TRANSACTIONS OF THE SECTIONS. 65 



secures from time to time a new supply of soluble alkalies. Now Liebig states that, 

 for the purpose of agriculture, it is quite indifferent whether the land be covered 

 with weeds, or with a plant which does not abstract the potash inclosed in it. Accord- 

 ingly, he would alternate with corn crops, which extract the alkalies of the soil, the 

 usual fallow plants in the family of the Leguminosce, because, " being remarkable on 

 account of the small quantity of alkalies or salts in general which they contain," 

 they neither extract alkalies from the soil, nor do they exercise any injurious influ- 

 ence on the corn which is cultivated after them. The farmer is hereby greatly ad- 

 vantaged in being able thus to steal, as it were, an intermediate crop from his land, 

 inasmuch as an entire absence of plants appropriating these unimportant quantities 

 of salts would of necessity compel him to the constant repetition of bare fallows, in 

 order that the soil, during an interval of rest, might regain its original fertility. 

 Such is the theory. The fact, however, most unquestionably is this, that the plants in 

 the family of the Leguminosa usually cultivated as fallow crops, so far from acting 

 but slightly on the saline constituents of the soil, are remarkable, above all others, 

 for the large quantities of soluble salts contained in them. 



The experiments by which this result may be arrived at are very simple. If two 

 pounds of bean straw, and of clover hay, be submitted to the action of fire and allowed 

 to burn till they cease to give any flame, they will yield about two ounces of ashes ; 

 and distilled water (about two pints) being poured upon the hot ashes, and repeatedly 

 filtered, after squeezing it from the insoluble residuum, is charged with the soluble 

 matter which, to a certain extent, is set at liberty by the process of combustion. The 

 quantity of soluble matter, chiefly potash, contained in the clover saline solution, 

 appears, upon evaporation, to be about ninety grains, and in the bean saline solution 

 about forty grains ; whereas by a similar Operation upon the ashes of wheat, barley, 

 and oat straw, the soluble saline matter does not amount to thirty grains. The pre- 

 sence of potash may be detected in these tolutions not only by the well-known smell 

 peculiar to Liquor potassa, but also by the characteristic crystalline precipitate on 

 the addition of bichloride of platinum, by the copious insoluble bitartrate cf potash 

 on adding the solutions to tartaric acid in excess, and by the salts of potash formed 

 with mineral acids. 



The saline solution from bean straw is also remarkable for containing lime in solu- 

 tion, and hence, probably, we have one important cause of the streugth of bean straw 

 manure. In twenty-four hours after the clear bean solution is obtained, a crystalline 

 precipitate of carbonate of lime is attached to the sides of a stoppered bottle, and, in 

 the course of a few days, it considerably increases in quantity. 



All the solutions, when evaporated to about half an ounce, exhibit a remarkable 

 precipitate, which, upon being separated and washed, ceases to be soluble in water, 

 and the action of acids and alkalies, as well as of the blowpipe upon this sub- 

 stance, is accompanied with phsenomena which deserve the attention of agricultural 

 chemists. 



The condition of carbon in these solutions ought also to be accurately exa- 

 mined. 



The author concludes with the following question : may it not be the case, that the 

 leaves which fall so abundantly from these plants, and the roots which remain in the 

 ground being so copiously supplied with saline matter from the presence of potash in 

 every cell, do really furnish more soluble alkalies by the subsequent process of tillage, 

 than the soil, especially when of a sandy nature, could in any other way obtain for 

 the future production of corn ? 



Mr. E. Solly, jun. exhibited specimens of the diseased bark of living ash trees, 

 occasioned by insects. 



On an Irregular Production of Flotvers, in an Aloe, at Ham Court, near 

 Bristol. By Dr. Daubeny, Prof, of Botany, Oxford. 



The aloe began to throw up its flower-stem in May 1841. The first blossoms 

 opened about the end of July, and it went on flowering till October. 



Several suckers were removed from the plant after the blossom was over, and one 

 which grew on a kind of underground stem of perhaps two feet and a half long, 

 which had apparently been lengthened in seeking for a convenient place to reach the 



1842. v 



