1838} 



FARMERS' REGISTER. 



369 



perience in practice, or by sufficient experiments 

 instituted for the purpose. Nor if it were, will it 

 account for tlie efl'ects produced. We are not pre- 

 pared or disposed to ticny, tliut these substances, 

 eniployeil in useful proportions, may act as septics 

 upon "undeconiposed manure in tiie ground; but 

 nolhmj}; certain of this nature is yet known on 

 sulTicient authority. 



They do not constitute the food of plants. No- 

 thing can enter into the composition of a plant, 

 unless accidentally, that is not an essentially com- 

 ponent part of a vegetable. We find silicious, 

 aluminous, calcareous earths in plants; we find 

 common salt, gypsum, soda, potash, phosphate of 

 lime and other substances in plants, when these 

 substances are (bund in the soil wherein the plants 

 grow. But the same plants can and do grow to 

 per/ijction without them. When these substances 

 are dissolved in minute quantities in the juices 

 which the plants by their roots drink up ti-om the 

 soil, they will of course enter into the sap; and if 

 the vital power of the secretory vessels be not 

 strong enough to excrete them, they will lie depo- 

 sited in the vessels and joints of the plants. As 

 the silicious tabasheer in the joints of the bam- 

 boo; as the silicious earth in the straw of the ce- 

 realia, and the scowring flag. So, the charcoal of 

 an old tree will very often strike fire with steel; 

 not so the charcoal of a young tree. So, gypsum 

 has been fbund in rhubarb, and calcareous earth 

 in potatoes manured with lime. So, the salsola 

 soda^ will yield soda rear the seaside, and potash, 

 when planted for some time inland, iill these 

 instances are manifestly cases of accidental pro- 

 duct and the substances enumerated are by no 

 means essential parts of the plants wherein they 

 happen to be fbund. 



[ conclude, therefore, that they cannot be con- 

 sidered as pabula. Moreover, the increase in 

 weight of vegetable food from these manures 

 cannot be accounted for from the weight of the 

 manure put on. Thus we were present at the 

 laying out of a clover-field, of which one half was 

 sown with clover without manure of any kind, 

 and the other half was sown with ground gypsum 

 after the clover had just appeared above ground, 

 in the pro])ortion of not quite two bushels, but 

 more than a bushel and a half to the acre. The 

 clover hay from the unmanured part, was a ton 

 and a half per acre; and double that quantity 

 fi-om the portion of the field manured with irypsum. 

 Now, the quantity of gypsum employed, even if 

 every particle of it had been taken up and con- 

 verted into (bod, could not have added more than 

 its own weight, or about 120 lbs.; but its effect 

 was, to produce an increase of a ton and a half 

 So, when lime is strewed on the soil, it remains 

 there; it is not eaten and digested by the planr. 

 Both lime and gypsum also, are manures for more 

 than one or two years. Hence, the increase of 

 vegetation cannot be accounted for from their me- 

 chanical action, or fi-om any chemical action, or 

 from their forming any part of the food of plants. 

 As to chemical action, it is none; for gypsum is 

 not decomposable in the common atmospheric 

 temperature; and the lime in a week becomes 

 carbonated by attracting carbonic acid from the 

 atmosphere. 



As to common salt, we know too little, experi- 

 mentally, about it. Mr. Ijcgrand ( Young's An- 

 nals of /Agriculture, Vol. V. p. 149) found that 

 Vol.. VI.— 47 



so far as sixteen bushels per acre, it was a usefid 

 manure; from thence to forty bushels, it gradually 

 destroyed vetrelation. Mr. Parke, the chemist, 

 published a letter on the advantages of using salt 

 as a manure, which Judge Peters procured to be 

 republished in Philadelphia, but we know no re- 

 sult of experience on this subject. 



Soap-boiler's ashes are a common manure in 

 England; they consist of Glauber's salt, common 

 sail, sulphuret of soda, and various impurities, 

 whose action can only be explained on the sug- 

 gestions we have just made. 



Sea-sand, the mud of salt marshes, and other 

 substances of a saline nature, must be referred 

 to the same explanation. They are all stimuli— 

 they irritate the fibres of the roots — they excite 

 stronger action. The perspiration from the leaves 

 m a clover-field manured with gypsum, is obvi- 

 ously increased, as well as the general vigor and 

 growth of the plant. 



Manures may act by furnishing nutriment to 

 the plant : as a pabulum or food, convertible into 

 the substance of the plant itself Nothing can be 

 an essential part of a plant that does not, ivhen 

 decomposed, furnish the substance of which a 

 plant consists. Of what substances does a plant 

 consist % Take a piece of oak-wood, fresh from 

 the tree; weigh it; cut it into small pieces; put it 

 into a glass retort; lute on a glass receiver; and to 

 this, lute on also a bent glass-tube to go under the 

 shelf of a pneumatic trough, and convey into in- 

 verted receivers the gases that would otherwise 

 escape; apply fire gradually; distil and receive all 

 the products. First, an aqueous and acid vapor 

 will come over, which may be condensed in the 

 receiver. This is accompanied with an empy- 

 reumatic oil, and is, in fact, the pyroligneous acid 

 procured by the gunpowder-makers, when they 

 distil wood to make their charcoal. Then come 

 over gases, viz. : carbonic acid gas, carburetted 

 hydrogen, carbonic oxide and hydrogen. In the 

 the retort, when more products come over, you 

 get charcoal, the same bulk as the wood, and 

 about one-fourth or one-fifth part in weight.* 

 Burn the charcoal, and about one part in 250, 

 by weight, in an old tree, will be ashes; the rest 

 will burn away in the open air, in the form of car- 

 bonic acid gas. Of these ashes, part are carbo- 

 nate of potash, and the rest, earths of the same 

 nature with the soil in which the tree grew. 

 The carbonate of potash in the ashes of oak- 

 wood, amounts to about f)ur pounds in a bushel, 

 or 1-15 part. In hickory they amount to six 

 pounds in a bushel of ashes. 



The essential oil of the pyroligneous acid, is 

 convertible by means of a red heat in an iron re- 

 tort, into carbonic acid and carburetted hydrogen; 

 that is, into carbon and hydrogen. 



The acid liquor, which is vinegar, is formed out 

 of oxygen, carbon and hydrogen. 



The water is oxygen and hydrogen. 



The gases that come over, are chiefly carbon 

 and hydrogen ; in the carbonic oxide, a small 

 quantity of oxygen. 



The earths are not essential to the plant, either 

 in kind or quantity; and the alkali is about yV of 



* By tfie experiments of Mr. Mushet, of tlie Clyde 

 iron works, 100 parts by weiglit of oak-wood, furiiish 

 76,895 of gas, water and acid; 22,682 of cfiarcoal; 

 and 0,432 of ashes, of wliich last, we know about 

 l-15th is carbonate of pot<ish. 



