FARMERS' REGISTER. 



[No. 11 



LECTURE I. 



INTRODUCTION. GENERAL VIEWS 

 OBJJKCTS OF THE COURSE, AND 

 ORDER IN WHICH THEY ARE TO 

 CUSSEO. 



OF THE 

 OF THE 



RE nis- 



Ii is with jrreat pleapurc that 1 receive the per- 

 mission to address so distinguished and eniighlened 

 an audience on the suLiject of agricultural che- 

 mistry. 



That any thing which I am able to bring for- 

 ward, should be thought worthy the attention of 

 the jjoard oC Agriculture, 1 consider as an honor; 

 and I shall endeavour to prove my gratitude, by 

 employing every exertion to illustrate this depart- 

 ment of knowledge, and to point out its uses. 



In attempting these objects, the peculiar state 

 of the inijuiry presents many dilficalties to a lec- 

 turer. Agricultural chemistry has not yet re- 

 ceived a regular and systematic form. It has 

 been pursued by competent experimenters for a 

 short time only : the doctrines have not as yet 

 been collected into any elementary treatise ; and 

 on an occasion when I am obliged to trust so much 

 to my own arrangements, and to my own limited 

 information. I cannot but leel dillident as to the 

 interest that may be excited, and doubilul of the 

 success of the undertaking. I know, however, 

 that your candor will induce you not to expect 

 any thing like a finished work upon a science as 

 yet in its inlimcy ; and I am sure you will receive 

 with indulgence the first attempt made in this 

 <".ountry to illustrate it, by a scries ol" experi- 

 mental demonstrations. 



Agricultural chemistry has for its objects all 

 those changes in the arrangements of matter con- 

 nected with the growth and nourishment of [)lants ; 

 the comparative values of their produce as food ; 

 the constitution of soils; the manner in which 

 Jands are enriched by manure, or rendered fertile 

 by the different processes of cultivation. Inqui- 

 ries of such a nature cannot but be interesting and 

 important, both to the theoretical agriculturist, 

 and to the practical farmer. To the first they are 

 necessary in supplying most of the fundamental 

 principles on which the theory of the art depends. 

 To the second they are useful in aflording simple 

 and easy experiments lor directing his labors, 

 and for enabling jiim to pursue a certain and eys- 

 tetnatic plan of improvement. 



It is scarcely possible to enter upon any inves- 

 tigation in agriculture without finding it connected, 

 more or less, with doctrines or elucidations derived 

 from chemistry. 



If land be unproductive, and a system of ame- 

 liorating it is to be attempted, the sure method of 

 obtaining the object is by determining the cause 

 of its sterility, which must necessarily depend 

 upon some defect in the constituton of the soil, 

 which may be easily discovered by chemical an- 

 alysis. 



Some lands of good apparent texture are yet 

 steril in a high degree ; and common observaton 

 and common practice afford no means of ascertain- 

 ing the cause, or of removing the effect. The 

 applicafion of chemical tests in such cases is ob- 

 vious; for the soil must contain some noxious 

 principle, which may be easily discovered, and 

 probably easily destroyed. 



Are any of the salts of iron present ? they may 



be decomposed by lime. Is there an excess of 

 siliceous sand 7 the system of improvement must 

 depend on the application of clay and calcareous 

 matter. Is there a delect of calcareous matter? 

 the remedy is obvious. Is an excess of veireiable 

 matler indicated? it may be removed by liming, 

 paring, and burning. Is there a deficiency of 

 vegetable matter ? it is to be supplied by manure. 



A question concerning the diHerent kinds of 

 limestone to be employed in cultivation often oc- 

 curs. To determine this fully in the common 

 way of experience, would demand a considerable 

 time, perhaps some years, and trials which might 

 be injurious to crops ; but by simple chemical 

 tests the nature of a limestone is discovered 

 in a few minutes ; and the fitness of its appli- 

 cation, whether as a manure for difi'erent soils, or 

 as a cement, determined. 



Peat earth of a certain consistence and compo- 

 sition is an excellent manure ; but there are some 

 varieties of peats which contain so large a quantity 

 of ferruginous matter as to be absolutely poi- 

 sonous to plants. Nothing can be more simple 

 than the chemical operation fiir determining the 

 nature, and the probable uses of a subtance of 

 this kind. 



There has been no question on which more dif- 

 ference of opinion has existed, than that of the 

 state in which manure ought to be ploughed into 

 the land ; whether recent, or when it has gone 

 throujrh the process of fermentation ; and this 

 question is still a subject of discussion. But who- 

 ever will refer to the simplest principles of che- 

 mistry, cannot entertain a doubt on the subject. 

 As soon as dung begins to decompose, it throws 

 off its volatile parts, which are the most valuable 

 and most efficient. Dung which has fermented, 

 so as to become a mere soft cohesive mass, has 

 generally lost from one third to one half of its 

 most useful constituent elements ; and, that it may 

 exert its full action upon the plant, and lose none 

 of its nutritive powers, it should evidently be ap- 

 plied much sooner, and long before decomposition 

 has arrived at its ultimate results. 



It would be easy to adduce a multitude of other 

 instances of the same kind ; but sufTicient, I trust, 

 has been said to prove, that the connection of che- 

 mistry with airriculturc, is not founded on mere 

 vague speculation, but that it offers principles 

 which ought to be understood and followed, and 

 which, in their progression and application, can 

 hardly fail to be highly beneficial to the commu- 

 nity. 



A view of the objects in this course of lec- 

 tures, and of the manner in which they are to be 

 treated, will not, I hope, be considered as an im- 

 proper introduction. It will inliirm you what you 

 are to expect; it will afford a general idoo of the 

 connection of the different parts of the subject, 

 and of their relative importance; it will enable me 

 10 give some historical details of the progress of 

 this branch of knowledge, and to reason from 

 what has been ascertained, concerning what re- 

 mains to be investigated and discovered. 



The phenomena of vegetation must be consi- 

 dered as an important branch of the science of 

 organized nature; but though exalted above inor- 

 ganic matter, vegetables are yet in a great mea- 

 sure dependent for their existence upon its laws. 

 They receive their nourishment from the external 

 elements; they assimilate it by means of peculiar 



