DISSOLVING VIEW INSTRUMENTS. 

 Fig. 796. 



379 



With oxy-hydrogen microscope, having three powers, 

 and several sliders with objects attached, as shown at A, 

 (fig. 796), additional. Price $110.00. 



With polariscope, and apparatus additional, $110.00. 



Telegraph Model (Fig. 797.) This model represents 

 the essential parts of Professor Morse's telegraph, con- 

 sisting of an electro-magnet with the poles upward, hav- 

 ing the ends of the wires surrounding the magnet connect- 

 ed to two brass cups with binding screws, which are 

 fastened to the base on which the instrument is mounted. 

 A brass roller, or spool, on which the narrow riband of 

 paper is Avound, and which may be drawn off as required, 

 passing through an opening or guide in the brass pillar 

 supporting the lever ; to the end of the lever, and just 

 over the poles of the electro-magnet, is an armature, or 

 bar of soft iron, not in contact, but a small distance above 



