ZOOLOGY AND BOTANY, .MICROSCOPY, ETC. 423 



(6") Miscellaneous. 



Miniature Dark-room for Use with the Microscope.* — R. T. Hance 

 says that all microscopists prefer to work either at night or in a 

 darkened room. Using the Microscope under such conditions does 

 away with the strain to which both the observing and the unused eye 

 are subjected by the side light, i.e. light coming from sources other 

 than through the tube. When working in darkened surroundings the 

 effect is that of looking at a picture on a screen. The image appears 

 brighter, and objects become clear that under the usual conditions are 

 scarcely visible. 



For several years the writer has been trying to devise some method 

 to control the light perfectly, and to do this without necessitating the 

 darkening the whole room. It is desirable that any apparatus for the 

 purpose should weigh little, and (for ease in carrying from one place to 

 another) it should be simple to take apart. It should, of course, be 

 adaptable to every condition. For further convenience of the worker 

 definite places should be present in such an apparatus for the usual 

 microscopical accessories — pens, pencils, drawing and memorandum 

 cards, and lens paper. 



The follovv'ing description is of a miniature dark-room for use with 

 the Microscope fulfilling these requirements. It was designed and made 

 by the writer last fall, and, after a year's use, he has found it to be 

 exceedingly practical in eliminating all the strain that results when the 

 eye is unshielded. In this darkened enclosure the eye not in use is at 

 perfect rest. Moreover, for drawing the light may be controlled so 

 that it is possible always to have light of the same intensity directed on 

 the drawing paper. 



Description (Fig. 31). — A, Base : \-m. white pine 12 by 18 in., with 

 a binder of the same wood across each end to prevent warping, 



B, Uprights : dowel sticks 1 in. in diameter cut to 18 in. in length. 



CO, Rods : common telescoping curtain rods. Each of the rods C 

 is cut 8 in. from the end that ordinarily would be used to fasten it to the 

 window, C is formed of the i-emainder, of the part between the ends. 



I), AYire : a piece of annealed wire ^ in. in diameter about 4i ft. 

 long bent as shown. 



To Assemble : — One 2-in. screw fastens each upright to the base. 

 The upright on the left can be seen to have two angle-irons aiding in 

 its support, but this is only necessary when the fan is added. Holes 

 are drilled in both uprights to correspond to the diameter of C, which 

 is inserted in them. The rods C are attached by one end to the tops 

 of the uprights by a screw through the eyelet in the rod. Through the 

 eyelet at the opposite end a small rod is passed as shown to prevent the 

 curtains from slipping off. The wire D is fastened to the outer sides 

 of the uprights by means of a single round head screw passed through 

 each flattened end. All the wood and metal-work is painted a dead black. 



For many valuable suggestions on the design of the curtains and 

 for the excellence of their construction I am indebted to my mother. 

 (See fig. 32.) 



* Trans. Amer. Micr. Soc, xsxv. (1916) pp. 60-4. 



