# Minim (unit)

The minim (abbreviated min, or ) is a unit of volume in both the imperial and US customary systems of measurement. Specifically it is 160 of a fluidram[1] or 1480 of a fluid ounce.[2][3]

The minim was introduced in the 1809 edition of the The pharmacopœia of the Royal College of Physicians of London as an alternative to the drop, which had previously been the smallest unit of Apothecaries' measure.[4] It was observed that the size of a drop can vary considerably depending upon the viscosity and specific gravity of the liquid. (At the time, the phenomenon of surface tension was not well-understood.) The minim, on the other hand, was measured with a graduated glass tube known as a "minimometer"[5] later known as the minim-tube.[6] The minim-tube was type of graduated pipette, a device invented in 1791 by Francois Antoine Henri Descroizilles.

Apothecaries' measures are fully described in the Weights and Measures Act of 1878. In the United Kingdom, the 1963 Weights and Measures Act provided for the abolition of the minim, fluid scruple, and fluid drachm, all already obsolete. Actual delegalization occurred on February 1, 1971.

While the use of the minim, along with other such measures, has been reduced by the adoption of the metric system, it still persists in some countries in the measurement of dosages of medicine.

## Definitions

Imperial minim
 1 imperial minim = 1⁄480 imperial fluid ounce = 1⁄60 imperial fluidram = 59.1938802083 microlitre (exactly)[7][8] ≈ 1⁄500 US fluid ounce ≈ 0.960759940 US fluid minim
US customary minim
 1 US minim = 1⁄480 US fluid ounce = 1⁄80 US teaspoon = 1⁄60 US fluidram = 61.611519921875 microliters (exactly)[9] ≈ 1⁄461 imperial fluid ounce ≈ 1.040842731 imperial minims

## References and notes

1. ^ also spelt fluid drachm or fluid dram
2. ^ CIA World Factbook
3. ^ Robert Thomas (médecin) (1819). The modern practice of physic, exhibiting the... symptoms, prognostics, morbid appearances and improved method of treating the diseases of all climates.... Longman. p. xv. Retrieved 17 December 2011.
4. ^ Royal College of Physicians of London; Richard Powell (1809). The pharmacopoeia of the Royal College of Physicians of London, M. DCCC. IX. Longman, Hurst, Rees, and Orme. pp. 6–7. Retrieved 18 December 2011.
5. ^ Philological Society (Great Britain) (1814). The European magazine, and London review. Philological Society of London. p. 123. Retrieved 18 December 2011.
6. ^ Clara S. Weeks-Shaw (1808). A text-book of nursing: for the use of training schools, families, and private students. D. Appleton. p. 107. Retrieved 18 December 2011.
7. ^ "The Units of Measurement Regulations 1995 SCHEDULE RELEVANT IMPERIAL UNITS, etc.". 2000-09-20. Retrieved 2006-04-18.
8. ^ The notation 3 indicates that the digit 3 is repeated infinitely.
9. ^ This assumes the international inch of exactly 25.4 millimeters. The US gallon of 231 cubic inches is the same as the English Wine gallon.