Established by Edward L. Youmans APPLETONS' POPULAR SCIENCE MONTHLY EDITED BY WILLIAM JAY YOUMANS VOL. LV MAY TO OCTOBER, 1899 NEW YORK D. APPLETON AND COMPANY 1899 COPYRIGHT, 1899, BY D. APPLETON AND COMPANY. [Illustration: THOMAS EGLESTON.] APPLETONS' POPULAR SCIENCE MONTHLY. JUNE, 1899. NEW METHOD OF ESTIMATING THE AGE OF NIAGARA FALLS. BY G. FREDERICK WRIGHT. Both the interest and the importance of the subject make it worth while to follow out every clew that may lead to the approximate determination of the age of Niagara Falls. During this past season, in connection with some work done for the New York Central Railroad upon their branch line which runs along the eastern face of the gorge from Bloody Run to Lewiston, I fortunately came into possession of data from which an estimate of the age of the falls can be made entirely independent of those which have heretofore been current. The bearing and importance of the new data can best be seen after a brief _résumé_ of the efforts heretofore made to solve this important problem. [Illustration: FIG. 1.--Looking north from below the Whirlpool, showing the electric road at the bottom of the east side of the gorge, and the steam road descending the face about halfway to the top.] In 1841 Sir Charles Lyell and the late Prof. James Hall visited the falls together; but, having no means of determining the rate of recession, except from the indefinite reports of residents and guides, they could place no great confidence in the "guess," made by Sir Charles Lyell, that it could not be more than one foot a year. As the length of the gorge from Lewiston up is about seven miles, the time required for its erosion at this rate would be thirty-five thousand years. The great authority and popularity of Lyell led the general public to put more confidence in this estimate than the distinguished authors themselves did. Mr. Bakewell, another eminent English geologist, at about the same time estimated the rate of the recession as threefold greater than Lyell and Hall had done, which would reduce the time to about eleven thousand years.