CUM'! CTIvn V AN'D l.r.MlNMSTTY OF M.AMKs C'NTAIMN<; \ \!' M;M-:I . 8ALT& |-J| 



It has already been shown that the free flame has a measurable though small 

 conductivity, and, for the sake of oompariaoa, the numbera obtained on p. 98 are 

 appended to those obtained by spraying half normal solutions of HC1 and H;.SO 4 . 



K.M.F. 



5-60 

 227 



Distilled water. 



64 



N 



iici. 



1-46 

 396 



105 



The conductivity of the acids is thus very small in OOmpariaoD with that of the 

 alkali salts.* 



We also investigated the conductivity of ammonium chloride, and found it to be 

 almost the same as that of an equivalent solution of hydrochloric acid. This is readily 

 explained by the dissociation of the salt into HC1 and NH, at the temperature of the 

 experiment. 



The following values, corrected for the conductivity of the free flame, were 

 obtained : 



In the flame the H 2 SO 4 is no doubt largely decomposed, yielding sulphur dioxide, 

 whilst the hydrochloric acid is more stable. This accounts for the greater conductivity 

 of the hydrochloric acid. 



It is possible that in these cases, where the conductivity is small, dust particles 

 entering with the air may have an appreciable effect. It is impossible to estimate 

 this effect ; we sought to reduce it as far as possible by filtering the air through 

 cotton wool. If we consider it to have been insignificant, it is possible to make a 

 comparison of the conducting power of water and hydrochloric acid in the flame. The 

 quantity of water vapour in the flame with a spray of distilled wat6r was many 

 hundred times, probably many thousand times, the quantity of hydrochloric acid in 

 the flame when a half normal solution was sprayed. The numbers given above show 

 that the conductivity of the hydrochloric acid is at least two or three times that due 

 to the water vapour alone. 



Experiments ivith Decolorized Flames containing Salt Vapours. 



The introduction of chloroform vapour into a flame coloured by the vapour of a 

 lithium salt completely destroys the coloration (SMITHELLS, 'Phil. Mag.,' (V), 39, 

 122, 1895). The chloroform affords a convenient means of supplying an abundance of 



VOL. cxciii. A. R 



