PLANT PRODUCTS 



INTRODUCTION 



The study of the products of plant life that are useful 

 to man formed one of the first deliberate actions of early 

 intelligence. Ancient records of China, India, and Egypt 

 alike show that the study of the products of plants attracted 

 early attention. 



The Latin authors, Virgil, Columella, and others who 

 wrote on Agricultural subjects, are well known in the schools, 

 and about two hundred years ago, Jethro Tull, the inventor 

 of the first seed drill, wrote on nitre, water, and fire 

 and earth, as the origins of plant products. Humphrey 

 Davy, one hundred years ago, published his Lectures on 

 Agricultural Chemistry, and up to thirty 3^ears ago many 

 of the Professors of Chemistr}^ in the Universities, as a 

 means of bringing home the truths of their science to the 

 members of their audience, drew more illustrations from 

 rural life than from the urban industries. 



Turning now to those who specialized in Agricultural 

 Science in England in recent years, we find such well-known 

 names as Lawes and Gilbert, who gave Rothamsted a world- 

 wide reputation, and Augustus Voelcker, whose work in the 

 Royal Agricultural Society laid the foundations of many of 

 the modern inquiries into Agricultural Science. Numerous 

 investigators have followed in the footsteps of these pioneers, 

 and the following pages will be found full of references to 

 their valuable work in building up an exact science of 

 chemistry applied to economic problems of the agriculture of 

 to-day. 



The sun is the source of power. The effective utilization 

 D. I 



