XXXVl 



WEIGHTS AND MEASURES. 



Commercial Fractions. 



12 drams, or f oz. 



11 ,, . • 



10 „ . . 



9 „ . . 



8 „ 



7 „ 



<3 „ 



oz. 



or 



Troy Grains. 



328.13 . 



300.78 . 



273.44 . 



246.09 . 



2I8.75 . 



191.41 . 



164.06 . 



136.72 . 



109.35 . 



82.03 . 



54.69 . 



27.34 , 



13.67 . 



APOTHECARIES' WEIGHT. 



A few choice articles of the Materia JMedica, as lapis bezoar, seed 

 pearl, white amber, balm of Mecca, oil of cinnamon, and some elec- 

 taries, high in popular estimation, and imported from Italy, as Venice 

 treacle and orvietan, were always weighed by the Troy ounce, and its 

 subdivisions into pennyweights and grains, and still pay duties at the 

 Custom-house by that weight, as may be seen in the Book of Rates. 

 But it was not until the directions given in the London Pharmacopoeia, 

 edition of 1720, that the Troy ounce was divided into the same frac- 

 tions of drams, scruples, and grains as the Avoirdupois, for the pur- 

 pose of dispensing all such drugs as were ordered by weight. This 

 alteration must have been, and is still, productive of very great confu- 

 sion, by obliging the same person to have two sets of weights — one 

 for buying and selling, the other for preparing the officinal preparations 

 and compounds, and for making up prescriptions. It does not clearly 

 appear why this alteration was made in respect only to drugs ordered 

 by weight, by which their proportion in the othcinal preparations and 

 compositions was increased I -10th ; as the Avoirdupois ounce, with its 

 old divisions into 2 drams, and drops, 60 of which were presumed equal 

 to the dram, was, and is still retained, in respect to drugs that are 

 dispensed by measure. 



TABLE OF apothecaries' WEIGHT. 



