234 Scientific Proceedings, Royal Dublin Society. 



was, however, subsequent to boiling, exposed in a thin layer to the air ; whilst 

 the tubes S3 and S4, on which Experiments 7, 8, 9, and 10 were performed, 

 contained unboiled sap of Ilex AquifoUum. 



In Experiment 3, after the bubble had been " closed " at a temperature of 

 63° C, the tube was maintained at about 61° C. for two days. During this 

 time no rupture appeared. 



The foregoing shows that the sap of trees has considerable tensile 

 strength, and in this respect does not differ from water. In the few 

 experiments made, the ease with which tension was generated and its 

 magnitude before rupture occurred possibly indicate that sap is somewhat 

 more stable under tension than pure water. 



LiTERATUKE. 



1. AsKENASY, E. — Ueber das Saftsteigen. Verb. d. Naturhist.-Med. 



Vereins zu Heidelberg, N.F., Bd. v. 1895. 



2. BoHM, J. — Capillaritat und Saftsteigen. Ber. d. Deutsch. Bot. Q-esell., 



1893, Bd. xi, p. 203. 



3. Dixon, Henry H. — A Transpiration Model. Proc. E. Dubl. Soc, 



vol. X (N.S.), Pt. 1, No. 9, 1903. 



4. Dixon, Henry H. — Note on the Tensile Strength of Water. 



Proc. R. Dubl. Soc, vol. xii (N.S.), No. 7, 1909, and Notes from 

 the Botanical School, Trinity College, Dublin, ii, No. 5, 1909. 



5. Dixon, Henry H., and J. Joly. — On the Ascent of Sap. Phil. Trans. 



R. Soc, vol. clxxxvi (1895), B. 



6. Tait, p. Gr. — Properties of Matter. Edinburgh, A. & C. Black, 



1885. 



7. Dksprung, a. — Zur Demonstration der Fliissigkeitskohasion. Ber. d. 



Deutsch. Bot. Gesell., 1913, Bd. xxxi. Heft 8. 



