200 ON THE COMPOSITION AND 



Art. XLVL— on THE COMPOSITION AND AGRICULTURAL 

 VALUE OF KELP. 



By John F. Hodges, Esq., M.D. 



[Read at a late meeting of Council of the Chemico- Agricultural 

 Society of Ulster.] 



Analysis of the water of the ocean shows lis, that in it are 

 contained all the inorganic ingredients which our crops take 

 away from the soil — that it is, in fact, a liquid soil, from 

 which myriads of vegetables receive the materials for their 

 perfect development. Along our coasts, the plants nourished 

 by the mineral and saline matters, dissolved in the waters of 

 the sea, have long been employed by the farmer as applica- 

 tions to the soil, and in many parts of the kingdom are 

 regarded as his sheet anchor — thus, in some small degree, 

 restoring to our fields the substances lost by the faulty 

 arrangements of our farm-yards and cities. My attention 

 was lately drawn to the sea-weeds of our coasts, from being- 

 engaged in the anah'sis of the well-known substance kelp, 

 produced by their incineration, and which is now exciting- 

 considerable interest, as a source of the valuable metallic- 

 looking substance iodine, at present so extensively employed 

 in medicine. So far as I am aware, no complete analysis 

 of our Irish kelp has yet been laid before the public. It 

 will, therefore, be of interest that the composition of this 

 valuable and accessible source of the materials required to 

 render our fields productive should be made known. 



The mode of preparing kelp, as generally ]iractised on our 

 coasts, is so well known, that I need not allude to it fui«t^er 

 than to state that the sample submitted to me for analysis 

 was prepared on the shores of the Lough of Strangford, 

 where, I understand, by the use of iron bottoms for the kilns, 

 and by the careful management of the weed, an article of 

 superior quality is produced. It ma}^ also be observed, that 

 when the object of the kelp-burner is to prepare a kelp rich 

 in iodine, only some particular species of the Fucus family 

 should be employed ; but when it is required merely for agri- 

 cultural purposes, all the numerous species, both of drift and 

 shore weed, may be used with advantage. 



The sea-weeds, as cast on our shores, or cut from the 

 rocks, contain a verv large amount of water — thus, the fresh. 



