WEIGHTS AND MEASURES. 49 



PRESCRIPTIONS. 



In writing prescriptions, Roman numerals are used instead of 

 Arabic (ordinary figures) and the numerals follow the symbols, 

 thus: ."> vii for 7 drams; f 3 xii for 12 fluid drams, etc. S. S. signifies 

 one half, thus: 5 ii s. s. for 2\ drams. 



FIELD EXPEDIENTS. 



In garrison, doses must be accurately measured by scales or 

 graduates, according to the tables of dry or liquid measure, but 

 in the field the following rough expedients may be used: 



Dry measure. 



II ounce of lead acetate. 

 | ounce of zinc sulphate. 

 2 drams of a powder. 

 1 ounce of a salt. 



( trdnance t in cup § of a quart. 



Full day's ration of medium-weight oats. 14 cups. 



Liquid measure. 



A drop 1 minim. 



A teaspoonful 1 fluid dram. 



A tablespoonful \ fluid ounce. 



Tin cup 28 ounces=| of a quart. 



