ELEMENTS OF AGRICULTURE. 
03 
matiutf of employing substances that are so necessary to 
the amelioration of his land. This knowledge must guide 
him both in his choice of ameliorations and in the manner 
of their execution, 'w is for this reason that, after the 
study of soils, we introduce that of ameliorators, the em¬ 
ployment of which, in many cases, is indispensable. 
QUESTIONS. 
1. Do animals furnish products useful to man ? 
2. What must be done to enable them to continue the supply ? 
3. What must be done for the earth to enable it to continue its supplies ? 
4. Are all plants equally exhausting ? 
5. What must the farmer do in this respect ? 
6. What is necessary that a soil should be productive l 
7. Are simple bodies always mixed in suitable proportions ? 
8. Why are there so many waste lands ? 
9. Which are the two species of elements required by the soil ? 
10. What are stimulants ? 
11. Can the same substances act in more waj^s than one on the soil? 
12. To proceed properly in the amelioration of soils, what knowledgy 
should the farmer possess 1 
LESSON II. 
liming lands, or the use of lime as an ameliorator. 
10. Lime, as we have seen, is a compound of oxygen 
and a simple body called calcium. To obtain it, carbon¬ 
ate of lime must be submitted to the action of heat until 
calcined. The water of crystallization escapes in the form 
of vapor, and the result is quick or caustic lime. 
11. Besides the use that is made of lime in building, it 
is also employed as an ameliorator in those localities in 
which agriculture is in a state of improvement; and if 
farmers have not often recourse to this means of increas¬ 
ing the value of their lands, it is because they are gener¬ 
ally ignorant of the good effects it produces, or because 
