146 LESSONS IN CHEMISTRY. 



and turnip-crops. The following are the ingredients useful 

 to plants, which 1 00 parts of Irish kelp contain* : — 



Potash, 8-22 



Soda, 25-82 



Lime, 5*17 



Magnesia, 8-47 



Sulphuric acid, 20-17 



Phosphoric acid, ...: 5-43 



Chlorine, 11-70 



Silicic acid, 5-71 



220. Kelp, therefore, presents us with a supply of some of 

 the most important and expensive elements of plants, in a 

 convenient and portable form, so that they can readily be 

 carried into the interior of the country, where their action 

 might bo expected to prove more beneficial than near the 

 coast, where sea- weeds are frequently applied to the land, and 

 the rains, cai'ried over the fields by the sea-breeze, deposit a 

 certain amount of saline matters. 



221. When sea- weeds are burned, to be used as manure, 

 the ashes should not be fused into solid masses, as is usual 

 in preparing kelp, as it is a very troublesome operation to 

 reduce them to powder; the vegetable matter should be only 

 half consumed, by which means the ashes will be obtained 

 in a loose form, more convenient for distribution over the 

 fields. Kelp is usually sold on the coasts of Ulster at from 

 30*. to £3 per ton. 



222. Peat — Among the numerous vegetable substances 

 which this country affords, capable of being employed by the 

 skilful farmer in maintaining the fertility of the soil, are the 

 contents of our bogs. 



There are three forms in which bog-stuff or peat is used 

 as manure by experienced fiirmers. 1 st, — Made into a com- 

 post with farm-yard manure. 2d, — Converted into a kind of 

 charcoal, by being burned with a smothered fire. And 3d, — 

 As consumed with free exposure to the air, and reduced to 

 ashes. I will describe the methods adopted for its prepara- 

 tion in the above forms, and also their properties. 



223. Peat earth, though from a very early period occa- 

 sionally employed as a manure, was first brought into general 



* The teacher will find some remarks on kelp as a manure, in a report 

 which I addressed to the Chemico- Agricultural Society of Ulster, in 

 May, 1846. 



