by Carnegie Library of Pittsburgh

1908

by Carnegie Endowment for International Peace

1921

by Carnegie Institution of Washington. Department of Terrestrial Magnetism

1905

by Carnegie Endowment for International Peace

1913

by Carnegie Foundation for the Advancement of Teaching

1909

by Carnegie Foundation for the Advancement of Teaching

1921

by Carnegie Library of Pittsburgh

1913

by Carnegie Institute

1898

by Carnegie Foundation for the Advancement of Teaching

1920

by Carnegie Institution of Washington

1922

by Carnegie Museum of Natural History

1900

by Carnegie Museum

1898