]{ei.[,. — Oxinicii from JiJe'irJit II 1/ ponder Sohitimis. 



27 



unfiltered, and containing 16 grammes per litre. The stoppered tube carried 

 5 c.c. cobalt-nitrate sohition, 0-005 N to 0-00125 N, and in the first series 

 of experiments 5 c.c. of water, in the second series 5 c.c. of the compound 

 imder examination. The flask and wide, tube were immersed in a large 

 thermostat with regulator and centrifugal stirrer. When the temperature 

 became uniform the rod stopper was raised and the catalytic agent run in. 

 Each experiment in the first series lasted about forty minutes. Somewhat 

 over 400 experiments were carried out, apart from all preliminary work. 



Part I. 



Specimen Experiment : Measurement of Gaseous Oxygen evolved. 



Taken, 25 c.c. bleaching-powder solution, turbid, 32 grammes per litre 

 5 c.c. cobalt-nitrate, 0-00125 N ; 5 c.c. water. 



Summarif of Results with Bleaching -fowder and Cobalt-nitrote. 



1. The velocity is proportional to the concentration of the cobalt 

 solution. 



2. The measurable velocity proceeds as for a unimolecular reaction. 



3. Increase of temperature increases the velocity. A rise of 10° C. 

 almost triples the initial velocity. 



4. Reversing the order of addition of the components alters the reaction- 

 velocity. 



5. Shaking alters the reaction-velocity. 



The velocity varied slightly with different batches of solution. 



For a solution containing, 25 c.c. bleaching-powder solution, 16 grammes 

 per litre ; 5 c.c. cobalt - nitrate solution, 0-0025 N ; and 5 c.c. water, 

 K - 0-01993 (c.c. per minute). 



Part il. 



In this part various additions were made to the cobalt-nitrate solution, 

 and their ei!ect on the reaction-velocity determined. A bleaching-powder 

 solution refiltered after twenty-four hours, of which 10 c.c. = 17-5 c.c. ^-^^ 

 arsenious acid was used, and was found to keep for weeks without change in 

 titration-value, although the reaction-velocity diminished very slightly. 



