912 G. F. Barker—New Vertical-lantern Galvanometer. 
square inches of zinc surface, was passin 
the center of a large wire coil, whose resistance was 0-295 ohm, 
and of twenty centimeters, of 10°. <A rotation of 90° gave a 
deflection of 12° and one of 180°, of 24°. These deflections 
was connected to the instrument. The heat from the hand 
placed at five centimeters distance caused a deflection of 3°. 
Two cubes of boiling water acted differentially on the pile. 
At the distance of five centimeters the deflection was 20°; 
moving one to ten centimeters, the deflection was reduced to 5°. 
oltaic current.—?%. A drop of water was placed on a zine 
plate. While one of the connecting copper wires touched the 
ra other was made to touch the water. The deflection 
was 16° 
The claim which is here made for the instrument, however, 1s 
rather for the general principle of its construction, than for the 
advantages peewee by the individual galvanometer above 
described, which was constructed at short notice, to meet aD 
emergency. The comparatively small cost for which it may be 
fitted to the vertical lantern, the readiness with which it may 
be brought into use, the brilliantly illuminated circle of light 
which it gives upon the screen, with its graduated circle and 
instrument by varying the coil and needles, so that all experi 
mental requirements may be answered, and finally, the satis: 
