464 Composition of Seaweed and Use as Manure, [sept., 



deep water is usually richer than Fucus cut from the rocks, 

 especially in potash. The kelp-burners also recognised its 

 superiority as a source of iodine. Mr. Hendrick's analyses 

 of Scotch seaweeds also bring out the same facts, but in 

 this case the samples are not all taken from the same place. 







Fresh weed. 



Percentage composition of dry matter. 



Water. 



Dry 

 matter. 



Organic 

 matter. 



Nitro- 

 gen. 



Ash. 



Potash. 



Lime. 



Phos- 

 phoric 

 acid. 



Fucus 



nodosus. 



January 

 October 



7078 

 74*99 



29-22 

 25'OI 



78-98 

 76-55 



2'60 



2-04 



21-02 

 23-45 



4-73 



3-38 



I-30 

 1-76 



0-32 

 0-36 



Laminaria ... 



March 



78-2 



218 



65-89 



2'57 



34-n 



6-84 



262 



o-8o 



(Transactions of the Highland and Agrictdtural Society , 1898, page 118.) 



Reference to Table I. will show that the other plants — 

 Zoster a, salicomia, &c. — thrown up on the shore are all poorer 

 in potash than the true seaweeds, while Zostera is also poorer 

 in nitrogen. This is very generally true, and is shown in 

 Table II., where analyses of a number of farm crops are given 

 for comparison with the analysis of seaweed. 



Table II. — Composition of the Dry Matter of Seaweed and 

 of certain Farm Crops, 





Fucus 

 and 

 Laminaria. 

 Mean. 



Buck- 

 wheat at 

 flowering. 



Rye 

 in ear. 



Mustard 

 at 



flowering. 



Meadow 

 hay. 



Clover 

 hay. 



Man- 

 golds 

 (roots). 



Wheat 

 straw. 



Nitrogen 



I-8 3 



Il8 



0-70 



2-30 



I-74 



2 60 



i-6 7 



o - 6o 



Pure ash ... 



25H7 



12-00 





14-70 



7'20 



6-85 



7-21 



5*35 



Potash 



4-40 



4'44 



2'10 



4*20 



I - 7 6 



2.'2.1 



377 



o-So 



Phosphoric acid. 



0-24 



I - 22 



0-59 



I OO 



0-43 



o-66 



0-62 



0-26 



Seaweed is therefoie characterised by containing more ash, 

 and less phosphoric acid, but about twice as much potash as 

 ordinary farm crops, excepting such specially rich crops as 

 mangolds, buckwheat, and mustard. 



Seaweed as Manure. — The material gathered by the farmer 

 is rather mixed, though one or two weeds usually preponder- 

 ate, especially if, as sometimes happens, weed is cut from 



