Apothecary weights

The signes of the waightes, which the Pothecaries vse now a daies.

A graine.is thus written.Gra .
A scruple.is thus written.℈.
A dramme.is thus written.ʒ.
An ounce.is thus written.℥.
A pounde.is thus written.lib.
A quarter.is thus written.qr.
Halfe a quarter.is thus written.s.
A handfull.is thus written.m.
Aureus.is thus written.aur.

Aureus doeth containe a dramme and a halfe.
Ana, signifieth altogither, and thus is written, An̄.

A pound.doth con∣teine.twelue. ℥. (Ounces) 
A quarter of a pound.doth con∣teine.thrée ℥. (Ounces)
Halfe a quarter.doth con∣teine.℥. s. (Ounces)
An ounce.doth con∣teine.eight ʒ. (Drams)
A dramme.doth con∣teine.thrée ℈. (Scruples)
A scruple.doth con∣teine.two ob. (1 obolus is approximately 10 grains or 0.65 grams) 
A halfe peny.doth con∣teine.thrée siliques. (1 Siliques =4 grains 3 Siliques = 12 grains or .78 grams)

According to the Encyclopedia Brittanica, Apothecaries' weight is a "traditional system of  weight in the British Isles used for the measuring and dispensing of pharmaceutical items and based on the grain, scruple (20 grains), dram (3 scruples), ounce (8 drams), and pound (12 ounces)." 
Siliqua is Latin for the seed of the Carob Tree (also referred to as St. John's bread or Locust Tree).  

In the Roman Weight System 1 scruple (1.2 grams or 20 grains) = 2 Obulus (1 Obolus = 0.65 grams or 10 grains)  = 6 Siliques  (Siliqua is ~ 4 grains)

A graine.Gra.     0.065 grams or 64.7  mg
A scruple.℈.     1.2  grams  or 20 grains
A dramme.ʒ.     1.772 grams
An ounce.℥.    31.103 grams or 480 grains 
A pounde.lib.     373.242 grams
A quarter.qr.     93.3 grams or  1440 grains 
Halfe a quarter.s.    46.65 grams or 720 grains
A handfull./Manipulus m.    A rough measure approximately 4 grams 
Aureus.aur.    1/40th of a Roman pound ~ 8 Grams

One graine of Siliqua is as much as sixe graines of Lentieles, the which graine doubled sixe times, commeth to xxxvi. and then they make a scruple, thrée ℈. makes a ʒ. viii. drammes makes a ℥. xvi. ℥. makes a lib. xx. wheate cornes makes a scruple also.

The primary unit of weight in the Apothecary system is the Grain (usually barley or wheat)
The primary unit of volume in the Apothecary system is the Minim 

To convert grains to grams

Multiply the grain value by 0.06479891 


En.wikipedia.org. 2020. Apothecaries' System. [online] Available at: <https://en.wikipedia.org/wiki/Apothecaries%27_system> [Accessed 4 August 2020].

Cafe, K., 2020. Apothecary, Avoirdupois & Unusual Conversions - RF Cafe. [online] Rfcafe.com. Available at: <https://www.rfcafe.com/references/general/apothecary-avoirdupois.htm> [Accessed 4 August 2020].

culinarylore.com. 2020. What Does The Word Carat Have To Do With Carob Seeds?. [online] Available at: <https://culinarylore.com/food-history:carat-and-carob-seeds/#:~:text=A%20carat%20is%20defined%20as,same%20as%20100%20carob%20seeds.> [Accessed 4 August 2020].

En.wiktionary.org. 2020. Siliqua - Wiktionary. [online] Available at: <https://en.wiktionary.org/wiki/siliqua#:~:text=A%20weight%20of%20four%20grains%3B%20a%20carat.> [Accessed 4 August 2020].

Name.umdl.umich.edu. 2020. Prepositas His Practise A Vvorke Very Necessary To Be Vsed For The Better Preseruation Of The Health Of Man. Wherein Are Not Onely Most Excellent And Approued Medicines, Receiptes, And Ointmentes Of Great Vertue, But Also Most Pretious Waters, Against Many Infirmities Of The Body. The Way How To Make Euery The Said Seuerall Medicines, Receiptes, And Ointmentes. With A Table For The Ready Finding Out Of Euery The Diseases, And The Remedies For The Same. Translated Out Of Latin Into English By L.M.. [online] Available at: <http://name.umdl.umich.edu/A09920.0001.001> [Accessed 4 August 2020].

Zupko, Ronald Edward. “Medieval Apothecary Weights and Measures: The Principal Units of England and France.” Pharmacy in History, vol. 32, no. 2, 1990, pp. 57–62. JSTOR, www.jstor.org/stable/41111300. Accessed 4 Aug. 2020.