How to Make Liquid Glue.--Take a wide mouthed bottle, and dissolve in
it 8 ounces beet glue in 1/2 pint water, by setting it in a vessel
of water, and heating until dissolved. Then add slowly 2-1/2 ounces
strong nitric acid 36 deg. Baume, stirring all the while. Effervescence
takes place, with generation of fumes. When all the acid has been added,
the liquid is allowed to cool. Keep it well corked, and it will be ready
for use at any time.
How the World is Weighed and Its Density and Mass Computed.--The
density, mass, or weight of the earth was found by the observed force
of attraction of a known mass of lead or iron for another mass; or
of a mountain by the deflection of a torsion thread or plumb line. In
this manner the mean density of the earth has been found to be from
4.71 to 6.56 times the weight of water, 5.66 being accredited as the
most reliable. The weight of a cubic foot of water being known, and
the contents of the earth being computed in cubic feet, we have but to
multiply the number of cubic feet by 5.66 times the weight of 1 cubic
foot of water to obtain the weight of the earth in pounds, or units of
gravity at its surface, which is the unit usually used. Another method
of determining the mean density of the earth is founded on the change
of the intensity of gravity in descending deep mines.
A Theory as to the Origin of Petroleum.--Professor Mendelejef has
recently advanced the theory that petroleum is of purely mineral origin
and that the formation of it is going on every day.
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