RECORD: Darwin, C. R. CUL-DAR57.130. (John van Wyhe ed., 2002-. The Complete Work of Charles Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Text prepared and edited by John van Wyhe. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volumes CUL-DAR 54-61 contain material for Darwin's book Insectivorous plants (1875).

130

The diameter of a sphere of spec: gr: 1.678  01555 millimètres or 1/65th  64 of a millimètre

The  diam. of a sphere of spec: gr: 1.678 1.658 & weighing 1/20,000,000th of a grain is .0006080  .0006088 of an inch or 1/1638th 1/1644th of an inch

The smallest object visible under the microscope is between .0002 & .0005 millimètres ,that us between 1/5000th & 1/2000th of a millimètre. This object is between 1/77th & 1/31th of the diameter of our sphere    1/5000 mm = .000007074inch  .000003034, 1/2000 mm = .000019635inch

(This is last & final report—)

130v

1/5000 mm = 1/127000 inch

 1 inch = 25.3995

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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

File last updated 30 November, 2025