TO THE

Academie des Sciences

OF

L' Institut De France

THE UNIVERSALLY ACKNOWLEDGED

LEADER OF THE WORLD

IN ALL LINES OF SCIENTIFIC THOUGHT

AS A MARK OF

THE AUTHOR'S GRATEFUL APPRECIATION OF THE

PROUD DISTINCTION CONFERRED UPON HIM

BY FRANCE

THROUGH ADMISSION TO ITS RANKS

ON DECEMBER 16, 1918.

AND AS AN EVIDENCE OF HIS PROFOUND ADMIRATION

AND REGARD FOR THE ENTIRE FRENCH NATION

THIS TREATISE

HIS FINAL CONTRIBUTION IN BOOK FORM

TO ENGINEERING LITERATURE

WITH THE ACADEMY'S KIND PERMISSION

IS MOST RESPECTFULLY

DEDICATED