318 Messrs. Haldane and Penibrey on an Improved Method 



During some experiments the psychrometer was very 

 steady; at other times it showed considerable fluctuations. 

 As examples may be given the readings of the wet and dry 

 bulbs for the experiments 1 and 5. 



Exp. 1. 



Dry. 



Wet. 



Exp. 2. 



Dry. 



Wet. 



11.39 A.M 



11.43 



11.47 



61-4 

 61-8 

 61-6 



529 

 53-1 

 52-9 



11.45 A.M 



11.49 



57-9 

 57-9 

 58-0 



55-9 

 56-0 

 56-0 



11.52 







It is to be noticed that a difference of two or three tenths 

 of a degree Fahrenheit in the reading alters greatly the 

 percentage error. 



I have also calculated out the tension given by the chemical 

 method, and have compared it with the results calculated 

 from the psychrometer by means of Glaisher's, Haeghen's, 

 Guyot's, and Wild's Tables. 



Table II. 





Experiment. 



Chemical Psychrometer. 



Metnod. „ . i . , i _, 



, Glaisher. , Haeghens. | Gruyot. 



Wild. 



1 



mm. 



7-43 7-76 7-37 7-21 



7-4 

 9-5 

 8-9 

 8-8 



10-7 

 7-4 



11-7 

 9-6 

 8-5 

 9-4 



11-9 

 9-5 



2 



9-15 9-55 

 8-99 9-00 



8-78 8-99 



9-54 9-51 



8-88 8-87 

 8-74 8-77 



3 



4 



5 



10-70 10-72 10-75 1 10-76 



7-63 7-78 7-39 7-34 



12-15 11-72 11-78 n -fin 



6 



7 



8 



991 9-65 9-57 



9-57 



9 



8-90 8-68 8-45 

 10-00 9-52 ft'38 



8-43 



9-41 



11-93 



9-57 



10 



11 



11-82 11-84 



11-93 



12 



10-23 9-67 



9-55 





Mean 



964 9-57 



9-44 



9-44 



9-44 



This Table shows that Glaisher' s Tables are the most 

 correct as far as my experiments go. These tables were 

 prepared by Glaisher from the Greenwich factors and Beg- 

 nault's Table of pressures, and are in general use in England. 

 Haeghen's Tables, which are used in France and Italy, 

 Guyot's, which are almost identical with the last and are 

 employed in America, and Wild's, which have been adopted 



