76 
MESSRS. G. F. C. SEARLE AND T. G. BEDFORD 
Experiments on Steel. 
§ 54. W — Bq Curve for Zero Stress .—The first set of experiments 'was made 
upon a steel rod •09125 sq. centim. in section. To find how Bq and W depend upon 
Hq, when there is no torsion, we made a series of observations for Bq and W, using the 
key of § 31, and varying Hq from 37‘4 to 5‘0; the results are given in the table 
below. The electro-dynamometer was not sensitive enough to allow us to work with 
magnetic forces less than 5 units. These observations will serve as an example of 
the application of the method described in this paj^er to determine the manner in 
which W depends upon Bq, when Bq is made to vary by changing Hq, the stress 
being constant. The curve representing these observations is shown in fig. 8. The 
numbers placed along the curve show the values of Hq for which the values of Bq and 
Wq were found. The curves (1) to (4) are considered in § 66. 
