POWELL AND LEALAND CONDENSER

C. 1891

SIGNED ON THE CONDENSER: POWELL & LEALAND

MODEL: HIGH POWER ACHROMATIC CONDENSER (improved version)

The Powell & Lealand 'Apochromatic High Power Achromatic Condenser' was made to fit the housing for the High Power Achromatic Condenser, simply by exchanging the optical portion.

With the introduction of apochromatic objectives, Powell & Lealand introduced an apochromatic one was also designed to be used dry, and had an advertized focal length of 1/4 inch, and N.A. of 0.95. This came as the optical part only, and screwed onto the High Power Achromatic condenser housing instead of the achromatic element.This design was later modified at the suggestion of E.M. Nelson, to include an adjustment for slide thickness operated by a lever. The example shown here was at one time in the past repaired, and the top element has been fitted with 3 tiny centering screws.

The cap is engraved: P & L N.A. 0.92 Apo condenser F=0.29" Dry OK in the unmistakeable handwriting and annotation of the late Horace Dall (1901-1986), optical genius, of Luton, England, by many considered to have been the last person who was capable of repairing defective Powell & Lealand objectives.