KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 



TE AMSTERDAM. 



PROCEEDINGS 



VOLUME XX 



N°. 1. 



President: Prof. H. A. Lorentz. 

 Secretary: Prof. P. ZEEMAN. 



(Translated from: "Verslag van de gewone vergaderingen der Wis- en 

 Natuurkundige Afdeeling," Vol. XXIV, XXV and XXVI). 



CONTENTS. 



H. A. Lorentz : "On Einstein's Theory of gravitation". Part III. p. 2, Ibid. Part IV, p. 20. 



J. P. Treub: "On the Saponification of Fats." I. (Communicated by Prof. P. Zeeman), p. 35. 



P. VAN ROMBURGH and J. M. VAN DER ZANDEN: "On Polymers of Methylchavicol. " (Preliminary 

 communication, p. 64. 



C. F. VAN DuiN: "Action of Organo-magnesium Compounds on, and Reduction ofCineol." (Commu- 

 nicated by Prof. P. VAN ROMBURQH), p. 66. 



Miss M. A. VAN HERWERDEN: "On the nature and the significance of volutin in Yeast-cells." (Com- 

 municated by Prof. C. A. PEKELHARING), p. 70. 



H. I. WATERMAN: "Influence of different compounds on the destruction of monosaccharids by 

 sodiumhydroxide and on the inversion of sucrose by hydrochloric acid. Constitution-formula 

 of a-amino-acids and of betain". (Communicated by Prof. J. BöESEKEN), p. 88. 



Th. DE Donder: "Sur les equations différentielles du champ gravifique". iCommunicated by Prof. 

 H. A. LORENTZ), p. 97. 



B. P. HAALMEIJER: "On Elementary Surfaces of the third order." (First communication). (Communi- 

 cated by Prof. L. E. J. BROUWER), p. 101. 



W. VAN Bemmelen and J. Boerema : "The semi-diurnal horizontal oscillation of the free atmosphere 

 up to 10 km. above sea level deduced from pilot balloon observations at Batavia". (Communi- 

 cated by Dr. J. P. VAN DER STOK), p 119. (With one plate). 



Proceedings Royal Acad. Amsterdam. Vol. XX. 



