T HE THIRD in the series of the Isaiah Bowman Memorial
Fund lectures was delivered by His Excellency Hans
W:son Ahlmann on August 13, 1952, as the principal ad-
dress at the meeting of the Seventeenth International Geo-
graphical Congress in Washington, D. C. The original
text of "Glacier Variations and Climatic Fluctuations"
has been augmented for publication by additional data
and references to serve as a summary of the author's latest
thinking on the subject. It brings together the findings
of the human and physical geographer, the geomorphol-
ogist, the climatologist and even the historian. Dr. Ahl-
mann has been Professor of Geography at the University
of Stockholm, and from 1948 to 1951 served as President
of the Commission on Snow and Ice of the International
Association of Hydrology (I. U. G. G.).

Dr. Ahlmann, now serving his country as Sweden's
Ambassador to Norway, has for two decades been the
leader in the work of relating changes in glaciers to
climatic fluctuations. His concept of the need for collabo-
ration between sciences--the team approach--and the ne-
cessity for initiating detailed observations to achieve a
better understanding of glacier regimen has changed the
whole scope of glaciology. He has pioneered in developing
methods for making precise measurements of accumula-
tion and wastage from which to determine a glacier's econ-
omy or hydrologic balance. These techniques not only
provide means of learning more about glaciers themselves,

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