Instrument Makers:  Ainsworth & Brunton

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Article taken from "Backsights" Magazine published by Surveyors Historical Society


by Dale R. Beeks

William Ainsworth was the founder of the Wm. Ainsworth Company which was in existence in Denver, Colorado, from 1880 through 1905.  The name was changed to Wm. Ainsworth and Sons in 1905 with the inclusion of his sons Robert and Alfred.

William Ainsworth immigrated to American at the age of 3 in the year 1853.  As a young man he became a master watchmaker for the Elgin Watch Company.  In 1874 he settled in Central City, Colorado, where he became recognized as a specialist watch repairman; repairing complicated Swiss repeater watches.  His repair skills brought him close to the circles associated with mine assaying, repairing the many English-made precision balances.  This association, and his knowledge of fine machine work soon developed into the production of precision balances.  Ainsworth's first balance was built in 1879.  The company's products soon became the standard for Assayers.  

Sometime during the late 19th Century, William Ainsworth Company began the manufacture of fine surveying instruments.  A 1905 Wm. Ainsworth & Sons catalogue states that his familiarity to the watch making trade,... "which is unequaled by any industry in the world for systematic accuracy, factory methods and results"... has prepared his company to produce the finest of instruments.  In 1907 the company built a precision circular dividing engine.

On September 18th, 1894, D. W. Brunton was granted a patent for his "Pocket Transit".  Brunton devised the combination instrument to serve for the necessary survey work required for commercial and legal mine-examinations.  The sole manufacturer for the patent instrument was the Wm. Ainsworth Company.  Brunton states in an account dated 1905, that the instrument was in use, "from Australia to Alaska".  He also notes that the instruction of the instrument was taught at ... "Lawrence Scientific School, Harvard University, Columbia University, and a number of western mining schools'.  At that time, neither Brunton or Ainsworth could have realized, that the success of the combination instrument was only just beginning to realize its potential; to date, almost 100 years of production and use.  William Ainsworth died on January 1st, 1917.  The company of Wm. Ainsworth & Sons continued the manufacture of Surveying instruments until 1938.



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