president's address. 21 



termed the gramme, is the weight of a cubic centimetre (the 

 T £o of a metre cubed) of distilled water weighed at its greatest 

 density (4° 0.), equal to 15*432 grains. The multiples of each of 

 these are derived from the Greek, deka for ten, hecto for 100, 

 kilo for 1000, and myria for 10,000. The prefixes for subdivision 

 are taken from the Latin, the tenth of a metre, litre, or gramme, 

 being the decimetre, deci-litre, and decigramme respectively; 

 the hundredth parts are known as the centimetre, centilitre, 

 and centigramme ; the thousandth parts are the millimetre, 

 the millilitre (more commonly called the cubic centimetre, 

 and this in turn usually contracted into c.c), and the milligramme. 

 In every day life many of these terms are not used ; lineal 

 measurements, less than one metre in length, are usually given in 

 millimetres only ; it is not usual to state the length in both centi- 

 metres and millimetres, neither are the multiples, deca and hecto- 

 metre, commonly used ; such lengths are expressed simply as 10 

 and 100 metres, and so on for other lengths less than a kilo-metre, 

 but the term kilometre is used because it is a convenient one, and 

 it is employed in much the same way, for measuring distances, as 

 we use the mile, of which it is roughly two-thirds. Myria-metre 

 is also seldom employed. Small cubic measures are usually given 

 in the terms of the cubic centimetre ; for larger volumes the litre 

 and hecto-litre and their multiples are the common commercial 

 measures. So too with weights ; practically only the terms milli- 

 grammes, grammes, and kilogrammes are used. 



It is sometimes convenient to bear in mind the approximate 

 values of some of the metric measurements as compared with 

 English ones, especially for rough mental conversions, e.g., the 

 metre is about 10% more than the yard, the kilometre is about 

 two-thirds of an English mile, 25 millimetres are about equal to 

 one inch, or 100 millimetres to four inches. The kilogramme is 

 equal to 2£Ib., or to 2Kb. plus 10% ; the limit of the international 

 parcel post is fixed at five kilos (hence the English limit of HK>s., 

 which is" practically 5 kilos) ; 1000 kilos equal 2200K>s., or 40ft>s. 

 less than a ton. The litre is equal to about If pints, or roughly 



