A manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia, and many other approved medicines / by J. Forbes Royle and Frederick W. Headland.

  • Royle, J. Forbes (John Forbes), 1798-1858.
Date:
1865
Catalogue details

Licence: Public Domain Mark

Credit: A manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia, and many other approved medicines / by J. Forbes Royle and Frederick W. Headland. Source: Wellcome Collection.

    18/792 (page 6)
    Pound weighs 7000 grains, and is divided into 16 ounces, each of 437| grains. IMPERIAL WEIGHTS. One Pound . ft = 16 oz. = TOOO grs. „ Ounce . 5 = . . . 437-5 „ Grain . gr. = . . . 1 „ Tliis weight was first adopted in the Dublin Pharmacopoeia of 1850, which, however, retained the old pharmaceutical weiohts of the drachm and the scruple, the drachm being the eighth part of the ounce, or 54*7 grains, the scruple the third part of the drachm, or ]8'22 grains. These weights are somewhat smaller than the drachm and scruple of Troy we'ght, as will be seen in the table below. As the Troy or Apothecaries' weight is on many accounts convenient for pre- scribing, and it will probably be long before its use is discontinued, we subjoin the table of this weight for purposes of comparison. It must be remembered that the drachm and scruple weights are no longer used. TROY WEIGHTS. One Pound . ib i. = 12 Ounces . xij. =: 5760 grs. „ Ounce . § i. = 8 Drachms 5 viij. = 480 „ „ Drachm 5 i. = 3 Scruples . 3 iij. = 60 „ „ Scruple 3 i. = 20 Grains. . gr. xx. =: 20 „ „ Grain . gr. 1. One pound, or twelve ounces, Troy, equals thirteen ounces and seventy- three grains of the Avoirdupois weight. Liquids used formerly to be weighed, but as it is much more con- venient to measure them, this method is now generally adopted. The Wine Measure was formerly employed ; but the Imperial Gallon is now used, and is thus divided and distinguished:— IMPERIAL MEASURE. Old Minims. Wine Measure. 61440 = 0 viij. 7680 = f 3 xvj. 480 = f 5 viij. 40 = in Ix. One Gallon . . C i. = 8 Pints ... 0 viij. = 76800 „ I'int . . . 0 i. = 20 Fluidounces . f § xx. = 9600 „ Fluidounce . f § i. = 8 Fluidrachms. f 5 viij. = 480 » „ Fluidrachm. f 5 i. = 60 Minims. , . nx Ix. = 60 „ Minim. . . rn,. The Imperial Gallon and Pint evidently contain much more than the Wine Measure, in the proportion of about 5 to 4 ; but by dividing the Pint into f^xx, instead of into f Jxvi, we obtain nearly the same quan- tities for the ounce, drachm, and minim. An Imperial ounce is equal to 7 drachms and 41 minims of the Wine Measure. It must be remembered that a minim does not weigh exactly a grain. The imperial minim of water weighs '91 grains, and the fluid drachm 54.7 grains. A Gallon is the measure of 10 lbs. of water. The Pint measures 1J lb. The fluid ounce is the measure of an ounce of water. Bodies occupying the same space are, however, well known to differ