268 



Consideration of Light. 



Vol. X. 



and satisfactorily in every case, but as they 

 do not belong to agriculture, it will not, per- 

 haps, be thought worth while to notice them 

 more particularly. As to the mode of appli- 

 cation and quantity per acre, we must again 

 fall back on the experience of England. 

 There it has been mixed with the usual 

 ight manures : ashes, plaster, charcoal, 

 muck, &c., and used in quantities from one 

 hundred and fifty pounds the acre, to four 

 hundred : in one case, weTliink as much as 

 six hundred were put on. Our impression 

 is, that it is as well to apply it alone, for two 

 reasons; one that you then know to what to 

 attribute the condition of your ciop; the 

 other, that being an extremely sensitive ar- 

 ticle, it is impossible to tell how far it may 

 have been effected by its companion. Changes 

 and decompositions may be produced that 

 might alter its whole character, and the 

 guano be made to bear the whole blame of a 

 failure, that was due rather to its associates. 

 We would prefer to throw it on the ground 

 in the spring, and let it be ploughed in at 

 the rate of two to three hundred pounds of 

 the Peruvian, and of three to four hundred 

 of the African. One absolute essential in 

 its use is, that the ground be moist. It will 

 have no effect, or but a bad one, if employed 

 in dry weather, or on a dry surface. We 

 must take advantage of a storm of rain, or 

 exert our judgment in the anticipation of 

 one. It is from this necessity of moisture, 

 that arises its extreme importance on sandy 

 soils — on stift' clays, it does not do so well. 



If this material should find favour with our 

 farmers, and a regular supply can be relied 

 on, it will produce two good effects, the 

 saving our barn-yard manure, and the keep- 

 ing our fields free from w-eeds, except such 

 as are kindly supplied by our benevolent 

 but negligent neighbours. Even if guano 

 were dearer than it now is, and it can now 

 be put upon our lands at about the same ex- 

 pense as fifty bushels of lime to the acre — 

 the saving of labour in the destruction of 

 weeds, the satisfaction of seeing our fields 

 cleared of this foreign vegetable population, 

 and the keeping our tempers untried, will 

 repay amply, even if there be no decided 

 additions to the crop. Besides, we have 

 very little doubt that the guano will be 

 found very destructive to the insects that 

 cut our corn to pieces, and to all which harass 

 us in our grains, vegetables, or fruits; at 

 least they must be more thin usually thick 

 skinned, to be able to bear the application of 

 so irritating a substance. 



In this imperfect way we have gone 

 through this important subject; but with 

 such scanty materials?, how could we say 

 any thing of much value to the practical 



farmer! He cannot go out of his way to 

 make experiments; he can place no confi- 

 dence in conjectures; he cannot aflxard to 

 change the whole conduct of his life to 

 adopt novelties, or act upon another's imper- 

 fect experience ; and in the matter before 

 us, where he has to deal with a thing that 

 is literally the edge-tool of agriculture, it 

 would be madness to run the hazard of 

 losing an entire crop, before the art of man- 

 aging the instrument had been ascertained 

 and perfected. 



A. L. Elwyn. 



Philadelphia, March 30th, 1846. ' 



Consideration of Light. 



It is highly probable that many of our readers will 

 conclude the following article, which we take from 

 Paxton's splendid Magazine of hotany, is too specula- 

 tive and scientific for the Farniers'Cabinet. To speak 

 frankly, the editor is more than half inclined to the 

 same opinion; but having read it with considerable 

 interest himself, he has no doubt many of his subscrib- 

 ers will do the same. — En. 



It is probable that we may never attain 

 to a knowledge of the precise nature of 

 light, because we cannot determine that of 

 its assured source — the Sun. Still there 

 are many phenomena which lead to a shrewd 

 conjecture of its elements, and to these we 

 may safely refer. 



There are three distinct series of phe- 

 nomena, traceable to solar influence, to 

 which we invite the attention of the inquir- 

 ing cultivator; namely, 1st, those of attrac- 

 tion — 2nd, those of temperature — and 3rd, 

 those of colouration. 



The principle of attraction is manifested 

 in the position assumed by leaves under the 

 several angles of sunlight at different hours 

 of the day. Thus, in Erythrina, we see 

 the leaflets brought into first the horizontal, 

 and then the upright position, at about eight 

 or nine o'clock of the forenoon, and thence 

 to mid-day — declining in proportion as the 

 sun advances to the west. Attraction, what- 

 ever be its medium, is demonstrative of elec- 

 tric agency; this, at all events, will not be 

 disputed when it is attended with luminous 

 appearances. 



But then it may be contended, that the 

 phenomena of magnetism and of chemical 

 attraction do not generally, or of necessity, 

 develope light. This is true, but as respects 

 magnetism — which is induced by the elec- 

 tric current, and therefore dependent upon 

 it; so much so, as all but to prove that elec- 

 tricity and magnetism are one in essence. 

 And as to the latter, when chemical attrac- 

 tion t;ikes place, as between acids and alka- 

 lies, the combining powers unite, and thus 



