VI 
HAROLD’S DISCUSSIONS. 
of the life that has existed in the geological 
ages of the past. The forces acting on life and 
the earth, recording their history, have been 
considered in the foregoing volume. The next 
five chapters discuss subjects pertaining to the 
outer envelope of our earth, namely, the atmos¬ 
phere, that plays so important a part in the 
evolution of life. Considerable attention is 
given to the movements of the air and their 
causes, and to the methods of observation by 
which we gain our knowledge. These chapters 
are the result of successful work done by the 
sixth grade. 
In the next six chapters we look out upon 
the earth’s surroundings—the sun, moon, plan¬ 
ets, stars, and nebulae, that contribute so greatly 
to our welfare and awaken in us feelings of 
wonder. 
Chapters XXII to XXX treat of the unity 
and variation of plant and animal life to be 
observed all about us. As far as these lines 
of discussion have been presented to seventh 
and eighth grades, they have proved accept¬ 
able and profitable to them. They seem to 
give them the foundation to read the more 
pretentious works. 
For information and suggestions I am in- 
