HOPPY Hopkins Vintage Split Image Transit Model G2 62 with Carrying Case & Base

The Hopkins 'Hoppy' G2 split image level was made to measure the slope of e.g. a floor. It was for example used in setting up the Hopkins Vision headlight alignment instrument to ascertain the grade of the shop floor. Essentially it is an abney level as it does not measure levels / heights directly. But as it was advertised as a level it shows up in this category in my collection. The instrument functions as follows: the target is set up at a distance from the instrument. The black line on the target is in between the two lenses. By adjusting the levelling knop at the back of the instrument (similar to a tribach adjustment) the instrument is made to tilt forwards or backwards untill the two images of the target align (e.g. the sightig line of the target is parallel to the floor between instrument and target. Using the large dial knob on the side of the instrument a level vial is then made to become level. The grade can now be read from the dial (as with an abney level). Using the distance between instrument and target as well as the dials on the instrument, the angle can be converted into a height difference. Untested - comes with everything in photos