1894 THE MICROSCOPE. 157 



set up will help my readers to comprehend my remarks about 

 it. These I will give in some little detail as I hope to have 

 others investigate and describe some of the parasites of our 

 birds. Most naturalists nowadavs own a camera and outfit 

 and also a microscope and its outfit. This is my case. In the 

 first place, then, I took my largest camera and placed it on a 

 long table as shown in the sketch. I removed its lens and lens- 

 boards, and fitted a cardboard front to take its place. Next I 

 took my largest microscope — a Beck's Monocular National — 

 and brought it into the horizontal position. I fitted the upper 

 end of its body, while in this position, into the cardboard front 

 of the camera. A substage condenser, and a three-fourth inch 

 objective were next attached to the microscope, and the camera 

 and the latter coupled together. Now most micro-photographers 

 omit using the eye-piece of the microscope, but with it I sub- 

 sequently obtained the best results. It is inserted after the 

 barrel or body of the microscope is run through the cardboard 

 into the front part of the camera-box. 



For an illuminator I used the dark-lantern of my photo- 

 graphic outfit — simply withdrawing the ruby-glass slide in 

 front, and fitting in its place a thick piece of cardboard, into 

 the center of which I inserted the lens from a small camera to 

 act as a "bull's-eye condenser." This is coupled with the sub- 

 stage condenser on the microscope by means of a broad rubber 

 band. My lantern I held nicely in the proper position by sus-* 

 pending it between the "rings" of a chemical standard, as shown 

 in my sketch ; but any simple device will hold your lantern up 

 in its proper place. It can even be ''built up" by putting books 

 under it. Both the lantern and microscope rest upon a very 

 thin board which travels with ease on tlie extension-bed of the 

 camera-box. By this latter simple contrivance, focussing your 

 specimen on the ground-glass of the camera is easih' managed. 

 The screws control the whole thing, and the rest can be with 

 ease understood from my sketch of the plan adopted. — Auk. 



SCIENC^^OSSIP. 



Hydrogen Dioxide. — This remarkable liquid which con- 

 tains the greatest percentage of oxygen of any compound known, 

 was, for sometime, considered as a mere solution of oxygen in 

 water, and consequently was called oxygenated water. It was 



