346 Scientific Intelligence. 



4" per cent more heat when their chlorophyl was abstracted by 

 ether or alcohol. In thick tough leaves such as lilac or elm, 

 however, I was unable to detect its influence. It will be seen 

 upon referring to the table that rather more heat seemed to be 

 transmitted by the petals of flowers than by leaves. Natural 

 selection has forced all leaves to the optimum as regards trans- 

 mission and absorption of heat, and hence we lind but little 

 difference in the behavior of leaves of widely different genera 

 of plants in this respect. Their surfaces have become the best 

 known absorbers of heat, and in order to counterbalance the 

 consequent disadvantage of being the best of radiators, the 

 dew, which collects upon them at night, cuts that radiation 

 down. 



In conclusion, it gives me pleasure to acknowledge my great 

 indebtedness to Professor Trowbridge, who kindly placed at 

 my disposal the excellent apparatus and facilities of the Jef- 

 ferson Physical Laboratory. 



Cambridge, October, 1892. 



BIBLIOGRAPHY. 



There appears to be no bibliography relating directly to the 

 whole subject of the above paper. For reference to some of 

 the few works relating more or less directly to it, I am indebted 

 to the kindness of Professor Goodale. 



Dntrochet, La Chaleur propre des etres vivants k basse temperature, Annales des 

 Sciences JSTaturelles, Botanique, 2 serie, tome xiii. 



Maquenne, La Diffusion, L' Absorption et L'Emission de la Chaleur par les 

 Feuilles ; Annales des Sciences Xaturelles, Botanique. 6 serie, tome x 



]ST. J. C. Muller, Handbuch der Botanik. Neunte AbtheDung : Einwirkung der 

 Warme. Heidelberg, 1880. 



Sachs, Physiologie Vegetale, Chapitre deuxieme. Geneve, 1868. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On an improved Boiling-point apparatus for determining 

 Molecular Masses. — Three effects are now made use of for deter- 

 mining molecular masses; (1) the decrease of vapor-pressure, (2) 

 the lowering of the freezing point, and (3) the raising of the 

 boiling point, of a solvent by dissolving in it the substance to be 

 examined. Sakurai has devised a simple and valuable modifica- 

 tion of the apparatus described by Beckmann for determining 

 the molecular mass of a substance by the elevation of the boil- 

 ing point which a known quantity of it produces when dissolved 

 in a known quantity of the solvent. The boiling vessel is a U 

 tube of glass about 2 cm in internal diameter and 21 cm in height. 

 Near the top of one of the legs is a lateral tube for attaching a 



