II 



UNITS OF LENGTH, AREA AND VOLUME 



29 



In the metric system a special name is given to the volume of a 

 cubic decimetre, that is, a cube having a decimetre edge. It is 

 called a litre, and is equal to about one and three-quarters 

 English pints. The sub-multiples and multiples of a litre are 

 named in a similar way to those of the metre. There is no 

 such simple relation between the measures of length and volume 

 in the English system, though the gallon is defined as a measure 

 which shall, contain 10 Ibs. of pure water at a certain tempera- 

 ture and pressure. 



British Units of Cubic Measure or Volume. 



1728 (= 12 x 12 x 12) cubic inches = 1 cubic foot. 

 27 (= 3 x 3 x 3) cubic feet = 1 cubic yard. 



Units of Volume in the Metric System. 



10 Centi-litres = 

 10 deci-litres = 

 10 litres 



10 deka-litres = 

 10 hecto -litres = 



1 deci-litre. 



1 litre = 1 cubic decimetre. 



1 deka-litre. 



1 hecto -litre. 



1 kilo-litre = 1 cubic metre. 



Exercises in the Measurement of Volumes. EXPT. 38. 

 Cut out a cubic centimetre and a cubic inch from a piece of 

 soap, or procure 

 them made in wood. 

 If possible, procure 

 also a cubic deci- 

 metre 'divided into 

 centimetre cubes 

 like ^ie cubic foot 

 shown in Fig. 18. 

 Place one cube alone 

 on a table ; then add 

 nine more to it, so 

 as to make a row of 

 10 cubic centimetres 

 (10 c. cm.).' Place 

 10 such rows upon 

 one another and there are 100 c. cm. ; and 10 such slabs of 

 100 c. cm. each make altogether 1,000 c. cm. One cubic 

 decimetre is thus shown to contain 1,000 c. cm. 



FIG. 18. Showing a small cube, a row of 12 

 cubes, a slab of 12 rows, and a cube of 12 slabs. 



