Mercury Manometer

Astronomy

Accession Number: 2019.ast.131 (DAA-0004)

Description:

This is a glass instrument attached to an upright wooden frame set in a rectangular wooden base. The glass instrument consists of a ‘u’-shaped tube, the left arm of which is full of mercury which sits in the base of the ‘u’ to the base of the right arm, where the inner diameter of tube appears to narrow. Resting on top of the mercury or where the tube narrows there is a small round ball.

The right arm of the ‘u’ rises vertically to the same height of the left arm, and then turns down again, forming a second inverted u-shape. At the base of this third vertical arm there is a glass tap seal. Below this the tube diverts left and right into a horizontal tube that is open at each end.

Between the arms of the ‘u’ filled with mercury, there is a metal scale mounted vertically. This is graduated in tenths and labelled in integers up from a 0-mark in the middle. This is mounted to a separate wooden strip which allows the scale to be raised and lowered by means of a wooden handle at the top.

There is a yellow label stuck to the front of the wooden base.

Alternative Name: Barometer

Primary Materials:

Glass, Wood, Metal: Iron Alloy, Metal: Mercury

Markings:

On the yellow label: “PMT TAMSON
ZOETERMEER – HOLLAND”

Scratched into the glass at the tap seal: “60”

Dimensions (cm):

Length = 16.5, Width = 9.3, Height = 32.3

Function:

This instrument can be used to measure changes in pressure.

Condition:

Very Good: The base of the object is very stained, apparently with water. This has affected the staining of the wood, particularly around the bottom surface and left-hand side of the base. The wood of the rest of the stand is in good condition. The glass and scale are in good condition except below the closed tap seal, where the glass is broken. Here, the glass is broken and a piece of clear tape has been added to protect the sharp glass edges.

Manufacturer: Tamson, Zoetermeer, Holland

Date of Manufacture: Late 20th Century

Provenance:

This object was moved from the David Dunlap Observatory in Richmond Hill in 2009, upon the sale of the observatory. They were stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.