582 PHILOSOPHICAL TRANSACTIONS. [aNNO 1748. 



reason I cannot say. We have as little reason to believe with John Bauhin that 

 it is what he calls kali vulgare : for Mr. de Jussieu has shown; that the true 

 barrilha is a different plant from any of these, from his own observations of it in 

 Spain, where it was cultivated ; of which he has given a particular account, by 

 the name of kali Hispanicum, supinuin, annuum, sedi foliis brevibus. Mem. 

 Academ. Anno 1717> p- 93, or Alicant glass-wort. 



The potash made of this plant, he says, makes the best soap, the finest 

 glass, and is the best for bleaching of any other ; for which reason it is much 

 sought after in all countries, where they value themselves for these manufac- 

 tures. But Dr. M. questions very much, whether our workmen have it either 

 pure and genuine, or in sufficient quantities for these purposes. All the use he 

 finds made of it among them, is to make hard soap ; though they say what they 

 have of it spoils their soft soap, by making it curdle. This is well known to be 

 the effects of sea-salt ; and Mr. de Jussieu and others say, that the true barrilha 

 is often adulterated with sea-weeds, which contain such a marine salt ; so that it 

 is probably only this adulterated sort that they have. Accordingly, all the bar- 

 rilha he had found here, was of a dark brown colour, and very foul and pon- 

 derous ; whereas the true sort is said, by all who know it, to be more porous, 

 pure, and of a bluish colour. It is for this reason, in all probability, that, not- 

 withstanding all the barrilha our workmen have at so dear a rate fi-om Spain, 

 yet they can never make so good soap, as what comes from thence, and some 

 other places. 



The only way then, by which we are likely to have this commodity either 

 pure and genuine, or in sufficient quantities at a reasonable rate, is from the 

 herb itself that produces it. Whether or not it would grow in England is not 

 known, as it has perhaps never been tried : but there is no doubt but it would 

 grow very well in our colonies in America, as he was certainly informed it did in 

 the Spanish colonies there, where they have great plenty of it ; and a sort that is 

 indigenous, particularly in Peru, which might probably be found in our colonies, 

 if sought for by those who knew it. But wherever it will grow in any of the 

 English dominions, there is no doubt but it would be a considerable improve- 

 ment, where potash of all kinds is so valuable a commodity, and so much 

 wanted ; for it grows on the same ground with corn of any kind, which it does 

 no harm to, as it is a small annual herb, that does not spread till the corn is 

 ripe, or off^ the ground. 



There are some other plants that are known to make a kind of potash, com- 

 monly called rochetta, which is said to be even preferable to the barrilha, espe- 

 cially for making glass. These are the first and second kinds of kali, described 

 by Prosper Alpinus, in his account of the plants of Egypt. The first of which 

 is the above-mentioned ficoides that grows in Italy, and all over the Levant, but 



