654 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
that part can be projected by an ordinary microprojection objective. 
The diaphragm plate C D is secured to the prismatic guides by a pair of 
double telescoping tubes, of which the inner one is steady, and the outer, 
by means of an Archimedean screw arrangement, slides on the inner ; 
this also answers for the fine adjustment, the coarse being worked by 
the milled head H. 
(4) Photomicrography. 
Gaylord’s Complete Photomicrographic Apparatus.* — Under the 
above title Prof. Gaylord describes the most recent and most developed 
form of an apparatus originally invented by himself, and afterwards im- 
proved by C. Winkel.f The principal feature of the construction is the 
placing of the entire apparatus upon one support, at the same time con- 
necting the camera and Microscope indirectly. 
The support upon which the apparatus rests is a solid cast-iron 
tripod a (fig. 159) through the feet of which are levelling screws 
6, b, b. Directly at the back of the levelling screws are rollers c, c, c, 
by means of which the entire apparatus may be moved. Rising from the 
centre of the tripod is a shaft d, upon the surface of which is a coarse 
screw. Engaged in this screw, and supporting the shaft upon the neck 
of the tripod, is a large collar e in the form of a wheel. On the shaft; d 
is cut a longitudinal slot in which a key is placed, and upon which the 
screw / impinges. By this arrangement, when / is loosened and e turned, 
the shaft d rises or falls according to the direction of rotation. The 
table g rests upon d , and is attached to it by a large pin fitting into its 
upper portion. The table is clamped fast by the screw l, and may be 
rotated in the short axis of d by loosening l. Attached to g are the 
camera support slide i and the illuminating bench h. The camera sup- 
* Zeitschr. f wiss. Mikr., xvi. (1899) pp. 289-94 (3 figs.), 
f Op. cit., xiv. (1897) p. 313. Cf. this Journal, 1898, p. 354. 
