TABLE OF CONTENTS
EXPLANATION OF ABBREVIATIONS, ETC.
The temperatures are stated in degrees centigrade (° C.), either on the Celsius scale, on which the freezing-point of water is 0°, or on the absolute scale, whose zero lies 273 degrees below the freezing-point of water, at -273° C. The equivalent temperatures on the Fahrenheit scale (freezing-point of water 32° F.) are added in brackets (° F.).
1 metre (m.) = 10 decimetres (dm.) = 100 centimetres (cm.) = 1000 millimetres (mm.) = 3.28 ft.; 1 kilometre (km.) = 1000 metres (m.) = 0.62 miles; 1 mile = 1.6 kilometres (km.).
Light travels in vacuo at the rate of 300,000 km. (nearly 200,000 miles) per second.