1898.] 



MICROSCOPICAL JOURNAL 



213 



to exactly fit the inside of the tube and permits the 

 bed plate to be revolved on its horizontal axis. The bed 

 plate is five feet long and five and one-half inches wide. 

 It consists of a piece of three-sixteenths-inch rolled 



steel, to which is riveted two dressed half-inch steel 

 tubes. These tubes are placed near each edge and give 

 rigidity as well as serve for guides for the camera and 

 microscope carriages. In the centre of the bed plate is 

 a rack for the adjustment of the camera and microscope 



