Excerpt from The American Journal of Science and Arts, 1870, Vol. 99: Nos. 145, 146, 147 Alexander von humboldt was born in Berlin on the 14th of September, 1769, and died there on the 6th of May, 1859, in the ninetieth year of his age. A rapid sketch of his youth and early manhood will serve to show how well he prepared him self, single-handed, to accomplish so much; more even than most of the learned academies of which he was a member, and certainly not less than any of the great V0 ages of Discovery, and celebrated Exploring Expeditions con ucted at the puhko expense. The course pursued with him was so peculiar, and contrasts so completely with the usual course of training in the colleges of this country, even in the scientific departments, that no dpains have been spared to render this account as complete an exact as possible. Unroll the scrolls of biography and no name will be found a bri hter example to stimulate, encour age and direct the youthful student than that of Humboldt. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Excerpt from The American Journal of Science and Arts, Vol. 100: July, September and November, 1870 In the experiments °ust detailed the highest average sensitive ness of the eye is o y rim while as before shown in practical use the average difference from the mean is less than 35 3 of the whole. This higher degree of accuracy results naturally from the mode in which the com ensations are made, (alternately by approach and recession, ) an the fact that the compensations are t us interwoven, in such a manner as to eliminate errors intro duced by the slightly varying sensibility of the eye. Experiments on the amount of light transmitted by plates of glass at a perpendicular incidence. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.