= 8 pints
= 20 fluid ounces
fl. OZ. XX.
1 fluid ounce
= 8 fluid drachms
fl. drs. viij.
1 fluid drachm
= 60 minims
=: 1 minim
All liquids are ordered by measure unless it is stated otherwise.
It will be observed, that in the above table symbols representing the different weights and measures have been introduced: lb. representing the pound, oz. the ounce, and gr. the grain; it will also be seen that the numbers made use of under the weights are of the Arabic character. The symbols for the measures are C, for the gallon; 0, the pint; fl. oz., the fluid ounce; fl. drm., the fluid drachm; and min., the minim; and the numbers, instead of being Arabic as in the case of the weights, are the Roman numerals.
In the present work, when quantities are introduced, the Arabic numbers have been in all cases adopted; in writing prescriptions either may be made use of.
It will be seen that the solid drachm and the scruple have been omitted from the Pharmacopoeia; if still made use of, they will represent sixty and twenty grains respectively in Great Britain, and not the eighth and twenty-fourth part of the avoirdupois ounce; but in Ireland these same symbols will only represent 54.68 and 18.22 grains. Such being the case, it will be advisable to discard the employment of these symbols altogether.
The avoirdupois fluid ounce corresponds to the solid ounce, in the case of distilled water at 60° Fah.; that is, one fluid ounce weighs exactly an ounce. A minim of distilled water, however, does not weigh one grain, as the fluid ounce is divided into 480 minims; the solid ounce into 437.5 grains only.
In Appendix D of the Pharmacopoeia the following table is contained, showing the relation between the measures and weights now made officinal in pharmacy, and likewise the relation of the weights and measures of the British Pharmacopoeia to those of the metrical system.