250 On the Chemical Examination of 



Chem tea I Eaxt n i (nation of Drift- Weed Kelp from Orkney. By 

 George W. Brown, Esq. of Glasgow. Communicated by 

 the Author, through Dr It. D. Thomson, and read before 

 the Philosophical Society of Glasgow.* 



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 

 depressions dug in the ground, t 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 Analyses. — Although the composition of the kelp 

 salts is well known, in a general point of view, to the profes- 

 sional 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 Annales de Chimie 1793, torn. 

 18, page 163), On the Alkaline Substances employed in 

 Bleaching Linen. The following is his analysis of what he 

 calls sweet barilla from Spain, which corresponds with kelp 

 in its physical characters. xf , rm 



Carbonic acid, . j& ^ . MC[imiJ [ n } c „ 16-66 



Carbon, . . ... . . ' » r. 14'9o 



T . > : feuwv in btr iloinw <89Jjmq8oifq • Q , 

 .Lime, . . . , . J y*4z 



Magnesia, . . :q Eifli ill bodriDga 2 -20 



.ioul ^o fcLiiiJ 9mo8 1o &od&& sdi 1 



* The author conducted the " Examination," under the immediate super- 

 intendence of Dr Thomson. 



t History and Description of the Kelp Manufactory. Proceedings of Glas- 

 gow Philosophical Society, vol. ii, page 241. By Mr Glassford. 



