682 



Micropliotograplis of tliese, enlarged about 500 times show immediately 

 that tlie theoretical deductions in my paper are confirmed. In fig. 8 

 a transverse section through a light-negative shows a strong deposit 

 of silver in the upper part of the gelalinelayer and liardly any 

 silverparticles in the deeper strata. A section through a Röntgen- 

 füm made with soft rays (3° Bknoist) is shown in fig. 9. The silver- 

 particles are almost equally distributed in the layer. From a negative 

 with hard X-rays [8° Bfnoist) I got the photograph shown in fig. 10, 



Fis. «■ 



Fiff. 9. 







Fig. 10. 

 in which the surface of the gelatine contains more silverparticles 

 than the deeper strata. With rays of medium hardness I found a 

 more even distribution of the silver particles, showing that these 

 rays contained only a limited amount of exti'emely soft rays. 



