by the "conventional term" gravitation, whether the cause of this effect may be known or unknown, I presume that the Newtonian philosophy would be thereby affected. However, I see very little reason to apprehend that it will be affected by this theory, at least so far as regards that well-known and well-established effect which we understand by the term gravitation. But, on the contrary, I am rather apprehensive that the "Mackintoshian philosophy" will be affected by the "conventional term" gravitation; and that it will furnish an objection of such weight and validity, as it will not be able to withstand.

These remarks may, perhaps, appear unnecessarily harsh and severe, and, in some measure, uncalled for, as Mr. Mackintosh has introduced his system to our notice in the modest garb of an hypothesis; but when the great truths of philosophy are called in question, I cannot afford to be polite.

However, having freely bestowed censure where it appeared to me that censure was due, I turn with much pleasure to some other points which appear to my mind to claim in an equal degree our praise and admiration. Indeed, it must be allowed that the whole theory has been drawn up with much ingenuity; that there is an air of plausibility, and, in some parts, even probability, about it, which renders it eminently worthy of investigation by the scientific world.

For example, what can appear more plausible than the theory of the two tides when explained upon electrical principles ?* The paradox of the tides has always formed a most formidable objection to the doctrine of universal gravitation, to which even La Place himself could never devise a satisfactory answer. But here, by the electrical theory, we find every appearance accounted for in a manner which is at once clear, simple, and beautiful; we find, from the principles laid down, that there ought to be TWO TIDES at the same time-one on that side which is nearest to the sun and moon, and one upon that which is farthest removed from those bodies which, as we well know, exactly correspond with the actual appearances. Whereas, by the law of universal gravitation, we find that there ought to be one tide only, and upon

For this see Mech. Mag, No. 634. ED. M. M.

that side which is nearest to the sun and moon when those bodies are in conjunction; the second tide, or that on the farthest side, remaining wholly unac counted for. It must, therefore, be admitted, that the electrical explanation is, in every respect, the most satisfactory of the two. But whilst I readily make this admission, I wish to guard against misconception. I apprehend there would be found some difficulty in explaining upon the same principle why a body near the earth's surface gravitates, or is attracted, if you will, towards the centre of the earth.

It appears, farther, that the tails of comets are accounted for and depend upon the same principle as the tides. The nucleus being negative, is attracted towards the sun-whilst the tail, being positive, is repelled at the same time, its immense length being a necessary consequence of the rareness of the gaseous matter of which it is composed. The appearances do certainly very strongly support this assumption; and also that the tail is continually decreasing in length has been fully verified, at least in one instance, by the late appearance of Halley's comet. Lang

But the most startling part of the hypothesis remains to be noticed. It is presumed, that the earth, the moon, and all the planets, are rapidly posting onwards to universal and certain destruction. That the moon is in every succeeding revolution approaching nearer to the earth, and will finally be precipitated upon the surface of the latter, is certainly a proposition the truth of which is of some moment; but upon the rate of her ap-. proach, or the probable time of the final catastrophe, the hypothesis furnishes us with no definite information. I should very much like to see something attempted upon this important point. Could not Iver M'Iver, Mr. Utting, or some of your mathematical correspondents, throw some light upon it? I suppose the redoubtable Mr. John Herapath has withdrawn the light of his countenance from us for ever; we cannot, therefore, expect to be. illuminated as heretofore with the reful. gence of his transcendant genius.

I intended to have made several re.... marks upon this part of the theory, but must defer it till another occasion; as to do it any thing like justice, would require more space than perhaps can be conve

one, direction round the stick that sup¬ ports it; I have often tried to make them, arn the apposite way, but never could succeed. It appears to me that this is an effect of electricity. Indeed I am of opinion, that the whole of the clinging tribe of plants are indebted solely to this agent for the support which they derive from the more solid bodies to which they eling. It appears to me; that the deli cate tendrils of these plants, when in an active state of vegetation and full of sap, are in a positive state, and are therefore attracted and upheld by the dry, bark or other body in their vicinity, which may be in a negative state as compared with. the highly active tendrils.

It has been noticed, that it is danger ous to stand under a tree during a thun der-storm; and also, that there is more danger under an ash than there is under those of any other species. It has also been noticed, that no sort of vegetable, but more particularly turnips, will thrive. under an ash, even when the tree is entirely isolated and standing in the middle of a large open field. The farmers say, that the droppings from the ash-leaves When it rains poison the soil; but I suspect the true cause to be, that the high and spreading branches having a very strong affinity for electrical matter, absorb so large a quantity, that the, turnips are deprived of the portion necessary to their proper vegetation. A friend and neighbour of mine, who has paid much attention to this subject, carries his no tions considerably farther than I have presumed to go. He gives it as his opinion, that when a field is dressed or manured with lime, although the soil may be enriched to a certain extent, that the augmentation and acceleration of growth which is derived from the soil itself is comparatively trifling, but that a larger quantity of the vegetable nutriment is drawn from the atmosphere, which he attributes, in a great measure, to the chemical and electrical affinities which are called into action by the presence of the lime. In support of his opinion, he says: If I were to dress a field with lime, and plant potatoes upon it, I should not expect to have a beasy crop, and for this reason, we know that a heavy crop of potatoes impoverishes the land very much, from which it would appear, that they draw their nourishment principally from the soil;

and as lime is of very little service to this crop, I conclude, that the land is not much enriched by its use. But if I sow barley in this field, I have the chemical action of the lime, aided by the bearded ears of the barley, forming so many thousands of conducting rods, drawing abundant nutriment from the atmosphere, which continually flows over them, charged with particles suited to their nourishment and growth."

With whatever respect these few ob servations may meet from your readers, I think, Mr. Editor, the subject of electrovegetation is one of great importance, and lies at the very root of agricultural science. If such of the readers of the Mechanics' Magazine, as may have the means of observing, would forward their remarks, that those which appeared valuable might be published, we would thus, by each casting his mite of knowledge into the public treasury, very soon be in possession of a practical informa tion, and be thereby enabled to extend our dominion over the physical world in all that relates to the means of subsist ence, which must be admitted by all to be an object of the highest utility. Yours obediently,

Nottingham,. April, 1936.

W. B.

STEAM CONVEYANCE BETWEEN PADDINGTON AND THE CITY FOR HIRE.

Mr. W. Hancock, whose perseverance certainly deserves success, commenced running his steam carriages,, the "Enterprise" and "Erin," on Wednesday morn ing last, at nine o'clock, from the station in the City-road to London Wall; from thence he proceeded to Paddington, and returned to the City. On the first day he performed three of these journeys, on the second, four, and on the third (yesterday), two, before noon, The average time of travelling over the above ground has been 1 hour and 10 minutes, including stoppages to take in passengers, water, and coke, This is just half the time the horse-omnibuses take in going over the same ground. In the 9 journeys performed, the number of passengers carried was 220, averaging about 12 per sons each single trip. Mr. Hancock in tends to run his carriages regularly the same number of journeys daily, for the present, and very shortly to increase the number.

9.6

NOTES AND NOTICES.

Currents in Water.-In the last number of Silllman's Journal, in an article on "currents in water," it is asserted, that if a tub or other vessel is filled with water, and a hole made near the middle of the bottom of it to discharge it, the water will acquire a rotatory motion from west to south, or opposed to the apparent motion of the sun; and if means are used to produce an opposite motion, upon withdrawing those means the former direction will be resumed. This cannot be the effect of chance, but of natural laws constantly operating.-Guernsey Star.

Household Manufacture of Sugar.-A remark able proof of the facility with which beet-root sugar manufactories may be established is presented at this moment at Wallers, in the department du Nord. Four of the villagers, by advancing 50 francs each, have formed a joint capital of 200 francs, and with this they produced between 40 and 50 lbs. of sugar, of rather inferior quality, a-day, They employ curry-combs to rasp the beet-roots, which they put into a napkin-pre-s to extract the jaice, and then boil the syrup in common culinary boilers.-Ibid.

New Ships' Signal Lantern.-A most admirable invention has recently been brought into use, and is likely to meet with general adoption, intended to prevent those accidents which are the cause of so much loss of property, as well as the annual sacrifice of a number of valuable lives. It consists of a ship's lantern, of copper, strongly and efficiently constructed, and possessing the means of being regulated so as to show a light of different colour, according to the tack upon which the vessel bearing it may be sailing, or the position in which she lies. A set of instructions accompanies each lantern, by which the master is informed what light he is to show on each change of tack and position, and thus a mutual understanding is attained amongst navi gators as to the meaning of the signals exhibited. The changes of colours are effected by the following simple contrivance:-The lantern contains an interior case, capable of being turned round, and having windows of glass of several colours. The lamp of the lantern has a strong reflector and powerful" bull's eye," or magnifier, to project the light, opposite which, in the outer case, is an apertare. By turning round the interior case, each coloured glass window is brought in front of the bull's eye, and thus a light of the colour required is projected.-Hull Packet.

Kemp's Submarine Apparatus.-We understand another attempt is about to be made to raise the hull of the Cameleon. by Mr. Kemp, who, having obtained a patent for the invention of his buoying principle, has received permission from Government to make an experiment on this ill-fated vessel, and in the event of its proving successful, the wreck as it may be raised will become the reward of the enterprise. Mr. Kemp's apparatus consists of a number of empty puncheons, each open at one end, and having a bar of iron across, by which, after being sunk, they are attached to a chain, previously passed round the wreck by the divers, who next employ themselves successively applying to each cask the elastic tube through which they are filled by the air-pump, and the water consequently expelled. The puncheons thus charged with air. acquire a perpendicular position, and are so buoyant as to render certain the raising of any weight proportionate to th number of them employed. The operation of filling the puncheons with air will be comparatively easy in this instance, as from the favourable circumstance of the wreck lying in less than thirteen fathoms of water little more than two atmospheres will be required, and scarcely any doubts are entertained of the attempt proving successful.-Dever Telegraph.

Massie and Ranwell's Paddle-Wheels.-A few days ago, the first public trial of this new wheel for steam vessels was made on

the R It was affixed to the Red Rover steamer, belonging to the Herne Bay Company, which conveyed the female emigrants and agricultural families to the ship at Gravesend in which they embarked for Van Dieman's Land. After the emigrants had left the steam-vesel, to the starboard side of which the new wheel was affixed, the larboard side being furnished with the common wheel, the Enigration Committee, visiters, and several naval officers, proceeded to inspect the new paddle-wheel, a model of which was submitted and familiarly explained by Mr. Massie and Mr. Ranwell. The principle seems to consist in the exposure of the entire surface of the float to the water while in the most advantageons position for propelling, which upon approaching the surface becomes divided into a series of angular bars, which suffer the water to pass through the interstices, and thus transfer the action of the steam-power to the next floats in succession, instead of useles-ly wasting it on the water-lift. A consi terable ferment in the water (though the swell was not so heavy) was apparent, which, however, a littl alteration in the construction will considerably diminish, and which the experiment will enable the inventors to accomplish.-Weekly Dispatch.

Coins in the Clouds!-A Brighton physician lately adopted the following singular means of preserv ing some of the coins of the realm. He enclosed several of the last impression in a ball of war, which he placed in a balloon of India-rubber suffi ciently inflated with gas to raise it several thou sand feet above the earth, where, floating in space the memory of our nation and its monarch, may be recorded for hundreds of thousands of years. Within the ball of wax was also placed a lip of parchment with the following letters cut out:"Anglia Martis X., 1336."-Dispatch.

Mr. W. J. Curtis- Received and intended for early insertion.

H. M. M. shall have a place soon-no charge.

Communications received from Mr. DeakinMr. Simons-Mr. Peacock-R.-W. B-Mr. Merritt-Mr. Millichap Americanus Mr. Mackintosh-F. N. O.-K. K.-A Railway Traveller.

The Supplement to Vol. XXIV., containing Ti tle, Contents, Index, &c., and embellished with a Portrait of Mr. Walter Hancock, C. E,, is now published, price 6d. Also the Volume complete ia boards, price 9s. 6d.

Patents taken out with economy and despatch; Specifications, Disclaimers, and Amend ments, prepared or revised; Caveats entered; and generally every Branch of Patent Business promptly transacted. Drawings of Machinery also executed by skilful assistants, on the shortest notice,

LONDON: Published by J. CUNNINGHAM, at the Mechanics' Magazine Office, No. 6, Peterberough-court, between 135 and 136, Fleet-street. Agent for the American Edition. Mr. O. Rick, 12. Red Lion square Sold by G. W. M. REYNOLDS, Proprie or of the French, English, and Americ Library, 55, Rue Neuve, Saint Augustin, Paris.

CUNNINGHAM and SALMON, Printers,
Fleet-street.