410 



SUMMAKY OF CURKENT RESEARCHES RELATING TO 



coincidence of the arms and divisions of tlie clip with the lines on 

 the slide the object will necessarily be in the tield of view. The 



Fig. 74, 



Fig. 75. 

 arrangement has been found sufficient for an Eipparchia scale, with a 

 power of 150. 



Burnett's Rotating Live-Box.— This is thus described by Mr. 

 E. T. Burnett, its designer : — " The arrangement of this live-box 

 is* very simple. Hitherto live-boxes have had the outer cases, 

 which hold the strong or bottom glass, screwed into, or fixed 

 firmly to, the plate that goes upon the stage. This one is constructed 

 so that the outer case fits into a flange or cylinder its own depth. 

 The cylinder is made fast to the plate, leaving the outer case, 

 tof^ether with the inner case, free to be rotated at the will of the 

 manipulator, forming, in point of fact, an ordinary live-box resting 

 within a deeply flanged plate. 



- In using the ordinary live-box, it has hitherto been necessary to 

 take it off the stage whenever the observer has been desirous^ of 

 turning the object round, or when, in the absence of an ' erector,' it 

 has be°en necessary to have an object which has been placed head 

 downwards changed to an upright position. This is avoided by the 



rotating live-box. , , . , , • . • at. 



Further, in using the ordinary live-box with high objectives, the 

 latter will project within the rim of the live-box ; consequently no such 



