10/15/2026
It's time for the next installation of
Hey....... What's That Artifact?
Sorry the October 1st posting was missed but our Curator was out of the Office on a Business Trip. She is back, though, and busy as ever.... but took the time to find us another interesting piece from the Collections here at Drake Well Museum & Park.
DW2003.10.2A-C –
Located in the Drake Well Collections Storage on Shelf 3215, this early 20th Century (sometime around 1919-1925) most likely would have been used by a petroleum engineer or a field technician during well testing and extraction to assess the quality of the oil coming out of the ground….. or by a refinery operator to classify incoming crude oil and determine how it needs to be processed….. or, even yet, by a laboratory analyst or a quality assurance inspector to verify that petroleum products meet precise standard specifications before being sent out for purchase and use by consumers.
A hydrometer is a laboratory instrument used to measure the specific gravity of liquids. The gravity is defined as the relative density which is arrived at a density of that liquid divided by the density of water. Made from a glass material, a hydrometer comprises a long cylindrical stem. There is a bulb that is weighted at the bottom either with lead or mercury to allow it to float upright and lend stability in the water. There is also a scale printed on its side to measure specific gravity. In order to ensure better accuracy, the reading has to be adjusted according to the temperature of the liquid at the time of measurement.
This scale also varies as per the industry application. For instance, the petroleum industry uses API gravity. API gravity is a specific gravity scale developed by the American Petroleum Institute (API) for measuring the relative density of various petroleum liquids, expressed in degrees. API gravity was designed so that most values would fall between 10° and 70° API gravity. The arbitrary formula used to obtain this effect is: API gravity = (141.5/SG at 60 degF) – 131.5, where SG is the specific gravity of the fluid.
A hydrometer is specifically used for measuring low-density liquids such as gasoline, alcohol and kerosene as well as high-density ones such as acids, brine and milk. The only difference is that it will go deeper in high-density whereas it will not be less deep in low-density. During the use, it is placed in the container holding that liquid. The value at the surface of the liquid actually provides the specific gravity of the liquid.
This hydrometer displays the American Petroleum Institute specific gravity scale.
Given by Barbara Zolli in 2003, this artifact would be described in 3 separate pieces: A) the case it is housed in, B) its Lid, and C) the Hydrometer itself. The following are the descriptions of all three, which is how a museum would address all three ‘pieces’ of the donated artifact: A- Case, rectangular, plywood nailed and varnished with cushioning inside of felt, cork and cotton. B- Lid, flat, rectangular piece of plywood with six nailed rectangular pieces of wood nailed inside as flanges. C- Hydrometer, blown glass tube with paper inside with text: "American Petroleum Institute Scale T/2 60º/ 60º F." and on the opposite side are lines and numbers from 10 to 40. This tube flares outward to form a larger tube in which is a rectangular piece of paper "MADE IN U.S.A.", then this tube tapers drastically then flares to form a ball with a pointed end which is filled with mercury.
MAKE SURE TO CHECK OUT DRAKE WELL MUSEUM & PARK’S FACEBOOK PAGE EVERY OTHER THURSDAY FOR A NEW SPOTLIGHT ON AN ARTIFACT IN THE NEW POST SERIES……
“Hey….. What’s That Artifact?”
