Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB346942A
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Individual
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Individual
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Priority to GB346942ApriorityCriticalpatent/GB551781A/en
Publication of GB551781ApublicationCriticalpatent/GB551781A/en
B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
B43L—ARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
B43L7/00—Straightedges
B43L7/005—Straightedges combined with other drawing aids
Landscapes
Drawing Aids And Blackboards
(AREA)
Length-Measuring Instruments Using Mechanical Means
(AREA)
Abstract
551,781. Protractors. MACLEAN, J. D. March 16, 1942, No. 3469. [Class 97 (iii)] A protractor of rectangular form has provided on two opposite sides of a face a datum mark A and the edges B marked in degrees from 0 degree to 360 degrees. Transverse slots C are also provided adjacent the ends with bevelled edges D showing the degree markings of the complementary angles. A longitudinal slot L may be provided adjacent which are marked suitable scales on both faces.
GB346942A1942-03-161942-03-16Improvements connected with protractors
ExpiredGB551781A
(en)
Fixed-camera technique, used to determine directions of flashing-light beacons in the sky, evaluated in terms of reduction of plates and expected accuracy