368 Intelligence and Miscellaneous Articles. 



tions with one and the same voltaic avc—Annalen der PhysiJc, 

 vol. xxvi. p. 518. 



ON THE DEVIATION OF OXYGEN FROM BOYLE AND MARIOTTE'S 

 LAW UNDER LOW PRESSURES. BY CHRISTIAN BOHR, OF 

 COPENHAGEN. 



In a series of absorptiometry determinations which I made in 

 the course of the last few years, on the loosely combined oxygen in 

 oxyhemoglobin, the experiments made under low pressures of 

 oxygen always showed irregularities, which, notwithstanding all 

 the trouble I expended, could not be eliminated. In inquiring 

 after the cause of these irregularities, I was led to look for it in 

 the calculations necessary, in all such experiments, for converting 

 the volume of the gas from the pressure before the absorption to 

 the smaller pressure after the absorption. 



This calculation was made of course by Boyle and Mariotte's 

 law. The object w^as therefore to investigate with what accuracy 

 oxygen follows the law in question under low pressures, in order, 

 if possible, to obtain data for the experiments on dissociation. In 

 this way arose the present series of experiments, in which it is 

 indisputably proved that oxygen differs considerably from the law 

 under the conditions in question. In the course of the experi- 

 ments, the unexpected phenomenon w x as met with that the curve 

 which expresses the relation between volume and tension exhibits a 

 strongly marked discontinuity at a certain tension, which seems to 

 suggest that here there is an alteration in the molecular compo- 

 sition of oxygen. Hence in the experiments great weight was laid 

 on an accurate determination of this point. 



After describing the experiments, the author sums up his con- 

 clusions as follows : — 



I. At a temperature between 11° and 14° C. oxygen deviates 

 from Boyle's law within the limits in question. The dependence 

 between volume and pressure for a value of the latter which is 

 greater than 0*70 millim. may be approximately expressed by the 

 formula 



(p + 0-109>=k; 



while the formula for values of the pressures which are less than 

 0-70 millim. is 



(j3 + O070> = k. 



II. If the pressure sinks below 0*70 millim., oxygen undergoes 

 a change of state ; by raising the pressure above 0*70 millim. it 

 may be restored to its original condition. — "Wiedemann's Annalen, 

 No'. 3, 1886. 



