270 



K. Y AM AG A WA 



From this onvvo, tein])oratiiros rorrosponiliniif to every 41.0 



- o 



.seconds or to f= T —. — were cnliMiliited, nrid the curves 

 y = ?(„ mil It: -qr 



= 7f,, COS -TT -ypr 



were (h'nwii ; cnrefnl measiireinents <rjive 



A^= - 24787. 



A[= - :52294.(;. 

 whence 



ß^ -= .-,2°-2!V_:U" 



a,- - 27.1 :iO 



Referring to the curve sliowing tlie relation hetween D Mnd N, 

 we nt once see that tlie vahie of .S, must he nearly tt. Now assuiiiing 

 that .S\ is near tt, e"-'"' would he exceedingly small, so tliat it is negli- 

 gihle in comparison with £+-'^' ; and with an assumed a|)|iroximate 

 value for 2 co.s 2.S',, the value of a, gives 

 ,S, = 2.990 



If -S'l l)e near tt, .^, , mnv he taken ciiual to iiiiitv for a hrst 

 ' e i'^i — I ■ ' 



a])])roxiuiation ; then 



tan l>i ^ ± tail (^ii n + S^) 

 Hence 



S^ = :5.272 or = :î.01 1 



If we eidculate ^ifroni these values, we o])(ain respecjtively 



ai = - 22.:i8 and ol^ - - 2(1.1 !■ 



Theri'fire the second \ahie must, he tlie first a[)[>ro.\imalion to the 

 true value. 



As — :;^ j- varies very slowly when N, is large, to calculate it. 



