IR.IXS.II I.IXI IC A'.//'/() ll.l.lirilOSr IKAXSMISSIOS 4}<5 



|i,irticular tiim- of day for wliirli i-acli of \\w sunsi-t curves is taken, is 

 that at which tin- static in I.oiulon bi'Kins to increase to lar^e ni^ht 

 values. In winter, this occurs about sunset, at the eciuinox al)out 

 one hour earlier, anil in siuniner about two hours earlier, as illustrated 

 in I'ig. 18. C'orrespondingK-, the time for which each of the sunrise 

 curves is taken, is that at which ihc iiii;Ii iiiijlit-iinie values have 

 reached the lower d.i\lii;hi \.iliir-. I'loin lit;. 1^ ii will be e\i<lent 



Fig. 21 — Relation of sunrise shuduw wall tonoiseat New Southgate, England- 

 (Jct. 28-29, 1923 



