Produced by Chris Curnow, Louise Pattison, Joseph Cooper and the Online Distributed Proofreading Team at http://www.pgdp.net [Transcriber's Notes: This is Paper 42 from the Smithsonian Institution United States National Museum Bulletin 240, comprising Papers 34-44, which will also be available as a complete e-book. The front material, introduction and relevant index entries from the Bulletin are included in each single-paper e-book. The Sections entitled "Alba F. Smith" and "Seth Wilmarth" appear in the original as boxed "side bars". They have been moved, along with Figure 13, from their original locations to the end of the paper to preserve the flow of the text. Typographical errors have been corrected as follows: p259: "as late as 1880 and has been under steam" (was stream). p267: "made with parabolic reflectors" (was parobolic).] SMITHSONIAN INSTITUTION UNITED STATES NATIONAL MUSEUM BULLETIN 240 [Illustration] SMITHSONIAN PRESS MUSEUM OF HISTORY AND TECHNOLOGY CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY _Papers 34-44_ _On Science and Technology_ SMITHSONIAN INSTITUTION . WASHINGTON, D.C. 1966 _Publications of the United States National Museum_ The scholarly and scientific publications of the United States National Museum include two series, _Proceedings of the United States National Museum_ and _United States National Museum Bulletin_. In these series, the Museum publishes original articles and monographs dealing with the collections and work of its constituent museums--The Museum of Natural History and the Museum of History and Technology--setting forth newly acquired facts in the fields of anthropology, biology, history, geology, and technology. Copies of each publication are distributed to libraries, to cultural and scientific organizations, and to specialists and others interested in the different subjects. The _Proceedings_, begun in 1878, are intended for the publication, in separate form, of shorter papers from the Museum of Natural History. These are gathered in volumes, octavo in size, with the publication date of each paper recorded in the table of contents of the volume. In the _Bulletin_ series, the first of which was issued in 1875, appear longer, separate publications consisting of monographs (occasionally in several parts) and volumes in which are collected works on related subjects. _Bulletins_ are either octavo or quarto in size, depending on the needs of the presentation. Since 1902 papers relating to the botanical collections of the Museum of Natural History have been published in the _Bulletin_ series under the heading _Contributions from the United States National Herbarium_, and since 1959, in _Bulletins_ titled "Contributions from the Museum of History and Technology," have been gathered shorter papers relating to the collections and research of that Museum.