|Description: Cardboard circular slide rulers. The sliding arm is made of clear plastic and is attached by a metal screw. The rulers are white with numbers printed in five circles around the ruler. The numbers are predominately black although one row is red. “St. Lawrence Starch Company Limited” is printed in blue around the centre in a circular fashion. There is a yellow/gold line running around the outer edge. The back of each ruler has conversions of various measurements radiating out from the centre to the outer edge. An example is “1 Yard = 0.9144 Meters, 35 opp.32”. These measurements are printed in black. Each ruler is in a small plastic bag.
History: The circular slide rule set was a promotional item given out by St. Lawrence Starch Co., Ltd. in Port Credit.
The St. Lawrence Starch Company was founded in 1889 by John Gray. It was a corn wet-milling operation with the purpose of producing starch and glucose from corn. Many of the product lines produced by St. Lawrence Starch are still in use today such as Durham Starch and Bee Hive Corn Syrup. Food products were only a small portion of the business done at St. Lawrence Starch as starch is an additive in many industrial products such as cement and plastic.
St. Lawrence Starch was located at the foot of Hurontario Street at Lakeshore Road in Port Credit. It was a major industry for this area. The milling operation closed down in 1990 due to competition and high tariffs on corn. In 1993 St. Lawrence Starch announced a marketing alliance with Cargill, Minneapolis, which provides Cargill with exclusive sales services of corn sweeteners and corn starches in the Canadian Market. For more information on the St Lawrence Starch Company, see “St Lawrence Starch 100 Years 1889-1989”.