to revolve uniformly; and the platform, with its load, is raised or depressed, according to the direction in which the handle is turned.

By this arrangement, the power required to elevate the platform c is rendered so trifling, that a child may effect it with ease, even when loaded with two or three tons weight. So great is the mechanical advantage, that when a block of marble, weighing about two tons, was standing on the platform, I could scarcely tell, by the resistance offered in turning the handle, whether I was raising or lowering of it. The space moved through in a given time is, of course, proportionably small; but then the range required is, in these cases, never large.

In addition to the vertical motion thus elegantly and conveniently obtained, a horizontal movement is afforded, on placing a short lever in the hole h; when the upper part of the platform revolves on its centre, being supported by a metallic bearing near its outer edge.

The stability and complete efficiency of this apparatus can hardly be conceived except by inspection; and those persons who feel interested in the employment of such a machine, will find it well worth while to pay a visit to the mintwhere Mr. Pistrucci's free and open disposition will readily afford them the means of forming their own conclusions on the merits of this invention.

I remain, Sir, yours, respectfully, WM. BADDeley. London, Nov. 7, 1838.

ORGANIC MATTERS THE PROPER AND ONLY SOURCE OF ANIMAL FOOD.

Sir, I am sorry to observe in your last number (797), that "Junius Redivivus," instead of candidly acknowledging himself in error, makes an ineffectual attempt to vindicate his former statements (page 36, No. 793), setting forth the future probability of nutritive food being prepared from inorganic matter. Although fully sensible of my inferiority to Junius Redivivus" in argumentative powers, I feel that he is so decidedly wrong, and so completely opposed to all recorded facts, in the position he at present endeavours to maintain, that I must beg to offer a few brief

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observations in reply to the matters broached in his last communication.

66 yet

"Junius Redivivus" misquotes me at the outset, for no apparent reason but that of introducing school-boys performing the exploit of swallowing live frogs -not as a means of subsistence, but out of mere sport-and the bolting of dead oysters, by grown up gourmands, as a matter of palatic gratification. He then goes on to assert that "the marble rock is but a congeries of living beings or their exuviæ." It is true that whole mountains and extensive districts in various parts of our globe, appear to be composed almost entirely of animal remains: but such mountains, and mirble rocks, are two distinct and widely d fferent things. Butchers, with their wives, and sons, and daughters, are next exhibited as fattening on the effluvia of meat: and "Junius Redivivus" says, surely these gases are not living matter." No, but they are most undoubtedly the produce of what was once living organic matter; and I shrewdly suspect, by the bye, that if the meat itself was withheld, the fattening influences of the gases would be of a very unsatisfactory character. We are, however, requested to return to the opinion of the philosophers, that is, of one- -Humboldt, "who has recorded that certain tribes of Indians, during certain periods of the year subsist on a white earth, which they dig up," and "Junius Redivivus" supposes this to substantiate the fact-not that man may derive nutriment from, but that he may subsist upon, inorganic matter. In the first place, that this white earth consists entirely of inorganic matter is "not proven;" in fact, its peculiar colour strongly induces a belief in the presence of organic (either animal or vegetable) matter, else whence the preference given it over other earths? Secondly, if it was, the mere subsistence for a short time on a substance devoid of nutriment, proves nothing; because in some diseases, mesenteric obstructions for instance, although food is regularly taken into the stomach, and many of the functions of life continue to perform their office, no nutriment is derived by the system, and the food might almost as well be white or any other coloured earth; yet the poor sufferer lingers for a considerable period - perhaps several months-and at length, nature having fairly exhausted all the repositories of

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Just as well might an Englishman fatten on the red earth constantly seen on the banks of his favourite Thames (the colouring matter of which is innumerable animalculæ), and boast of his subsistence on inorganic matter! The mushroom and the olive, brought forward by Junius Redivivus"-being both organic substances by no means assist his argument: he seems to depend greatly upon his assertion that we scarcely know where the stone ends and the vegetable begins, or where the vegetable ends and the animal begins." It has long been a favourite notion with speculative naturalists, that organised beings might be arranged in a continued series, every part of which, like the links of a chain, should be conencted with that which preceded and that which fol lowed it. Linnæus was even impressed with the idea, that nature, in the formation of animals, had never passed abruptly from one kind of structure to another. But the idea of a chain, or continuous gradation of being, was cherished with enthusiastic ardour by Bonnet, who, assuming man as the standard of excellence, attempted to trace a regular series, descending from him to the unorganised materials of the mineral world. Many other writers have adopted this fanciful speculation; but none have carried it to a more extravagant length than Lamarck, who blends it with the wildest and most absurd hypothesis that was ever devised, to account for the diversities of animal structures.

The fact is, the parts, which by their assemblage constitute an organised body, when compared with inorganic matter, exhibit in their chemical, as well as in their mechanical characters, the most well-marked and striking contrast. The solids and fluids of which organic structures are composed, differ very materially in their chemical constitution from the productions of the mineral kingdom. Their elements are combined by a much more complicated arrangement, and united by less powerful affinities; or rather, the balance of affinities, by which they are held together is more easily de

*The peculiar office of fat as a magazine of nutriment, for the support of the body during the period when food is scarce, is strikingly exemplified in numerous instances, especially in all the hybernating animals.

stroyed, and thus proneness to decomposition is constantly present.

It is an incontrovertible law of nature, that a constant supply of nutritive matter is essential for the continuance of life; and when we come to analyze the proximate principles from which animal nutriment is derived, we find them reducible to the following: namely, fibrin, albumen, oil, gelatin, and sugar; together with a few others, such as osmazone, which are of minor importance. Perhaps the most exact classification is that of Magendie, who refers all alimentary substances, whether animal or vegetable, to the following heads: namely, farinaceous, mucilaginous, saccharine, acidulous, oily, gaseous, gelatinous, albuminous, and fibrinous. These are adapted to the purposes of nutrition by the functions of assimilation, absorption, circulation, and respiration.

When any of these proximate principles are found to exist in inorganic matter, then-and not till then-will man find nutriment therein. "Junius Redivivus" may perhaps go on to ultimate elements; but this will advantage him nothing, as they form organic substances only in definite proportions.

It is too frequently the practice with flighty theorists, though both unphilosophical and unjust, to push their speculations beyond all reasonable limits; and, when challenged, to reply, that " philosophy is not yet a perfect science;" and when met by some insurmountable difficulty, to content themselves by declaring, that " our chemistry is at fault."

I would merely ask, was it not by similar baseless arguments, and such idle speculations of old, that the reign of ignorance was so long perpetuated? and shall we—after the lessons of a Bacon, and the example of a Newton-suffer imagination to run wild, regardless of all recorded experience.

I trust there are none who would assert that our knowledge is perfect, even with reference to the points now under review ; but this may be admitted, that whatever further insights the perseverance and ingenuity of man may obtain, into the mysterious operations of nature, we are even now in possession of certain facts, and have acquaintance with several governing laws, that will continue to operate, unchanged, to the end of time. We have positive data to proceed from, however limited our range beyond; and

ly; abundance of time for communicating motion to the new carriage (C).

If the last carriage (L) be furnished with several coils of spring, as many must be put in gear as are thought necessary, according to the weight of C. Let C be placed near the rails, and as L rope becomes attached to passes the C, and begins to run out; it remains to get C upon the rails as soon as possible after L has passed. This may be done in various ways.

1st way: Let C be placed on a frame parellel to the rails, and be set on the rails by a strong spring, which L releases in passing, and by a motion perpendicular to that of the train. By this way, however, at least 1" of time is lost.

2nd way: Let C be placed on a side rail slightly curved and leading into the railroad, then motion commences the instant L passes, and this motion may be aided by a strong spring released by L and propelling C; or (which might be still better) by a tube containing compressed

air.

B

b

F

f

Fig. 1 explains the construction of the side rail.-A B, FE, the railroad; GHB FL K, the side rail elevated 6 or 8 inches above A F, and decending into it at B and F. Let the portions B H, FL, be in the po

sitions bh, fl, and PO in the position J O moveable round a hinge at O. When L comes to it, it becomes attached to C, and releases the spring which propels C. On passing O, another spring puts p O

EB, Fig. 2, the rail (slightly curved) down which C descends. A portion, H B, of this rail is moveable about a hinge H, and can be raised into the position H K, so as to allow the wheels of the trains to pass under it. The instant L passes B, KH falls, or is set in the position H B. The instant H B is so set, C reaches H, and begins to descend down HB. This will be effected by a trigger, at I, released by L, and having its distance from A properly adjusted. If, then, the height

of E, from which C begins its descent be properly assumed (allowing for friction, &c.) C may be made to arrive at B with a velocity greater than that of the train. C will then overtake the train, and by a simple device become attached to it.

This method has the advantage of being very simple, and in deep cuttings the necessary apparatus would be erected at a small expense. On plain ground, and where land can be easily obtained, the tractrix would probably be preferable.

E