380 MICROSCOPY. 
Mr. Cooke became satisfied that the spores were originally concate- 
nate, though soon breaking up into subglobose individuals, and he 
therefore describes them as anew species of Torula (Torula incar- 
cerata Cooke) notwithstanding their anomalous habitat. As a 
Torula it must be considered a sequence rather than the cause of 
the decay of the seed, while the opposite would be fairly presumed 
of an Ustilago. 
TripEscent Encravine.— Mr. Rutherford of New York, long 
ago contrived a machine, worked by an electro-magnetic engine, 
which ruled upon glass microscopical test objects consisting of lines 
of iridescent fineness; and the beautiful iridescence of Nobert’s 
lines by opaque or dark-field illumination is almost as familiar to 
microscopists as that of mother-of-pearl or of some of the diatoms. 
Recently Mr. Wm. A. Rogers of the Cambridge Observatory 
has engraved upon glass, lines of great beauty and considerable ` 
fineness. Those of medium fineness, especially, glisten beautifully 
with rainbow-colored light. The lines from 4 inch to z,/55 inch, 
suitable for use in optical instruments as a substitute for spider- 
web or diamond rulings on glass, are remarkably clear, distinct 
and uniform in their spacing; while the finer lines excel in fine- 
ness and distinctness any engraving previously seen by the writer. 
Those of 553,55 inch are perfectly successful, while those of ssd00 
inch are capable of being defined and counted. Some of Mr. 
Rogers’ engraving are made in stars like Mr. Stanistreet’s lines. 
APERTURES OF OBJECTIVES. — The Tolles y, sent to London 
as proof of the utilization of more than 82° aperture in balsam, 
has been carefully examined by Messrs. C. Brooke, H. Lawson, 
W. J. Gray and S. J. M’Intire, who report an angle in air of 145°, 
in water 91°, in balsam 79°. Mr. Wenham believes the balsam 
angle might have been three degrees higher in hard instead of fluid 
balsam. Doubtless four more competent judges could not have 
been selected in the world, and their report will be likely to be 
generally accepted unless it can be shown that a higher angle 
might have been utilized at some other point of practically useful 
adjustment, a question which te can scarcely have failed to con- 
sider in preparing the report 
UNDER-CORRECTED Ossectives.—The advantage of these lenses; 
which have only lately attracted much attention, was distinctly and 
ey. acknowledged by Mr. Wales in the year 1865. At that 
