26 



T. Terada 



the actual annual course of the daily variation under the light of 



the present theory. 



27ric 

 Referring to § 5, we have, when a = a+b cos— ^j 



A I A I 



putting yi=p in (13). If ^ is large compared with 1 and we may 

 neglect 1 against p^, we have approximately 



27tX 



»J I oc 



a + hp^ cos 



I 



The assumption that p is large, corresponds to the case when 

 we are considering the local irregularities of the daily amplitude 

 of temperature within a narrow extent of land and water, whose 

 linear dimension is negligibly small in comparison with the earth's 

 circumference. In such a case, the quantity h, representing the 

 deviation of the amplitude from the mean value, will necessarily 

 be small in comparison with a. 



If hp^<za, «1 will have one maximum at a;=0 and a minimum 

 at x=lß. But if hp^^>a, \ a^ \ may have two maxima at and t: and 

 two zero between them. Taking the equation for the general 

 value oi p, compare two special points x=^0 and x=I/2, for which 

 the amplitudes are a^ and a/ respectively. Then 



a 



1— ^(i^' + l) 

 a 



Now consider 6 as a periodic function of season, and put 



6 = 6(1 + 6i cos 7i{t + (f), 

 then we have 



1 + io_(y + 1) + A_(p2 + 1) cos n(^ + ip) 



l_A.(y+l) — ^(/+l)cosw(^ + ^) 

 a a 



a) If both bo(p^+l)/a and bj{p^ + l)/a be small compared with unity, 



