Early North Coast Scientific Instruments

c. 1850 – c. 1950

Richard Paselk, Curator

Measuring the Land and its Wealth

A wide variety of instruments have been used to survey land and estimate the value of resources. On display are a classic American surveying instrument, the Vernier Surveyors Compass and a more recent instrument to value Timber, a Timber Estimator.

Though a resident of Minnesota, Clinton Walker, the inventor of the Timber Estimator, designed his device for the “Pacific Slope, [where] the trees grow large and to a great height…” and it is difficult to find the number of logs a given tree will give. As described in the patent, the device is very easy to use as well as a convenient size to carry into the woods.

Vertical sights for aiming at distant objects characterize the surveyor’s compass. It was designed around 1600 for colonial use where land was plentiful—Ireland and, by the 1750’s, America. The Vernier Surveyor’s Compass is in an American invention, adding a variation arc and vernier to enable surveyor’s to accurately compensate for magnetic variation. David Rittenhouse, clock and instrument maker, renowned man of science and patriot, made one of the earliest c. 1780. John Roach (1813–1891) made the displayed instrument. Born in Ireland, he was listed as a “philosophical instrument maker” in New York City in 1833. He continued working independently, then in partnership with Henry Warner, then again on his own as an optician and maker of surveying instruments until he moved to San Francisco in 1855. Within a short time John Roach was the leading West Coast instrument dealer. S.W. Foreman*, U.S. Deputy Surveyor, used this compass while doing a survey in Humboldt Co. in August of 1874 ("Humboldt Meridian Range"). The compass was given to A. A. Hadley for his assistance on the survey. Hadley was a Humboldt pioneer and one of the original settlers in the Mattole Valley, arriving in 1852.

* A quick internet search turns up a variety of surveys performed by Foreman in California and other Western States in the second half of the nineteenth century.

© R. Paselk 2013, Last modified 31 December 2020