ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 103 



pass the platimnn wires. The bearers are fastened on a circular porcelain 

 plate, and are connected with four contact collars placed on the back of 

 the plate : these collars being themselves connected with the same 

 number of plugs inserted into a slate block and fitted with clamp screws. 

 Means are provided for accurate centring of the light. The slate block, 

 which is circular in form, bears on. its circumference a flange which 

 forms the rear wall of the diaphragm arrangement of the projection 

 apparatus. Kohler's combination system of lenses for microprojection 

 is used for the light concentration. This system yields the maximum 

 light-intensity of the Nernst lamp. It consists of three lenses, the first 

 of which, alone or in combination with two others, collects the light- 

 rays. The condenser with a suitable condenser is available either for 

 weak or for the higliest magnifications. The lenses and lamp are 

 mounted on a horizontal base board which acts as the optical bench, and 

 is large enough to carry also the Microscope. Means are provided for 

 raising or lowering the whole apparatus as required. A plane mirror, 

 inclined at 45°, is fitted to the l)ody tube of the Microscope, which is, of 

 course, horizontal, and reflects the image on to the drawing-table at 

 ■which the student sits. This table is adjustable in height, and this con- 

 venience added to the vertical adjustability of the optical bench gives 

 considerable control over the distance between the ]\Iicroscope and the 

 table top. The arrangement has been found very convenient for photo- 

 micrography, the drawing apparatus being, of course, replaced by a 

 camera ; the uniform illumination afforded by the Nernst lamp specially 

 lends itself to such work. 



The author has found the Nernst lamp of the greatest service in the 

 intensive illumination of small objects by incident light. This appli- 

 cation is useful not only for photomicrography, but for many other 

 purposes, e.g. the minute examination of manuscript, preparations of 

 embryos, etc. He describes some 10 or 12 different forms of the lamp, 

 the details being modified for special purposes. 



(4) Photomicrography. 



Deegener — Der. mikrophotographische Apparat von H. 0. Juel. 



Natur. ZcitscJir. Land. Foist w., iv. pp. 220-6. 



Eder, J. M. — Wichtigere Fortschritte auf dem Gebiete der Mikrophotographie und 

 des Projektionswesens. Jahrhnch filr Photographic unci Rcxirudiiktions- 



technik filr das JaJir 1906 ; and as a separate 

 pamphlet (8 pp.), Halle (W. Knapp). 

 Ernst, H. E.— Ultra-violet photomicrography. 



Journ. of Med. Research, xiv.(1906) pp. 463-9. 



Ernst, H. E., & S. B. Wolbach — Ultra-violet Photomicrography. 



[A preliminary communication.] Tom. cit., No. 3. 



(5) Microscopical Optics and Manipulation. 



Ultramicroscopes : Ultramicroscopic Objects.* — The above is a 

 title of a work by A. Cotton and H. j\Iouton which deals with the present 

 state of knowledge on this branch of Microscopy. It is written in a 



* Les Ultramicroscopes : les Objets ultramicroscopiques. Paris : Masson et 

 Cie., 232 pp., 17 figs. 



