216 



PKOCEEDINGS OF THE AMERICAN ACADEMY. 



Length of windings = 485.3 cms. = 15 ft. 11 t^^ in. 



Outside diameter = 5.96 cms. 



Inside diameter =2.86 cms. 



Number of turns = 10452 for each of the two coils. 



TABLE VI. [No Figure.] 



November 6, 1906. 



Diani. = 0.2381 cm. = 3/32 in. 



Eeveesals. 



The two coils were used in parallel, so that the magnetizing field is 

 H' = 27.064 c.g.s. units for each ampere. 



The first rod tried in this solenoid was one of 0.9525 cm. diameter 

 (= I inch), and was a complete failure, although it gave some very 

 interesting results. No two consecutive step method magnetization 

 curves would agree. The rod was 15 feet long, so that m = 480. 



