1824.] Mr. Chilton on an improved Rain Gauge. 



Ill 



Table 1. Trot/ Weight. 



Grains. 



One pound troy, = 5760 



One ounce, 

 One drachm, 

 One scruple, 



= 480 

 = 60 

 = 20 



Table 2. For reducing Avoir- 

 dupois Weight. 



Troy grains. 



One pound avoir- 

 dupois, = 7000 

 Half pound, = 3500 

 ^- of a pound, = 1750 

 Two ounces, = 875 

 One ounce, = 437*5 

 Half ounce, = 218-75 

 Quarter ounce, = 109-375 



An Example showing the Use of the Tables. 



Suppose the weight of the water in the gauge corrected by- 

 subtracting the weight of the gauge, to be 201b. 5-L ounces 

 avoirdupois, required the height or number of inches of rain? 



f] lb. = 7000 grs. which x 20 = 14000 



1 . From Table 2. 

 lb. oz. 



20 



5,V = 



4 oz. 

 1 do. 

 J- do. 



1750 

 437-5 

 218-75 



The sum = the weight in grs. 142406-25 



