WEIGHTS AND MEASURES. 



Medicines, except a few hereafter mentioned, were formerly sold, 

 and the prescriptions of physicians made up, by the common English 

 weight, called Avoirdupois. The ounce of that weight being then, as 

 appears by all the old authors on arithmetic, subdivided into 8 drams, 

 24 scruples, and 480 English grains ; the medical pound differing from 

 the common by its containing only twelve ounces, while the Troy 

 ounce had for its fractions pennyweights and Troy grains. The Col- 

 lege of Physicians having at length, in the 1720 edition of the Phar- 

 macopoeia, ordered the drams, scruples, and grains to be adjusted to 

 the Troy ounce, hence, as the dispensers of medicines were the only 

 persons who used these small weights, those adjusted to the Avoirdu- 

 pois ounce went out of use, and were no longer made, and the quarter 

 ounce was the smallest Avoidupois weight in common use, as it still 

 continues ; but as the Italian rotolo for raw silk has been adjusted to 

 the Avoirdupois weight, and made 24 ounces a pound; a smaller 

 weight, the Spanish adarme, equal to the 16th part of the Avoir- 

 dupois ounce, was used under the name of a dram, for weighing silk, 

 and this has now become an established fraction of this ounce, but it 

 flH scarcely used by any other persons than haberdashers, and for all 

 [weights less than the quarter of an ounce Troy, Apothecaries' weights 

 ire employed, although, as the Avoirdupois pound is established by 

 itatute at 7000 Troy grains, the quarter ounce containing 109 gr. 

 175, and the dram 27 gr. 34375, are most inconvenient numbers for 

 reduction. 



TABLE OP AVOIRDUPOIS WEIGHT. 



Decimal Fractions. 



1.0000 



0.9375 



0.8750 

 0.8125 

 0.7500 

 0.6875 

 0.6250 

 0.5625 

 0.5000 

 0.4375 

 0.3750 

 0.3125 

 0.2500 

 0.1875 

 0.1250 

 0.0625 

 0.0586 

 0.0547 

 0.0508 

 c2 



= 1.0000 



= 0.9375 



= 0.8750 

 = 0.8125 



