ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
337 
peculiar shaped foot and of the joint at one side of the pillar. These 
constructions first appeared in a ‘ single-lever Microscope/ designed by 
C. Yarley, and made by H. Powell in 1843. The gold Isis medal of 
the Society of Arts was presented to C. Varley for this Microscope. 
We are now able to place the date of Powell’s Iron Microscope between 
the above date, 1843, and 1848, when the first published account of it 
appeared; the date therefore given in my original communication was 
too early. 
“ The accompanying block (fig. 84) unfortunately arrived too late for 
insertion in its proper place on p. 211 of the last number of the Journal. 
It is a cut of an important Microscope ; as it is the first compound achro- 
matic Microscope made in this country. It was made by Mr. Tulley 
from original drawings supplied by Mr. J. J. Lister, and it was com- 
pleted on May 30th, 1826. It is of interest to note that the substage 
held a combination of lenses, or what we should now call a chromatic 
substage condenser.” 
Gates, Dr. Elmer. — Million-fold Magnification. " 
[This is stated to be obtained by use of low-power lenses, and by substituting 
a second Microscope for the ocular of an ordinary Microscope.] 
Amer. Mon. Micr. Journ., XIX. pp. 189-202 (1 pi. and 1 fig.). 
Van Heurck, Dr. H. — -Etude sur les objectifs apochromatiques. 
[The form of lens figured in this paper is that of the old apochromats when 
they were first introduced, and not that of those now manufactured.] 
Ann. Soc. Beige de Microscopie , XXIII. (1899) pp. 41-73 (1 pi. and 9 figs.). 
Wallace, Dr. Jas. — Eye-piece for photographing through the Microscope. 
Micros. Bull. (Philadelphia), 1899, p. 8 (1 fig.). 
(3)^Illuminating ancTother Apparatus. 
Direct-Vision [Spectroscope. — This small direct-vision spectroscope 
(fig. 85) has been sent to us by Mr. C. L. Curties. It is on a new model, 
inasmuch as the eye-piece is jointed ; this permits a large amount of 
dispersion to be used together with a high-power eye-piece. 
Fig. 85. 
By means of the joint the spectrum can be searched low down in the 
red and high up in the violet, so that the A and H lines can be brought 
into the middle of the field. The slit is of very good quality, and 
the sodium lines are shown sharply divided. It is in every way suitable 
for microscopical work, and can be readily adapted to an eye-piece. 
Davis’ New Ebonite Reversible Compressor. — This instrument 
(fig. 86), manufactured by Messrs. Beck, is specially designed for the 
examination of living objects, and consists of a lower ebonite plate A, 
which in the[ centre has a circular hole recessed to receive a circular 
brass ring B, resting loosely in the recess. On the recessed portion of 
A is carried an oblong thin glass held in position by two screws, one 
of w r hich appears at C. Two end plates D D slide on to the plate A, 
