Whiteley Style Quadrant - Trigonometer Made by Danner Circa 1840s

Whiteley patented his instrument in December 1836. In December 1842 Benjamin Hyde Benton of Middleburg, VA was granted US Patent 2,880 “Improvement in Surveying Instruments”. This is basically a trigonometer incorporated into Whiteley’s instrument (and probably violated Whiteley's patent). Most Whiteley instruments encountered today are of this form. This subsequent form of surveying instrument evolved from Whitley's and Benton's patent quadrants. US patent 2880 is attached below in jpeg form.

Like Whiteley, Benton was not an instrument maker. His connection to the Whiteley Quadrant is unknown.

A Danner Trigonometer combines Whiteley’s quadrant patent with Benton’s grid patent. There were two Jacob Danner’s, which creates some confusion here. Jacob Danner was the father of Jacob S. Danner. Dale Beeks and others believed that Jacob Danner (the dad) made Whiteley’s quadrants and then made the combination Whiteley - Benton Trigonometers. There is an unsigned Trigonometer out there that looks exactly like my signed Jacob S.Danner Trigonometer. As you can see in the pic below, mine is clearly signed J. S. Danner. The instructions for using the instrument are included in the Benton Patent (see pics below).

Like a Whiteley Quadrant, a Danner Trigonometer could be used as a compass to take bearings by setting the compass to point to North/South and then moving one of the arms to appropriate amount of degrees. The instrument could also be used to measure angles independently of the needle, like a Railroad Compass. The instrument could be used on its side as a Quadrant for taking vertical degrees. Finally, the sine grid allowed a surveyor to make trigonometric calculations as well (The trigonometer allows the calculation of the two sides of a right triangle when the hypotenuse and one angle are known).

So either Jacob S. (the son) made all of the Whiteley quadrants and Whiteley - Benton Trigonometers, or Jacob and Jacob S. made them together. Attached below is the Smart write-up for both Jacob and Jacob S.

Also attached below is the pic of an unsigned Whiteley - Benton Trigonometers that looks like my Danner Trigonometer. The pic is from a 1980s listing in the Antiquarian Scientist (AS) catalogue, and offered for $1875. The AS has a decent but somewhat dated write-up on the evolution of the Whiteley quadrant - trigonometers, which is worth reading.