ELASTIC PROPERTIES OF SELENIUM. 



139 



that the changes in the rate of fall, due to illumination, in 

 the cases examined, were much greater than those due to 

 the small variations which took place in temperature. 



Table I. 



Date. 

 1916 

 A pril 



Time. 



Reading 

 cm. 



R;tte 



10- 6 cm. 



r>f Pall 

 per min. 



Temp. 



° C. 



7th 



4-30 p.m. 



2- 9286 



129 



Dark 



21-4 



8th 



9-10 a.m. 



2-7995 







21-2 









471 



Light 





51 



12 09 p.m. 



2-7151 



59 



Dark 



21-2 



10th 



9-30 a.m. 



^•5534 



304 



Light 



20-7 



>5. 



11-08 a.m. 



2-5236 



264 



Light 



21-2 



>) 



1-09 p.m. 



2-4917 



201 



Dark 



21-0 



J> 



2-13 p.m. 



2-4788 



145 



Dark 



21-0 



5> 



3-40 p m. 



2-4622 



98 



Dark 



21-0 



5J 



4-34 p.m. 



2-4609 



62 



Dark 



20-8 



11th 



9-45 a.m. 



2-3970 



167 



Light 



20-5 



» 



10-03 a.m. 



2-3940 







20-8 



>' 



11-11 a.m. 



2-3787 



225 



Light 



20-9 



1) 



12-05 p.m. 



2-3646 



. 261 

 163 



Light 

 Dark 



21-0 



J5 



1-10 p.m. 



2-3540 



126 



Dark 



21-1 



>) 



2-07 p.m. 



2-3468 



128 



Dark 



21-0 



" 



3*33 p.m. 



2-3358 







21-2 



In the example recorded the intensity of illumination 

 probably varied considerably at different times as diffused 

 daylight was used, so that comparisons may not be made 

 of the various results obtained in the light. At the time 



