A dial to measure the height of mercury in a barometer
Date
13 January 1698
Creator
Unknown, Artist
Object type
Archive reference number
Manuscript page number
p2
Material
Dimensions
height (page): 297mm
width (page): 184mm
width (page): 184mm
Subject
Content object
Description
Design of a dial to measure the height of mercury in a barometer to one-hundredth of an inch, from a letter from William Derham to Hans Sloane dated 13 January 1698. It was printed in Philosophical Transactions of the Royal Society, vol. 20, no. 237 (1698).
Transcription
This figure representeth the circle and the toothed Ruler, without the interposition of the weather plate, that the contrivance may be the better seen.
AA The Ruler with teeth, made to slide up and down.
b. The little Finger that pointeth to the Mercury’s Height (which is placed higher on the toothed Rule than it ought to be, that it may be seen.)
c.c.c.c. The Index or Dial-wheel.
D.D.D.D. The Circle
e.e. The Index.
Transcribed by the Making Visible project
AA The Ruler with teeth, made to slide up and down.
b. The little Finger that pointeth to the Mercury’s Height (which is placed higher on the toothed Rule than it ought to be, that it may be seen.)
c.c.c.c. The Index or Dial-wheel.
D.D.D.D. The Circle
e.e. The Index.
Transcribed by the Making Visible project
Object history
Printed as fig. 1, barometer, in W. Derham, ‘A contrivance to measure the height of the Mercury in the barometer, by a circle on one of the weather plates, with a register of the weather, etc. for the Year 1697’, Phil. Trans. vol. 20, no. 237 (February 1698), pp. 45-48 (ref. to figure at p. 46).
Related fellows
Associated place