Phil.Mag.S.5.Vol.30.Pi.X. 



100 200 300 400 500 600 700 800 900 I00O 



Pig. 6 . 

 Bow-shaped cycles, cb.bccLn&cl irv comparing 

 i}ic Tait irith the JBourdoTV gauge. 



Tffin±err<. Bros . Tith.. 



