xliv INTRODUCTORY CHAPTER. 



would probably have yielded one ounce of salt more ; in this 

 case, supposing- the 38 pounds had yielded 20 ounces, the entire 

 plant will give nearly three pounds lour ounces and a quarter 

 from 100 pounds original weight; but the value of this addi- 

 tional ounce from each hundred pounds, would be more than 

 counterbalanced by the time employed in stripping the leaves, 

 and their much slower combustion than when the plant is burnt 

 entire, as cut or pulled from the ground. The ashes from No. 1 

 (per steelyard) weighed four pounds : those from No. 3, three 

 pounds and three-quarters. 



As you wished to ascertain the comparative quantity of salt 

 to be procured from furze, and the bramble or blackberry, I made 



the following trials. 



Oz. Scrup. 

 No. 4. Seventy pounds of furze yielded of impure 



vegetable alkali somewhat deliquescent - i 2 



No. 5. Seventy pounds of the blackberry-bush 



yielded of the same .sort of salt - - 5f 



The bushes were cut down from nearly contiguous thickets and 

 burnt on the spot, and the ashes afterwards removed under cover. 

 I think they would have yielded more salt had they been burnt in 

 a grate under shelter, because some of the ashes were scattered 

 by occasional puffs of wind ; but these had an equal effect on both 

 piles. The ashes from No. 5 weighed (per steelyard) one pound 

 and three-quarters. The weight of those from No. 4 I could not 

 determine, as there was some earth intermixed with them. There 

 are two species of blackberry here ; that used was the smaller 

 sort, with green stems and paler leaves." 



Doctor Kay's experiments having been conducted in the same 

 manner throughout, are so far valuable, that they shew with 

 minute accuracy the respective proportions of alkali produced from 



