THE METRIC SYSTEM.

Hawera Star, Volume XLV, 21 July 1925, Page 8

THE METRIC SYSTEM.

A DETAILED EXPLANATION. ITS ADVANTAGES STRESSED Seeing tliat the V eights -".nd Measures Amendment- Bill J>nw before the House ot : Representatives proposes to give the Government power to introduce the jnetriy system of weights and measures to :\mv Zealand, a Star reporter waited upon Mr. A. It. Larkman, engineering instructor at Ha went Technical High .School, ‘Suggesting that, he .might favour the public with a popular explanation of metric weights and measures, and perhaps set forth some of the advantages of the system. The pressman, did not realise that he was approaching such an enthusiast; but Mr. Larkman gladly- fell in with the suggestion and went to considerable pains to furnish the following particulars : The basis of measurement in the metric system is the metre, the other standard units being derived from this unit. The metre was originally, intended to b e a’.ten-millionth part of the earth’s quadrant measured on a geographical meridian from the equator to the pole. It is now the length of a certain bar or platinum of 0 degrees Centigrade, kept under the authority of the French Government, conies of which bar exist in England. The use of the metric system has been authorised by British Act of Parliament for many years, but, inforlnnately, that Act did not at the’ same time make the use.of other weights and measures illegal. The great value- of the metric system is due to the fact that it adopts decimal elivisians for its sub-units, and that, larger units are expressed by multiples in 10, 100, 1000, times the fundamental unit, and so such clumsy and time wasting methods as the British system of weights and measures are avoided. Latin prefixes are used in connection with the fundamental units to express the sub-multiples of length, area, volume, and weight. These prefixes are: — Deci., signifying one-tenth. Centi., signifying one-liundredth. Milli, signifying one-thousandth. Thus, for example, a centimetre is 1-100 of a metre, and a centigramme the 1-100 part of a gramme. Greek prefixes are used for the multiples of the fundamental units, thus: Deca., indicates 10 times the unit. Hecto.. indicates 100 times the unit. Kilo., indicates 1000 times the unit.

For example, the kilogramme is 1000 grams, and the kilometre 1000 metres. The whole of the metric weights and measures are shown in the table below :

This table is built up in the following way: Columns 1,2, and 5 are allotted to length, area, and volume. The main units are printed in capitals and all depend, as will be seen, on the metre. Above these units arc placed their multiples, and helow them their sub-multiples. Any unit jn col. 1 is 10 times as large as the one below it, but if we compare two squares whose sides' are one and 10 units long, vve realise their areas are one and 100 respectively, and so units of area (col. 2) are each 100 times as large as the next below. Similarly, two cubes'whose edges are one 1 and TO units long have volumes one and 1000 respectively, .and so units of volume (col 5) arc each-1000 times as large as the next below. Now, the weight of a cubic centimetre of' pure water (at 14 degrees Centigrade, at-which temperature water is at its greatest density) i s taken as the unit weight and is called the gramme. In column six the grain (the metric unit of weight) i s placed in mid column with its multiples above jt and mill-multiples below.

When it is realised that «• cubic metre (e.m.) is about the volume occupied by a lead of gravel, and that the cubic centigrade (e.m.) would about half fill a thimble, it will he appreciated that the Frenchman who decided on a cubic- decimetre (c.dm.), which is about two and a-half pints, as the litre or unit for measuring wine, had some commonsense! The connection ;is shown in the table, where 'in column four we have the litre in mid column with multiples above and sub-multiples below, as with the other Columns. There remains hut one column to deal with—that given to land measure. Here, a square decametre (a square with a side of about 3‘2£ feet) .is chosen as the main unit for land measure; this is about 1-Joth of an acre. The hectare is about two and a-half acres, and the venture is not used ; indeed, all units in the table which ar e enclosed in brackets are not in common usage; the people who use the metric; system would write 100 gin. instead of one hedtogr.amnio, 01 gm. instead of one centigramme, and so on. ■lt'"should now he evident-that the system is extremely simple, and it may be of interest to point out some of its advantages.

We substitute the one simple table (or rather six in one) tor all those weird tables which waste so much time and which so few can even remember, ibis wastage of time needs stressing. It is certain that it would 1 be possible to cut down time given to arithmetic in the schools hv half; this is about half an hour saved in a live-hour day, and means children could start secondary education after nine years primary work instead of 10 as is now the average case. ' . The saving of time remains ns the main advantage all through lile for all of tis, the more so, of course, fon those, who have most vacillating to do; for example, a tank measures IS by 1/ by 16 inches, its volume, in cubic inches is 4-800 cuvans or 2- *5-0 cubic, feet, the Standards Department of the Board ot Trade in 1800 fixed the weight of one subic foot of water as 62.-786 lbs. at 62 degrees Fahrenheit and a 30 degrees barometer! So we multiply 2 5-6 by 62.3 and arrive at the weight ot water roughly. Compare this kind of thin,,- with metric work: tank measures 46 by 43 bv 41 centimetres, its volume is 81098 cubic centimetres, and the weight of water it holds is 81008 grams or 81.089 kilograms. Dimensions in drawings expressed iu feet, inches, mid! fraction or an inch are far better shown as a clean number of metres, centimetres, or millimetres; thus 2ft. 2sin.. wood be written 673 millimetres.

Nothing hut metric measures are used by the scientist, so the man in the street who may read a scientific article doesn’t make the contract he might with, things that matter. The whole of the Continental peoples use metric measures, and the fact that vv e English do not is something they can’t understand, and just one moio obstacle to easier commerce. This opens up the fact, too, that they all use a. decimal coinage, and we do not, though our IDs note. Is piece, and penny piece give us all we need to initiate such a. change. The advantages of decimal coinage are known to all and there is no need to argue for Another change along similar lines is the complete adoption of the Centigrade thermometer in place of the Fahrenheit. All know the former fs marked 0 and 100, and the latter 32 and 212, to indicate temperature ot freezing and boiling water respectively, but only engineers realise what obstructions in calculation are caused, by that obnoxious 32 degrees and the division of the scale into 180 parts instead Of 100. ... -r Possibly the principal reason, at truth were todl, for the conservatism which has prevented the adoption of the metric system, is the fact that those whose school davs are over don’t like the idea of making themselves familiar with fresh tables. . But the fact that the metre equals 39.37 inches, or about- a. va-rd : the kilogram equals 2.2 lbs; and the litre about-equals a quart should help reconcile them to deciding to make the change. One hopes that this measure now before the House may go through in its entirety, and so set forth yet another example of progressiveness that other Dominions may follow. Decimal weight, measures and coinage throughout our Empire, together with the absolute scrapoing of all other weights, measures and coinage, would help us wonderfully in our recovery from the wastage of war.

(1) w (3) (^) (5) <«) 10 100 100 10 1000 10 Length Area Land Capacity Volume Weight Km. Sq. lvm. (Kl.) Kg. - (Hm.) (.Sq. Elm.) .FI.a. (HI.) (Hg.) (Dm.) (Sq. Dm.) (Dl.) (Dg.) METRE SQ. METRE ARE LITRE ' C. METRE GRAM. (dm.) (sq. dm.) (dl.) (c.dm.) (d-g.) 'em. sq. cm. (e.a.) ' (cl.) e.cm. («-g-) min. s<j. mm. c.mm. (m.g.)