Equipotential Lines of an Electric Current. 423 
The measurement with calipers in this case was not made 
with great care, and the correction here applied is open to 
some suspicion. 
With this strip the space between the brass strips B, B 
(fig. 1) was about 3:2 millim. 
B. ..(No..1.) 
Length of main strip when weighed . 4°58 cm. 
Width of main strip when weighed. . 1:08cm. 
Area, including that of thearms . . 5°32 cm. sq. 
Ben ee ee es. PhS 4 ee 
Density .. Pita aati fo, 
Average i fuom fheco! fala 4s 23"°00403em:- 
From the indications of the calipers I concluded that the 
thickness between the arms was about 13 per cent. greater 
than the average thickness. 
Hence thickness between the arms ‘00409 cm. This value, 
like that given for A, may be wrong to the extent of several 
per cent. “Distance between strips B, B about 3°2 cm. 
Capt No. Es) 
Length of main strip when weighed . 38°75 cm. 
Width of main strip when weighed. . 1:08 cm. 
Area of whole se when Beret . 4°39 cm. sq. 
Meo ht ..!. . 4502 L085 arma, 
Density. . 844 
Average thickness from these data. . 00292 cm. 
By calipers, thickness at one end ‘0034 ; at other end -0032; 
between arms ‘0034; average ‘00333 cm. Take, then, for true 
thickness between arms, ‘00299 cm. Distance between strips 
B, B, about 3:2 cm. 
De 2: (Neel:) 
Length of main strip when weighed . 3°86cm. 
Width of main strip when Peer . 1:07 cm. 
Area of whole stri oe . . 445 cm. sq. 
vee! . 7. get shen 3. UT OS® mene 
Density .. See Ore 
Average thickness from these data. . -00291 cm. 
_ By calipers, thickness at one end ‘0030 ; at other end ‘0030 ; 
between arms ‘0032; average ‘00307cm. Take for true 
_ thickness between arms, ‘00304 cm. Distance between strips 
B, B, about 3:2 cm. 
