BARILLA. 265 



or twelve days. At this time it is a concrete sub- 

 stance of a hard and somewhat spongy consistence ; 

 this is broken into large fragments, and is the article 

 known in commerce as barilla. That which is pro- 

 duced from the barilla plant is of a bluish grey 

 colour. The product of the gazul resembles it, but 

 is of a deeper and more glossy hue when broken. 

 The other kinds are nearly black within, and have a 

 greater specific gravity. About a ton of barilla is 

 generally obtained from plants sown on an acre of 

 ground. The barilla cultivated near the sea-shore is 

 of the best quality. It is, however, cultivated not 

 only on the coast of Spain, but at a distance of forty 

 leagues from the sea j the plants grown so far inland 

 produce barilla of an inferior quality*. 



According to Jameson, barilla contains from eight 

 and a half to twenty-three per cent, of pure alkali. 

 Parkes analyzed barilla of various qualities ; from a 

 very fine specimen he obtained thirty and a quarter 

 per cent, of pure dry soda this was an unusually 

 large proportion. 



Soda is likewise obtained by the incineration of a 

 species of another genus of marine plants called Sea- 

 wrack, or Fucus ; the alkali thus procured is known 

 in commerce under the name of kelp. This is of home 

 production. An inferior kelp has for a very long- 

 time been made in Ireland. In the year 1730 this 

 manufacture was introduced by Mr. Macleod from 

 that country into the Scottish Isles, where kelp of a 

 much superior quality was soon produced in large 

 quantities. In consequence of the heavy duty on 

 barilla, it could be procured only at so high a price 

 that the manufacture of kelp was attended with great 

 advantage, since this latter article, being unburthened 

 with any imposts, could be sold at a much cheaper 

 * Pictet. Phil. Mag, 13th vol. Lewis' Com. Phil. Tech. 



2 A 



