The new North-west. [volume] (Deer Lodge, Mont.) 1869-1897, 1870-05-27
SPECIFIC GRN1TX:

/
This il rather e6ghty t6pic f. from.
tier newspaper, but having recently looked
into the subject for our own information,
We believe We can. wi,hout offering any.
thing new or original, present few facts
which will be entertaining and instructive
to very many of our readers.
Specific gravity ID defined to be 1.-THE pro.
portion Of the weight ofa body to that Of
an equal volume of some other substance,
adopted - . standard of reference.
Aeriform bodies, such as gases. etc., arc
referred to the cir Is a standard; but we pro-
pose now to speak only Of solids.
For solids and liquids the standard Is pure
water, At temperature Of 90 degrees fahren-
heit, the barometer being Il 80 inches. In
other words, water Is made the unit of
measurement Of weight, and when We say
1.-THE specific gravity Of gold is 1885," we
mean that given quantity of gold is 1ei
times as heavy as the same bulk of water:
When we say ",he specific gravity Of cork
is O24," we mean that it is 24-10o or less
than / the weight of water. .....
The heaviest known bodies are usually
metals, Of Which about 50 have been dis
covered. The specific GRANTEES Of those best
known are as follows: Platinum 221, gold
1875, mercury II. lead ia, silver 1915, bis.
nuth 0o, copper SO, nickel SO, iron 10. tin
rs, zinc ~, anthony 6.7, aluminium 80,
or just one.third the weight Of iron. lrl-
dunn, very rare metal, with specific
gravity OF g, is the heaviest substance
known. Tungsten, an exceedingly hard
iron-gray metal, sometimes used in the
manufacture of steel, has the high specific
gravity Of 17.6. There are three metals
whose specific gravity is less than that of
water. They are sodium oo7, potassium
0.S6 and lithium $50. But these as well as
most of the other metals not named, are OK.
ceedingly rare and seldom seen outside the
laboratory of the chemist.
OF gems and precious stones, the specific
gravity of the ruby and garct is 4.3, Of the
sapphire 4. diamond and topaz SO, coral 8. 5,
amethyst and turquo Use 90. emerald pearl
and bloodstonc 81, and Of the opal 81.
It is held as general rule that the specific
gravity of any wood can be taken as u very
sure criterion of its hardness, but not SO
certainly Of its strength. The woods of the
soft frs, poplar, willow, and many others, do
not exceed, and many of them do not equal,
half the weight of water: those of the ash,
hickory, locust, plum, apple, mahogany,
oaks, etc. approach more or less nearly
three. fourths the weight of water; while
the Italian and African oaks, lockwood,
ironwood, lignumvitG, the manzanita of
California. the mountain mahogany of the
Great Basin, and the ironbark Of New South
Wales, have q specific gravity almost inyari-
ably above l. and So sink in water. Of
these. the ironbark having specific gravity
Of 1.43, and strength of II times that Of
English oak, is believed to be the heaviest
and solitlest wood known. The cortica of
Brazil is the lightest true wood known,
having specific gravity of only o21, or less
than cork.
Of ether well known substances, the
specific gravity of marble. limestone and
granite Is from 2.6 to 2.8, brick 2. chalk 2.S,
common salt 81, sulphur 2, quartz as to
90, clay 10, alum ~, amber IL, bitumin-
Gus coal Ia, anthracite 49,
We have thus given the meaning of the
term. and the Specific Gravity Of the most
valuable and useful solids. There being con-
siderable difference among writers as 10 the
exact gravity of some bodies. the highest
authority has been cited and the figures will
approximate closely to exactness.