68 THE MICROSCOPE AND ITS ACCESSORIES. 



move with the body when attached to the connecting rod of a 

 camera for photo-micrography, no alteration has to be made on 

 the rod when using different powers. 



Fig. 17 illustrates the Histological Microscope of this firm. 

 This has a large stage, the continental length of body with draw- 

 tube, and is made with a sliding body for focussing, or with rack- 

 work as shown in the figure. It is provided with double mirror, 

 and all fittings are of the universal size, so that any accessories 

 may be used. 



The Students' Petrological Stand of Messrs. Watson is built on 

 a similar plan to their Students' Stand. No further comment need 

 be made on them beyond stating that it has a revolving glass stage 

 with divided edge and all necessary apparatus for petrological 

 research. 



It must not be considered that all the better class of students' 

 stands have been here mentioned, nor that the instruments of 

 other makers may not be quite as reliable. But these notes should 

 only be taken as representing some of the more reliable instru- 

 ments from a few of our London makers who try to keep pace 

 with the demand for a working stand at a moderate price. 



It will probably be noticed that the monocular form of instru- 

 ment has been adhered to. This has been done for two reasons : 

 one being that the monocular is cheaper than the binocular ; and 

 the other, that with high powers better work and greater definition is 

 got out of the single form than out of its double-barrelled and 

 more costly relative. 



Since writing the above, other forms of Microscopes have been 

 brought to our notice, which we hope to describe on a future 

 occasion. 



It is said that a larger cave than the Mammoth Cave, situated 

 on the Ozark Mountains, near Galena, Mo., has been explored for 

 a distance of more than thirty miles. In it have been found bones 

 of recent and prehistoric animals, including the hyena or cave-bear, 

 and flint arrow-heads, but no bones of man. A few animals of the 

 usual forms found in caves are still living there, including a white 

 newt. 



