A column of water 27.67 inches high has a pressure of 1 pound to the square inch at the bottom.

Doubling the diameter of a pipe increases its capacity four times.

A hot water boiler will consume from 3 to 8 pounds of coal per hour per square foot of grate, the difference depending upon conditions of draft, fuel, system and management.

A cubic foot of anthracite coal averages 50 pounds. A cubic foot of bituminous coal weighs 40 pounds.

Liquid Measure.

4 Gills make 1 Pint 2 Pints make 1 Quart

4 Quarts make 1 Gallon 31½ Gals. make 1 Barrel

To find the area of a rectangle, multiply the length by the breadth.

To find the area of triangle, multiply the base by one-half the perpendicular height.

To find the circumference of a circle, multiply the diameter by 3.1416.

To find the area of a circle, multiply the diameter by itself, and the result by .7854.

To find the diameter of a circle of a given area, divide the area by .7854, and find the square root of the result.

To find the diameter of a circle which shall have the same area as a given square, multiply one side of the square by 1.128.

To find the number of gallons in a cylindrical tank, multiply the diameter in inches by itself, this by the height in inches, and the result by .34. To find the number of gallons in a rectangular tank, multiply together the length, breadth and height in feet, and this result by 7.4. If the dimensions are in inches, multiply the product by .004329. To find the pressure in pounds per square inch, of a column of water, multiply the height of the column in feet by .434.

To find the head which will produce a given velocity of water through a pipe of a given diameter and length: Multiply the square of the velocity, expressed in feet per second, by the length of pipe multiplied by the quotient obtained by dividing 13.9 by the diameter of the pipe in inches, and divide the result obtained by 2,500. The final amount will give the head in feet.

Example. The horizontal length of pipe is 1,200 feet, and the diameter is 4 inches. What head must be secured to produce a flow of 3 feet per second?

3X3=9; 13.9÷4=3.475. 9X1,200X3.475=37,530. 37,530÷2,500=15 ft.

To find the velocity of water flowing through a horizontal straight pipe of given length and diameter, the head of water above the center of the pipe being known: Multiply the head in feet by 2,500, and divide the result by the length of pipe in feet multiplied by 13.9, divided by the inner diameter of the pipe in inches. The square root of the quotient gives the velocity in feet per second.

To find the head in feet, the pressure being known, multiply the pressure per square inch by

2.31.

To find the contents of a barrel. To twice the square of the largest diameter, add the square of the smallest diameter and multiply this by the height, and the result by 2,618. This will give the cubic inches in the barrel, and this divided by 231 will give the number of gallons.

To find the head in feet, the pressure being known, multiply the pressure per square inch by 2.31.

To find the lateral pressure of water upon the side of a tank, multiply in inches, the area of the submerged side, by the pressure due to one-half the depth.

Example - Suppose a tank to be 12 feet long and 12 feet deep. Find the pressure on the side of the tank.

144 x 144=20,736 square inches area of side.

12 x .43=5.16, pressure at bottom of tank. Pressure at the top of tank is 0. Average pressure will then be 2.6. Therefore 20,736 x 2.6=53,914 pounds pressure on side of tank.

To find the number of gallons in a foot of pipe of any given diameter, multiply the square of diameter of the pipe in inches, by .0408.

To find the diameter of pipe to discharge a given volume of water per minute in cubic feet, multiply the square of the quantity in cubic feet per minute by 96. This will give the diameter in inches.

To find the weight of any length of lead pipe, when the diameter and thickness of the lead are known: Multiply the square of the outer diameter in inches, by the weight of 12 cylindrical inches, then multiply the square of the inner diameter in inches by the same amount, subtracting the product of the latter from that of the former. The remainder multiplied by the length gives the desired result.

Example

Find the weight of 1,200 feet of lead pipe, the outer diameter being 7/8 inch, and the inner diameter 9-16 inch.

The weight of 12 cylindrical inches, 1 foot long, 1 inch in diameter, is 3.8697 lbs.

7/8 X 7/8=49-64=.765625.

9-16 X 9-16=81-256=.316406.

.765625 - .316406=.449219 X 3.8697 X 1,200=2,086 lbs.

Cleaning Rusted Iron

Place the articles to be cleaned in a saturated solution of chloride of tin and allow them to stand for a half day or more.

When removed, wash the articles in water, then in ammonia. Dry quickly, rubbing them hard.

Removing Boiler Scale

Kerosene oil will accomplish this purpose, often better than specially prepared compounds.

Cleaning Brass

Mix in a stone jar one part of nitric acid, one-half part of sulphuric acid. Dip the brass work into this mixture, wash it off with water, and dry with sawdust. If greasy, dip the work into a strong mixture of potash, soda, and water, to remove the grease, and wash it off with water.

Removing Grease Stains From Marble

Mix 1½ parts of soft soap, 3 parts of Fuller's earth and I½ parts of potash, with boiling water. Cover the grease spots with this mixture, and allow it to stand a few hours.