An analysis of white silk gave identical products; and in amount differing only fractionally from the above; except in the particular of the resinous colouring matter, which was indeed present, but in a very much smaller proportion. It is probable that the varieties of colour observable in cocoons, the yellow, the orange, the buff, the white, and the greenish hues, depend only upon the greater or less amount of this resin in the fibre. Journal of the Asiatic Society of Bengal, vol. iv. p. 710.

WATER-TANKS.

At the late meeting of the Cornwall Polytechnic Society, a description was given of nine tanks, which had proved eminently useful during the late three dry summers on the Sussex property of Davies Gilbert, Esq., the President of the Society. As these tanks are cheaply and easily constructed, and not liable to decay like wooden vessels. and as rain enough falls on every house in England for the use of its inhabitants, no family would be deficient in good soft water who made a tank to retain it; and such tanks being paved over, take up no room.

The tanks at East Bourn vary in size: one of less than seven feet deep and wide has served two labourers' families for three years; whilst most of the springs in the neighbourhood were dry.

A tank 12 feet by 7 had supplied with water a large family and six horses. This was surrounded by only 4 inch brick-work resting solid against the sides, in consequence of being smaller at the bottom than higher up; and the dome is constructed on the Egyptian plan, by projecting horizontally each row of materials one-third of their length beyond those below, and filling up the back with earth as it proceeded, to balance the weight of this projecting masonry.

At the East Bourn Workhouse for fourteen parishes, a tank has been made, 23 feet deep by 11 wide, of the roaghest materials, being only flint stones, and though they require more mortar than if they had been regularly

shaped, only 90 bushels of lime were allowed, including two coats of plaster, and the workmanship is executed like field walls at 10s. per 100 square feet; the only essential being, that no clay be used (which worms bore through), and that the lime or Parker's cement be good.

A current of air is said to promote the purity of water in tanks, and this is easily effected by the earthenware or other pipe which conveys the rain from the roof, being six or eight inches in diameter, and an opening left for the surplus water to run away; and where the prevailing winds do not blow soot and leaves on the house, the water remains good, even for drinking, without clearing out the rubbish more than once a year; but in some cases filtering by ascension may be found useful, and be effected by the water being delivered by the pipe at the bottom of a cask or other vessel from which it cannot escape till it has risen through the holes in a board covered with pebbles, sand, or pow dered charcoal.

Upwards of twenty labourers' gardens have been watered by the rain which formerly injured the public road, and was therefore turned into a sink well, which sink well was enlarged and surrounded by 9-inch masonry, and the water is drawn up by a cast-iron curb. This water was used in planting potatoes, and occasioned good crops in 1835, when setts not watered failed. And, should the profit-, able mode of stall-feeding now practised at Armagh be happily extended to England, and fatting oxen be kept in pairs not tied up under, shelter, it will be found that preserving in tanks the water which falls on the barns and stalls will amply supply them, whilst it prevents the rain washing away the strength of the manure when straw is spread in the open yard.

Ponds have been made with equal success, dug 4 feet only below the surface, what is excavated being added to the sides, and covered one foot thick like a road with peb. bles and good line mortar. Such ponds are become general on the dry soil of the South Downs for the use of the large flocks of sheep: and had such ponds been made in Romney Marsh, &c., during the late dry years, the sheep would not have died in such numbers as materially raised the price of meat in London.-Bath aud Cheltenham Gazette.

TUNNEL UNDER THE NIAGARA

Sir, I perceive in some former Number of your Magazine, you have related an account of a proposed tunnel under the Ohio river at Cincinnati; your correpondent does not state that the bed of the river there, is a limestone rock, and the

huge building of immense thickness, and nine or eleven stories bigh in the water, stands on the rock, and all the stone to build it was procured from the bed of the river at low water. However, I am not going to relate any thing of the difficulties of that affair; my business is to sug. gest to your readers, and all others whom it may concern, that the greatest, best, and most magnificent tunnel in the world, would be in Canada, under the river Niagara, at the rapids of Fort Erie, opposite Buffalo in the United States; I say the best, and the easiest made, for the Niagara river there is narrowest, and its bottom is a flat, hard rock, which is a natural shield of itself, and below it a softer rock, which is easily cut. Captain B. Hall, in his "Travels" in America, has particularly described the strata a little lower down at the falls.

Now, if Brother Jonathan would agree to meet us half way, the thing, though of so great a magnitude, would be easier performed than any thing of the kind in any other part of the world. The only attention required would be to plug up with clay any fissures in the rock which might occur, and cement them over.

No great

depth is required; the water seems as shallow there as at the falls on the same rock. All Lake Erie is on a complete bed of rock, and so level that an anchor slides along hundreds of yards at a time without holding. The whole is particularly suitable for such a purpose; and whenever done (if ever done), your pub lication will have the honour of first pointing out to the public its true nature. Your constant well-wisher, A TRAVELLER.

Wilden, Sept. 30, 1836.

NEW PLAN FOR TAKING THE VOTES IN THE HOUSE OF COMMONS.

Sir, In the House of Commons a considerable loss of time occurs at every division. To obviate this, I would propose that every Member should have a small knob at each hand, placed before him by his seat, with wires attached, to be continued (under the floor) to some convenient part of the House, there to be connected to small slides, in wood or metal, and coloured black and white, with the name of the Member engraved on each. By pressing either of the knobs when a division took place, the Member would raise either a black or white slide

at the same time; and the motion might be so arranged as that a small ball should fall at the same time into two general receiving drawers-the black to denote the noes, and the white the ayes. The balls could be counted over in a few minutes, and the number given out to the House; and while the next business was going forward, the names of the different Members could be copied off the elevated slides by two clerks-one for the whites, the other for the blacks. After this, the slips could be pressed down by them to their places, leaving them ready for the next division, and so on. By this plan the Members would be saved all the trouble of going out into the lobby. Each Member should have a key to his knobs, so that when not in his place, his next neighbour might not be able to press it for him.

ON

MR. MACKINTOSH'S THIRD LECTURE
THE ELECTRICAL THEORY OF THE UNI-
VERSE.

Mr. Mackintosh commenced by observing, that expansion and contraction of matter, to which he had in his first lecture traced all motion, were two real forces, or effects resulting from two real forces, and their conjoint action was fully competent to explain all natural phenomena. One of these forces, attraction, or the contraction of matter, had been recognised in all ages under the names of weight, gravity, &c. because its effects were visible. All men could see large masses of condensed or contracted matter falling to the earth, or approaching a centre; but the expansive force worked in an invisible way, not under the immediate cognisance of the senses, and therefore, although necessarily equal in power and extent with the contractive force, had not been so readily recognised. Its knowledge was approached by reason. Our senses were sufficient to inform us of the approach of a rain-drop towards the earth under the contractive force, but it was by inductive reasoning that we came to the knowledge that that rain-drop had receded from the earth under the expansive force-that. the expanded matter had been condensed and contracted into a globular form like the earth in the upper or remote regions of the atmosphere; and that in this condensed form, being under the influence of the contractive force, it must of necessity be attracted towards the centre, from which it had receded, in an expanded form.

He wished here to correct a mistake into which he had fallen with respect to the original formation of comets. He still mainthey were derived from the sun,

a mass; he considered that the

matter of which they were formed issued in the most expanded form that from be conceived, to be again contracted into globular masses in the remote regions of the system, in a manner analogous to the formation of a rain-drop, and as the condensation continued, so must they of necessity continue to approach the centre.

The expansion and contraction of matter, he continued, were the two pillars upon which the "electrical theory of the universe" was based; but it might be objected, that under the action of these two forces, matter ought to proceed from and to the centre in right lines, whereas, we know that the planets and satellites move in circular orbits. This, he said, was a fair and proper objection, and required an answer. In the first place, it must be borne in mind, that there are two forces. If their lines of action were diametrically opposed to each other, it was evident that the motion of bodies under each force would be retarded, so far, at least, as they interfered with each other; but if the two forces were not diametrically opposed, but inclined at a certain angle to each other, the opposing forces must necessarily produce a rotary or circular motion, causing the condensed matter or solid bodies to move in circular paths, and the expanded or fluid matter to move in vortices somewhat like, those of the Cartesians. Now the orbi's and axes of the sun and all the planets, he remarked, were thus inclined to the ecliptic and to each other; and in this was seen the wisdom of the Deity, who so arranged this great machine, that all the parts were fitted together so as to aid in working out his great design. He illustrated the action of two forces thus inclined to each other by a windmill; it was by the sails being inclined at a certain angle to the wind that the rotary or circular motion of the windmill was produced, which rotary motion of the windmill again imparts a circular motion to the fluid in which it revolves. He introduced some experiments and observations, tending to show that all fluid matter proceeded with a twisting or spiral motion, the ultimate cause of which he considered might be traced to the various inclinations of . the orbits and axes of the sun and planets.

He further proceeded to show, that the hardest bodies in nature, such as quartz, diamond, &c. might, by galvanic agency, be converted into vapour so subtle as to be wholly invisible; whilst by the same galvanic agency, under a different modification of circumstances, hard and solid crystals may be formed, as is well known from the experiments of Mr. Crosse, of Broomfield :-thus

the expansion and contraction of matter in the most eminent sense may be traced to galvanic agency,-galvanic and electrical agency being identical, or different modifications of the same power or powers. This theory was properly and appropriately entitled the "electrical theory of the universe." It appeared to him, that galvanic or electrical agency might be considered as the highest, most active, or ultimate source of motion in the physical world, of which we have any knowledge next to the Deity himself, whose power is not a physical but a moral power, the power of mind over matter, and exercised in a manner which passes our limited comprehension, and is therefore not a fit object of our reasoning faculties. All that we can or ought to attempt, is to discover the physical agents employed by Him in carrying forward the various processes of nature, that thereby we may be enabled to extend the power and dominion of man over the material creation, and thus minister to the knowledge and happiness of the whole human race.

JONES'S PATENT WROUGHT-IRON WHEELS

FOR LOCOMOTIVE-ENGINES AND RAILWAY CARRIAGES.

Sir, It is an unfortunate, though well observed fact, that out of every ten American patents, nine are for some impracticable or useless process, or for some slight modification of previous English inventions.

Any person acquainted with the patent wrought-iron wheel of Messrs. Theodore Jones and Co., will at once perceive it to have been the prototype of the cast-iron wheel patented by Mr. Arundius Tiers, of Pennsylvania: a description of which is copied into your 683rd Number from the Franklin Journal of July last. It is really curious to observe the various shapes into which an useful invention is tortured by would-be inventors or improvers; such has been the fate of Mr. Jones's wheel, which has been tried in almost every possible shape, in this and other countries, by ringing the changes upon wrought and cast-iron, &c., but carefully avoiding the particular mode of construction patented by its ingenious inventor, which is alone calculated to realise all the advantages pertaining to this particular form of wheel. There are several reasons why the mode of construction adopted by Mr. Arundius Tiers should not succeed in practice, and one of them has been very ably pointed out by a previous improver of locomotiveengine wheels, whose patent was reported in the Franklin Journal for November, 1835, inserted at page 325 of your 24th

volume.

"It is well known," says Mr. Baldwin (the patentee), to engineers upon railroads, that, in running upon iron tracks, the wrought tire forming the tread of the wheel, when the wheel is altogether of iron, is gradually stretched and becomes loose."

This is true enough, and the evil consequences of this effect being wholly unprovided for in the wheel of Mr. Tiers, should the spokes hold out long enough, he will most assuredly find the iron tire FE, page 398, will soon become loose, and prove exceedingly troublesome. From the very unfavourable position in which the metal is placed, however, there is great probability that other parts of the wheel will fail before this effect takes place. Valuable as is the principle of the iron suspension wheels, no portion

of their advantages will be obtained by the method of construction attempted by Mr. Tiers.

Two of the greatest difficulties consequent upon the introduction of locomotives, were in obtaining boilers and wheels suited to this particular purpose. Considerable improvement, the result of long and expensive experience, has been effected in the manufacture of boilers; nevertheless, a good and durable boiler is to this day a desideratum in this particular application of steam power.

Several different forms of wheels, and various modes of construction, have been tried; but none has yet been found in every way adapted to this kind of work, with the exception of the patent wroughtiron wheels of Messrs. Jones and Co., which, from some long and carefully conducted experiments on the Manchester and Liverpool Railway, appear to meet every exigency, and to obviate all the difficulties hitherto experienced in this branch of locomotive economy.

The great superiority of the iron wheels for transporting heavy weights on common roads, has long since been satisfactorily established; suffice it to say, that their superiority is fully maintained upon railroads, a species of work for which they are especially adapted.

Fig. 1 is a front view, and fig. 2 a section of one of Messrs. Theodore Jones and Co.'s patent wheels for locomotiveengines. The rim a a is of the best malleable iron, rolled into the form shown by the section. The spokes bb are conical at the head, to give them a firm bearing from the outer edge of the rim, and are tapped at the other end to receive the nuts cc, by which they are drawn up tight, and the nave d suspended in the centre of the wheel. Split keys e e pass through a slit in the spokes, and through a hole in the nuts, to prevent them from turning and thereby loosening the spokes: f is the axle, to which the wheel is keyed up.

Some of the more striking advantages of this wheel, as applied to railwayengines, are: first, they are lighter than any other wheel of equal strength, or they are stronger than any other wheel of equal weight, in consequence of the metal being employed in the most favourable manner, i. e. in a state of tension, in which, it is almost needless to say, it is capable of enduring the greatest strain