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This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Jacobus C. Kapteyn (1851-1922) was a Dutch astronomer who contributed heavily to major catalogs of star positions, such as the Cape Photographic Durchmusterung and the Harvard-Groningen Durchmusterung, and arranged extensive international collaboration through his Plan of Selected Areas. He contributed to the establishment of statistical astronomy and structure and dynamics of the Sidereal System. All aspects of Kapteyn’s life are discussed, from his birth in Barneveld, the Netherlands, to his death in Amsterdam, and his entire resume of scientific achievements in between. Kapteyn had some conflicts with others in his field, especially after the world became divided on how to handle scientific contributions from Germany post-World War I. Both Kapteyn's struggles and achievements are written against the backdrop of both the historical context of the world at that time as well as the scientific one.

"Letters to the Editor" issued as Part 2 and separately paged from v. 148, 1967.