Table of Hyperbolic Logarithms—Continued.

Number. Logarithms. Number. Logarithms. Number. Logarithms.

Table of Natural Sines, Co-sines, Tangents, Co-tangents, Secants and Co-secants to every degree of the Quadrant.

Table of the Expansion of Air by Heat, that at 32° Fahrenheit

NOTE.-One hundred parts of pure air by weight contain 75.55 parts of nitrogen, 23.32 parts oxygen, and 1·3 carbonic acid, and watery vapour.

The weight or pressure of the atmosphere equal a column of water 34 feet in height, or a column of mercury 30 inches in height, or 14.7 pounds per square inch at a mean temperature.

The resistance of air increases as the square of the velocity, and the resistance per square foot as the velocity multiplied by 002288.

Table of the Relative Indications of Barometer and Thermometer at the boiling points of Fresh Water.

When the Barometer indicates 30 inches, the boiling point is 212° Fah., and 0.589 of barometric pressure corresponds to a difference of 1° Fah.

To find the height of a mountain by the Barometer.

RULE 1.-Multiply the difference between 32° Fah. and the mean temperature of the air by 21, and add the product to 87 if the mean temperature be above 32°, but subtract it if below.

RULE 2.-Multiply the sum or difference as found above by thirty times the difference between the barometric heights in tenths of inches, and divide the product by the mean of the barometric heights; the quotient is the approximated elevation.

RULE 3.—Multiply the difference between the mercurial temperatures by 2.833 feet, and add the product to the approximated elevation if that of the upper barometer be the greatest, otherwise subtract it; the result will be the corrected elevation in English feet.