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By the English statute the dry gallon must contain 2684 cubic or solid inches. The corn or Winchester bushel must contain 2150 cubic or solid inches. This measure is of a cylindric form, 8 inches deep and 181 inches in diameter.

By an act of Parliament, which took effect the 1st of January, 1826, the imperial gallon of 277-274 cubic inches was adopted as the only gallon. This gallon was to consist of 10 pounds, avoirdupois, of distilled water.

NOTE.-If we divide 1728, the number of cubic inches in one cubic foot, by 277-274, the number of cubic inches in the gallon, we shall obtain 6.2321 for a quotient, which is the number of gallons in one cubic foot. Multiplying 6-2321 by 10, the number of pounds in one gallon, we obtain 62-321 for the number of avoirdupois pounds in one cubic foot of water. In one avoirdupois pound there are 7000 grains, and in 10 pounds there are 70000 grains. But 10 pounds is the weight of one gallon, which contains 277-274 cubic inches. Hence, dividing 70000 by 277.274, we find 252-458, the weight in grains of one cubic inch of water.

According to the Revised Statutes of the state of New York, a cubic foot of distilled water, when estimated under prescribed circumstances, is to consist of 62 pounds, or 1000 ounces avoirdupois weight. Eight pounds of such water is to constitute the gallon for liquid measure, and ten pounds is to make the gallon for dry measure.

What articles are measured by Dry Measure? Repeat the Table. How many cubic inches in the dry gallon, according to the English statute? How many cubic inches in a bushel? What is the form and dimensions of the Winchester bushel measure? How many cubic inches in the English imperial gallon? The imperial gallon contains how many pounds of distilled water? One cubic foot of water weighs how many avoirdupois pounds? How many Troy pounds? One cubic inch of water weighs how many grains? How many pounds of water constitute the dry gallon, according to the Revised Statutes of New York? How many pounds make the liquid gallon?

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The true length of the solar year is 365-242217 days

or about 365 da. 5 hr. 48 m. 47 sec.

The civil year is also divided into 12 calendar months

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then

If the year exceeded 365 days by 6 hours exactly, once in four years these hours would amount to another day. Hence, once in four years, an additional day is given to the month of February; and such years are called

Bissextile or Leap years. But, since this excess is not quite 6 hours, this rule of adding one day to February every fourth year is interrupted, and the centennial years, which are not divisible by 400, are regarded as common years.* Hence, any year, (except a centennial year,) which is divisible by 4, is a Leap year, or consists of 366 days.

Centennial years which are divisible by 400 are regarded as Leap years; all others are considered as common years. 1796, 1804, 1808, 1812, 1816, 1820, 1824, 1828, 1832, 1836, 1840, were all Leap years. 1800, not being divisible by 400, was a common year of 365 days; the same may be said of 1900; but the year 2000, being divisible by 400, will be a Leap year.

The number of days in the respective months may be recalled by recollecting the following versification:

Thirty days hath September,
April, June, and November-
All the rest have thirty-one,
Excepting February alone,

Which has but twenty-eight in fine,

Till Leap Year gives it twenty-nine.

Repeat the Table for Time. What is the length of the solar year to the nearest second? What is the more accurate value in decimals? Into how many calendar months is the civil year divided? Repeat their names and the number of days belonging to each. How often in general is an additional day added to February? What are such years styled? Is the rule of counting every fourth year Leap year correct? Are centennial years, which are not divisible by 400, Leap years? Was 1800 a Leap year? Mention the next preceding and next following Leap year to 1800.

It is very desirable to be able readily to determine the number of days from any particular date to any other date. For this purpose, we will give the following

* There is still a further modification which takes place at the end of every 1000 years, which it is unnecessary to explain in this place.

TABLE,

SHOWING THE NUMBER OF DAYS FROM ANY DAY OF ONE MONTH TO THE SAME DAY OF ANY OTHER MONTH IN THE SAME YEAR.

FROM ANY

DAY OF

JANUARY,

FEBRUARY,

MARCH,

APRIL,

MAY,

JUNE,

JULY,

AUGUST,

TO THE SAME DAY OF

Jan. Feb. | Mar. | Ap'l May June July Aug. Sept. Oct. [Nov. Dec.

365 31 59 90 120 151 181 212 243 273 304 334 334 365 28 59 89 120 150 181 212 242 273 303 306 337 365 31 61 92 122 153 184 214 245 275 275 306 334 365 30 61 91 122 153 183 214 244 245 276 304 335 365 31 61 92122 153 184 214 214 245 273 304 334 365 30 61 92122 153 183 184 215 243 274 304 335 365 31 62 92 123 153 153 184 212 243 273 304 334 365 31 61 92122 SEPTEMBER, 122 153 181 212 242 273 303 334 365 30 61 91 OCTOBER, 92 123 151 182 212 243 273 304 335 365 31 61 NOVEMBER, 61 92 120 151 181 212 242 273 304 334 365 30 DECEMBER, 31 62 90 121 151 182 212 243 274 304 335 365

As an example, suppose we wish the number of days from November 6th to the 15th of next April. We find November in the left-hand vertical column, and April at the top line of the table, and at the intersection we find 151 days. So that from November 6th to April 6th is 151 days; consequently, adding 9, we find 160 for the number of days between November 6th and April 15th.

This table is constructed on the supposition of 28 days to February. When there are 29 days in February the proper allowance must be made.

EXAMPLES.

1. How many days from May 3d to the 4th of the next

July?

Ans. 62 days.

2. How many days from July 4th to the 25th of the next December? Ans. 174 days. 3. How many days from March 21st to the 23d of the next September? Ans. 186 days. 4. How many days from September 23d to the 21st of the next March? Ans. 179 days. 5. How many days from June 21st to the 22d of the next December? Ans. 184 days. 6. How many days from December 22d to the 21st of the next June? Ans. 181 days. 7. How many days from March 21st to the 21st of the next June? Ans. 92 days. 8. How many days from Jan. 13th, 1848, to September 17th of the same year?

Ans. 248 days.

CIRCULAR MEASURE, OR MOTION.

77. By this is estimated Laurude and Longitude, and the motion of the heaven. oodies

A

hich appear to move

in circles. Every circle, wnether great or small, is divided

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