9. In the wedge, the friction is at least equal to the power, as it retains any position it is driven into; therefore in the wedge, the power must be to the weight at least as twice the base to the height, to overcome any resistance.
10. To find the friction of any engine, begin at the power, and consider the velocity and the weight at the first rubbing part; and estimate its quantity of friction by some of the foregoing articles; then proceed to the next rubbing part, and do the same for it, and so on through the whole.
And note that something more is to be allowed for increase of friction by every new addition to the power.
FRILL. An ornamental appendage to the shirt which officers and soldiers generally wear with regimentals. A small aperture is usually made at the top to admit the hook and eye of the uniform coat. Detached frills for the privates are certainly preferable to those which are fixed to the shirts, as three per week, at the regular times allotted for a change of linen, would answer every purpose of cleanliness.
FRISE. Fr. See [Chevaux de Frize].
FRISRUTTER. An instrument made of iron, and used for the purpose of blocking up an haven, or a river. The following description of it is among General Monk’s observations on political and military affairs.
The beams through which the upright bars pass must be twelve feet in length, and the upright bars that go through the beam must be of that length, so that when one of these iron frisrutters is let down into an haven or river, the perpendicular bars of this iron instrument shall be deep enough to reach at high water within five feet of the surface. See [Chevaux-de-Frize].
FROCK, the undress regimental coat is very often so called.
FRONDE, Fr. a sling. This weapon was used in France by the Huguenots at Sancerre, as late as the year 1572, in order to save their powder. There are two sorts, one which is used in throwing a stone from the arm, and the other that was fixed to a lever, and was so contrived, that a large quantity of stones might be thrown out of a machine, either from a camp into a besieged town, or from a town into the enemy’s camp. This machine has been used since the invention of cannon.
The fronde or sling was used by the Romans on three different occasions, viz. when they sent their light-armed men, called velites, forward to skirmish before a general engagement; when they wished to drive the enemy from under the walls of a town which they were preparing to storm, and finally to harrass and wound the men in the enemy’s works. This weapon, in fact, together with the bow and arrow, may be numbered among the primitive arms of mankind.