448 



Prof. J. Perry on Liquid Friction. 



A small B arisen flame was applied underneath the trough 

 when a temperature higher than the room had to be main- 

 tained for a considerable length of time. 



As the temperature varied slightly, and we wished to reduce 

 our observations to constant temperatures, we afterwards made 

 two sets of observations at very varying temperatures but 

 constant speeds. These later observations we shall consider 

 first. They are given in Tables II. and III. 



Table II.— March 29th, 1892. (1 = 8*275 centim.) 









40 D 



' 





n. 



e°c. 



D. 



n I+\' 



,. 



/x calculated. 



39-5 



135 



189 



21-09 



•400 



•446 



39-5 



171 



165 



17-60 



•334 



•357 



40 



19-5 



150 



16-53 



•318 



•317 



40 



24-0 



134 



14-77 



•287 



•266 



40 



25-3 



126-5 



13-94 



•268 



•254 



40 



28-9 



111-5 



12-28 



•236 



•228 



40 



32-0 



109 



11-46 







40 



42-5 



88 



9-70 







40 



46-9 



81 



8-65 







40 



58-5 



67 



7-11 







40 



64-0 



58 



6-39 







40 



71-0 



56 



6-17 







40 



77-0 



50 



5-51 







40 



85-5 



46-5 



5-12 





i 



The numbers in the column headed 



40 D 



v— r- are obviously 



intended to be corrections of D/(l + \) for the constant speed 

 of 40 revolutions per minute. 



Table III.— March 30th, 1892. (/=7-78 centim.) 









9 D 







n. 



e°c. 



D. 



n ?+\' 



li. 



H calculated. 



8-75 



5-2 



160 



19-19 



1-64 



2-06 



9-75 



8-0 



85 



9-15 



0-78 



0-82 



9-2 



10-0 



57 



6-56 



0-73 



0-62 



9-0 



10-8 



47 



5-48 



047 



0-56 



9-0 



16-6 



36-5 



4-26 



0-363 



0-366 



9-2 



24-8 



26-5 



3-02 



0-258 



0-259 



9-0 



35 



19-5 



2-27 



0-194 



0-196 



90 



47-0 



14-0 



1-63 



0-139 



0-137 



9-0 



56-5 



10-2 



1-19 



0-101 



0104 



9-0 



67-0 



8-0 



0-93 



0079 



0-081 



9-0 



89-0 



5-4 



063 



0-060 



0-058 



9-0 



84-5 



6-0 



0-70 



0054 



0054 



