MEASURE, among Botanists. In describing the parts of plants, Tournefort introduced a geometrical scale, which many of his followers have retained. They measured every part of the plant; and the essence of the description consisted in an accurate mensuration of the whole.
As the parts of plants, however, are liable to variation in no circumstance so much as that of dimension, Linnaeus very rarely admits any other mensuration than that arising from the respective length and breadth of the parts compared together. In cases that require actual mensuration, the same author recommends, in lieu of Tournefort's artificial scale, the following natural scale of the human body, which he thinks is much more convenient, and equally accurate.
The scale in question consists of 11 degrees, which are as follow: 1. A hair's breadth, or the diameter of a hair, (capillus). 2. A line, (linea), the breadth of the crescent or white appearance at the root of the
finger (not thumb, measured from the skin towards the body of the nail; a line is equal to 12 hairbreadths, and is the 12th part of a Parisian inch). 3. A nail (unguis), the length of a finger nail; equal to six lines, or half a Parisian inch. 4. A thumb (pollex), the length of the first or outermost joint of the thumb; equal to a Parisian inch. 5. A palm (palmus), the breadth of the palm exclusive of the thumb; equal to three Parisian inches. 6. A span (spithama), the distance between the extremity of the thumb and that of the first finger when extended; equal to seven Parisian inches. 7. A great span (dodrans), the distance between the extremity of the thumb and that of the little finger, when extended; equal to nine inches. 8. A foot (pes), measuring from the elbow to the basis of the thumb; equal to 12 Parisian inches. 9. A cubit (cubitus), from the elbow to the extremity of the middle finger; equal to 17 inches. 10. An arm length (brachium), from the armpit to the extremity of the middle finger; equal to 24 Parisian inches, or two feet. 11. A fathom (orgyia), the measure of the human stature; the distance between the extremities of the two middle fingers, when the arms are extended; equal, where greatest, to six feet.