Medicines are made up by troy weight, although drugs are bought by
avoirdupois weight. There are twelve ounces to the pound troy, which
is marked lb.; the ounce, which contains eight drachms, is marked
[*ounce]i. [looks like a z on top of a 3]; the drachm, containing
three scruples, is marked [*drachm]i. [looks like a 3]; and the
scruple of twenty grains is marked [*scruple]i. [looks like a
backwards C with a horizontal cross-bar]. The grain weights are marked
by little circles, thus:
-------
|o o|
Five | o | Grains
|o o|
-------
Each of the grain weights, in addition to the circles denoting their
several weights, bears also the stamp of a crown. Care must be taken
not to mistake this for one of the numerals. Besides these weights
there are others marked [*scruple]ss, which means half a scruple;
[*drachm]ss, meaning half a drachm; and [*ounce]ss, meaning half an
ounce. When there are ounces, drachms, or scruples, the number of them
is shown by Roman figures, thus:--i. ii. iii. iv. v., &c., and
prescriptions are written in this style.