THE AGRICULTURAL JOURNAL. 58'J 



benefit by applications of artificial fertili- 

 zers. In all cases it is better not to apply 

 manures or fertilizers in direct contact 

 with the seed. The animal manure should 

 be dug in previous to planting, the arti- 

 ficial may be applied either before or after 

 planting, or both before and after. The 

 potato drills should be made deep enough 

 that the potato sets may be covered to the 



depth of three or four inches. When the 

 shoots appear, and have grown to three or 

 four inches above the soil, they may be 

 hilled up a little, and if they grow up 

 high, hilled a second time. Much hilling 

 is not desirable in any but very wet 

 places. The weeds ought to be scrupu- 

 lously kept down. 



Agricultural Chemistry for Beginners^ 



CHAPTER I. 



By Archibald Pearcb, 



JT is quite true, as Mr. Thorrold so feel- 

 X ingly laments in his letter of October 

 13th, that to a layman chemistry is as 

 bad as Greek ; and yet, like most other 

 things, it? difficulties vanish when it is 

 understood. It is no very serious task to 

 grasp so much of the elements of the sub- 

 ject as will enable one to take an intelli- 

 gent interest in such semi-technical writ- 

 ings as ordinarily appear in agricultural 

 literature, and I propose to write a series 

 of short articles on the subject of Agricul- 

 tural Chemistry, with the hope of afford- 

 ing some assistance to those who regret 

 the absence of a scientific education. It 

 will, throughout, be my aim to write 

 plainly and avoid technicalities as much 

 as possible ; to limit the articles chiefly to 

 that branch of the subject which is con- 

 cerned with fertilizers and soils ; and to 

 introduce only so much theory as is 

 necessary for clear explanation. In two 

 matters I must beg the reader's indulgence; 

 first, that he should follow the series from 

 the beginning, as the various chemical 

 terms used will be explained as they 

 occur, and not a second time ; and, 

 secondly, for my own deficiencies, of 

 which 1 am only too well aware. There 

 is so much that might be said that a choice 

 becomes difficult, and my choice may not 

 always be the best ; but I shall use my 

 beet discretion. 



In treating a new subject of whatever 

 kind it is usual to carefully define some 

 of the new terms to be used. To com- 

 mence with, chemistry is essentially the 

 study of Elements and their Compounds. 



Elements. 



An element is a substance which no 

 one has yet succeeded in breaking up into 

 two or more simpler substances, or, in 

 other words, which is composed of one 

 kind of matter only. It is not impossible 

 that some things now called elements 

 may be eventually so divided, but until 

 this happens they are considered to be 

 indivisible substances. Elements are, so to 

 speak, the bricks of which all other known 

 substances are built up. There are be- 

 tween 70 and 80 known, some of them 

 quite rare ; those that will chiefly concern 

 us aie : — Oxygen, Hydrogen, Nitrogen, 

 Chlorine, Carbon, Phosphorus, ^xilphur, 

 Silicon, Calcium, Iron, Aluminium, Potas- 

 sium, Sodium, and Magnesium. The last 

 six are metals, the rest non-metals. All 

 other substances are formed by the com- 

 bination of various elements in various 

 proportions, and substances of this kind 

 are known as compounds. 



Compounds. 

 It is essential to grasp the chemical 

 meaning of this word ; the elements 

 which form a compound are so united to- 

 gether, and held in combination by a 

 force called chemical attraction or affinity, 

 that they cannot be separated by merely 

 mechanical means. A simple experiment 

 will make this clearer. If we take a little 

 powdered sulphur, and grind it up with 

 about twice its M'eight of iron filings, we 

 shall see the particles of iron and sulphur 

 lying side by side, and could wash away 

 all the sulphur from the iron, or separate 



