Jefferson County Online
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Practical Rules
for Every Day Use

The following is a chapter from "The History of Jefferson County, Iowa", Pages 284-287, published by the Western Historical Company of Chicago in 1879.

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Practical Rules for Every Day Use.


How to find the gain or loss per cent. when the cost and selling price are given.

Rule.--Find the difference between the cost and selling price, which will be the gain or loss.

Annex two ciphers to the gain or loss, and divide it by the cost price; the result will be the gain or loss per cent.


How to change gold into currency.

Rule.--Multiply the given sum of gold by the price of gold.

How to change currency into gold.

Divide the amount in currency by the price of gold.


How to find each partner's share of the gain or loss in a copartnership business.

Rule.--Divide the whole gain or loss by the entire stock, the quotient will be the gain or loss per cent.

Multiply each partner's stock by this per cent., the result will be each one's share of the gain or loss.


How to find the gross and net weight and price of hogs.
A short and simple method for finding the net weight, or price of hogs, when the gross weight or price is given, and vice versa.

Note.--It is generally assumed that the gross weight of Hogs diminished by 1-5 or 20 per cent. of itself gives the net weight, and the net weight increased by or 25 per cent. of itself equals the gross weight.

To find the net weight or gross price.
Multiply the given number by .8 (tenths.)
To find the gross weight or net price.
Divide the given number by .8 (tenths.)


How to find the capacity of a granary, bin, or wagon-bed.

Rule.--Multiply (by short method) the number of cubic feet by 6308, and point off ONE decimal place -- the result will be the correct nswer (sic) in bushels and tenths of a bushel.

For only an approximate answer, multiply the cubic feet by 8, and point off one decimal place.


How to find the contents of a corn-crib.

Rule.--Multiply the number of cubic feet by 54, short method, or by 4 ordinary method, and point off ONE decimal place -- the result will be the answer in bushels.

Note.--In estimating corn in the ear, the quality and the time it has been cribbed must be taken into consideration, since corn will shrink considerably during the Winter and Spring. This rule generally holds good for corn measured at the time it is cribbed, provided it is sound and clean.


How to find the contents of a cistern or tank.

Rule.--Multiply the square of the mean diameter by the depth (all in feet) and this product by 5681 (short method), and point off ONE decimal place -- the result will be the contents in barrels of 31 gallons.


How to find the contents of a barrel or cask.

Rule.--Under the square of the mean diameter, write the length (all in inches) in REVERSED order, so that its UNITS will fall under the TENS; multiply by short method, and this product again by 430; point off one decimal place, and the result will be the answer in wine gallons.


How to measure boards.

Rule.--Multiply the length (in feet) by the width (in inches) and divide the product by 12 -- the result will be the contents in square feet.


How to measure scantlings, joists, planks, sills, etc.

Rule.--Multiply the width, the thickness, and the length together (the width and thickness in inches, and the length in feet), and divide the product by 12 -- the result will be square feet.


How to find the number of acres in a body of land.

Rule.--Multiply the length by the width (in rods) [note: 1 rod = 16.5 feet], and divide the product by 160 (carrying the division to 2 decimal places if there is a remainder); the result will be the answer in acres and hundredths.

When the opposite sides of a piece of land are of unequal length, add them together and take one-half for the mean length or width.


How to find the number of square yards in a floor or wall.

Rule.--Multiply the length by the width or height (in feet), and divide the product by 9, the result will be square yards.


How to find the number of bricks required in a building.

Rule.--Multiply the number of cubic feet by 22.

The number of cubic feet is found by multiplying the length, height nd (sic) thickness (in feet) together.

Bricks are usually made 8 inches long, 4 inches wide, and two inches thick; hence, it requires 27 bricks to make a cubic foot without mortar, but it is generally assumed that the mortar fills 1-6 of the space.


How to find the number of shingles required in a roof.

Rule.--Multiply the number of square feet in the roof by 8, if the shingles are exposed 4 inches, or by 7 1-5 if exposed 5 inches.

To find the number of square feet, multiply the length of the roof by twice the length of the rafters.

To find the length of the rafters, at ONE-FOURTH pitch, multiply the width of the building by .56 (hundredths); at ONE-THIRD pitch, by .6 (tenths); at TWO-FIFTHS pitch, by .64 (hundredths); at ONE-HALF pitch, by .71 (hundredths). This gives the length of the rafters from the apex to the end of the wall, and whatever they are to protect must be taken in to consideration.

Note.--By or 1/8 pitch is meant that the apex or comb of the roof is to be or 1/8 the width of the building higher than the walls or base of the rafters.


How to reckon the cost of hay.

Rule.--Multiply the number of pounds by half the price per ton, and remove the decimal point three places to the left.


How to measure grain.

Rule.--Level the grain; ascertain the space it occupies in cubic feet; multiply the number of cubic feet by 8, and point off one place to the left.

Note.--Exactness requires the addition to every three hundred bushels of one extra bushel.

The foregoing rule may be used for finding the number of gallons, by multiplying the number of bushels by 8.

If the corn in the box is in the ear, divide the answer by 2, to find the number of bushels of shelled corn, because it requires 2 bushels of ear corn to make 1 of shelled corn.


Rapid rules for measuring land without instruments.

In measuring land, the first thing to ascertain is the contents of any given plot in square yards; then, given the number of yards, find out the number of rods and acres.

The most ancient and simplest measure of distance is a step. Now, an ordinary-sized man can train himself to cover one yard at a stride, on the average, with sufficent accuracy for ordinary purposes.

To make use of this means of measuring distances, it is essential to walk in a straight line; to do this, fix the eye on two objects in a line straight ahead, one comparatively near, the other remote; and, in walking, keep these objects constantly in line.


Farmers and others by adopting the following simple and ingenious contrivance, may always carry with them the scale to construct a correct yard measure.

Take a foot rule, and commencing at the base of the little finger of the left hand, mark the quarters of the foot on the outer borders of the left arm, pricking in the marks with indelible ink.


To find how many rods in length will make an acre, the width being given.

Rule.--Divide 160 by the width, and the quotient will be the answer.


How to find the number of acres in any plot of land, the number of rods being given.

Rule.--Dividie the number of rods by 8, multiply the quotient by 5, and remove the decimal point two places to the left.


The diameter being given, to find the circumference.

Rule.--Multiply the diameter by 3 1-7.


How to find the diameter, when the circumference is given.

Rule.--Divide the circumference by 3 1-7.


To find how many solid feet a round stick of timber of the same thickness throughout will contain when squared.

Rule.--Square half the diameter in inches, multiply by 2, multiply by the length in feet, and divide the product by 144.


General rule for measuring timber, to find the solid contents in feet.

Rule.--Multiply the depth in inches by the breadth in inches, and then multiply by the length in feet, and divide by 144.


To find the number of feet of timber in trees with the bark on.

Rule.--Multiply the square of one-fifth of the circumference in inches, by twice the length, in feet, and divide by 144. Deduct 1-10 to 1-15 according to the thickness of the bark.


Howard's new rule for computing interest.

Rule.--The reciprocal of the rate is the time for which the interest on any sum of money will be shown by simply removing the decimal point two places to the left; for ten times that time, remove the point one place to the left; for 1-10 of the same time, remove the point three places to the left.

Increase or diminish the results to suit the time given.

Note.--The reciprocal of the rate is found by inverting the rate; thus 3 per cent. per month, inverted, becomes 1/3 of a month, or 10 days.

When the rate is expressed by one figure, always write it thus: 3-1, three ones.


Rule for converting English into American currency.

Multiply the pounds, with the shillings and pence stated in decimals, by 400 plus the premium in fourths, and divide the product by 90.


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