be quite as good, or possibly all the better for the beautiful virtues with which it is blended from the aforesaid temples and other sources (tastes will differ, you know, Mr. Editor), this very gentleman tells us in one page that he has been drinking the New River water for forty years, and "is perfectly sound under the treatment;" and in the next confesses that all the water he drinks "unboiled" is taken from wells, leaving it to be inferred that the soundness of his constitution arises from drinking all other water after it is purified by fire. A very nice admission from a champion of the monopolists.

The following paragraph is really exquisite in its way. I am sure your readers will not grudge to read over again so much fine writing, especially as it is incumbered with such a small tax upon their brains:

"Now, thank goodness, Mr. Editor, I am still cockney enough to bless the name of Sir Hugh Middleton, and to think him one of the greatest benefactors of the human race, in a joint stock company way, that has ever appeared. But since it is plain that we are not much longer to be suffered to use the undisintegrated water of the silver Thames and the chalk-fed Lea, prepared in Nature's most perfect laboratory, I thank my stars that, by the blessing of Providence, guiding the hand and wit of man as its instrument, there are ample supplies of pumpwater in all parts of London, (inaccessible to the approach of filterers,) from which I myself, and my neighbours too, (judging by the number of pitchers that are seen carrying about just before the hour of dinner,) are supplied with all the unboiled water which we drink."

Is not this logic delightful-almost as extraordinary as Mr. Baddeley's important discovery of cleansing cisterns? To begin with praising Sir Hugh Middleton for the New River water, and to end with declaring that "all the unboiled water" the worthy gentleman and his neighbours drink is taken by pitchers from wells, and not one drop "unboiled" from the aforesaid Sir Hugh Middleton's New River Company.

This gentleman is however wise in his generation; he only recommends others to drink the unfiltered water of the various companies; he does not drink it unboiled himself. To others he thinks it really may be all the better for having lime in it, nay, rendered almost perfect from the admixture of gas manufactories, dead leaves, and rotten carcases, and quite superlative, no doubt, if well amalgamated with the contents of a hundred common sewers-only he would rather not drink it himself!

These things, however, are all matters of taste. A great authority, almost equal to "the nursery maid," who taught the erudite gentleman "philosophy and fudge," y'cleped, I believe, Joseph Miller, records an instance of a brewing of ale into which a black man fell, was drowned, and was boiled, making the barley bree" all the richer in the estimation of the customers for having so much precious material in addition to the malt and hops. So indeed, if it be as this gentleman says, beneficial to drink "lime" in water, in order to furnish the proper pabulum for our bones, so it may be equally beneficial to take over again in the unfiltered water of the metropolitan monopolists' decomposed matters with which our stomachs have been previously acquainted.

But a truce to such nonsense and such perversity of taste. Those slight skirmishes in favour of dirty and unhealthy water, or rather of the avarice that prevents such water being cleansed and purified, can last but for a short period. I observe by the London Gazette and the Times, that Mr. Stuckey's plan of filtration is coming before Parliament, and Parliament is the proper arena in which the battle can be fought. God defend the right!

I have the honour to be, Sir,
Your obedient servant,

IMPROVED VENTILATION OF MINES.

(From the Mining Journal.)

B.

Sir,-In the Mechanics' Magazine, of the 1st October, is described the principle of "certain improvements in the construction and application of rotary engines," for which I have taken out letters patent; to one branch of those improvements, may I beg to call the attention of those interested in mining affairs, through the medium of your valuable Journal-viz., to an improved ventilation of mines. I have recently had constructed and applied in a colliery, belonging to Earl Fitzwilliam, a ventilator, on the principle described in the above journal. It is a wheel, four feet in diameter, six inches deep, and having ten vanes or arms, with the outer extremity at an angle of forty-five degrees with the plane of motion; upon the periphery of the wheel are a number of small buckets to receive the jet of water, which is the power employed to give motion to it. The wheel is fixed in the circular opening of a vertical wooden frame, placed near the bottom of the air-shaft; the stream of water, which moves the wheel, falls down the shaft, from a cistern fixed in the side, twenty-six yards from the bottom. The cistern will contain fifty-four gallons, and,

at present, the supply fills it in four minutes twenty seconds, so that the available power to turn the wheel is the weight and momentum of about twelve and a half gallons of water per minute, with a head of seventyeight feet. The water from the cistern is conveyed to the wheel through a lead pipe, one and a half inches in diameter, and issues thereon through a conical jet, three-eighths of an inch in diameter, which is rather too large for the supply of water at present falling into the cistern. So long as water remains in the cistern, the issuing jet is sufficient to turn the ventilator 136 revolutions per minute, which is reduced to 116 per minute when partially working upon air. In order to provide for a larger supply of water falling upon the wheel (as it is thought, after so long a dry time, that the present supply is nearly a minimum), the discharge pipe a, through the bottom of the cistern, reaches nearly to the top, and a moveable cap b, fits over it, which is balanced on a lever c, and can be regulated to any height by a wire d, extending to the bottom of the shaft; it, therefore, acts as a syphon, and gives the stream an intermitting character, more or less frequent, at pleasure, as, when the water in the cistern is below the bottom of the cap, the air getting underneath, stops any further outlet until the cistern is again filled, when it reissues with full force, as before.

a

With regard to the quantity of air which passes through the ventilator, according to the principle described in the Mechanics' Magazine, and which I have every reason to believe is perfectly correct-a cylinder of air, having a base of four feet diameter, and height the circumference of the wheel (4 × 3·14), will pass through at every revolution. This cylinder is equal to 157.8 cubic feet, so that, with a stream constantly issuing from a three-eighth jet, with a head of seventy-eight feet, upwards of 21,000 cubic feet of air would be withdrawn from the mine every minute; or, in this case, with the present supply of water, upwards of 18,000 cubic feet; or (to state the case differently), in the first instance, the air passes through the ventilator at the rate of 28 feet, and in

the last of 24 feet per second. That the air passes through in lines perpendicular to the base, and at uniform velocity at any point of the wheel, is clearly shown, when holding a piece of lighted tarred rope within the influence of the wheel, by the appearance of the smoke and flame; or, if the rope be allowed to touch the wheel, by the direction of the sparks, which are thrown off with great velocity, in lines perpendicular to the wheel, for a considerable distance.

It

The advantages of this method of ventilating over the "furnace plan" (especially, as in this instance, where the power costs nothing), will be at once obvious to all acquainted with mining affairs, for, when once set in motion, its action may be said to be perpetual, and will need no further attention than occasionally a little oil to the axle. removes all danger to which a furnace is liable from contact with the carburetted hydrogen; and, what is of more importance, as being, perhaps, the greatest source of accidents, it removes the danger arising from the carelessness or neglect of those appointed to attend the furnaces, and its cheapness and simplicity can scarcely be excelled.

Fig. 1.

Fig. 2.

-M

N

M

same in principle as Parker's Patent Fountain Lamp, but that the action of the latter is exceedingly imperfect. This arises not from any error in the principle, but from its being imperfectly carried out, by a faulty construction of the lamp, which prevents the end in view being obtained. Having one of these (Parker's) lamps, which I could never get to succeed, I had it altered with the view of rectifying the faults alluded to, and the result fully answered my expectation; for the action of the lamp has

ever since been as steady and uniform as that of the common fountain lamp. Should readers be in possession of any of your one of these lamps, and, after fruitless efforts, have laid it aside as useless, it may be satisfactory to them to know, that with very little trouble and expense, their lamp may be rendered a very serviceable instrument for giving light, the alterations required being nothing but what any common tin smith is competent to undertake.

The form of the lamp in my possession

is that of a hollow pillar, containing a cylindrical tin case, which constitutes the lamp. Fig. 1 is a section of the tin case or lamp in its original state; fig. 2, of the same in its altered state. An inspection will show in what respects they differ, and, assisted with a short explanation, what alteration is required to render the lamp manageable and certain in its action.

The upper compartment, corresponding with the reservoir of the common fountain lamp, is to have an opening (1) at top for filling it with oil, which is to be fitted with an air-tight screw cap; the only communication it has with the external air, is by an air hole (shown by a small circle) at bottom, communicating with the centre tube, which passes down through the middle of the instrument; this communication is closed, while filling in the oil, by a valve attached to the end of a wire passing through a stuffing-box and fixed to the rack, which raises the wick. The tube (2) communicating with the middle compartment, has also an airtight screw cap, and is so made in the patent lamps. A case, 3, encloses the lower part of the tube going up to the burner, and a short tube communicating with the lower compartment, and rising about 1 inch higher: the only communication between this case and the middle compartment is by an air hole in its side (shown by a small circle) midway between the bottom and top of the two tubes just mentioned. The centre tube terminates near the bottom of an open box, or case (4), which is soldered to it, and has a semicircular notch or lip cut in its upper edge to cause the oil to drop over in a more steady and gradual manner. This case should be made of such capacity as to contain, without flowing over at the lip, as much oil as would fill the centre tube up to or above the air hole of the upper compartment; and there should be left sufficient space at the bottom of the lower compartment to contain the oil dropping over at the lip, as the action of the lamp becomes impaired when the oil rises above the level of the lip. Another point to be attended to, is to make M M, the distance from the air hole of the upper compartment to the lip of the case (4,) equal to N N, the distance from the air hole of case 3, to the top of the wick tube, or burner, or more usefully, to within ths

VOL. XXXVII.

of an inch of the top, in order to obviate the risk of the oil flowing over by any moving of the lamp.

To prepare the lamp for use.-The cap 2 being taken off, pour in at the centre tube as much oil as will fill the case 4; then fill the middle compartment at 2, and screw on the cap: then, having filled the upper compartment and screwed on the cap 1, open the valve by turning the rack, and oil will descend into the centre tube until it rises to the level of the air hole; at the same time, the compression of the included air will be raising a corresponding column of oil to the burner.

To restore the lamp after it has been used-Invert the case, when the oil in the lower compartment will flow into, and fill the middle one, the surplus passing down the burner tube and flowing out; then return it to its right position, and removing the cap 2, pour in oil at the centre tube, until bubbles of air begin to come up through the oil in the middle compartment, and then screw on the cap again next supply the upper compartment with oil as before.. I am, Sir, &c.

December, 1842.

N. N. L.

ON INSTRUMENTS OF MUSIC, PLAYED BY THE FINGER AND BY MECHANICAL

FRICTION.

Sir,-In a former communication on the subject of musical instruments, whose sounds are produced on the principle of the free reed, I adverted to some others which have the great advantage of their sounds being varied in power and quality by the pressure of the finger of the performer; and as this affords a capability of expression but little inferior to that possessed by the violinist, combined with the advantage of the parts being executed by one performer, I trust an examination of the construction of them, and the advantages possessed by the different methods which have been employed to effect the above purpose, may be at least bearable to such of your readers as delight in the "concord of sweet sounds."

It may be remarked, that, in nearly all the musical instruments which have been designed to have their sounds swelled by the pressure of the finger of the performer, the vibrations of the elastic body,

on which the pitch of their sounds depends, has been either excited or continued by the friction of some moving substance, acting in a similar manner to the bow of the violin; and indeed the great desideratum appears to be to contrive a substitute for a bow, which shall be capable of eliciting tones comparable to those produced by that simple contrivance in the hand of a Paganini. From the perfect swell obtained by performers on wind instruments by more forcible blowing, it would naturally be supposed that a perfect swell could be obtained in the organ by having a command over the pressure of air in the wind-chest; but, unfortunately, this puts the instrument out of tune, and we are compelled to bear with that very imperfect substitute, a swell pedal, which merely opens a box, but cannot affect the relative power of any one sound produced by the pipes within it. In the eolophon, and other instruments constructed on the free reed or valve principle, a very perfeet swell may be obtained by increasing the pressure of the wind, which does not materially alter the pitch; and by having an extra bellows, and two or more rows of keys, I am convinced very expressive effects may be attained. The earliest instrument of continued sound with which I am acquainted, whose sounds depend on friction, is the once common hurdygurdy, or vielle; and, however barbarous its sounds may be deemed, they are an expressive type of a rather large class of bad mechanical fiddles, which have been tried and found wanting during the last half century. In this instrument a wooden (!!) wheel or cylinder is made to rub against the strings; and, between the dead harshness of the tone produced by the "wooden" wheel, and the chattering of the strings, produced by imperfect stopping at what should be their aliquot parts, the noise is almost enough to produce a mortification of our auditory nerves. A monstrous hurdy-gurdy-it had a fairer name given to it, but it was one-was constructed, about ten or twelve

years since, for the Italian Opera, with the modest intention of superseding the double basses, &c.; but from the difficulty of stopping, which was attempted by an action similar to that of the harp, and perhaps its defects of tone, it was laid aside, to the great relief of Messrs. Linley, Dragonetti, and Co., who no

doubt had a horror of the monster's "excessive competition," equalling that of Robert Owen himself.

The best mechanical fiddle ever constructed is that powerful and full-toned instrument, the claviol, or keyed violin, of my respected friend, John Isaac Haw. kins, Esq., the excellence of whose tone is probably due to the construction of the wheels, or substitutes for bows, and a more scientific adjustment of the velocity of their motions to the rates of the vibrations of the strings; for it is of great practical importance, for the purpose of ensuring an equal quality of tone throughout the compass of such instru ments, that the motions of the bows, or whatever is substituted for bows, should be well proportioned to the pitch of the sounds. In a compass of six octaves, perhaps, the motion of the high treble bow should be five or six times as rapid as that for the lower bass sounds. In the claviol the substitutes for bows are hoops perforated by a great number of holes, through which horse hair is passed, so that the interior surface of each hoop becomes a polygon, whose angles are very numerous.

It was a favourite theory with the mathematicians, that a circle is only that impossible bull "an infinite number" of straight lines, whose angles of intersec tion are infinitely small. Now, for every practical purpose, the angles formed by the crossing within the hoop are infinitely small; for, from their relative position and great number, combined with the elasticity of the hair, the ear is unable to detect any inequality of tone. This excellent contrivance, worthy its talented author, was pirated by the French for an instrument termed the orchestrina, and, like the ever-pointed pencil of the same individual, is less known to the public as the production of its inventor, than as associated with other names. The claviol has many other advantages, in particular that of standing remarkably well in tune, which is effected by protecting the gut strings from atmospheric humidity by a coating of varnish, and preserving an almost perfectly uniform force of tension, by attaching one end of each string to a very long helical spring, made of hardened and tempered steel wire. By these arrangements the pitch is prevented from undergoing any considerable variation with the extreme vari