1893.] MICROSCOPICAL JOURNAL. 303 



be was intensel}' interested in instruments of precision. In 

 1850, he happened into the workshop of the late Mr. C. A. Spen- 

 cer, the celebrated microscope maker, and became his pupil. 

 While at Canastota his dearly beloved wife died. To drown 

 the bitterness of his grief, he threw the whole energy of his in- 

 ventive mind into the difficult work of improving the various 

 parts of the microscope. How industrious he was is seen from 

 the following partial list of his productions : 



Invented and patented his solid eyepiece. 



Invented his achromatic amplifier. 



Achromatic pocket magnifier; flat field ; triple len- 



Cover adjustment by moving the back and middle 

 combinations, the front remaining stationar}'. 



5. 1864. Invented his binocular eyepiece. Both this and 

 one other, were copied by a German maker and sold as his 

 own inventions. 



6. 1864. Telescopic magnifier. The principle rediscovered 

 in Europe. 



7. 1866. Prism in the side of the objective for illuminating 

 opaque objects. 



8. 1867. Made his first immersion lens objective a l-16th, 

 that resolved Nobert's 19th band, probably the first time it was 

 ever seen. Witnesses ; Messrs R. C. Greenleaf and Charles Stod- 

 der, late of Boston. 



9. 1867-8-9. Wet and dry fronts to the same objectives. 



10. 1871-2. Very thin stage with rectangular motions by 

 friction rollers with complete rotation on optical axis — one thing 

 that has not been copied nor imitated. 



11. 1872. Semi-clyinder for proving that the angle of objec- 

 tives may exceed 82° with objects mounted in balsam, by ex- 

 cluding all 1 ght of less incidence than half of the maximum 

 angle. 



12. 1873. The l-75th inch objective. 



13. 1875. Illuminating apparatus for microscope, swinging 

 concentrically around the object of focal point. Universally 

 adopted. 



14. He was the first to claim 180° of angular aperture and 

 p rove it. 



15. Simplified Camera Lucida, 



