Part 3

Air, how perceived 29

" composition of 29

" weight of 30

Barometer, principle of 30

Winds, course of 31

Vapour, condensation of 31

Snow, hail, and frost 32

" red and green 32

Air, temperature of 32

Dew, cause of 33

" artificial formation of 34

Clouds and fogs 35

Lightning 36

" conductors 37

Thunder-storms 38

Rainbow 39

Air, the source of nourishment 40

" carbonic acid of 41

" the source of coal 41

THE EARTH.

Elements, list of 45

Earths, list of 46

Silica 46

Alumina, Lime, Potassa 47

Soda 48

The Earth, surface of 49

Strata 49

" diagram of 50