TRANSACTIONS OF SECTION B. 



487 



S. The Velocity of Explosion of a Mixture of Carbonic Oxide and Oxygen 

 ivith varying quantities of Aqueous Vapour} By H. B. Dixon, M.A. 

 The author endeavoured to compare the velocities of explosion of mixtures of car- 

 Ibonic oxide and oxygen with varying quantities of aqueous vapour hy observing the 

 pressure registered in a mercurial gauge attached to the Eudiometer in which the 

 -gases were tired. In each experiment the same mass of carbonic oxide and oxj-gen 

 was exploded at nearly constant temperature and volume. The gauge was U-shaped 

 And contained air in the closed limb. An index, similar to those used in Six's ther- 

 mometers, was carried up and left at the highest position reached by the mercury. 

 Near the bend of the gauge, two bulbs were blown in the tube as reservoirs, enabling 

 the mercury to be lowered in the Eudiometer without permitting the air to escape 

 from the closed limb. 



In two experiments a trace only of aqueous vapour was present. The Eudio- 

 meter was dried at 80^ by drawing through it for half an hour airwhich had 

 passed through two sulphuric acid drying tubes and a small tube containing phos- 

 phoric oxide. It was found that, by this method of drying, just sufficient aqueous 

 vapour remained in the tube to enable the explosion to talje place slowly when 

 sparks from a Ruhmkorff's coil were passed through the mixture of carbonic oxide 

 and oxygen. In the first experiment several sparks were passed before the gases 

 took fire. In both experiments the flame took about two seconds in passing down 

 the length of 500 mm. occupied by the gases in the Eudiometer. In three other 

 experiments measured quantities of aqueous vapour were added, the vapour being 

 kept below the satiu-ation point ; and in the last two experiments the space was 

 satm-ated with aqueous vapour, and the sides of the Eudiometer were wet. The 

 following table gives the quantities of aqueous vapour in each experiment,^ the 

 readings of the pressure gauge and the pressures corresponding with these readings. 



Explosion of Carbonic Oxide and Oxygen with varying rpiantities of Aqueous 



Vapour. 



On the Boiling Points and Vapour Tension of Mercury, of Sulphur, and 

 of some Compounds of Carbon, determined by means of the Hydrogen 

 Thermometer. By Professor J. M. Grafts. — See Reports, p. 317. 



5. On the Occurrence of Telluritcm and Selenium in Japan. By Professor 

 Edward Diveks, M.B., and Masachika Shimos^. 



Notice of the occurrence of tellurium and selenium in sulphuric acid ruade from 

 Japanese sulphur was given by one of the authors to the British Association at its 



' Printed in extenso, Chemical Kervs, vol. xcvi. p. 151. 



