CONTENTS XV 



Physics. H. R. Woltjer and H. Kamerlingh Onnes: "Further experiments 

 with liquid helium. T. Magnetic researches. XXIII. On the magnetisation 

 of gadolinium sulphate at temperatures obtainable with liquid helium." 

 626. 

 — A. MiCHELS: "The influence of rotation on the sensitiveness and the 

 accuracy of a pressure balance." 805. 



— G. Breit and H. Kamerlingh Onnes: "Magnetic researches. XXVI. 

 Measurements of magnetic permeabilities of chromium chloride and 

 gadolinium sulphate at the boiling point of liquid hydrogen in alternating 

 fields of frequency 369.000 per second". 840. 



Physiology. H. J. Hamburger: "A new form of correlation between organs." 

 420. 



J. B. Zwaardemaker: "The presence of cardio-regulative nerves in 

 petromyzon fluviatilis. ' 438. 



— R. Brinkman and A. v. Szent Gyorgyi: "Researches on the chemical 

 causes of normal and pathological haemolysis." 470. 



— H. Zwaardemaker, W. E. Ringer and E. Smits: "Is caesium radio 

 active?" 575. 



— W. F. Einthoven : "The string galvanometer in wireless telegraphy." 

 635. 



— Miss L. Kaiser: "Contributions to an experimental phonetic investiga- 

 tion of the Dutch language. I. Tiie short o." 745. 



— J. van der Hoeve and H. J. Flieringa: "Determination of the power 

 of the accommodation-muscle." 763. 



— J. G. DussER DE Barenne and J. B. Zwaardemaker: "On the influence 

 of the vagi on the frequency of the action currents of the diaphragm 

 during its respiratory movements." 771. 



Plane pencils (On the) containing three straight lines of a given algebraical 

 congruence of rays. 522. 



Pliocene and pleistocene mammals (New findings of) in Noord Brabant, 

 and their geological significance. 199. 



Points of continuity (On the) of functions. 187. 



Points of space (Representation of a tetrahedral complex on the). 390. 



Polarity (On the determination of) in the epidermal ciliated cell. (After 

 experiments on amphibian larvae). 702. 



Polarkurven (Ueber die zu einem Punkte und einer Geraden gehörigen) 

 inbezug aut eine gegebene algebraïsche Kurve. 783. 



Posthumus (O.). Contributions to our knowledge of the palaeontology of 

 the Netherlands. I. Otoliths of teleostei from the oligocene and the 

 miocene of the Peel-district and of Winterswijk. 231. 

 — Contributions to our knowledge of the palaeontology of the Netherlands. 

 II. On the fauna of the phosphatic deposits in Twente. (Lower oligo- 

 cene). 235. 



