Dixon — On the Tensile Strength of Sap. 



233 



Table. 



For the oaleulation of the results displayed in the table the formula 

 kindly given to me for my previous work by Mr. J. E. Cotter has been used, 

 viz. : — 



{n - (/) (U - ti) 



T = 



/3[1 -aif,- h)] + 



^^- 



■ + — 



in this 



T = tension in atmospheres. 



a = coefficient of expansion of water over the range.* 



jS = „ compressibility of water.f 



g = „ cubic expansion of glass = 2'4 x 10^ 



fo = temperature when the tube is full, viz. a ' closing' temperature. 



ti = „ „ rupture occurs. 



R = External radius of tube. 



r = Internal ,, ,, 



k = Compression modulus of glass (volume elasticity) = 4 x 10'* atra. 



n = Torsion modulus of glass (torsional rigidity) = 3 x lO'* atm. 



The tubes Si and Sj were filled with boiled sap of lagu& 



, which 



* Landolt-Bomstein, Physikalisch- Chemische Tabellen, Berlin, 1905, pp. 38 and 39. 

 t Idem, p. 60. 



2o 



SOIENT. PBGC. R.D.S., VOL, XIV., NO. XVI. 



