6013. Log Lines

6013.    Log Lines. 1 knot = 51.1625 feet, or 51 feet 1 3/4 + inches. 1 fathom = 5.11625 feet, or 5 feet 11/3 + inches, estimating a mile at 61391/2 feet, and using a 30" glass. If a 28" glass is used, and eight divisions, then 1 knot = 47 feet 9 + inches. 1 fathom = 5 feet ll 5/8 inches. The line should be about 150 fathoms long, having 10 fathoms between the chip and first knot for stray line. Miles X .87 = knots. Knots X 1.15 = miles. Feet per minute X .01 = knots per hour. 1 knot = 6082.66 feet; 1 statute mile = 5280 feet.

6014. The Decimal System of Weights and Measures

6014.       The Decimal System of Weights and Measures. A permissive law has already been passed by the American and British governments, adopting the decimal system as applied to weights and measures. It is substantially the same as the French decimal system, and founded on units of the same value. The multiples and subdivisions of the different units are the same; Greek prefixes being used to denote the multiples, and Latin prefixes the fractional parts of the units.

6015. Official Standard Metre

6015.    Official Standard Metre. The following information was lately given by Mr. Hilgard, of the United States Coast Survey, to the Journal of the Franklin Institute : "There are, in the custody of the Treasury Department, at the Office of "Weights and Measures, the following authentic copies of the standard metre and kilogramme of France, viz.: Metre of platinum, compared and certified by Arago; metre of steel, compared and certified by Silbermann; kilogramme of platinum, compared and certified by Arago; kilogramme of brass (gilt), compared and certified by Silbermann. The length of the metre is 39.3685 inches of the United States standard scale, and the kilogramme is 15432.2 grains, or 2 pounds, 3 ounces, 119.7 grains avoirdupois. There is also another metre, the property of the American Philosophical Society, which is one of the twelve original metres made by the French Government, and was brought to this country by Mr. Hassler, the originator of the United States Coast Survey. A comparison between this bar and the standard of France at the Conservatory of Arts and Trades was made by Dr. F. A. P. Barnard, with the result that, at the temperature of melting ice, there is no appreciable difference, by the most delicate means of comparison, between the platinum standard of the Conservatory and this iron metre."

The above standard metre of 39.3685 inches would make the equatorial circumference of the earth measure 24.854 statute miles. Bes-sel's calculations, given in Chambers' Encyclopaedia, give the equatorial circumference at 24.901 4/11 miles. If this measurement be correct, the standard metre should be 39.371 inches. This difference, however, is so trifling that it would not be appreciable for all practical purposes.

6016. Decimal Measures of Length

6016.    Decimal Measures of Length. Myriametre              =         10,000 metres. Kilometre =          1,000 metres. Hectometre =             100 metres. Dekametre =               10 metres. Metre =                1 metre. Decimetre =                    1/10 metre. Centimetre = 1/100 metre. Millimetre = 1/1000 metre.