Rev. J. B. Emmett on Capillary Attraction. 333 



The volume of A = -^; volume of B = -^ ; volume of C 

 _ ^ + ^ 



But since each substance A, B, is diffused throughout the 

 whole volume, 



'^ + ^ .jL::a: density of A in its diffused state = j— ; 



c ' n 



also ^-t^ ■.-^::b: density of B in its diffused state = ■^^. 

 Hence, (Note f, p. 118, No. for February) 



Force of A = H. ^-^; force of B = «.^; and the 

 sum of these forces is equal to the force of the compound 



h'c; i. e. 



iid + hc _j^, (a) 



d + e 



and H'{d^e\- nd^ ^ ^ ^j^^ 



But if, as generally happens, three tubes of different dia- 

 meters A, 8, S, are used respectively for the liquids A, B, C ; 



then h' = —c T- ^''' 



V\d-\-e\ 



Again : since the force of attraction is proportional to the 

 altitude of the column, multiplied into the density of the liquid, 

 in the same tube ; 



Force of C = /.'c = i^t^- [d) 



By transposing the equations c and d, the forces of attraction 

 may be found under all circumstances. • , , . 



The primary formula (a) may be derived more simply, but 

 not so satisfactorily, thus : ^ „ , r c n hi 



Force of A = Hr/; force of ^ = he; force of C = A 

 \d + e\\ the same tube being used. h </ + a c 



But n d + he = h' [d+e]; therefore h' = -^z^-, as 



%Tanv solution or compound .Z and ^ being known ; and 

 H and //, or II and h', or h and h' being found by experiment, 

 the force may be found, when the tubes are equal, by iomnila. 

 (a) or (h) ; or in uncjual tubes by (c), or (c) transposed, if H or 

 /: be reciuired : and the force of attraction between tlie solid 

 and the compound, or the solid and one of the component 

 parts of the liquid at any temperature is found by {tl). 



The following table exhibits a few results, the data of the 

 ° annexed 



