CHAPTER I. 



HISTORICAL AND INTRODUCTORY. 



In all ages the growth of plants has interested thoughtful men. 

 The mystery of the change of an apparently lifeless seed to a 

 vigorous growing plant never loses its freshness, and consti- 

 tutes, indeed, no small part of the charm of gardening. The 

 economic problems are of vital importance, and become more 

 and more urgent as time goes on and populations increase and 

 their needs become more complex. 



There was an extensive literature on agriculture in Roman 

 times which maintained a pre-eminent position until compara- 

 tively recently. In this we find collected many of the facts 

 which it has subsequently been the business of agricultural 

 chemists to classify and explain. The Roman literature was 

 collected and condensed into one volume about the year 1 240 

 by a senator of Bologna, Petrus Crescentius, whose book ^ was 

 one of the most popular treatises on agriculture of any time, 

 being frequently copied, and in the early days of printing, 

 passing through many editions — some of them very handsome, 

 and ultimately giving rise to the large standard European 

 treatises of the sixteenth and seventeenth centuries. Many 

 other agricultural books appeared in the fifteenth and early 

 sixteenth centuries, notably in Italy, and later in France. In 

 some of these are found certain ingenious speculations that 

 have been justified by later work. Such, for instance, is 

 Palissy's remarkable statement in 1563 (222) 2; "You will 

 admit that when you bring dung into the field it is to return 

 to the soil something that has been taken away. . . . When a 



^De agricultura vulgare, Augsburg, 1471, and many subsequent editions. 

 2 The numbers in brackets refer to the Bibliography at the end of the book> 



I 



