AND IJ-MIMKITY <>! n..\\n iININO T APOBBD L2fi 



<TO KC1 161, 



., KBr 1G3, 



KNO, icu, 



. 171. 



The conductivities of the four salts art- almost equal at the concentration used ; the 

 two haloid salts have somewhat less values than the two oxysalts. 



It appears, therefore, that the smaller quantity of water in the cyanogen flame has 

 not had a marked effect in bringing out the individual conductivities of the salta It 

 would, however, be unsafe to draw any positive conclusion as to the cause of con- 

 ductivity from these experiments. We were deterred from prosecuting the enquiry 

 further, because of the non-comparable character of the two flames in resj>ect of 

 temperature, a factor which has so great an influence on conductivity. 



It will be noticed that the conductivity of salts in a cyanogen flame is about 

 ten times that which they have in a coal-gas flame. The cyanogen flame without salt 

 also conducted about ten times as well as the coal-gas flame without salt. We found 

 that a cyanogen flame, into which a bead of salt was introduced by means of a platinum 

 wire, showed a very high degree of conductivity. This was largely due to the very 

 rapid rate at which the bead was vaporised ; it shows at the same time that high 

 conductivity may occur in the absence of hydroxides. 



Consideration of ftesidts. 



We have not given, and do not think it necessary to give, an account of all previous 

 investigations on the electrical conductivity of flame gases.* In recent times the 

 conductivity of salt vapours has been investigated by WIEDEMANN and EBERT 

 (' Wied. Ann.,' 35, 209, 1888), J. J. THOMSON (' Phil. Mag.,' (V), 29, 356 and 441), and 

 by ARRHENIUS (loc. cit.), with a view to determining its character, whether electro- 

 lytic or otherwise. WIEDEMANN and EBERT, working with high electromotive force 

 and comparatively cool electrodes, came to the conclusion that the discharge through 

 flames was of a disruptive character, and facilitated in different degrees by the vapours 

 of different salts. THOMSON, using a highly heated porcelain tube, provided with 

 platinum electrodes, considered his results to indicate an electrolytic conduction. The 

 conclusions of ARRHENIUS, as has already been stated, are entirely in favour of the 

 view that the conduction of salt vapours is electrolytic in character. 



Our own results do not seem to admit of any other explanation than that the 

 conduction of salt vapours is electrolytic in character. At the same time the features 

 presented by the conduction in the case of salt vapours do not correspond in every 

 particular to those of the conduction of salts when dissolved in liquid solvents. In 



* A good summary is given by HEMITINNE (' Zeitschf. f. Phys. Chem.,' 12, 244, 1893). 





