MEASUREMENT OF VOLUME 19 



jar, and so find the number of centimetres in a half -pint. Repeat the 

 operation, so as to determine the number of cubic centimetres in one pint. 



(c) Pour lOOO c.c., that is, 1 litre, of water into a vessel. Then measure 

 this amount of liquid in pints, so as to find the value of 1000 c.c. in British 

 measure. 



vi. Volumes of solids determined by displacement. (a) Fill a metric 

 measuring jar about half way up with water. Notice the level. Hold a cubic 

 inch of wood in the water by means of a long pin. 

 Notice the rise of level. The difference between 

 the two levels evidently represents the number of 

 cubic centimetres equal to one cubic inch. 



(6) Determine the volume of a stone or any 

 irregular solid by observing the difference of level 

 when it is immersed in water (Fig. 18). 



vii. Burette. Examine a burette (Fig. 17). 

 Notice that the divisions are numbered from the 



top downwards. Fix the burette upright in a 



clamp, and about half fill it with water. Notice =- 



the level. Find the volume of a piece of glass is The rise of level 



tubing by gently lowering it into the water and O f the water when the stone 

 noticing the rise of level produced. (The glass is put in shows the volume 

 must, of course, be completely immersed in water. ) of the stone. 



Measurement of volume. The volume of a thing is its size, or bulk, 

 expressed in proper units. In dealing with volumes, three dimensions 

 have to be considered. Just as a plane surface, or area, measuring one 

 foot in each of the directions length and breadth is called a square 

 foot from the name of the figure which it forms, so a solid which is 

 obtained by measuring a foot in three directions length, breadth, and 

 thickness is called a cubic foot, from the name cube given to the 

 solid so formed. Similarly, using the Metric system, the term cubic 

 metre, or cubic decimetre, is used. 



A hollow vessel is capable of holding a certain volume, and this is 

 usually referred to as the capacity of the vessel. In the metric system 

 a special name is given to the capacity of a hollow cubic decimetre, 

 that is, a hollow 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 measure 

 of length and volume in the English system, though the gallon is defined 

 as a measure which contains 10 Ibs. of pure water at a certain tempera- 

 ture and pressure. A gallon has a volume of 277| cubic inches. 



In measuring the volumes of irregular solids, advantage is usually 

 taken of the fact that when immersed in a fluid they displace a volume 

 of fluid equal to their own volume. This may be measured as a differ- 

 ence of level (Fig. 18). The water displaced could also be poured into 

 a cubic inch box or into a cubic centimetre box, and the number of 



