The Microscope. 383 



I found myself in a second story front room, about sixteen 

 feet square, furnished with three foot-power lathes, a plain pine 

 table, a couple of cupboards, a couple of stools, a couple of 

 chairs, and — nothing more. The magic evidently was in the 

 fingers, not in the machinery. 



Among the relics of the elder Spencer, the son showed me a 

 box containing bits of spar selected to make lenses of, and one 

 old lens, constructed more than thirty years ago, in which the 

 spar has become laminated and cracked, rendering the lens use- 

 less. It was on account of this tendency of spar to deteriorate 

 that Mr. Spencer abandoned its use for lenses in his objectives, 

 to have it taken up again, and hailed as the' very latest advance 

 in scientific microscope making, long after he was in his grave. 



I also saw the little lathe on which much of his work was 

 done, a rough looking little affair made by his own hands in a 

 Canastota blacksmith shop. 



After looking over these and some other relics of the old times 

 and watching the deft fingers of Herbert and his partner shap. 

 ing the bits of glass that were to form portions of sundry new 

 lenses, we came down to the real business of the afternoon, the 

 critical examination of some of their latest work. 



The first thing was one of the new formula dry |^, aperture 

 150° air (about 0.95 N. A.) This was screwed on to the old 

 stand, evidently a veteran, and a slide of Podura scale slipped on 

 the stage. The illumination was from the edge of the fiame of a 

 common flat-wicked kerosene lamp and the concave mirror. No 

 Abbe condenser to bedevil the light with its excessive spherical 

 and chromatic " abbe " ration. But there was no lack of light 

 even when the \ inch ocular was used, and what sharpness of 

 definition and limpid colorlessness of field ! With the same 

 lens and various oculars, the balsam mounted Moller Probe- 

 Platte was attacked with oblique illumination, still from the 

 lamp and mirror only, and still with ample light and a field 

 almost as free from color as with a central light. No. 18 yielded 

 easily and, by careful manipulation, the striae on No. 19 could 

 be seen. And just here the superb qualities of the new eye- 

 pieces were demonstrated. Objectives which had done well 

 with the lower power eye-pieces of the Huyghenian type did 

 better with the | and ^-inch eye-pieces of the new formula, the 

 chief improvement being in the more perfect correction for 



