9), but this word, which is translated par fumeur in the French version, only indicates that the preparation of fragrant unguents and incense formed, even at that early date, a part of pharmacy, since the drugs mentioned, viz.
Wright, p. 118 seq.) in the r 2th century describes the mart of Mecca in the eight days following the feast as full of gems, unguents, precious drugs, and all rare merchandise from India, Irak, Khorasan, and every part of the Moslem world.
Unguents.The most important kind of resistance in machines is the friction or rubbing resistance of surfaces which slide over each other.
Heat of Friction: Unguents.The work lost in friction is employed in producing heat.
The heat produced by friction, when moderate in amount, is useful in softening and liquefying thick unguents; but when excessive it is prejudicial, by decomposing the unguents, and sometimes even by softening the metal of the bearings, and raising their temperature so high as to set fire to neighboring combustible matters.