142 



Intelligence and Miscellaneous Articles. 



The balloon containing the iodine is introduced into a horizontal 

 muffle made of fireclay ; this is placed in a stove heated by heavy 

 coal-oil, which comes through a graduated and very delicate cock. 

 For determining the temperature, I have utilized the new air-ther- 

 mometer described by M. H. Sainte-Claire Deville and me at the 

 meeting of the 29th of March last. The following are the results 

 of the experiments, made at elevated and easily-obtained tempera- 

 tures : — 





I. 



II. 



III. 



Volume of the balloon 



269-4 cub. cent. 



16°-5 

 756-14 millims. 

 -0-056 gram. 

 16-1 cub. cent. 



19° 



753-4 millims. 



14 cub. cent. 



21° -4 



541-4 millims. 



46-24 cub. cent. 



1-38 



21°-6 



438 millims. 



1235° -5 



5-82 



255 cub. cent. 



16°-5 

 755 millims. 

 +0-008 gram. 

 5-1 cub. cent. 



27° 

 745 millims. 

 14-2 cub. cent. 



27° _ 

 544-4 millims. 

 46-24 cub. cent. 

 1-59 



27°-7 

 440 millims. 



1241° 



5-71 



252 cub. cent. 



15°-8 

 757 millims. 

 -0-021 gram. 

 8 "6 cub. cent. 



18°-5 

 757 millims. 

 13 - 5 cub. cent. 



16°-2 

 534 millims. 

 46-24 cub. cent. 

 1-40 „ 



16° 

 434-3 millim. 



1250° 



5-65 



Temperature of the balance 



Atmospheric pressure 



Increase of weight , 



Gas remaining, measured moist... 

 Temperature 



Pressure 



G-as drawn from the reservoir . . . 

 Temperature 



Pressure 



Volume of the reservoir 



Gas drawn from the compensator 

 Temperature 



Pressure 



Temperature deduced 



Density, obtained by means of ] 

 the coefficient of expansion of j» 

 the air J 





The numbers given in this Table for the vapour-density of iodine 

 were calculated by assuming that that vapour possesses a constant 

 coefficient of expansion and equal to that of air. Is it right to 

 make that assumption ? I thought it necessary, in order to solve 

 this question, to make other experiments. These are the results 

 which I obtained by taking the densities at the constant tempera- 

 ture of the ebullition of sulphur, but under variable pressures : — 





I. 



II. 



III. 



.TV- 



V. 



Volume of the balloon 



Temperature of the balance 



Atmospheric pressure 



Excess of weight 



334 c.c. 



9°-5 



768-5 mm. 



+ 10-01 gr. 



4 c.c. 



9°-5 



768 mm. 



768 „ 

 8-70 



281 c.c. 



19°-8 



758-82 mm. 



-0-238 gr. 



0-7 c.c. 



23° 



676-8 mm. 



67-2 „ 

 8-20 



295 c.c. 

 20° 



755-72 mm. 



-0-286 gr. 



0-6 c.c. 



22°-5 



495 mm. 



48-6 mm. 



7-75 



3203 c.c. 



20° 



764-6 mm. 



-0-3035 gr. 



0-63 c.c. 



22° -8 



735-9 mm. 



48-57 mm. 

 7-76 



310 c.c. 



18°-8 



758 mm. 



-0-325 gr. 



0-6 c.c. 



24° 



485-5 mm. 



34*52 mm. 

 7-35 



Air remaining 



Temperature 



Pressure 



Presure at closing the"! 



balloon J 



Density obtained on ap- 1 

 plying Mariotte's law.. J 



The numbers given in this second Table were calculated on the hy- 

 pothesis that iodine vapour follows Mariotte's law exactly. 



