426 



DK. T. R. LYLE ON THE SELF-INDUCTANCE OF 



sides. These figures will enable the G.M.D. for values of c/b or b/c, intermediate to 

 those given in the table, and consequently the first or important term of L for such 

 intermediate values to be obtained with great accuracy. 



Table II.- contains the values of the coefficients m,, m 2 , n l} n. it n x , for thick coils, that 

 is for ones in which b is greater than c for different values of the ratio c/b, and 

 Table III. contains the values of the same coefficients for thin coils, that is for ones in 

 which b is less than c for different values of the ratio b/c, 



TABLE II. 



It will have been noticed that the coefficient m Y and m a are algebraic and can be 

 easily calculated for any value of c/b. Those in the tables are given for convenience. 

 6. If the formula for L given in 2 be written in the form 



a [7, d 2 , d*\, Sa , , , <P , , cZ 4 l 

 L = t-ran* f l+m, -,+m, -Jlog -r-^+Z, - 2 +4 -, L 



L \ d \JU I 'ji C* C* _J 



tables giving m lt m 2 , Z , l lt and 1 2 , for different values of c/b would also render easy 

 the computation of the self inductances of coils. Such tables have been computed from 

 WEINSTEIN'S formula by STEFAN,* but he is in error in thinking that the second order 

 coefficient has the same value for a given value of b/c in a thin coil as it has for the 



WIED. Ann.,' 22, p. 113, 1884. 



