1904.] The Chemical Dynamics of Photographic Development. 463 

 Table VII Developer Fe = N/25, KBr = N/500, K = -0203.* 



Time. Density. K 



15-0 mins. 0-259 0-0048 



20-0 0-452 0-0066 



30-0 0-643 0-0068 



40-0 0-816 0-0070 



50-0 0-960 0-0071 



60-0 1-042 0-0068 



70-0 1-089 0-0062 



80-0 1-214 0-0067 



90-0 1-302 0-0069 



100-0 1-333 0-0065 



120-0 1-423 0-0064 



12 hrs. 1-713 



14 1-712 



Mean, K = '0067, i.e., a reduction to one-third of its former value. 

 This was for an opened box kept in laboratory cupboard. 



Table VIII. 



Table Villa. 



The values obtained six months before were 



N/500 B~r. K = 0-0203. N/1000. K = 0-0280, 



so that in this case the speed has been about halved, 

 sealed box kept in laboratory cupboard. 



Further, for an opened box kept in college locker : 



This was for a 



* See table, pp. 458459. 



VOL. LXXIV. 



2 M 



