Antiquity Of Tin And Medical Use
Moses, who was born 1600 B.C., mentions tin, and history records its use
500 B.C., but not for filling teeth; much later on, the Ph[oe]nicians
took it from Cornwall, England, to Tyre and Sidon.
The alchemistic name for tin is Jove, and in the alchemistic
nomenclature medicinal preparations made from it are called Jovial
Hindoo native doctors give tin salts for urinary affection
Fothergill, and Richter claim to have expelled worms from the human
system, by administering tin filings.
Blackie, in "Lays of Highlands and Islands," referring to tin as money,
"And is this all? And have I seen the whole
Cathedral, chapel, nunnery, and graves?
'Tis scantly worth the tin, upon my soul."
"Tin-penny."--A customary duty formerly paid to the tithingmen in
England for liberty to dig in the tin-mines.
In 1846, Tin (Stannum, symbol Sn) was found in the United States only at
Jackson, N. H. Since then it has been found, to a limited extent, in
West Virginia and adjoining parts of Ohio, North Carolina, Utah, and
North Dakota. The richest tin mines of the world, however, are in
Cornwall, England, which have been worked from the time of the
The tin which is found in Malacca and Banca, India, is of great purity,
and is called "Straits Tin" or "Stream Tin." It occurs in alluvial
deposits in the form of small rounded grains, which are washed, stamped,
mixed with slag and scoriae, and smelted with charcoal, then run into
basins, where the upper portion, after being removed, is known as the
best refined tin. Stream tin is not pure metallic tin, but is the result
of the disintegration of granitic and other rocks which contain veins of
tinstone. Banca tin is 99.961 parts tin, 0.019 iron, 0.014 lead in 100
parts; it is sold in blocks of 40 and 120 pounds, and a bar 0.5 meter
long, 0.1 broad, 0.005 deep can be bent seventy-four times without being
broken. Subjected to friction, tin emits a characteristic odor.
Tin in solution is largely used in electro-metallurgy for plating. Pure
tin may be obtained by dissolving commercial tin in hydrochloric acid,
by which it is converted into stannous chlorid; after filtering, this
solution is evaporated to a small bulk, and treated with nitric acid,
which converts it into stannic oxid, which in turn is thoroughly washed
and dried, then heated to redness in a crucible with charcoal, producing
a button of tin which is found at the bottom of the crucible.
Pure tin may be precipitated in quadratic crystals by a slight galvanic
current excited by immersing a plate of tin in a strong solution of
stannous chlorid; water is carefully poured in so as not to disturb the
layer of tin solution; the pure metal will be deposited on the plate of
tin, at the point of junction of the water and metallic solution.
In the study of tin as a material for filling teeth, we have deemed it
expedient to consider some of its physical characteristics, in order
that what follows may be more clearly understood.
Tin possesses a crystallized structure, and can be obtained in
well-formed crystals of the tetragonal or quadratic system (form right
square prism), and on account of this crystalline structure, a bar of
tin when bent emits a creaking sound, termed the "cry of tin;" the purer
the tin the more marked the cry.
The specific gravity is 7.29; electrical state positive; fusing point
442 deg. F.; tensile strength per square inch in tons, 2 to 3. Tensile
strength is the resistance of the fibers or particles of a body to
separation, so that the amount stated is the weight or power required
to tear asunder a bar of pure tin having a cross-section of one square
Tenacity: Iron is the most tenacious of metals. To pull asunder an iron
wire 0.787 of a line in diameter requires a weight of 549 lbs. To pull
asunder a gold wire of the same size, 150 lbs.; tin wire, 34 lbs.; gold
being thus shown to be more than four times as tenacious as tin.
Malleability: Pure tin may be beaten into leaves one-fortieth of a
millimeter thick, thus requiring 1020 to make an inch in thickness.
Miller states that it can be beaten into leaves .008 of a millimeter
thick, thus requiring 3175 to make an inch in thickness. Richardson says
that ordinary tin foil is about 0.001 of an inch in thickness.
If the difficulty with which a mass of gold (the most malleable of
metals) can be hammered or rolled into a thin sheet without being torn,
be taken as one, then it will be four times as difficult to manipulate
tin into thin sheets.
Ductility: If the difficulty with which gold (the most ductile of
metals) can be drawn be taken as one, then it will be seven times as
difficult to draw tin into a wire. At a temperature of 212 deg. it has
considerable ductility, and can be drawn into wire.
Among the metals, silver is the best conductor of heat. If the
conductivity of silver be taken as 100, then the conducting power of
gold would be 53.2; tin, 14.5; gold being thus shown to be nearly four
times as good a conductor of heat as tin. Among the metals, silver is
the best conductor of electricity. If its electrical conductivity be
taken at 100, then the conducting power of gold would be 77.96; tin,
12.36; gold being thus shown to be more than six times as good a
conductor of electricity as tin.
Resistance to air: If exposed to dry, pure air, tin resists any change
for a great length of time, but if exposed to air containing moisture,
carbonic acid, etc., its time resistance is reduced, although even then
it resists corrosion much better than copper or iron.
As to linear expansion, when raised from 32 deg. to 212 deg. F., aluminum
expands the most of any of the metals. Taking its expansion as 1, that
of tin would be 3, i.e., aluminum expands three times as much as tin.
(Dixon, "Vade Mecum.")
Solids generally expand equally in all directions, and on cooling return
to their original shape. Within certain limits, metals expand uniformly
in direct proportion to the increase in temperature, but the rate of
expansion varies with different metals; thus, under like conditions, tin
expands nearly twice (1-3/5) as much as gold, but the rate of
expansion for gold is nearly twice (1-7/10) that of tin.
The capacity for absorbing heat varies with each metal; that of gold is
about twice (1-3/4) that of tin.
Tin has a scale hardness of about 4, on a scale of 12 where lead is
taken as the softest and platinum the hardest. (Dixon, "Vade Mecum.")
Tin has a scale hardness of about 2. (Dr. Miller.)
To fuse a tin wire one centimeter in diameter requires a fusing current
of electricity of 405.5 amperes. Up to 225 deg. C., the rise in resistance
to the passage of an electric current is more rapid in tin than in gold.
In some minerals the current follows the trend of the crystals.
Gold wire coated with tin, and held in the flame of a Bunsen burner,
will melt like a tin wire. At 1600 deg. to 1800 deg. tin boils and may be