E., Professor of Chemistry, Anderson’s College, Glasgow. 
I. THE PRINCIPAL SALINE COMPONENTS. 
Sea-water has long been known to consist in the main of a solution of the chlorides 
and sulphates of sodium, magnesium, potassium, and calcium. A quantitative analysis 
which correctly reports these few acids and bases, gives almost as close an approximation 
to the proportion of total solids as it is possible to obtain. And yet, from the fact of the 
ocean being what it is, it follows almost of necessity that there must be numerous minor 
components. Perhaps no element is entirely absent from sea- water ; but according to 
Forchhammer only the following (in addition to the predominating components already 
named) have been proved to be present : — 
Bromine : easily detected in the mother-liquor obtained in the preparation of sea-salt 
by crystallisation. 
Iodine : this element is present only in very minute traces ; its presence until lately 
was only inferred, from its relatively abundant occurrence in the ashes of sea-weeds. 
Fluorine : detected directly ; also found in the boiler crusts of transatlantic steamers. 
Phosphorus : in phosphate. 
Nitrogen : in ammonia, and in the organic matter necessarily diffused throughout the 
ocean. 
(PHYS. CHEM. CHALL. EXP. — PART I. — 1884.) A 1 
