ZOOLOGY AND BOTANY, MIOKOSOOPY, ETC. 1025 



objects projected, as it were, in the image of the source of light focused 

 by the condenser. It is, without doubt, highly desirable to have a series 

 of achromatic condensers of different foci, to suit the field of view of 

 objectives of different power. It appears not to be generally known that 

 distancing the lamp from the Microscope will give a considerable range 

 of size of luminous field, with one and the same condenser. 



Steickek, S.— [Electric Microscope.] 



[" By the use of his electric Microscope and of silver bromide plates, Prof, 

 Strieker is enabled to get very fine photographs of living bacteria and other 

 moving cells. He has taken pliotographs of living white blood-corpuscles 

 with high-power lenses, which showed clearly and distinctly the network- 

 like structure of those bodies."] 



Engl. Mech., XL VI. (1888) p. 475. 



(Sj Eye-pieces and Objectives. 



Defective Objectives and the Binocular Microscope. — It has been 

 observed that badly corrected objectives appear worse with the Binocular 

 Microscope than with the single tube. The reason of this is that with a 

 badly corrected lens the different parts of the aperture will not work 

 together exactly, the images formed by different parts disagreeing. In 

 using the binocular different parts of the aperture are always made 

 effective in forming the two images, so that the binocular is to this 

 extent a test for good correction. 



Heueck, H. va n. — Las nouveaux objectifs apochromatiques de M. Reichert. (The 

 new apochromatic objectives of Herr Eeichert.) 



Bull. Soc. Belg. Micr., XIV. (1888) pp. 156-9. 

 ScHULZE, A. — The new Apochromatic Micro-objectives and Compensating Oculars 

 of Dr. Carl Zeiss. 



Proa, and Trans. Nat. Hist. Soc. Glasgow, II. .(1888) pp. 154-62. 

 ScHULTZE, F. E. — Eine von Herrn Westien in Rostock angefertigte DoppeUoupe. 

 (A double lens made by Herr Westien of Eoatock.) 



SB. Gesell. Nat. Freunde Berlin, 1887, pp. 146-7 . 

 „ „ TJeber eine binoculare Praparirloupe. (On a binocular dissect- 



ing lens.) Tagebl. 60. Versamml. Deutsch. Naturf., 1887, p. 112 



(3) Illuminating- and other Apparatus. 



Koch's and Max Wolz's Reflector. — Mr. T. Christy has recently 

 exhibited a novel form of lamp. The lamp is shaded by a metal cover, 

 near the bottom of which is inserted a solid curved rod of glass with a 

 plane end. The light from the lamp passes into the rod, and after 

 various internal total reflections, arrives at the end of the rod, where it 

 may be directed upon the object. 



The apparatus has been patented in Germany by Dr. W. Koch and 

 Herr Max Wolz of Bonn, of whose specification the following is a trans- 

 lation : — * 



" As is well known, rays proceeding from a source of light in a glass 

 body on emergence are deflected from the normal. The more oblique 

 the rays, the more are they deflected, the consequence of which is that 

 finally they can no longer emerge, but are reflected back. This happens 

 if the angle of incidence (for glass) amounts to 40f ° and over. Use is 



* Patentschrift No. 42,818, Klasse 4, 29th July, 1887. 



