od. Trowbridge on a new form of Galvanometer. 119 
plane of the coil in its new position, inclined at an angle of 
90° —S% to the horizon. 
It will be readily seen that if A O represents the intensity of 
the current passing through the coil, OC will be the component 
& that will deflect the needle; but OC= 
3 AOcos$=Icos $. The intensities 
@ will therefore be proportional to the co- 
sines of the inclination of the plane of 
the current, measuring the angle from 
the vertical OC. 
he instrument with which I experi- 
mented had the following dimensions: 
The diameter of the circle around which 
the current passed was twelve inches, 
and the length of the needle 1-4 inches; 
; it was provided with long aluminum 
pointers. The inclinations of the plane of the current were 
tead from a vertical scale perpendicular to both the plane of 
the current and to the plane in which the needle moved. 
The manner of experimenting was as follows: The resist- 
ance of the battery—one Daniell’s cell—having been determined 
with care, and also the resistance of the circuit, the instrument 
Was used as a tangent galvanometer with the plane of the 
current vertical. . 
ae ee 
s a 090 | -014 oe 078 | -002 
at =; 158 | -016 a 139 | -003 
sage 16° - 226 | -026 al 195 | ‘005 
Se ree, 354. | 021 4 342 | -009 
ne = 428 | 028. | ak 422 | -022 
ee ° a 542 | 013 os 544 | “O15 
bias = a 701 009 aS 672 | -020 
eae 3 ee 325 | -015 a 785 | ‘025 
