Colloquium publications.

PREFACE.

ix

II. THE CAMBRIDGE COLLOQUIUM, 1898.
(a) Professor WILLIAM F. OSGOOD, of Harvard University:
"Selected Topics in the Theory of Functions."
This colloquium was published in the Bulletin of the
Amer. ]iath. Soc., ser. 2, vol. 5 (1898), p. 59.
(b) Professor ARTHUR G. WEBSTER, of Clark University: "The
Partial Differential Equations of Wave Propagation."
III. THE ITHACA COLLOQUIUM, 1901.
(a) Professor OSCAR BOLZA, of the University of Chicago: "The
Simplest Type of Problems in the Calculus of Variations."
Published in amplified form under the title: Lectures on
the Calculus of Variations, Chicago, 1904.
(b) Professor ERNEST W. BROWN, of Haverford College: Modern Methods of Treating Dynamical Problems, and in Particular the Problem of Three Bodies."
IV. THE BOSTON COLLOQUIUM, 1903.
(a) Professor HENRY S. WHITE, of Northwestern University:
three lectures on "Linear Systems of Curves on Algebraic
Surfaces."
(b) Professor FREDERICK S. WOODS, of the Massachusetts Institute
of Technology: three lectures on " Forms of Non-Euclidean
Space."
(c) Professor EDWARD B. VAN VLECK, of Wesleyan University;
six lectures on " Selected Topics in the Theory of Divergent
Series and Continued Fractions."
This colloquium is here published in full.
At Commencement, 1903, Professor John Monroe Van Vleck,
M.A., LL.D., completed his fiftieth year of service at Wesleyan
University, and retired shortly after from the chair of Mathematics