Back Matter Source: The Scientific Monthly, Vol. 56, No. 2 (Feb., 1943), pp. v-vi Published by: American Association for the Advancement of Science Stable URL: http://www.jstor.org/stable/17800 . Accessed: 01/05/2014 14:38 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . American Association for the Advancement of Science is collaborating with JSTOR to digitize, preserve and extend access to The Scientific Monthly. http://www.jstor.org This content downloaded from 130.132.123.28 on Thu, 1 May 2014 14:38:11 PM All use subject to JSTOR Terms and Conditions
Transcript
Back MatterSource: The Scientific Monthly, Vol. 56, No. 2 (Feb., 1943), pp. v-viPublished by: American Association for the Advancement of ScienceStable URL: http://www.jstor.org/stable/17800 .
Accessed: 01/05/2014 14:38
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp
.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].
.
American Association for the Advancement of Science is collaborating with JSTOR to digitize, preserve andextend access to The Scientific Monthly.
http://www.jstor.org
This content downloaded from 130.132.123.28 on Thu, 1 May 2014 14:38:11 PMAll use subject to JSTOR Terms and Conditions
OF THE TOLERANCE SPECIFIED s Illustrated above are the elements of a parfocal ten-inch lens with a focal length of 25 feet. It was specified by the astro- nomical observatory which ordered it, that the lens should be parfocal for the C and K spectral lines, with a maximum differ- ence of 1 millimeter (0.039 inch). As pro- duced in the Perkin-Elmer plant the lens was actually parfocal within a quarter of this tolerance . . . one fourth of one milli- meter (0.010 inch).
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This popular basic text for physical science survey courses is brought completely up to date with the publication of the revised edition. Every important development in the physical sciences is covered including such modern developments as polarized light, synthetic rubber, sulfanilamide, frequency modulation, etc. Each section in the new edition has been checked for accuracy by at least five outside experts.
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