APOTHECARIES' WEIGHTS.

20 grains = 1 scruple. 3 scruples = 1 dram. 8 drams = 1 ounce. 12 ounces = 1 pound.

This gives 480 grains to the ounce and 5760 grains to the pound. When you buy 1 ounce of a chemical from your dealer you will only get 437 1/2 grains, because he sells by avoirdupois weight, yet if you obtain one pound, you will get 7000 grains, because there are 16 avoirdupois ounces to the pound.

AVOIRDUPOIS WEIGHT.

437 1/2 Grains = 1 Ounce. 16 Ounces = 1 Pound = 7000 Grains. 1/4 ounce =109 grains; 1/2 ounce = 219 grains; 3/4 ounce = 328 grains.

COINS AS WEIGHTS. Silver coinage is minted by weight in proportion to its value, viz., 436 4/17 grains for every 5s. The threepenny bit is 21•8 grs. ; a sixpence, 43•6 ; shilling, 87•2 ; florin, 517•4 ; half-crown, 218 grs. One sovereign weighs 123•27 grs. ; the half-sovereign, 61•63 grs. 1/4 oz. (avoir.) = one half-penny and one threepenny piece. 1/2 ,, ,, =two half-pennies and a farthing.

1 ,, ,, = three pennies (or five half-pennies).

2 ,, ,, =six pennies (or ten half-pennies).

4 ,, ,, = twelve pennies or twenty half-pennies.

FLUID MEASURE.

60 Minims = 1 Drachm.

8 Drachms =1 Ounce = 480 Minims. 20 Ounces =1 Pint = 160 Drachms = 9600 Minims.

2 Pints = 1 Quart = 40 Ounces = 320 Drachms.

4 Quarts =1 Gallon = 160 Ounces = 1280 Drachms.

1 fluid ounce of water weighs 437 1/2 grains, therefore every minim weighs 0•91 grains.

FRENCH COINS AS METRIC WEIGHTS. (Lord Crawford's Table.)

With the bronze coins each centime weighs 1 gramme. Thus 5 centimes equal 5 grammes ; 10 centimes equal 10 grammes, and so on.

The weights of the silver coins are as follows : - 50 centimes = 2 1/2 gms., 1 franc = 5 gms., 2 francs=10 gms., 5 francs = 25 gms.

The unit of weight in the metric system is the gramme, written ""gm.," and this is about 15 grains, 1 avoirdupois ounce = about 30 gms.

The abbreviation " kilo " is usually employed for kilogramme = 1000 grammes = 35•274 ozs. avoirdupois. The unit of liquid measure is the cubic centimeter (c.c). 1 c.c. =about 17 minims, 1 fl. oz. = about 30 c.c.

A litre is 1000 c.c.