24 



ELEMENTARY GENERAL SCIENCE 



CHAP.. 



British to Metric. 



1 inch 

 1 foot 

 lyard 

 1 mile 



25-399 millimetres. 

 0-305 metre. 

 0-914 metre. 

 1609-000 metres. 

 1-609 kilometres. 



Simple application of Measurements of Length. 

 EXPT. 29. Measure the circumference of a glass bottle by 

 winding a strip of paper around the curved 

 surface and marking the point where the 

 edga meets the commencing corner. Deter- 

 mine the length of the paper from the 

 corner to the mark by measuring it with a 

 centimetre scale. Next measure carefully 

 the diameter of the bottle. Repeat the 

 experiment with other objects, such as a 

 cylindrical canister or a wooden cylinder 

 or disc. Set down the results in parallel 

 columns and use them to find the ratio of 

 the circumference of a circle to the dia- 

 meter, 



Measurement of Area. In describing 

 ^ the measures of area (or space of two di- 

 ll mensions) according to the English system 

 we use the same names as when measures 

 of length are referred to, simply prefixing 

 the word square. Thus we speak of square 

 inches and square feet, and since there are 

 12 linear inches in a linear foot, there will 

 be 12 X 12 = 144 square inches in a square 

 foot, and similarly throughout the measure. 

 In the same way it is the custom to speak 

 of an area, as of so many square centimetres, or square metres, 

 as the case may be. 



