CHEMICAL DEPARTMENT. 25 



PoTASSic Manures. — Useful where potatoes or beans are grown, or where 

 straw is sold. Increases clover. Seldom required where much dung 

 is used. Sometimes injurious if applied with the seed. Should he 

 applied very early. 



Lime. — Better slaked in large heap, and then carted on and spread, than 

 slaked in small heaps on land. Better two small limings than one 

 big one. Best results on clayey land and moorland. As a pre- 

 ventive of finger-and-toe, lime is better applied to the lea before the 

 oat crop than to the stubble. It is of little use for that purpose 

 when applied to the fallow immediately before turnip sowing. 



NOTES EEGARDING ANALYSES. 



1. MANURES. 



The three ingredients of greatest importance in manures are phosphoric 

 acid, nitrogen, and potash. 



1. Phosphoric Acid is present in manures as such, and also as phos- 

 phates of lime, magnesia,, iron, and alumina. 



Phosphate of Lime is most important, and exists in two states, insoluble 



and soluble. 

 Insoluble — 



Insoluble phosphate of lime, called also | ^^^^^.^^ ^^^^^^ ^^y 

 rricalcic phosphate, and \ i,, ^oric acid. 



Iribasic phosphate 01 lime, ) 



Soluhle — 



Soluble phosphate of lime, called also | ^^^^^.^^ ^^^^^^ ^ c/ 



Acid phosphate of lime, and erroneously > ^r i ^„- ^- 1 

 -.r 4 • 1 -i . <• T ^ ( phosrjhoric acid. 



Monabasic phosphate oi lime, ) 



Some analysts prefer to state the soluble phosphate as 



Biphosphate of lime, called also '( contains about 72% 



Monobasic phosphate, ^ phosphoric acid. 



The soluble phosphates are usually stated as equivalent to 



so much tricalcic or insoluble phosphate. 



cj 1 n u -u *. u- T 1 T n ( gives the equivalent of 



Soluble pho.sphate, multiplied by U" tricalcic phosphate 

 Biphosphate, ^ „ „ 1^ ^^^^^^,^ 



Much confusion has arisen from the vario^is methods of stating soluble 

 phosphate. To escape from this confusion, it has nov) become the 

 custom to consider the term "soluble phosphate" to mean 

 " phosphate of lime rendered soluble." In other words, soluhle 

 phosjdiate vuans the insoluble phosphate from which it vns 

 derived. 

 Phos])hato of magnesia occurs in small quantity in bones, &c., and is 



usually reckoned as tricalcic phosphate. 

 Phosphates of iron and alumina, when occurring in small quantify, 

 are usually reckoned as tricalcic phosphate, but if the (quantity is 

 considerable it should be S(.qtar:itfly i-^timated. 



2. Nitrogen occurs in manures mostly in throe forms — Ammonia silts. 



nitrates, and albuminoid matter. 



Ammonia sulphate (pure), contains 25?% ammonia. 



:h 



»» 



Ammonium chloride (])ure), „ 31 



Nitrate of soda (pure), contains nitrogen equal to 20% ammonia 



Albuminoid mutter contains iibout lO,,, nitr(»gen, equal to about 19% 



ammonia, most of which sooner or later becomes available as plant 



food. 



