336 



NATURE'S TEACHINGS. 



wards, is due to the same principle. By the action of sucking 

 a partial vacuum is formed, and the pressure of the atmosphere 

 upon the breasts forces the milk into the mouth of the young. 



We might multiply examples ad infinitum, and we will there- 

 fore pass to another subject. 



SEED-DRILLS. 



AMONG the modern improvements in agriculture we may 

 reckon the invention of the Seed-drill as one of the most 

 important. By means of this invention, seed is greatly 



ICHNEUMON -FLY. 

 GRASSHOPPER. 



SEED-DRILL. 



economized, the supply can be regulated, and the sower knows 

 exactly where every grain of seed goes. There is no scatter- 

 ing, as in the wasteful broadcast plan, by which the seeds are 

 flung almost at random over the field, and may or may not fall 

 into the furrows. The Seed-drill, on the contrary, either stamps 

 holes or ploughs narrow furrows, measures the seed into 

 them, and in some machines replaces the earth. The 

 former kind of machine rather deserves the name of a dibble, 

 and was invented for the purpose of superseding the use of the 

 hand-dibble. 



