Backstaff or Davis Quadrant 18th Century

This Davis Quadrant also called backstaff is an antique nautical instrument, a rare piece of the early 18th Century made of lignum vitae wood. On one side, the small arc is divided 0-60º, and the great arc divided 0-25º and 65-90º. On the other side, the longer arm is decorated with a small backstaff and stars.


This Davis Quadrant (also called Backstaff) is an antique nautical instrument. This piece, in particular, was made in the 18th Century and we have in great shape and cure. As you may know, it is an instrument mostly useful in navigational contexts to measure the altitude of a celestial body, most of the time to measure the altitude of the sun or the moon. It is a historical invention from the English sailor John Davis. As it is similar to an ancient crossbow then it leads to new inventions that took into mind this structure.

As you can see this is a rare piece of lignum vitae wood of the early 18th Century. On one side, on the small arc has divisions from 0º to 60º. The great arc has two divisions from 0-25º and from 65-90º. On the other side, the longer arm has decorations for example with a small backstaff and stars. In conclusion, in this Davis quadrant or backstaff you will be able to have a very fine piece from the 18th century.

Looking for more antique quadrants? please contact us. We are specialists in antique scientific and nautical instruments like this one. You can discover more of them here. Feel free to ask anything. Also, you can try also our Instagram professional profile.