208 Mk. G. W. Brown on Drift Weed Kelp from Orkney. 



of the American " New Observations on the Winds and Climate of the 

 Atlantic." 



XXVI. — The following paper was read last Session, but was not 

 printed in the proceedings : — 



Chemical Examinaiion of Drift Weed Kdp from Orkney. By Mr. George 

 William Brown. 



Drift weed kelp is derived from the sea weeds which grow on the rocks 

 at the bottom of the Atlantic Ocean. These plants being torn from their 

 native soils by the force of tides and currents, are drifted to the north 

 and north-west coasts of Scotland and Ireland, on which they are thrown 

 by the surge, and being gathered, are burnt either in kilns or in depres- 

 sions dug in the ground.* By this process most of the organic matter is 

 removed, although in the specimen of kelp investigated and described in 

 this paper, a small portion of carbon and nitrogen still remained. The 

 most important constituents of kelp are the iodine and potash salts. The 

 carbonates were formerly used by the soapmakers, and the insoluble salts 

 for the manufacture of bottle glass. 



Previous Analysis. — Although the composition of the kelp salts is well 

 known in a general point of view to the professional chemist, it does not 

 appear, from any experiments which have been recorded, that they have 

 been made the subject of recent minute investigation. Mr. Kirwan, in 

 the end of the last century, published a paper (Memoir read at the Royal 

 Dublin Society and A.nnales de Chimie, 1793, tom. 18, p. 163,) on the 

 alkaline substances employed in bleaching linen. The following is his 

 analysis of what he calls sweet barilha from Spain, which corresponds 

 with kelp in its physical characters : — 



Carbonic acid, 1666 



Carbon, 1495 



Lime, 942 



Magnesia,.. 2-20 



Clay, 2-27 



Silica, 4-38 



Soda, pure, 14-68 



Soda, impure, 4'34 



Soda, with common salt, 2'20 



Sulphate of soda, 2*17 



Chloride of sodium, 1'21 



Earthy deposit, 0-34 



Water, 25-23 



In another volume of the Annales de Chimie, there is a paper by M. 

 Gay Lussac (Annales de Chimie for 1828, tom. 39, pp. 159-163,) on 



* History and Description of the kelp manufactory. Proceedings of Glasgow 

 Philosophical Society, vol. ii. p. 241. By C. F. 0. Glassford. 



