294 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fig. 42. 



introduction by Dr. N. Lieberkuhn, in 1738), which slides beneath the 



cross-arm on the top of the instrument ; (2) of two sliding plates each 



provided with tliree different 

 powers, numbered from 2 to 

 7, also sliding beneath the 

 cross-arm ; (3) a perforated 

 conical reflector, acting after 

 the manner of a Lieberkuhn, 

 which can be ai^plied in con- 

 junction with the low-powers 

 in one of the sliding plates. 

 The mirror is concave, and is 

 hinged on a pivot applied in 

 a socket at the end of the 

 sliding tail-piece. The focus- 

 ing is by means of a bent 

 lever at the back moving the 

 stage up or down. The limb 

 is hinged at the back to in- 

 cline on an ornamental sup- 

 port fitted to rotate on the 

 pillar and tripod. A fish- 

 plate, a silver box with per- 

 forated sliding lid, articulated 

 stage-forceps, hand-forceps, 

 ivory box for talcs and rings, 



and six object-slides, together with the whole Microscope, pack neatly in a 



box about 3^ X 2J X 1^ in.* 



Gakrison, F. L. — See infra, /3 (2). 

 Howl AND, E. P. — [Microscopic Projection,] 



[" My experience leads me to believe that the direct projection of microscopic 

 objects can only be successfully accomplished in small rooms. For public 

 exhibitions and for projection generally i5hott)graphs are to be preferred. The 

 use of a projecting Microscope is quite satisfactory with low powers, but it is 

 difficult to concentrate the light sufficiently to admit the use of high powers. 

 These remarks refer to tlie use of calcium light. With the electric light better 

 results may be obtained."] 



Amer. Mon. Micr. Journ., VIII. (1887) pp. 38-9. 

 Pe. — Ausstellung wissenschaftlicher Apparate, Instruments, und Praparate. (Exhibi- 

 tion of Scientific Apparatus, Instruments, and Preparations.) II. 



[Exhibition at 13erlin. Includes an Electrical Arc Lamp with Microscope — 

 ♦ Strieker's Electrical Projection Microscope — Nehmer's Incandescence Lamps — 

 Microscopes by Schieck & Wannbrunn and Quilitz & Co.] 



Zeitschr.f. Indrunientenk., VI. (1886) pp. 425-3L 

 Cf. "W.," arde, p. 161. 

 Pfeffee, W. — Bezugsquelle und Preis einiger Apparate. (Place to obtain and price 

 of some apparatus.) 



[Includes Microscopes.] Bot. Ztq , XLV. (1887) pp. 27-31. 



[(2) Eye-pieces and Objectives. 



Frazer's Centering Nose-piece for use with Double Nose-pieces.t — 

 " When the nose-piece is moved in the usual way, and one objective put in 

 place of another," writes Mr. A. Frazer, " it seldom happens that an object 

 which was in the focus of one power is also in the focus of the other ; and, 

 as a consequence, the operation of focusing must be performed. This 



* Cf. Society of Arts Cantor Lectures on the Microscope, by J. Mayall, junr. (re- 

 print in collected form), 1886, p. 43 (1 fig.). 



t Trans. Edinburgh Naturalists' Field Club, i. (1885-6) pp. 333-5. 



