The present thesis consists of three papers recently
published by His Majesty's Stationery Office in the series of
"Scientific Investigations" issued under the authority of the
Fishery board for Scotland. The inclusive title and the subtitles
of these papers appear on the respective title-pages and
are given in the foregoing contents table. The relationship
of the inclusive title to that under which this thesis is
presented is discussed in the concluding chapter of the thesis.
Appended to the above publications are two shorter papers,
one of which has also been published, the other having been
communicated on behalf of the writer to the body named on the
title-page. All five papers are original in form and in subtance, the work having been performed at the Marine Laboratory
of the fishery Board for Scotland in Aberdeen, under the supervision
of the Board's Scientific Superintendent, Alexander
Bowman, D.Sc., F.R.S.E., on whose initiative the experiments
dealt with in the main body of the thesis were carried out.
The experiments in question consisted in the liberation of
large numbers of specially-prepared, floating bottles, from
numerous widespread points in the Northern and Middle North Sea,
the southern reaches of the Norwegian Sea and the Faroe-Shetland
Channel. Primarily, they were designed to yield information of
consequence to marine biological research in connection with
the Northern North Sea fisheries and, already, the results so
far obtained have been of service in this direction. It may
be added that, along with the liberation of drift-bottles,
physical observations of the temperature and salinity of the
sea water were taken at practically every 'liberation-station'
and this material is presently forming the subject of a separate
study to which the drift-bottle interpretations are proving a
valuable asset.
From the biological standpoint the original aim of the drift-
bottle work was to obtain an understanding of matters relative
to the passive transport of fish eggs, larval forms and indeed,
all plankton. Physically, therefore, its immediate objective
was the elucidation of surface water movements in the above areas,
or, more specifically, the measurement of the quantity generally
referred to as the surface drift*, in its chief characteristics
of direction and velocity. A definition of the term 'surface
drift' is given in the concluding chapter to the thesis.
From the biological standpoint the original aim of the drift-
bottle work was to obtain an understanding of matters relative
to the passive transport of fish eggs, larval forms and indeed,
all plankton. Physically, therefore, its immediate objective
was the elucidation of surface water movements in the above areas,
or, more specifically, the measurement of the quantity generally
referred to as the surface drift*, in its chief characteristics
of direction and velocity. A definition of the term 'surface
drift' is given in the concluding chapter to the thesis.
As submitted, the main thesis consists of two parts.
Part I is a statistical treatment, on fairly broad lines,
of the data pertaining to the five years, 1910 to 1914 inclusive and is in the nature of an introductory to Part II.
The latter comprises two sections, of which the first is
a detailed analysis, on a cartographical basis, of the results
of the 1910 liberations and the second, a similarly exhaustive
study,of the 1911 data. In oruer to complete ?art II on
the lines originally laid down in accordance with the exigencies
of departmental economy, three more sections remain to be
published at intervals, as circumstances allow. For the
purposes of this thesis, however, the three n papers now
presented form a complete whole in so far as the analyses of
the materials for the two years above-mentioned have resulted
in new knowledge which has been taken to a definite climax
and much of which is remarkably corroboreted within these
pages, This last circumstance also bespeaks the wider
applicability of these analytical results than as representative merely of the two years in question.
Consequent upon the necessity of publishing this work
in sections, each memoir, as it appeared, was concluded with
a summary chapter based on the results obtained from each
analysis, in a final chanter to the present thesis these
results and especially their significance are discussed with
somewhat greater latitude, introducing certain ideas conceived in the course of this investigation and pointing the
way to further research.
