Index

aeroplanes

13

air

pressure

37,

40–42

anemometer

46

aneroid

barometer

42

atomic

clocks

36

Balanced

Rock

24

barometers

40–42

Beaufort

Wind

Scale

45

calendar

sticks

27

calendars

25,

27,

29

candle

clocks

34

cars

15

Celsius

scale

39

clocks

25,

32–36

compasses

14

days

26,

27,

29,

30

direction

14

distance

5–16

Egyptians

21,

22,

27,

29,

33

Fahrenheit

scale

39

Fujita

Scale

47

gravity

17,

35

Gregorian

calendar

29

hourglasses

34

imperial

system

9

Julian

calendar

29

knotmeter

16

lunar

calendars

27

mechanical

clocks

35

metric

system

10,

11