The

facts and experiments have been adduced in each instance, it appears to follow that electricity is the great principle by which vegetation is carried forward. And as they apply severally to air, vapours, and light, they manifest the existence of this principle in each of those elements. Now, if it is found floating in an uncombined state in the air; if by its being extracted from vapours they are reduced to a liquid state; and if in the form of light, it performs the galvanic effect of decomposition, is not strong direct evidence afforded that the same solar fluid is manifested under the three forms of light, heat, and electricity? If this be admitted, it appears to me that considerable light will be thrown upon this system of nature, and the relation between plants and animals. sensible effects of electricity are in gene. ral disagreeable and injurious; they are, however, we conceive, no other than the effects of the solar fluid floating in a state of separation from gravitating matter, and seeking to obtain an equable diffusion among its particles. A small quantity of it alighting on solids, especially if they be non-conductors, quickly assumes the form of electricity, as it cannot enter their pores and separate their closely united particles with sufficient facility to become latent within their substance. If in the form of light it strikes the surface of water, it easily combines with a small portion of it in a state of vapour; and its electrical properties are thus neutralised. By impingeing upon the earth, and being reflected into the atmosphere, a greater or less degree of electricity is probably produced, especially if the surface of the earth is dry; but the effect is greatly alleviated by the readiness with which the air, in common with all gaseous bodies, opens to receive the fluid in the form of a moderately increasing temperature and rare. faction. According to these views, there is an increasing necessity for neutralising the action of the solar beams to a certain extent; or of diverting their operations from the forms of light, heat, and electricity, as the summer season advances, to some other necessary and useful purposes. And these purposes appear to be effected by the increasing foliage of plants. The moisture upon the surface of the soil being quickly evaporated, there is the greater necessity for that copious supply of moisture which is constantly yielded under the action of light from the leaves and even

the green stems; and every particle which is thus rendered latent in the form of aqueous gas, diminishes the quantity of sensible heat and the glare of light which would otherwise remain in the atmosphere.

But we also find that a process of greater and more absolute necessity, both to the animal and vegetable systems, is going forward at the same time, though in a less perceptible and more gradual manner, by means of a similar action of the solar beams upon the carbonic acid, of which these organs are the constant absorbents. It is by means of these con. curring properties of the leaves, and of the light acting upon them, that we are enabled to account for a large portion, at least, of the carbon which we find entering into the substance of plants, and of the oxygen gas by which the vital principle is maintained in animals. It is an observation of Sir H. Davy, that we know of "no process in nature by which the carbonic acid formed during fermentation, combustion, putrefaction, respiration, and a number of operations taking place on the surface of the earth is destroyed, but by vegetation." "When," he observes, a growing plant, the roots of which are supplied with proper nonishment, is exposed in the presence of solar light to a given quantity of atmospherical gas, containing its due proportion of carbonic acid, the carbonic acid, after a certain time, is destroyed, and a certain quantity of oxygen is found in its place. If new quantities of carbonic acid be supplied, the same result occurs; so that carbon is added to plants from the air, by the process of vegetation in sunshine ; and oxygen gas is added to the atmosphere. This circumstance is proved by a number of experiments made by Drs. Priestley, Ingenhotz, and Woodhouse, and M. T. de Saussure, many of which I have repeated with similar results." I have been induced to add these extracts from Sir H. Davy's observation in conformation of my former statements, both on account of the importance of the principle they advocate, and the beautiful harmony which it presents between the functions of plants and animals, and because it still appears a prevailing opinion of physiologists, that vegetables are almost identified with ani

* Agricultural Chemistry, 4th ed. pp. 194 and 203.

mals with regard to their respirative and their digestive functions. In page 453, of the same work, from which the above short extract on the necessity of carbon to the growth of plants is made, it is said, on the authority of Professor Burnet, that the process of respiration in plants is supposed to be continual, and to be accompanied, as in animals, by the formation and emission of carbonic acid gas." It is admitted, however, that during their exposure to the light of the sun, the decomposition of this gas from the atmosphere, and the absorption of the carbon from the acid is effected. In other words, carbonic acid is removed from the atmosphere, and oxygen gas is produced. It is surely an extraordinary supposition" that plants are giving out carbonic acid to the atmosphere at the same time, and under the same circumstances, in which it has been clearly proved, that they are effecting its removal. But this last is ascribed to "the process

of digestion in plants; whereas a separate process of respiration, it seems to be taken for granted, must also be carrying forward; but to identify plants with animals, and from that hypothesis to make a supposition in opposition to a fact clearly proved and admitted, is a mode of proceeding not very congenial with the true spirit of philosophy.

We trust it has been proved that plants, instead of continually emitting carbonic acid, are imbibing it by their leaves as continually as it is exposed to their action; a process which indeed seems essential to the aggregation of that large proportion of carbon which enters into their composition; and with which the supposition of their being subjected to the continual loss of carbon by an opposite process is utterly irreconcilable. In truth, the analogy, or rather identification, which is sometimes represented as existing between plants and animals, with respect at least to their digestive and respiratory functions, appears to have much less foundation in reality than has been imagined. What strong marks of resemblance are there between the most perfect of the orders of animals, and the most perfeet of the vegetable tribes? Or with what degree of correctness can the favourite comparison between the lungs of an animal and the leaves of a plant be maintained? The former are admirably constituted for the purpose of admitting

large supplies of air into their expanded vesicles; of receiving from it that supply of caloric which is necessary to the uniform heat and vitality of the animal; and at the same time, of transmitting to the oxygen a portion of carbon, which, if retained in the blood, would impede its circulation. The leaves of plants, on the contrary, from their origin in buds to their full expansion, manifest no such property. In proof of this position, I have made several experiments with seeds growing under the receiver of an air-pump carefully kept in a state of exhaustion; from which I think myself fully justified in the assertion, that cresses and mustardseed at least will germinate, grow, and flourish, in a state of exhaustion, in which any of the more perfect orders of animals, those especially which live by meaus of well-developed organs of respiration, would almost instantly perish. We have in the foregoing papers endeavoured to show that plants derive the vital principle not by a respiratory process, but by that electric action on the air and vapours for which their whole structure, and particularly their pointed and edged extremities, are so admirably calculated. This property they no doubt continue to exert so long as they retain these conducting organs in a state fitted for action; and the enlargement of the plant with its increasing foliage must extend its electrical influence. But as the growing stage of its existence passes into that of maturity, we have seen that a different process is going forward to an increasing extent; the leaves become fully developed, but we repeat our statement, that from every observation we have been enabled to make, as confirmed by those of the great names to which we have appealed, these effects with respect to carbonic acid are the reverse of those which are produced by animal respiration. In my fourth letter on electro-vegetation, I have stated the experiments by which I unexpectedly was led to the conviction, that leaves imbibe carbonic acid with avidity in the absence of light, and during the night season, and which, as they consist simply in placing leaves, or sprigs of leaves, whether on the trees, or imme diately after they have been plucked, in water or air containing a small quantity of carbonic acid, too large a quantity proving deleterious, can easily be re

peated. It being also known that they perform the same function under the ac tion of light, when oxygen gas is extracted, the conclusion appears indubitable that the function of the expanded leaf is, in this respect, the reverse of that of animal respiration, consisting in the absorption of carbonic acid, both by night and day; while under the influence of light it emits pure oxygen gas to the atmosphere.

If the principles which we have advocated be founded in fact, vegetation is, in every point of view, and by means of its several effects upon the surrounding elements, conducive to the existence and welfare of the animal creation. It derives its vitality from the same solar fluid as that by which the animal heat and life is maintained. But it is drawn by elastic action from those portions of it which floating on the air, or set loose by condensing vapours, would otherwise either augment the quantity of electricity or of heat in the atmosphere in excessive degrees. Carbon, forming a large portion of its nutriment, and an essential of its existence, is imbibed by it in its connexion with oxygen apparently in a like proportion to that in which it is given out by the several opposite processes, and in particular by animal respiration. By this process, in connexion with that of evaporation, it is eminently conducive to the existence and well-being of animals, during the period of its greatest vigour and luxuriance; as by these means the solar fluid is combined with oxygen in a state of fitness for maintaining their vital principle; or by combining with water, a cooling shade is formed in the atmosphere-and by both these processes, but especially by the latter, great quantities both of heat and of electricity are prevented from accumulating in it.

In the forming of these conclusions, facts have either preceded or gone hand in hand with theory; but I hope that many of your readers will concur in the sentiment, that the harmony and coincidence of the parts tends considerably to confirm the credibility of the general results. Upon the principles we have advocated, vegetation stands in a corresponding state of subordination and subservience to the animal system as it respects the means of vitality, and the general temperature and tranquillity of the atmosphere, that it does to the means

of subsistence, comfort, and enjoyment in other respects. As it produces compounds from bare elenientary bodies suited for the food of animals, so it produces a compound of air exactly suited to their respiratory organs. And thus, in a scale gradually ascending from elementary and inorganised matter, the inferior orders of beings and of substances are made subservient to the higher. T. PINE.

PERPETUAL MOTION.

Sir,-From the tone of Nautilus's reply, I am afraid he is losing his temper. If he be really in search of truth, he will succeed all the better, I think, by proceeding coolly, and his observations would have more weight too, if he were to deliver them in language a little more respectable than he has employed in his last. He says, 66 'as for the assertion that Kinclaven has been knocked on the head with the lump of lead on the arm of the fly-wheel, I leave it to himself to deny it; I can find no marks of the dent in any of his letters." Now it may be true that Nautilus cannot perceive the dent, and yet there may be a very deep dent, notwithstanding; all persons are not gifted alike with the faculty of perception, and, as he very candidly confesses his dulness, it may not be thought uncharitable to give him a little aid on this occasion. Well, Nautilus, Kinclaven commenced his attack upon the electrical theory, by announcing, in the most confident terms, that the Newtonian system had been rigidly demonstrated, and that therefore the electrical theory must be false. was meekly reminded of two propositions that have not yet had the benefit of any demonstration whatever, although they happen to be the very two upon which the whole system depends, and was respectfully solicited to supply this deficiency before he said any more about the "rigid demonstrations." Kinclaven, finding himself in a somewhat awkward predicament, has very kindly referred me to the parson for one of the demonstrations, which he says is to be, not of the mathematical, but of the orthodox kind; as for the other, Kinclaven keeps it in imo pectore, as Nautilus says, in reference to the perpetual motion problem. Here then, Nautilus, are two very plain dents, but if they are still imper

He

ceptible to your mental vision, I am afraid you must remain in darkness, your case is hopeless.

Nautilus and Trebor Valentine little imagine, I presume, that the same argument that they have advanced to show the absurdity of expecting a perpetual motion from the wheel and magnet, may be applied with almost equal force, to show the absurdity of the Newtonian system. Let us try what a little transposition will do.

"How then can it be expected, gravity being powerful enough to restrain the earth, and keep her in her orbit, thereby nullifying the angular velocity, that the said velocity is to remain for ever unnullified."-Nautilus.

"It must be plain to every one, that the momentum, the very power which is said to give motion to the earth and planets, is completely neutralized by the power of gravity." -Trebor.

There, Nautilus and Trebor Valentine, you see that you have unwittingly given the electrical theory a "pretty consi

derable lift," for which I beg to offer you my most humble thanks; and in your future meditations upon the "great problem" of the wheel, you will take this consideration along with you, that when you have succeeded in proving its absurdity, you will at the same time succeed in proving the absurdity of the Newto nian system; after which happy result of your deep cogitations, it will be found that the electrical theory is not so very absurd as some wise folks have supposed. I am, Sir, &c.

T. S. MACKINTOSH.

FRODUCTION OF LIFE BY GALVANISM

ANIMATION OF HORSE HAIRS!

Sir, I have been delighted and overjoyed to see in your last Number (705), Mr. Crosse's account of the production of living animals by the judicious combinations of water, mineral matter, another galvanic fluid. I look upon this, as a clear experimental proof of the truth of the theory which I have been inculting for the last twenty years, which is the identity of all life, with the electric, galvanic, magnetic, or solar substance. In Number 401, p. 98, of the Mechanics' Magazine, your readers will see, that in speaking of the vital rudiments and phosphorescence " of the sea, I use

66

these words, "I mean, that the vitality and electricity, the electricity and vitality, are one and the same thing."

In the course of my observations on the electromotive theory of the universe, I shall come to an explanation of the modus operandi in the progression of the galvanic particles into vegetable and animal existence.

I also endeavour to account for the plague, yellow fever, and similar epidemics, on analagous principles; principles, in fact, which are now beginning to be applied to the "dry rot" in timber.

In 1818, I communicated my galvanoelectrical ideas to an acquaintance of great philosophical acquirements, and requested him to try the experiment (as he had the necessary apparatus) of placing a fresh pulled horse-hair in a glass vessel containing pond water, exposed to the sun, and keeping a constant current of galvanic fluid passing longitudinally through the horse-hair.

Very shortly afterwards, I had occasion to go abroad, but I met Dr. Foster some time afterward, and he assured me that at the end of three weeks' submission to the galvanic influence, the hair had increased to the size of a thick straw, and gave him satisfactory proofs of real identical vitality.

I do not well remember how the business ended, but I recollect that he attributed the subsequent death of this his first-born, to the ligatures with which he had attached it to the wires. He promised to repeat that experiment, and others on different substances and infusions. But he shortly after went to Scotland, and I have heard is now prac tising with distinction at Edinburgh. I hope he may see this.

Many people have all along called me insane, in consequence of opinions on vitality, the identity of all matter, &c., partly set forth in Numbers 400 and 401, and now intended to be more developed. in the series of articles I have recently sent you. Perhaps Mr. Crosse will not disdain to try the horse-hair. I shall, and other things too, when I can get an electromotive apparatus.

I am, Sir,

Your obedient servant,

F. MACERONI.

THE BIRMINGHAM SEVENTH HALF-
YEARLY REPORT.-REMARKS.

The publication of this Report has produced a great sensation in what may be called the railway world, and combined with the general depression which has lately prevailed in the money market, and consequent distaste for enterprise and speculation, has exercised, and, we fear, is still exercising, a most injurious influence on all railway projects. Whe ther the facts which it discloses are of a nature to warrant such a decline of confidence in the railway system, becomes therefore a subject of earnest inquiryto all, at least, who think with us that there is more good to come to the country from the rapid and general adoption of that system, than from any other class of public undertakings whatever.

The grand fact promulgated by the Report that which is in every one's mouth, and is disquieting and unsettling the minds of not a few-is, that "the contemplated works for the efficiency of the railway in the carrying department, as well as for the road itself," will require a sum of nearly two millions more than the sum originally estimated to be requisite. Certainly this is a large excess; but before we leap to the conclusion (as is the fashion of the day), that we should therefore cease to have any faith in the safety and the eligibility of this or any similar undertaking, as a means of pe cuniary investment, there are two preliminary questions which ought in all fairness to be carefully examined and disposed of (if so they can be) in the negative.

First. Is the excess accounted for on just and reasonable grounds?

And, second. Will this excess increase the total expenditure to so disproportionate an amount that the railway will no longer yield an adequate return to the shareholders?

I. Now with respect to the first question, let us see how the excess is stated in the Report to have arisen.

"Land and Compensation.”—The Parliamentary Estimate under this head was 250,000l.; the actual cost has been 506,5007.-more than double. The promoters of the undertaking had, we dare say, calculated, that the owners and occupiers of the land required for the railway, would, in consideration of all

the rest of their estates being incalculably improved in value by its passing through them (to say nothing of the higher and purer consideration of the public good), have been content to accept of the actual value of the land taken from them, and a fair compensation for the actual loss otherwise sustained by them; or, at all events, with the double of such actual value and double compensation for such actual loss. Nay, perchance they may have even fancied it not without the limits of probability, that some of the more distinguished of these persons for wealth and station-noblemen and gentlemen, for example, with vast landed possessions and more than princely incomes-would have public spirit enough to make the undertaking a present of the few paltry acres required from them. Instances of such enlightened liberality have not been rare in railway cases on the other side of the Atlantic; and it may have been supposed (fondly, at least, however erroneously,) that the flame of patriotism still burns as brightly in the old or father-land of the English race as in the new. Certain, at all events, it is, that the Parliamentary estimate for land and compensation must have exhibited the full amount, which, in the judgment of competent persons, ought to have been paid under this head; for it is only upon evidence to such an effect and of such a character, given too upon oath, that the Bill for the undertaking could have passed the Upper House of Parliament. But all these reasonable calculations-these valuations on oath notwithstanding, we find the actual has been more than double the estimated cost? And whose fault is this? Not the Company's assuredly. The Directors state that they have been obliged to purchase 800 acres of land more than they laid their account with, and that the much higher price which they have been "compelled to pay," for it was, "in some degree, extorted by the necessity of obtaining possession at an earlier period than by the provisions of the Act of Incorporation the Company could legally enforce." But how else extorted, they do not say; and for not speaking out a little more boldly, are, we submit, much to blame. We think the justice of the case demanded a full exposure of all the extortion to which they have been subjected, through all its degrees of enormity.