342 



DOMESTIC NOTICES. 



a healthy atmosphere, and these elements are so 

 adjusted by the laws of chemical combination, as to 

 support the vital system of organized beings in a 



vigorous condition. Many causes, however, exist 

 to derange the gaseous equivalents, and aridity is 

 one of the greatest , which is invariably produced by 

 a high temperature, in consequence of its in- 

 creased capacity for carrying off moisture from 

 every thing within its influence that possesses it. 

 The organic elements of the atmosphere, are de- 

 composed by the heat, and carried off by the ra- 

 riiied air, until carbonic acid, &c., remains in 

 excess to act upon the vegetable functions. 



It is a well known fact, that green-house plants 

 are. more frequently injured by an excess of car- 

 bonic acid than an excess of oxygen. This can 

 be proved simply by the presence of a substance 

 having an affinity for it, such as hydrate of lime, 

 which will soon be converted into a carbonate, 

 and will absorb 6 times the quantity of carbonic 

 acid, that vegetable beinsjs covering the same 

 space, in the same period, would have consumed 

 in the process of assimilation. This fact may 

 account for the suffocating smell so frequently 

 felt in hot-houses, and which is only perceptible 

 ■when the atmosphere is deprived of its proper 

 equivalent of oxygen and aqueous vapor. And 

 hence the necessity of artificial evaporation. 



We might view this in another light, by con- 

 sidering the action of these gasses on the vegeta- 

 ble system. We cannot tell the process or the 

 power by which these elements are converted in- 

 to cellulose and proteine. Chemical affinity ap- 

 pears to be controlled and directed by the princi- 

 ple of vitality. But we know the substances 

 which enter into these combinations, and the re- 

 sult of their action under certain conditions, and 

 when these conditions are unfavourable, the effect 

 ceases to be produced. 



Let us take as an example, the cellular tissue, 

 which is formed from the elements of carbonic 

 acid and water, by the separation of oxygen. 

 Twelve equivalents of carbonic acid, with ten 

 equivalents of water. C. 12. O. 24+H. 10, O. 

 10=C. 12, H. 10, O. 10-f-lO 0; or one equiva- 

 lent of cellulose and ten of oxygen. In the for- 

 mation of proteine, the elements of ammonia are 

 added to those of carbonic acid and water; forty 

 equivalents of carbonic acid, with fifteen of water, 

 and five of ammonia=one equivalent of proteine, 

 and eighty-three of oxygen. Proteine, under cer- 

 tain circumstances, absorbs oxygen, and is de- 

 composed into ammonia and humid acid. This 

 last is formed from woody fibre by the loss of the 

 elements of water and carbonic acid. 



With these facts before him, I will now ask 

 M C. by what method of reasoning he supports 

 his hypothesis, that an arid atmosphere is bene- 

 ficial to the process of assimilation, or upon what 

 foundation he condemns me for keeping the house 

 pretty close, and saturating the atmosphere. His 

 error will appear the more flagrant when we con- 

 sider the difficulty of saturating the atmosphere, 



at high temperatures. It has by calculation been 

 found, that a house containing 4000 cubic feet of 

 air, will by the admission of currents of air heat- 

 ed to 100 degrees, carry off upwards of 20 gal- 

 lons of water in 24 hours. Our atmosphere at 

 the surface of the earth, is frequently above this 

 in the hot days of summer, and its effects on 

 vegetation are known to every one. Yours, R. 

 B. Leuchars. New Haven, Ct., Dec. 11, 1849. 



Healthy and Diseased Foliage. — Dear Sir — 

 Has the matter referred to in the extract from 

 Liebig, which I herewith send you, anything to 

 do with leaf-blight in fruit trees, and especially 

 the pear tree? C. Smith. Newport, N. Y., Dec. 

 10th, 1849. 



[It no doubt bears decidedly on the subject, and 

 we commend it to practical cultivators:] 



" It is by means of moisture that plants receive 

 the necessary alkalies and salts from the soil. In 

 dry summers a phenomena is observed, which 

 when the importance of mineral elements was un- 

 known, could not be explained. The leaves of 

 plants first developed and perfected, and there- 

 fore nearer the surface of the soil, shrivel up and 

 become yellow, lose their vitality, and fall off 

 while the plant is in an active state of growth, 

 without any visible cause. The phenomena is not 

 seen in moist years, nor in evergreen plants, and 

 but rarely in plants which have long roots, nor is 

 it seen in perennials in autumn and winter. 



'"' The cause of this premature decay is now 

 obvious. The fully developed leaves, absorb con- 

 tinually, carbonic acid and ammonia from the at- 

 mosphere, which are converted into elements of 

 new leaves, buds, and shoots, but this metamor- 

 phosis cannot be effected without the aid of the 

 alkalies and other mineral substances. If the soil 

 is moist, the latter are continually supplied to the 

 adequate amount, and the plant retains its lively 

 green color; but if this supply ceases from want 

 of moisture to dissolve the mineral elements, a 

 separation takes place in the plant itself. The 

 mineral constituents of the juice are withdrawn 

 from the leaves already formed, and are used for 

 the formation of the young shoots, and as soon as 

 the seeds are developed, the vitality of the leaves 

 completely ceases. These withered leaves con- 

 tain only minute traces of soluble salts, while the 

 buds and shoots are very rich in them." 



Special Manures. — I have been much pleased 

 as well as profited by the several articles on 

 " Special Manures," published in the Horticul- 

 turist, and I herewith send you a statement of 

 the manner in which I treated a tree in my own 

 garden, and its results, though whether it is a 

 " case in point" I leave you to judge. 



In the spring of 1845, I set two grafts of the 

 White Doyenne on the common quince. They 

 were transplanted the succeeding fall. During 

 the summer of 1848 both trees blossomed, and one 

 of them set one pear, but after it had grown about 



