ELECTRIC DISCHARGE WITH THE CHLORIDE OF SILVER BATTERY. 
89 
body of tbe microscope, which is bent for the convenience of observation. That 
part beyond the upright is formed of ebonite, in order to protect the eye from 
accidental shocks. The discharger used when this microscope is employed is 
Fig. 17. 
Fig. 18. 
horizontal, as seen in the figure, in order to permit of the employment of the mirror 
which is mounted on a horizontal axis ; the point P is placed in the fixed upright, and 
the disc D in that upright which is attached to the adjustable slide. The screw S' is 
used to approach or recede the microscope in order to adjust to focus ; S" to bring 
the point horizontally, and S to elevate or depress the microscope by means of a 
pinion and rack to adjust the point vertically in the field. O is the object-glass and 
E the eye-piece ; W, a multiplying-wheel giving five revolutions of the mirror for one 
turn of the handle, which may be rotated with ease 200 times in a minute, so that the 
mirror can be caused to make 1000 revolutions in a minute, or about 17 revolutions 
in a second. The whole framework of the stand is of ebonite to ensure insulation. 
MDCCCLXXVIII. 
N 
