Mark" which guarantees the proper degree of purity, is usually stamped on the ring that suspends the watch, and on parts of the case.

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A pound Troy of standard silver is coined into 66 shillings; accordingly the weight of a shilling is 87.27273 grs., in which there are 80-72727 grs. of pure silver. The Mint price of standard silver is 5/6 per oz. Troy; this exceeds considerably the market price of the metal, which is at present about 5/2 per oz. Whatever profit is made in this way is called Seignorage. From the year 1600 to the year 1816, the pound troy was coined into 62 shillings; but as the market price of silver sometimes advanced beyond the Mint price, there existed an inducement to melt down, or export the silver coinage, and as this led to much inconvenience, the present system was adopted.

Gold coins are the only legal tender without limitation. Silver coin is not a legal tender beyond 40 shillings, nor is copper coin a legal tender for more than twelve pence in one payment.

Leap-year occurs once in every four years, when one day must be added to 365, the number of days in a Common year. The month which takes this additional day is February, which in leap year has 29 days. If the date of the year be divided by 4, and there be no remainder, that year will be leap year; and 1, 2, or 3, will remain, according as the year is 1, 2, or 3 years after leap year. The number expressed by the last two figures only of the date may be used instead of the complete date, as the remainder arising from division by 4 will be the same; thus, the year 1852 is leap year, since 52 is exactly divisible by 4. The addition of a day every fourth year is rendered necessary on account of the ordinary year being taken as 365 days, instead of 365 days, which it is within a few minutes; so that in 4 years a whole day would otherwise be overlooked. Even as it is, the few minutes just noticed, by which 3651 days differs from the true year, as shown by the sun, accumulate to an error of about 3 days 24 hours in 400 years. This error is an error of excess; for the true solar year is 365 d. 5 h. 48 m. 49 sec. To remove the effect of this error, it has been fixed that when the year consists of complete centuries (a century being 100 years), although the date would be exactly divisible by 4, yet the year is not to be considered as leap year, unless the date, omitting the two final noughts or zeros, is also divisible by 4: thus, the years 1800, 1900, 2100, &c., are to be reckoned as common years, since 18, 19, 21, &c., are not divisible by 4; but 1600, 2000, &c., are leap years. With this correction the civil reckoning so far agrees, on the average, with the astronomical determination .of the year, as to be only one day in advance of the strict truth in 3546 years,—an error which for the purposes of life it is unnecessary to make any provision for.

The year is divided into twelve parts,-January, February, March, April, May, June, July, August, September, October, November, and December. These are called the 12 calendar months. Each of these, except February in a common year, contains more than 4 weeks, or 28 days; yet, in ordinary language, 4 weeks is called a month. There are 13 of these months in a calendar year. The number of days in each calendar month may be easily recollected by aid of the following lines:—

Thirty days have September,
April, June, and November,
February has twenty-eight alone,
And all the rest have thirty-one;
But leap year, coming once in four,
February then has one day more.

441

Table No. 11.-TABLE FOR FINDING THE NUMBER OF DAYS BETWEEN ONE

(1.) From the 1st of January to the 1st of December, 334 days.

(2.) From the 1st of June to the 1st of April, 304 days.

(3.) From the 10th of January to the 12th of June, 151 + 2 = 153 days. (4.) From the 8th of June to the 1st of January, 214-7=207 days.

If both days are inclusive, add one day. If it be leap year, and February be included, add one day.

Table No. 12.-VOLUME MEASURE OF INCHES CONTAINED IN A FOOT.

A Cylinder, 1 foot high, and 1 foot in diameter, contains.. 1357.17 cubic inches. A Sphere, Í foot in diameter, contains...

A Cone, 1 foot high, and 1 foot in diameter, at base

904.78 cubic inches. 452.39 cubic inches.

1 Cubic foot, contains 2200 cylindrical inches of 1 inch long, and 1 inch diameter.

3300 spherical inches of 1 inch diameter.

6600 conical inches of 1 in. high, and 1 in. diameter at base.

Table No. 13.-MISCELLANEOUS ARTICLES.

A hogshead of tobacco

12 articles

1 long dozen

Table No.14.-TABLE OF THE DENSITIES AND VALUES OF SPIRITS AT 60° FAHRENHEIT CORRESPONDING TO EVERY WHOLE INDICATION OF SYKES' HYDROMETER.

TABLE OF THE DENSITIES AND VALUES OF SPIRITS, &C., (Continued.)

NOTE-The specific gravities in this Table are such as on being referred to Gilpin's Tables will give the expressions of proof strength answering to whole indications of the revenue hydrometer. Intermediate values at fifths of indications may be had by taking proportional differences between the nearest tabular numbers. Thus to find the specific gravity that should stand opposite to Indication 706, we first obtain the difference between the densities standing in a line with Indications 70 and 71 respectively, and then say, as 1 06: 000192. 00115 and 94135 + 00115 = 94250, the specific gravity required.

Table No. 15.-TABLE FOR FINDING THE SPECIFIC GRAVITY OF ANY SPIRIT AT 60° WHEN THE SPECIFIC GRAVITY AT ANY OTHER TEMPERATURE IS GIVEN.

The Table is to be entered with the existing specific gravity of the liquor, against which will be found the correction to be added to it for every degree its temperature is higher, or subtracted for every degree it is lower than 60°.

Example. If a quantity of spirit is of the specific gravity 894 at 73°, what will be its specific gravity at 60°?

Here the specific gravity being between 890 and 900, we must add 450 for each degree of temperature between 73° and 60°. The specific gravity at 60°, would therefore be 894 +490 × 13899.85.

Table No. 16.-TABLE FOR FINDING THE PER-CENTAGE VALUE AT PROOF, AND THE AMOUNT OF CONCENTRATION OF ANY SPIRIT AT 60° F., WHEN ITS SPECIFIC GRAVITY AT THAT TEMPERATURE IS GIVEN

the

N.B.-These numbers may be obtained from Gilpin's Tables by dividing the per-centage in his 7th column opposite to each specific gravity by 61-57 per-centage of proof at 60o. Proof spirit is here assumed to have the sp. gr. 920 at 600 F., which is very nearly accurate.

USE OF THE PRECEDING TABLE.

This Table is to be entered with the specific gravity next below that of the spirit at 60°, against which there will be found, in the 2nd column, the per-centage if that were really the specific gravity, and in the 3rd column the per-centage to be subtracted for every unit that its specific gravity exceeds the number in the 1st column. The 4th column, in like manner, contains the concentration per cent. of the liquor against whose specific gravity it stands; and the 5th column the correction to be applied to the concentration for every unit which the specific gravity differs from the nearest in the 1st column.

Example. Let the specific gravity be 883 at 48°. Required the strength per-cent.

and the concentration?

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By Table No. 15, above given, the specific gravity of the liquor at 60° would be 883456 x 12877.5. We see also by the present Table, that if the specifie gravity at 60° were 875, the per-centage would be 133-07, but that, as it is 877-5 we must subtract 670 × 2.5 or 1.67 from the per-centage opposite to 875; the real percentage of the liquor, therefore, at 60° is, 133:07 -1.67 1314. The quantity of water requisite to reduce these 131-4 gallons to proof is found from the column of concentration. The concentration of spirit of 875 sp. gr. at 60° is 1.86 per-cent, and that of spirit of specific gravity, 877.5 1.86048 × 2.5 174, therefore 31-4 +1.74 or 33·14 gallons is the quantity of water to be added to the 100 gallons to reduce it to proof, making only 131:40 gallons in the whole.

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