182) CG. Rockwood—Motion of a Tower by Solar Heat. 
any such retarding effect as has been supposed should be greater 
when the absolute amount of motion was greater, and therefore, 
should be more evident on the curve for clear days. 
morning observation (marked 1), may be found upon a curve 
nearly similar to the one for clear days. And the distorted 
day. Consequently, when the effect begins to be bet the 
tained out of its normal position by a considerable amount. 
ellipse should be to each other as sin 21° to sin 90°, or ass 
to 100. Now the minor axis is about 7” hence the major 
would probably also affect this element. : oo 
The curve deduced from the observations is thus seen 
exhibit a sufficient degree of correspondence, with what had 
been anticipated from theoretical considerations, to co firm the 
truth of the reasoning ; the departures from the perfect ellipse 
can etrical 
be ascribed to the unsymm 
