under the Influence of the Electric Discharge, 409 



The numbers in the last columns of I and II agree as well 

 as the complicated conditions of experiment allow. They 

 show that " the quantity of energy absorbed from the discharge 

 to change the band spectrum into the line spectrum for a given 

 quantity of hydrogen is independent of the pressure.-" The 

 ratio of the quantities of heat necessary per unit of area in 

 order to convert band spectrum into line spectrum in I and 

 II is, since the lengths of tubes giving off heat are equal, 

 (0-183) 2 x 0-0000155 x 11-84 _ 617 x 1Q- 8 _ 

 (0-304) 2 x 0-00000565 x 12-08 ~~ 631 x 10~ 8 ~ u ' J7y ^ 

 a number as nearly equal to unity as can be expected in ex- 

 periments of such unusual difficulty. 



We may hence conclude that the quantity of heat to be given 

 up by the discharge to the unit weight of gas in order to change 

 the band spectrum into the line spectrum is independent of the 

 pressure and of the section of the tube. We may also easily 

 calculate (1) how great the quantity of heat is in absolute mea- 

 sure necessary for 1 gr. hydrogen to effect this change; (2) how 

 great a quantity of electricity is necessary at any given pressure. 



The water-equivalent of the calorimeter I is 11*84, the rise 

 of temperature for each discharge 0*0000155, the length of 

 the portion of tube in the calorimeter 4*2 centims.; so that the 

 quantity of heat given per unit length in each discharge is 



11-84x0*0000155 . . 



t—^ calories. 



4*2 



The volume of the gas per unit length is, since the section of 

 the tube is 0*0029 square centim., 0*0029 cubic centim., and 



. , , , 1 „ r 1 1x0*0029x0-069 

 its weight at 1 millim. pressure =^ X 7"9-qa & r * 



The quantity of heat necessary for 1 gr. hydrogen is therefore 



11-84x0-0000155x760x773-3 1QQ3nn , . 



-j-q — n — ( =128o00 calories. 



4'2 x 0*0029 x 0*069 



Let us further determine the quantity of electricity per unit 

 area of 1 square millim. to convert the band spectrum into the 

 line spectrum. 



If we choose the case when the pressure was 2*2 millims. in 

 the first tube, the number of discharges for a deflection of 

 100 (when the band spectrum changes to the line spectrum) 

 was about 200. A deflection of 0*5 corresponds therefore to 

 one discharge in which the quantity of electricity passes across 

 a section of 0*29 square millim.; so that the quantity of elec- 

 tricity per square millimetre corresponds to a deflection 1*73, 



0*000336x1-73 rtnAnnnKQ1 -n . „ «. 

 = ~~Tm = 0*00000581 Damell-Siemons. 



