the Hot (lases from Flames. 89 



must assume that in our case the charged carrier has joined 

 on to it a number of uncharged particles which increase 

 its mass without increasing the charge, thus lowering its 

 velocity under an electric force. We have not data enough 

 to determine the size of the carrier even if we assume that it 

 carries the atomic charge, as the carrier is so small that the 

 equations of viscous motion. do not apply. 



4. Difference of Velocity between Positive and Negative 

 Carriers. 



As we have seen, the above method of determining the 

 velocity of the carrier under an electric force gave results 

 which did not vary in a number of determinations by more 

 than 10 per cent. 



These determinations seemed to point to a difference in the 

 velocity of the positive and negative carriers ; and a large 

 number of experiments were made to settle the point. 



The velocities of the positive and negative carriers were 

 determined alternately a number of times by charging the 

 terminals alternately negatively and positively in the method 

 described above. As the method involves the ratio of two 

 rates of leak in the same direction in determining each 

 velocity, any want of symmetry in the deflexions of the 

 electrometer is eliminated. The results showed that the 

 velocity of the negative carrier was about 15 per cent, greater 

 than that of the positive carrier. 



The following experiment would be easily explained by the 

 negative carrier having a greater velocity than the positive. 

 The gas from the flame is drawn up a tube A connected to 

 earth, and through a metal box B which is insulated and filled 

 with a loose plug of glass wool. B is joined to a pair of 

 quadrants of an electrometer, the other pair being to earth. 

 In the tube is a terminal C, which can be joined to one pole 

 of an alternating circuit, the other pole being earthed. The 

 positive and negative carriers, passing through the glass wool, 

 give up their charge to it. 



When C is to earth the boxB gets a small negative charge; 

 we always do get a small negative charge from the gas from 

 a Bunsen flame. (Kelvin, ' Nature,' April 22nd, 1897.) 



"When now the terminal C is joined to the alternating 

 E.M.F., if the negative carriers move faster than the positive, 

 and the intensity and frequency of the E.M.F. be such that 

 not all the carriers of both signs are discharged, we get more 

 negative carriers discharged than positive, and the box B gets 

 an excess of positive. 



