4 Domestic Science 



The prefixes milli-, centi-, and deci- are derived from 

 the Latin, and are used to signify -j^, T Jo> Vo re ~ 

 spectively, while deca-, hecto-, and &ifo- are from the 

 Greek, and imply 10 ; 100, 1000. 



5. Examination of the above table reveals two 

 points in which it is superior to the British table. The 

 name of one measure only has to be learnt and the names 

 of the derived units are obtained by the addition of 

 suitable prefixes to the name of the standard unit. One 

 factor 10 is used throughout, whereas in the British 

 table each new unit involves the memorising of a new 

 factor. A further advantage of the Metric system 

 which is not brought out by the consideration of a 

 single table is that the same set of prefixes is used 

 in other tables, thus further lessening the tax upon 

 the memory. Other points of advantage will be 

 pointed out as they arise in later work. 



6. The value of a length expressed in terms of 

 any one unit may readily be found in terms of any 

 other, all that is necessary being the removal of the 

 decimal point a certain number of places to the left 

 or right, as the case may be, together with the addition, 

 in some cases, of a number of zeros. Thus, 3*405 hecto- 

 metres is evidently equivalent to 0*3405 kilometres or 

 to 340,500 millimetres. 



Exercises for Student. 



1. Write down the number of centimetres in (a) 48 '07, kilometres ; 

 (6) 6-0103 metres; (c) 0*17 mm. 



2. Write down the number of kilometres in (a) 870 '6 milli- 

 metres ; (6) 4670800 metres. 



3. 1 metre = 39-37. .. inches. How many yards are there 

 in 10 kilometres ? How many kilometres are approximately 

 equivalent to 62 miles ? 



