AGRICULTURAL VALUE OF KELP. 



201 



leaves {Frond) of the Eladdered Wrack (Fi/cvs 'cesicrdosiis), 

 and of the tangie {Lam tii aria dlgitata), which are found in 

 so g-reat ahimdance on our coasts, when dried at 212 degTees, 

 and incinerated, yielded 



Water. Organic matter. Ash. 



Bladdered Wrack 68-8 26-2 5.0 



Tangle 18-1 IS'l 5-8 



Of the stalks of the tangle, which are considered so valuahle 

 by the kelp-burners on the north-east coast, two samples 

 g-ave as follows : — 



No. 1. No. -2. 



Water 8400 8310 



Organic combustible matter 10'40 11"06 



Incombustible matter, or ash 5'GO 5-84 



100-00 100-00 



Mean of ash afforded by leaves and stalks together, 5*5 per 

 cent., or a ton of the weed, as taken from the sea, would 

 yield about 123 lb. of incombustible mineral matter or kelp. 

 The inquiry now presents itself, how far the ash is capable of 

 supplying our fields with the mineral and saline matters 

 removed by cultivation. 



As kelp is a substance remarkably complex in its composi- 

 tion, and contains a number of ingredients with which our 

 farmers are not familiar, and the enumeration of which 

 would only serve to perplex them, I consider that it will be 

 sufficient to state the proportion of those ingredients which 

 possess an agricultural value. From the great variety of 

 weeds employed in its manufacture, the composition of kelp 

 must be expected to vary considerably. The specimen 

 from which I obtained the following results was received 

 from a member of our society, A. H. IMontgomery, Esq. of 

 Tyrella, County Down, and was prepared on the shore of 

 Strang'ford Lough, near Greyabbey : — 



100 lb. of this kelp contained — 



Potash 8-22, or 184^ lb. per ton. 



Soda 25-82, or 578^ lb. per ton. 



Lime 5*17 



Magnesia 8-47 



Sulphuric acid (vitriol) 20-17 



Phosphoric acid 5-43 



Chlorine, one of the ingredients of common salt 11-70 



Silicic acid 2-71 



The analysis just given shows that in kelp we have a rich 



