JOURNAL OF MICROSCOPICAL SCIENCE. 
EXPLANATION OF PLATE I, 
Illustrating Dr. Royston-Pigott’s paper on Microscopical 
Vision. 
Fig. 
1.—a, 6, ¢, d,e. Transparent refracting spherules, showing a gradually 
increasing dark annulus as the aperture of the objective is 
gradually diminished. 
f. The fused extremity of a thread of glass, forming a lens =2,,th 
of an inch in diameter, and exhibiting the cross bars of a 
window frame. The annulus large and broad from reduced 
aperture. 
2, 3.—Threads of spun glass: black bands and lenticular annuli dependent 
on aperture. 
4.—Appearance of the window and details, when seen in the focus of an 
aplanatic condenser. 
5.—Jet black bands of minute glass cylindrical threads and central spec- 
trum of intersection (a). 
6, 7, 8.—Remarkable appearances of Podura markings. In fig. 7, a double 
development of black lines as seen with the 1th immersion 
and oblique light from a concave mirror. Fig 8. Tor Stanp- 
arp Test Marxine oF Popura Curvico.tis, being ezdo/a, or 
false images caused by confusion of the true images of double 
structure. 
9.—Black borders of the finest hairs of the Axztenne of the male gnat, 
showing spectral bright spaces at a, a, a, analogous to those 
of fig. 5 in refracting cylinders intersecting. 
10.—The display of Resipuary ABERRATION by using a fine objective as 
condenser and viewing it with an imperfect microscope, sup- 
posed to be of fine quality. 
11.—The same thing exhibited by a very highly corrected instrument. (See 
‘Phil. Transactions of the Royal Society,’ vol. ii, 1870.) 
12.—One example of false images. Wire gauze appeared translucent ; like 
threads of opaline glass; interspersed with chequered black 
dots, sharply defined. In an unknown structure such false 
appearances might readily be mistaken for true. 
