THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. III. 



New York, November, 1882. 



No. 11. 



Grunow's New Camera Lucida. 



Mr. J. Grunow of this city has con- 

 structed a new camera lucida, which 

 deserves the attention of micros- 

 copists. 



It was described by the Editor at 

 a recent meeting of the New York 

 Microscopical Society. 



The instrument consists of three 

 rectangular, equilateral prisms, so 

 arranged that when placed over the 

 eye-piece with the microscope in- 

 clined, which is the most convenient 

 position, a portion of the surface of the 

 work-table of the size of about 12 by 

 15 inches is projected into the field 

 of view, so as to be distinctly and 

 clearly seen together with th& object 

 on the stage. 



Fig. 



43- 



The two prisms e, /, g, and h, f, g 

 are cemented together so as to form 

 a cube; the sides h, g, and/, e, being 

 parallel. The hypothenuse /, g, of 

 the prism h,f,g, is silvered, to do 

 away with the blue halo, otherwise 



peculiar to this form of prism, which 

 would greatly obscure the reflected 

 image. 



The silver is removed at the centre 

 of the coating, at the point 0, so as to 

 leave a clear space about half the 

 diameter of the pupil of the eye. 

 *The other prism /,/, k, is placed with 

 the side j, k, inclined to the cube 

 hy g, f, e, at such an angle as may be 

 most desirable. 



In viewing the object under obser- 

 vation in the direction of iV, M, 

 through the aperture at o, we see the 

 whole field of view, while at the same 

 time the drawing board and pencil 

 are reflected from the side /,/, of the 

 prism I, J, k, to the silvered surface 

 f, g, and then reflected to the eye in 

 the direction of /*, JV. 



Both the pencil point and the ob- 

 ject are very clearly seen without any 

 strain upon the eye. 



It is in this respect that the maker 

 claims for this camera lucida superi- 

 ority to any other form. 



It can be immediately applied, 

 while the microscope is in an inclined 

 or vertical position, without any 

 change of conditions or loss of time. 



The camera is simply slipped over 

 the eye-piece, the paper placed on 

 the table, and the drawing proceeded 

 with. 



Javelle Water for Microscopical 

 Purposes.* 



Pearls and Altmann have used Ja- 

 velle water for the destruction of 

 animal tissues, and thereby have 

 found that the fat withstands the 



* Abstract of an article by Dr. F. C. Noll, 

 Zoologischer Anzeiger. 



