other material, and which, as they are of higher boiling point than ethyl alcohol, occur in largest quantity in the last portions of the distillate. Besides ethyl or ordinary alcohol, and amyl alcohol, which are present in them all, there have been found in fusel oil several other bodies of the CnH2n+1·OH series, also certain ethers, and members of the CnH2n+1·CO2H series of fatty acids. Normal propyl alcohol is contained in the fusel oil of the marc brandy of the south of France, and isoprimary butyl alcohol in that of beet-root molasses. The chief constituent of the fusel oil procured in the manufacture of alcohol from potatoes and grain, usually known as fusel oil and potato-spirit, is isoprimary amyl alcohol, or isobutylcarbinol. Ordinary fusel oil yields also an isomeric amyl alcohol (active amyl alcohol) boiling at about 128°. Variable quantities of fusel oil, less or greater according to the stage of ripening, exist in commercial spirits (see Spirits).
Fusel oil and its chief constituent, amyl alcohol, are direct nerve poisons. In small doses it causes only thirst and headache, with furred tongue and some excitement. In large doses it is a convulsent poison. Impure beverages induce all the graver neurotic and visceral disorders in alcoholism; and, like fusel oil, furfurol and the essence of absinthe, are convulsent poisons. Pure ethyl alcohol intoxication, indeed, is rarely seen, being modified in the case of spirits by the higher alcohols contained in fusel oil. According to Rabuteau the toxic properties of the higher alcohols increase with their molecular weight and boiling point. Richet considers that the fusel oil contained in spirits constitutes the chief danger in the consumption of alcoholic beverages. The expert can immediately detect the peculiarly virulent characters of the mixed intoxication due to the consumption of spirits containing a large percentage of fusel oil.
FUSIBLE METAL, a term applied to certain alloys, generally
composed of bismuth, lead and tin, which possess the property of
melting at comparatively low temperatures. Newton’s fusible
metal (named after Sir Isaac Newton) contains 50 parts of
bismuth, 31.25 of lead and 18.75 of tin; that of Jean Darcet
(1725–1801), 50 parts of bismuth with 25 each of lead and tin;
and that of Valentin Rose the elder, 50 of bismuth with 28.1 of
lead and 24.1 of tin. These melt between 91° and 95° C. The
addition of cadmium gives still greater fusibility; in Wood’s
metal, for instance, which is Darcet’s metal with half the tin
replaced by cadmium, the melting point is lowered to 66°–71° C.;
while another described by Lipowitz and containing 15 parts of
bismuth, 8 of lead, 4 of tin and 3 of cadmium, softens at about
55° and is completely liquid a little above 60°. By the addition
of mercury to Darcet’s metal the melting point may be reduced
so low as 45°. These fusible metals have the peculiarity of
expanding as they cool; Rose’s metal, for instance, remains pasty
for a considerable range of temperature below its fusing point,
contracts somewhat rapidly from 80° to 55°, expands from 55°
to 35°, and contracts again from 35° to 0°. For this reason they
may be used for taking casts of anatomical specimens or making
clichés from wood-blocks, the expansion on cooling securing
sharp impressions. By suitable modification in the proportions
of the components, a series of alloys can be made which melt
at various temperatures above the boiling point of water; for
example, with 8 parts of bismuth, 8 of lead and 3 of tin the
melting point is 123°, and with 8 of bismuth, 30 of lead and 24 of
tin it is 172°. With tin and lead only in equal proportions it is
241°. Such alloys are used for making the fusible plugs inserted
in the furnace-crowns of steam boilers, as a safeguard in the event
of the water-level being allowed to fall too low. When this
happens the plug being no longer covered with water is heated
to such a temperature that it melts and allows the contents of
the boiler to escape into the furnace. In automatic fire-sprinklers
the orifices of the pipes are closed with fusible metal, which melts
and liberates the water when, owing to an outbreak of fire in
the room, the temperature rises above a predetermined limit.
FUSILIER, originally (in French about 1670, in English about
1680) the name of a soldier armed with a light flintlock musket
called the fusil; now a regimental designation. Various forms
of flintlock small arms had been used in warfare since the middle
of the 16th century. At the time of the English civil war (1642–1652)
the term “firelock” was usually employed to distinguish
these weapons from the more common matchlock musket. The
special value of the firelock in armies of the 17th century lay
in the fact that the artillery of the time used open powder barrels
for the service of the guns, making it unsafe to allow lighted
matches in the muskets of the escort. Further, a military escort
was required, not only for the protection, but also for the
surveillance of the artillerymen of those days. Companies of
“firelocks” were therefore organized for these duties, and out of
these companies grew the “fusiliers” who were employed in
the same way in the wars of Louis XIV. In the latter part of
the Thirty Years’ War (1643) fusiliers were simply mounted
troops armed with the fusil, as carabiniers were with the carbine.
But the escort companies of artillery came to be known by the
name shortly afterwards, and the regiment of French Royal
Fusiliers, organized in 1671 by Vauban, was considered the model
for Europe. The general adoption of the flintlock musket and
the suppression of the pike in the armies of Europe put an end
to the original special duties of fusiliers, and they were subsequently
employed to a large extent in light infantry work,
perhaps on account of the greater individual aptitude for
detached duties naturally shown by soldiers who had never been
restricted to a fixed and unchangeable place in the line of battle.
The senior fusilier regiment in the British service, the (7th)
Royal Fusiliers (City of London Regiment), was formed on the
French model in 1685; the 5th foot (now Northumberland
Fusiliers), senior to the 7th in the army, was not at that time
a fusilier regiment. The distinctive head-dress of fusiliers in the
British service is a fur cap, generally resembling, but smaller
than and different in details from, that of the Foot Guards.
In Germany the name “fusilier” is borne by certain infantry regiments and by one battalion in each grenadier regiment.
FUSION, the term generally applied to the melting of a solid
substance, or the change of state of aggregation from the solid
to the liquid. The term “liquefaction” is frequently employed
in the same sense, but is often restricted to the condensation
of a gas or vapour. The converse process of freezing or solidification,
the change from the liquid to the solid state, is subject to
the same laws, and must be considered together with fusion.
The solution of a solid in a foreign liquid, and the deposition or
crystallization of a solid from a solution, are so closely related
to the fusion of a pure substance, that it will also be necessary
to consider some of the analogies which they present.
1. General Phenomena.—There are two chief varieties of the process of fusion, namely, crystalline and amorphous, which are in many ways distinct, although it is possible to find intermediate cases which partake of the characteristics of both. The melting of ice may be taken as a typical case of crystalline fusion. The passage from rigid solid to mobile liquid occurs at a definite surface without any intermediate stage or plastic condition. The change takes place at a definite temperature, the fusing or freezing point (abbreviated F.P.), and requires the addition of a definite quantity of heat to the solid, which is called the latent heat of fusion. There is also in general a considerable change of volume during fusion, which amounts in the case of ice to a contraction of 9%. Typical cases of amorphous solidification are those of silica, glass, plastic sulphur, pitch, alcohol and many organic liquids. In this type the liquid gradually becomes more and more viscous as the temperature falls, and ultimately attains the rigidity characteristic of a solid, without any definite freezing point or latent heat. The condition of the substance remains uniform throughout, if its temperature is uniform; there is no separation into the two distinct phases of solid and liquid, and there is no sudden change of volume at any temperature.
A change or transition from one crystalline form to another may occur in the solid state with evolution or absorption of heat at a definite temperature, and is analogous to the change from solid to liquid, but usually takes place more slowly owing to the small molecular mobility of the solid state. Thus rhombic sulphur when heated passes slowly at 95.6° C. into the
