DESCRIPTION:
The lens housing of this focusing magnifier screws on to a cutout base with three supports or 'legs' attached to a bottom knurled ring. Screwing it up or down achieves focus. It is embossed on one of the three legs 'LABAN HEATH' and on another, 'DÉPOSÉ No 6082' and on the third with 'PATENT MAY 1, 1866'. In reality the actual patent date is May 8, 1866.
Although Laban Heath's later folding 'Improved Adjustible Compound Microscope', patented in 1877. sometimes called his 'Counterfeit detector' is not uncommon, this other version of a magnifier is earlier and rather rare, as is his combined microscope, telescope, and magnifier.