Of Medicine, in Eight Books

by Aulus Cornelius Celsus

Note 1st. The Romans divided all integers, as they did their as, into twelve equal parts called unciæ. Thus the sextans was the sixth part of the as, containing two of these unciæ, quadrans one fourth, or three unciæ, triens the third part, or four unciæ, semis one half, or six unciæ, bes or bessis two-thirds, or eight unciæ, dodrans three-fourths being nine unciæ. The weight of these then differs, as the integer is the libra, the uncia, or denarius, which the attentive reader will easily reduce, if he is disposed to calculate the quantities, observing that they are not to be taken for aliquot parts of the denarius, but when they follow the mark of the denarius. The integer preceding, and the nature of the composition will be the best explication.

Note 2. The denarius mark was X or 𐆖

, as containing originally ten small asses. This by the copiers has been often confounded with X, denoting the number of ten denarii; so that after all the pains of critics and commentators, the proportions of the ingredients in several compositions seem to be irrecoverably lost. For this reason, I suppose the later editors have thought fit to change it for the common asterisk.

Note 3. The characters for quantities are variously marked in different authors, and the same note has several values. There is one of this uncertainty in Celsus, that is Z, which we are told expresses the libra, the sescuncia, the sextans of a pound, the denarius and the sextans of a denarius[ W ]. Which of these different values it bears in any particular place must be determined by the connection. When it follows the mark of the denarius, it can mean no more than the sextans of a denarius.

Note 4. p. stands for pondo, which is an indeclinable word, and when joined with numbers, signifies libra or a pound; when with other weights, it stands for no more than pondus or weight in general.

For an example of the reduction of Celsus’s weights to ours, the following may serve.

Lib. v. cap. 19. no. 7. Philotas’s plaister contains,

Of Eretrian earth		℥	Ʒ	℈	gr.
— chalcitis, each p. iv.*.	==	1/2 :	0 :	0 :	8	viz. Ʒi. gr. ii. multiplied by 4 —and so all the rest.
— myrrh
— calcined copper, each p. x.*.	==	1  :	2 :	1 :	0
— isinglass p. vi. *.	==	0  :	6 :	0 :	12
— rasile verdigrease
— round allum
— crude misy
— birthwort, of each p. viii.*.	==	1  :	0 :	0 :	16
— copper scales p. xx.*	==	21/2 :	0 :	2 :	0
— male frankincense, p. ii.*.	==	0  :	2 :	0 :	4
— oil of roses
— Bitter oil, of each three cyathi, or 1 quartarius = between 1/4 and 1/3 of an English pint.
— vinegar, a sufficient quantity.