842 



is the relation between the ordinate at the minimum z^ of one of 

 the curves and its width 2p ^). 



^ 7. Before proceeding to the discussion of the case I- <^ we shall 

 first consider another problem, that of the ascension (or depression) 

 of a liquid on the outside of a wide circular tube which is immer- 

 sed in an inünitely extended liquid ; the meridional curve then shows 

 an infinitely extended branch RST (fig. 3) which may also be 



Fig. 3. 



realised, in that case up to Q (cf. § 12), by lifting from the liquid 

 a broad circular plate which is moistened by it. 



The equation to this branch is found in a similar way to that 

 of the branch OEAB in fig. 1. We may again divide the curve 

 into a marginal part whose abscissae measured from .ry = I are 

 small with respect to / and a more distant part in which u becomes 

 comparable to / and even large as compared to it, (f differing little 

 from zero (<^ = at infinity). 



In the same way as in §^ 2 and 3 (equation (2) is still valid) 

 considering that 2 = for cp =: 2-t and u = for <p = Jt we find 



1) Putting XG—XD = 25, this gives pV'k = q^k — 0,532 (see § 3), and 



z, |/yfc=: 1,842 e-n^^- ...... (20') 



