Philosophical Facts

The greatest height at which visible clouds ever exist does not exceed

ten miles.



Air is about eight hundred and fifteen times lighter than water.



The pressure of the atmosphere upon every square foot of the earth

amounts to two thousand one hundred and sixty pounds.



The violence of the expansion of water when freezing is sufficient to

cleave a globe of copper of such thickness as to require a force of

27,000 pounds, to produce the same effect.



During the conversion of ice into water one hundred and forty degrees of

heat are absorbed.



Water, when converted into steam, increases in bulk eighteen hundred

times.



In one second of time--in one beat of the pendulum of a clock--light

travels two hundred thousand miles. Were a cannon ball shot toward the

sun, and were it to maintain full speed, it would be twenty years in

reaching it, and yet light travels through this space in seven or eight

minutes.



Strange as it may appear, a ball of a ton weight, and another of the

same material of an ounce weight, falling from any height will reach the

ground at the same time.



The heat does not increase as we rise above the earth nearer to the sun,

but decreases rapidly until, beyond the regions of the atmosphere, in

void, it is estimated that the cold is about seventy degrees below zero.

The line of perpetual frost at the equator is 15,000 feet altitude;

13,000 feet between the tropics; and 9,000 to 4,000 between the

latitudes of forty degrees and forty-nine degrees.



At a depth of forty-five feet under ground, the temperature of the earth

is uniform throughout the year.



The human ear is so extremely sensitive that it can hear a sound that

lasts only the twenty-four thousandth part of a second.



Sound travels at the rate of one thousand one hundred and forty-two feet

per second-about thirteen miles in a minute. So that if we hear a clap

of thunder half a minute after the flash, we may calculate that the

discharge of electricity is six and a half miles off.