356 



Duane — Velocity of Chemical Reactions. 



contains the values of 



2-3026 



calculated from the formula 





k 



1 i 2 > 







2*3026 





t 



cm. 



cm. 



k 



2-3026 













20 



34-55 



34-35 





41 



29-66 



29-46 



•00318 



55 



26-87 



26-67 



•00314 



70 



24-28 



24-08 



•00308 



85 



21-61 



21-41 



•00316 



100 



19-83 



19-63 



•00303 



115 



17-86 



17-66 



•00304 



130 



1612 



15-92 



00303 



145 



14-99 



14-79 



•00292 



160 



13 80 



13-60 



•00287 



175 



12-70 



12-50 



•00284 



190 



11-85 



11-65 



00276 



205 



10 96 



10-76 



•00272 



220 



10-63 



10-43 



•00259 



235 



9-92 



9-72 



•00255 



250 



9-37 



9-17 



•00249 



265 



8-80 



8-60 



•00245 





We see that h decreases, indicating as before that the velocity 

 is less rapid at the end than would be expected from Gould- 

 berg and Waage's law. 



If desired, a complete record of the position of the mercury 

 column could be obtained by any of the methods for recording 

 the readings of a mercury thermometer. 



The chief advantages of the above described methods are, 

 first that the chemical system is not disturbed during the reac- 

 tion ; second, that no time is lost in titration or other chemical 

 tests for the state of the system, thus making it possible to 

 investigate rapid reactions ; third, that it is not necessary for 

 the experimenter to make observations during the reaction, 

 which is a tedious piece of work if the velocity is very small ; 

 and fourth, the curves are drawn by purely mechanical 

 processes, thus avoiding the influence of the personal equation. 



A third method 1 based upon the change in the index of 

 refraction of the chemical system as measured by the motion 

 of interference bands is being perfected. 



In conclusion I wish to thank my assistant, Mr. F. C. Blake, 

 for the care with which he has helped me obtain the above 

 data. He and his brother, Mr. J. C. Blake, are at work apply- 

 ing the methods to hitherto uninvestigated reactions. 



Hale Physical Laboratory, 

 University of Colorado. 



