316 PIONEERS OF SCIENCE IN AMERICA. 



Massachusetts. This induced some zealous and active citi- 

 zens of Lowell to ask me to deliver a course of lectures on 

 agricultural chemistry." 



From the notes of these lectures the Muck Manual was 

 prepared. " The work," Dr. Dana states further, " was fa- 

 vourably received at home and abroad, where a consider- 

 able portion was reprinted. It has passed through sev- 

 eral editions, each being enlarged by the addition of new 

 matter, to keep pace with the times. To the present edition 

 is added an entire new chapter on bones and superphosphates 

 of lime and alkalies. . . . 



" One word respecting the title of my book. It is my own. 

 I have neither begged, borrowed, or stolen it. That last has 

 been done by an English author, who seems to be ashamed, 

 not of the act, but of the name he has filched from me, and so 

 eases his conscience by apologizing for his 'homely title.' I 

 shall not discredit my child by being ashamed of his name. It 

 was good at the christening, and I trust will be thought re- 

 spectable in manhood." 



This edition of the Manual consists of nine chapters. In 

 the first three the author tells the origin and nature of the in- 

 organic ingredients of soil, and in the fourth he describes simi- 

 larly the organic constituents. Dr. Dana vigorously combats 

 the idea that the kind of rock underlying a district has any- 

 thing to do with the character of the soil in that district, show- 

 ing that the soil at any place is a mixture of materials, most of 

 which have been brought from a distance. His full Explana- 

 tions of the several topics that he takes up are summarized in. 

 brief statements in a conspicuous type, which he puts forth as 

 the first, second, third, etc., principles of agricultural chemis- 

 try. Among these are, " Rocks do not affect the vegetation 

 which covers them " ; " Soils contain enough of all the mineral 

 elements to grow any crop " (but it is otherwise with organic 

 constituents) ; " One base may be substituted for another in an 

 equivalent proportion." 



After describing the mutual action of these two classes 

 of substances, he takes up the subject of manure. His chapter 

 opens characteristically : 



"The true farmer, no less a sage than the ancient orator 

 who gave to action the first, second, and third place in elo- 

 quence, will answer, if it is asked him what is his first requisite, 



