CONTENTS Xin 



Mixtures (Isotherms of di-atomic substances and their binary). XX. The 

 critical curve of oxygen-nitrogen mixtures, the critical phenomena and 

 some isotherms of two mixtures with 50"',! and 75 "'o by volume of 

 oxygen in the neighbourhood of the critical point. 49. 



Movements (On stimulation in auxotonic). 171. 



Nerves (The presence of cardio-regulative) in Petromyzon fluviatilis. 438. 



Neurology. C. Winkler; "A partial foetus removed from a child." 493. 



Nitrogen fixation by means of the cyanide-process and atomic structure. 

 480. 



Null system (A) (1, 2, 3). 124. 



Oligocene (Otoliths of teleostei from the) and the miocene of the Peel- 

 district and of Winterswijk. 231. 



Oligocènes (Sur quelques nouveaux insectes des lignites) de Rott. Sieben- 



gebirge (Rhénanie). 605. 

 On nes (H. Kamerling h) and W. Tuyn. Further experiments with 



liquid helium. S. On the electric resistance of pure metals, etc. XII. 



Measurements concerning the electric resistance of indium in the 



temperature field of liquid heliuin. 504. 



— and H. R. Woltjer. Further experiments with liquid helium. T. 

 Magnetic researches. XXIII. On the magnetisation of gadolinium sulphate 

 at temperatures obtainable with liquid helium. 626. 



— and G. Breit. 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. 



OoRDT (G. J. VAN). Secondary sex-characters and testis of the ten-spined 

 stickleback (Gasterosteus pungitius L.). 309. 



Organs (A new form of correlation between). 420. 



Osthoff's estimates of star-colours (On the magnitude equation of). 12. 



Otoliths of teleostei from the oligocene and the miocene of the Peel-district 

 and of Winterswijk. 231. 



Oxygen-nitrogen (The critical curve of) mixtures, the critical phenomena 

 and some isotherms of two mixtures with 50 "/g and 75 " n by volume 

 of oxygen in the neighbourhood of the critical point. 49. 



Palaeo-botany. O. Posthumus: "Etapteris Bertrandi Scott, a new etapteris 

 from the upper carboniferous (lower coal-measures) from England, and 

 its bearing to stelar-morphological questions." 669. 



Palaeontology. I. Swemle and L. Rutten : "New findings of pliocene and 

 pleistocene mammals in Noord Brabant, and their geological signific- 

 ance." 199. 



