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that the nose-piece shall be at least two inches 

 from the stage and place the . upper end of screw 

 of objective in the thread of the nose-piece, hold 

 the lower end between the fore and middle fingers 

 (left hand) palm upwards, so that it is in line with 

 the tube and gently pressing upward, revolve the 

 objective with the thumb and forefinger of the 

 other hand (right hand) by the large milled edge 

 at its upper end, until shoulder sets against 

 shoulder. To properly attach an objective is not 

 always simple and cannot be done too carefully. 

 One danger lies in the fact that the objective may 

 be dropped onto the object and thus injure or 

 destroy a one or the other or both and another that 

 the thread is started wrong by holding the objec- 

 tive sideways and the threads may thus be 

 destroyed. 



In this connection we draw particular attention 

 again to the convenience of the double, triple and 

 quadruple nose-pieces. The convenience which is 

 obtained from their use, freedom from danger to 

 objective and object and saving of time, com- 

 mend them in all cases where two or more objec- 

 tives are used. 



Finding an Object. The slide upon which 

 the object is mounted is placed upon the front of 

 the stage and slipped under the two spring clips 

 to a point where the object c.omes as nearly as 

 possible in the center of the opening of the stage. 



