198 A. M. Mayer— Researches in Electro-Magnetism. 
The following table — the results, each number being the 
mean. of four experimen 
Column (1) gives the aia of the center of needle from 
core; (2) the readings of the tangent galvanometer; (8) the de- 
flection of the compass needle for the distances given 1n column 
~() @) @) @ , & 6) @ 
Dist. from Nat. ‘Tan: |}: 2 1 
Core. Tan. Gal. | Deflection. Defi. | ad q?-1404 Dif. 
4 ft. or 1 51° 45/ 38° 16/ “788336 | “788336 “788336 “000000 
fo Paar bie 46" . “424475 | "829042 “782392 005944 
(Rigas! At) 51° 30’ 14° 30° -258618 *872835 “785629 “002707 
7 ot TB 1° 45S 9° 457 “111831 | ‘917888 “796385 008049 
oko 51° 30° 6° 44’ "118063 | -944504 “789144 “000808 
(1); the nat. tangs. of the angles of (8); (5) the products of the 
nat. tans. of the angles of deflection by the cubes of the distances 
in (1); these products being obtained by multiplying the nat. 
tan. of each angle of deflection by the corresponding distance 
pa the core raised to the cube, sould: if the law. followed the 
e can therefore assume eh “e intensity of the force (for this 
Geparnbas) varies inversely as the 2°7404 power (or as d™ Teo *) of 
distance from the core. 
res were made of each size wire. Hach core of de 
wire eontiied 100 pieces, while each core of the , wire con- 
sisted of 400 ¢ wires of one core of each size wire, 
(after having been cated, as in Ex. 7, that they were equally 
