290 ^' J- Anderson, A panoramic arrangement for the Microscope. 



The disc must be so placed that it will be perfectly parallel to 

 the front of the case and the light must fall on the face of the disc. 

 The former condition is secured by means of the levelling screws and 

 a square and the latter by having the case in front of a Window. 



The microscope is fitted to a brass plate which slides in a second 

 plate fixed to the front of the case on the same level as the axle of 

 the apparatus and at a distance equal to the semidiameter of the disc. 



A lateral motion of the microscope is best caused by a wheel and 

 racket arrangement. The possible movement is one inch. 



The microscope, then, being fixed for any specimen, it is evident 

 that the screw button on the axis serves to focus the specimen and 

 is similar to a fine adjustment. Secondly a specimen may be examined 

 from side to side by means of the lateral motion of the microscope. 

 Thirdly the specimen may be swept from above down by the handle 

 moving the disc and lastly a whole series may be examined one after 

 another. It is quite safe to place the instrument in a museum case. 

 No one can injure the microscopic slides or spoil the microscope as the 

 limits of motion are fixed, and the student can thus study a series 

 of specimens without supervision. 



The instrument may be used in the same position for class de- 

 monstration. Or it may be turned, levelled and thus used in the hori- 

 zontal position by means of an ordinary arrangement for reflected light. 



The microscope tube is under ordinary circumstances, so close to 

 the vertical portion of the stand, that a special stand is necessary for 

 use in the horizontal position. 



The museum case should be provided with curtains as some pre- 

 served specimens are injured by the light and heat. 



