85. Circular protractor by J. Ramsden
England, second half of XVIII cen.
Jesse Ramsden (Halifax 1735-Brightelmstone 1800)
diameter 20.2 cm, length of bar 16.3 cm
[Inv. MdS-72]

This circular protractor was made by Jesse Ramsden, one of the best precision instrument makers of the second half of the XVIIIth century and designer of the first dividing machine that could work the limbs of small diameter circles with great accuracy. The whole circumference of the protractor is divided into degrees and the vernier is divided into 20 parts.
M. Daumas (1953), pp. 264, 318.
E. Miotto, G. Tagliaferri, P. Tucci, p. 113.
J.A. Repsold (1908, 1914).