Page:EB1911 - Volume 28.djvu/507

18 inches; yard of 36 inches, 1/2, 1/4, 1/8, 1/16 yard, nail, inch, and duodecimal, decimal and binary parts of the inch.

Imperial Measures of Capacity.—Liquid measures from 32 gallons to 1 gallon, quart, pint, 1/2 pint, gill, 1/2 gill, 1/4 gill. Dry measures of bushel, 1/2 bushel, peck, gallon, quart, pint, 1/2 pint.

Apothecaries’ Measures.—40 fluid ounces to 1/2 fl. oz., 16 fluid drachms to 1/2 fl. dr., 60 minims to 1 minim.

Avoirdupois Weights.—Cental (100 ℔), 56 ℔ (1/2 cwt.), 28 ℔, 14 ℔ (stone), 7, 4., 2, 1 ℔; 8, 4, 2, 1, 1/2 ounce (8 drams); 4, 2, 1, 1/2 drams.

Troy Weights.—The ounce (480 gr.) and multiples and decimal parts of the ounce troy from 500 ounces to 0·001 oz.

Apothecaries’ Weights.—10 oz. to 1 oz. (480 gr.); 4 drachms to 1/2 oz.; 2, 1 drachms; 2 scruples to 1/2 scruple; and 6 grains to 1/2 grain.

Pennyweights.— 20 dwt. (480 grains), 10, 5, 3, 2, 1 dwts.

Grain Weights.—4000, 2000, 1000 gr. (making 7000 gr. or 1 ℔), 500 to 0·01 gr.

2. The international trade metric weights and measures 1897) handled in shops, &c., of which there are also Board of Trade standards, are set out as follows:—

Length.—Decametre or 10 metres; double metre; metre or 1000 millimetres; decimetre or 0·1 metre; centimetre or 0·001 metre; millimetre.

Capacity. 20 litres; 10 litres or decalitre; 5, 2, 1, 0·5, 0·2, 0·1 (decilitre); 0·05, 0·02, 0·01 (centilitre); 0·005, 0·002, 0·001 (millilitre) litres.

Cubic Measures.—1000 (litre), 500, 200, 100, 50, 20, 10, 5, 2 cubic centimetres, 1 c.c. or 1000 cubic millimetres.

Weights.—20, 10, 5, 2, 1 kilograms; 500 to 1 gramme; 5 to 1 decigram; 5 to 1 centigram; 5 to 1 milligram. (Series 5, 2¹, 2, 1, i.e. with a duplicate weight of “2.”)

Fig. 9.—International Metric Trade Weights and Measures, 1897. A, linear; B, capacity; C, and D, weights.

3. Equivalents.—The metric equivalents of the units of the metric system in terms of the imperial system, as recalculated in 1897, are as follows:—^[1]

Imperial to Metric

1 yard	＝  0·914399 m.
1 square yard	＝  0·836126 m2.
1 cubic inch	＝ 16·387 c.c.
1 gallon[2]	＝  4·5459631 l.
1 pound (7000 grains)	＝  0·45359243 kg.
1 ounce troy (480 gr.)	＝ 31·1035 grammes.
1 fluid drachm	＝  3·552 millilitres (ml.).
1 fluid ounce	＝  2·84123 centilitres (cl.)

Metric to Imperial

1 metre (m.) at 0° C.		＝	39·370113 inches at 62°F.
1 square metre (m2.)		＝	10·7639 square feet.
1 cubic decimetre (c.d.)	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}$	＝	61·024 cubic inches.
or
1000 cubic centimetres (c.c.)
1 litre (l.)		＝	1·7598 pints.
1 kilogram (kg.)		＝	2·2046223 ℔ avoir.
1 gramme (g.)		＝$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	15·4323564 grains
			or
			0·7716 scruple.

1. Metric Equivalents, King’s Printers (1898).
2. The equivalent of the litre in gallons may also be derived as follows:—
   
   Let P(1−p/d)＝P¹(1−p/d′), where P is the weight of the water contained in the gallon when weighed in London—g. at London＝g. at Paris (45°)×1·000577.
   
   The correction for temperature, 62° F., is −0·0906 in.; hence 29·9094 inches. One inch＝25·4 mm.; also 29·9094×25·4＝759·69876; and 759·698761·×1·000577＝760·137 mm. P¹ is the weight of the brass weights (10 ℔) Δ＝8·143.
   
   p, the density (0·001218738) of dry air, containing 4 vols. of carbonic acid in 10,000 vols.; t＝16·667°C.; B＝760·137 mm. of mercury at 0°, lat. 45°, and at sea-level. Coefficient of expansion of air＝0·00367; Δ mercury at 0° C.＝13·595. d is the density of water at 62° F. (16·667° C.)＝0·9988611. d¹, the density of the brass as above. 10 ℔＝4·5359243 kg.
   
   From the above it follows that P＝4·5407857 kg. Therefore—1 gallon＝P/0·9988611＝4·5459631 litres.