A treatise on pharmacy for students and pharmacists / by Charles Caspari, Jr.

  • Caspari, Charles, 1850-1917.
Date:
1895
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on pharmacy for students and pharmacists / by Charles Caspari, Jr. Source: Wellcome Collection.

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    grains; hence to find the corresponding value in avoirdupois ounces of any given number of troy or apothecaries' ounces, add to the latter _ or number, thus gxxiv = 24 ^ 17 avoirdupois ounces plus -— of 24, which is 24 + 2.33, or 26.33 175 ounces; if, on the other hand, avoirdupois weight is to be converted into apothecaries' or troy weight, subtract from the number of ounces 421 35 17^ ^^^^^ Tq^ = ( ) number, thus 26.33 ounces = 26.33 — _1Z of 26.33, which is equal to 26.33 — 2.33, or 24 apothecaries' or troy ounces. While apothecaries' weight is employed in compounding prescrip- tions both in this country and Great Britain, it is not used in either the United States or British Pharmacopoeias, and will no doubt be entirely abolished in the course of time, when a uniform international system of weights shall have been adopted by the medical and phar- maceutical professions of both countries. The grain is the connect- ing link between avoirdupois, troy, apothecaries' and Imperial weight, being the same in all. The fluid measure used by pharmacists of the United States is derived from the old wine measure of England (now extinct), which allowed to each wine gallon the volume of 231 cubic inches, or 58340.011 grains of distilled water at 15° C. (59° F.); the Im- perial gallon of Great Britain contains 277.273 cubic inches, or 70,000 grains of distilled water at 62° Fahr. In both cases the gallon is divided into 8 pints, but the pint of wine measure con- tains 16 fluidounces, while the Imperial pint contains 20 fluid- ounces. The United States fluid measure has the following units: the minim, the fluidrachm, and the fluidounce, which are repre- sented by the following signs : ir^, f5; fo ; in addition, the pint and gallon are sometimes employed in commercial transactions, being designated by the abbreviations 0, from Octa7'iu8, for pint, Cong.y from Congius, for gallon. The units of Imperial fluid measure bear the same names as those employed for United States fluid measure, but differ from them in value ; thus, while the Imperial minim of water weighs 0.91 (0.9114583) grain, the United States minim of water weighs 0.95 (0.9493) grain, and, since both fluidounces contain 480 minims, the Imperial fluidounce of water weighs 437.5 grains, but the United States fluidounce 455.70 grains, at 15.6° C. (60° F.). Each fluidounce is divided into 8 fluidrachms and each fluidrachm into 60 minims. It must not be overlooked that many liquids, although dispensed and sold by the apothecary by fluid measure, are purchased from the manufacturer by weight, and whenever the specific gravity of the liquid differs materially from that of water there must be also a