A gravity instrument is housed within two nested cylindrical cases (2023.ph.871.1). An additional aluminum platform (2023.ph.871.2) is included with the instrument.
2023.ph.871.1: The gravimeter consists of a polished cylindrical case. This is oriented horizontally. A dull grey base features three adjustable feet. Two handles of the same colour and material as the base are located at the upper portion of the instrument.
A plastic battery holder is attached to the perimeter of the instrument with two large zip ties. This holds two cylindrical D cell batteries that have been removed from the instrument and paced in a Ziploc bag.
The instrument is topped by a circular black console that features a number of elements including a microscope ocular for viewing the inner mechanism, a removable illuminator, a window for viewing an inner bubble level, and an adjusting element with a knurled knob.
The instrument is stored in two nested metal containers. Both are cylindrical in form with removable lids that are held in place by three butterfly latches. There are handles at the top centre of each lid.
The inner container has a fabric cushion at its inner base as well as a bungee-like cord arranged in a triangular fashion at the centre of the interior. A ring-like cushion is placed around the top of the instrument for storage to hold it in place when the inner lid is closed.
The outer container has three fabric cushions, oriented vertically around its inner perimeter, for securing the inner container in place. There are additional fabric cushions on the bottom inner surface and lining the bottom of the removeable lid.
2023.ph.871.2: A circular aluminum platform was acquired along with this instrument. The top surface of this platform is slightly concave. This has three tapered legs around its perimeter as well as three elements with holds, one of which has a length of cord attached. Two plastic disks , joined at two points with wire, have been fixed to the top surface of the platform with duct tape. The purpose of this platform is probably to provide a surface for positioning the instrument in the field. The purpose of the plastic disks is unclear.
Accession Number: 2023.ph.871.1-2
Worden-type Gravimeter, Unstable or Astatic Gravimeter
Primary Materials: Iron Alloy, Aluminum Alloy, Plastic
Stenciled in red paint on the surface of the outer container: “HANDLE WITH CARE// DELICATE INSTRUMENT”
“SHARPE INSTRUMENTS// OF CANADA LIMITED// DOWNSVIEW, ONTARIO”
Written in dark ink on a paper label surrounded by black tape: “PROPERTY OF// GEOPHYSICS// DEPT OF PHYSICS// UNIVERSITY OF TORONTO// TORONTO, ONTARIO// M5S 1A1”
Written in black in on a white adhesive label: “To: W.M. Schwerdtner// Geology Dept// University of// Toronto”
A paper label taped to the top surface of the lid includes the following information: “MESSAGE FOR Hall[s?] WHILE YOU WERE OUT// Mr. Sodin// OF Gravity Meter// PHONE NO. 1-905-886-8632″// Date 2/10 Time 2:00”
Written in faded dark in on he lid of the outer container: “GRAVIMETER”
Several other adhesive labels are damaged or obscured.
A damaged label reads, in part: “TRANSAIR LIMITED [?????] LAKE”
Stenciled in red pain on the surface of the inner container: “HANDLE WITH CARE// DELICATE INSTRUMENT”
“SHARPE INSTRUMENTS// OF CANADA LIMITED// DOWNSVIEW, ONTARIO”
“THIS SIDE UP”
A black and silver maker’s label on the surface of the instrument reads as follows: “GRAVITY METER CG-2// SERIAL No 205-G// SHARPE INSTRUMENTS OF CANADA LIMITED”
Outer Case: Height = 65 Max Diameter = 34.5; Gravimeter Instrument: Height = 41, Width = 19, Length = 19; Platform (2023.ph.871.2): Height = 9, Max Diameter = 22.5.
Gravity meters are used to measure the gravitational field at a given location. They are commonly used for geophysical field work.
The gravimeter instrument appears to be functional. It is in good cosmetic condition with small patches of dirt and old adhesive on its outer surface. The finish on various exposed edges is worn. The batteries have been removed from the battery compartment to prevent damage.
Sharpe Instruments of Canada Limited, Toronto, Canada.
Date of Manufacture: c. 1961 – 1967.
This item was acquired February 1st, 2023 from the Physics Learning Service of the University of Toronto Department of Physics.
The instrument was likely used by geophysicist Allan Spector when he took part in a survey of piercement structures found on the Queen Elizabeth Islands of the Canadian Arctic Archipelago. Spector was then a graduate student at the University of Toronto Department of Physics. Piercement structures, also known as diapirs, are unusual dome-like geological features.
The study was led by Fried Schwerdtner of the University of Toronto Department of Earth Sciences. The overall survey project is described in Schwerdtner and Clark 1967. The gravimetric study is described in Spector and Hornal, 1970.
This instrument was later used in student instruction at the University of Toronto undergraduate applied geophysics program. In an email message on March 17, 2023, Professor Emeritus Henry Halls wrote, in part:
“My familiarity with the gravimeter, is that it was used in my undergraduate applied geophysics program, approximately from the late 70’s to the late 80’s. It played a major role as a class exercise in helping to locate a buried valley that can be seen outcropping on the eastern side of a stream valley just west of the E-W road along which the survey was located. If I recall correctly the road was at the extreme western end of Burnhamthorpe road just before it ends at the valley. About ten students were in the class of 1976 and ever since that time we have assembled at the PDAC for an evening meal. All of them clearly remember the gravity survey and I think it had a major impact on the students’ lives because more than half of them later went on in careers in geological/geophysical consulting. After the course ended due to insufficient student numbers the gravimeter resided in my paleomagnetism laboratory (along Principals road at UTM), until the lab was closed in 2019, at which time it was returned to the St. George Physics department, still in perfect condition. “
W. M. Schwerdtner and A. R. Clark. “Structural Analysis of Mokka Fiord and South Fiord Domes, Axel Heiberg Island, Canadian Arctic.” Canadian Journal of Earth Sciences 4, no. 6 (1967): 1229–45.
Allan Spector and Robert W. Hornal. “Gravity Studies over Three Evaporite Piercement Domes in the Canadian Arctic.” Geophysics 35, no. 1 (1970): 57–65.
Gravimeters have traditionally been used in the application of gravimetry to the exploration and discovery of oil and minerals throughout the world both historically and presently. They have been alternatively referred to as gravity meters historically.
The Worden gravimeter was patented in the United States in the mid 1950s. In the 1960s, E.J. Sharpe Instruments of Canada Ltd. (later Scintrex Ltd) began producing Worden-type gravimeters. Wolf Sodin, a scientific glassblower who build the mechanism for the Scintrex instruments, later started his own company.
- Donated to UTSIC