2

The prefixed sketch was taken from a drawing exhibited this season at the Royal Academy, and recommended to general attention by the scientific name of Mac Culloch. It displays an admirable adaptation of a peculiar style (the Egyptian) to a purpose for which it is, perhaps, best of all suited. Were we, indeed, of a poetical temperament, it would be no difficult task to fancy to ourselves that a colony of Cyclops had settled in Glamorganshire, and that the edifice here presented to our view was their veritable workshop. Much, we have often thought, would be gained to architecture, were the styles so classified, as to proceed from the "grave to the gay,” according to the use for which each building is intended. We might, in that case, have some hopes of seeing those huge packing boxes of brick and mortar-the warehouses of London-converted into something of architectural character, so as both to please the eye and inform the mind. There is only one species of factory building in which this has in any way been attempted (with the exception of the one before us), and the attempt has certainly been in no way creditable to those concerned: -we refer to the floor cloth factories. In these, the intention to be striking and characteristic is apparent enough; yet we are free to confess that Carpenter's Gothic bas in no instance reached a higher excellence in its peculiar style.

an

The buildings represented in the prefixed engraving form only the eighth part of one side of a square, which is in the course of erection. The effect, when this square is completed, cannot be otherwise than magnificent. In the ornamental détail, the architect appears to have

availed himself of the ruins of a temple at Dendyra, in Upper Egypt. C. D.

OBSERVATIONS ON WINN'S IMPROVEMENTS IN CHURCH AND TURRET CLOCKS.

BY MR. JAMES HARRISON.

Sir,-On lately reading an article in No. 45 of your estimable Miscellany, entitled "Wiun's Improvements in Church and Turret Clocks," I was much struck with some assertions of the author. And though it may seem strange that an article published so long ago should not have been noticed sooner, yet such is the fact. But as it is plain that the object of your work is to place those useful matters which are admitted into its columns in their true light, I flatter myself you will deem it due to the cause of truth to insert the following remarks, in reply to that article; and that being merely late-timed will not be an obstacle to their admission.

Mr. W. very justly observes, that "perhaps no piece of mechanism at present manufactured possesses imperfections in a greater degree than the clocks in common use." However, the imperfection he complains of is not in the clock itself, but in the connexion between the clock and the hammer. He says, "It has been ascertained by an experiment made on a clock at the Royal Military College, which is one of modern construction, and consequently a fair criterion to judge by, that the spring called the 'counter-spring,' which is placed under the shank of the hammer, to prevent it from chattering on the bell, opposes a resistance equal to four-fifths of the force generated." I cannot but agree with Mr. W. respecting the very disadvantageous manner which the hammers are usually connected with church clocks; and indeed, it would scarcely be conceived that the judgment of the generality of professional men should be so defective in this particular, did not facts show it to be actually the case: though certainly the spring placed

in

under the hammer shank is not to prevent its chattering on the bell, but to prevent it from resting_on the bell after it has struck. But that this spring opposes a resistance equal to four fifths of the force generated, is what I cannot assent to; in short, I conceive its resistance to the blow to be so small as to be quite imperceptible. It is true it opposes a small resistance to the fall of the hammer; but, on the other hand, it yields the same efforts in raising it up; so that the hammer is lifted just so much higher than it otherwise would be by the action of the machinery alone; hence the additional height to which it is raised countervails against the resistance opposed to its fall. Indeed, the na ture of springs is obvious: their efforts and resistance are necessarily the same; and it seems odd that Mr. W. did not perceive so plain a

matter.

I agree with Mr. W. that "the pistons of steam-engines oppose a much greater resistance by friction than any object necessary to be called into action in clock-work;" and also that the sounds of church bells, when struck by the clock hammers, are generally so feeble as to be useful only to a very confined neighbourhood; and in this particular it is proper to go a step farther than Mr. W. has ventured.

"That every person may judge for himself of the great deficiency of power in church clocks," Mr. W. invites a comparison between the sound produced when a bell is rung with a rope, and the sound produced by the clock hammer. But this being a matter in which both bells and clocks are comprised, though only a very brief observation is required on the occasion, yet some premises are necessary to show that what I have to advance hereon is not merely speculative.

I have fixed and adjusted many clock and chime hammers, and I have made some church clocks, and perhaps I may claim some title to clock-making, by descent, the mechanical knowledge of my ancestors, and their abilities in clock

work, being not quite unknown to the public. My grandfather, James Harrison, was the workman who made the two regulators for the time-keeper for ascertaining the longitude at sea; and the two first machines or time-keepers were like. wise almost entirely made by him,

the first being made at Barrow, and the second in London. I have a son also in the profession of mak. ing church and turret clocks, who has principally received his rudiments from me; and we have introduced some peculiarities into our clocks, which we esteem to be considerable improvements: one of which (though not the greatest) I will take the liberty to mention. To reduce the friction between the teeth of the wheels and pinions most effectually, we have adopted the superior principle of rollers instead of teeth or leaves in the pinions throughout the watch part, and in the first pinion of the striking part, this pinion having the hammer to lift; also the curved part of the teeth are portions of epicycloids. Now, the epicycloid is known to be a true principle, which has the property of imparting an equable motion to the driven wheel, whatever the number of teeth in the wheel may be,even though they consist of the fewest teeth that can possibly act; nevertheless, this principle is little regarded by the generality of practitioners, whose methods of forming teeth consequently deviate more or less. But since the less the number of teeth in any wheel is, the greater will be the quantity of curvature contained in the rounded parts, and of course the farther any erroneous method is liable to deviate; it follows that the application of this curve is particularly necessary in clock-work, because of the low numbers of the pinions. And although the curve, to act against rollers which are placed in the cir cumference, is quite different to that which acts against the straight part of the teeth, which tends direct to the centre; yet the epicycloidal principle is applied with equal facility to the one as to the other, and

may be adjusted to the size of the rollers with equal truth as the others are to the radii.

In chimes which play on church bells there is, perhaps, a still greater necessity to employ true principles than in clocks; the great number of hammers, and the far greater number and repetition of the blows on the bells, necessarily requiring a far greater impulse from the weight. Hence, to produce the required effect with the least weight, may also worthily exercise the judgment of the most skilful artist. As it would be too prolix to particularize my improved chimes, it may suffice to observe that they must play the tunes in the most exact time, because their principle is such that they necessarily do so, and cannot do otherwise; while, by striking the most effectual blows on the bells, they at once produce not only louder sounds, but more musical notes, in consequence of that due fulness of vibration in all the parts of the bells, which constitute their best tones; and at the same time an equal loudness of the different notes is procured. Particular care is taken that the hammers impinge fair on the bells, or in the direction to have the greatest effect, and on the proper part, too, for rendering them as "sweetly sonorous" as possible.

With respect to my knowledge of bells, it is proper to state that casting and hanging church bells is my profession; and to improve those branches, so as not only to produce the most melodious tones, but also to ascertain those proportions of the parts of bells which will afford the most flowing and deepest sounds that the bell shape can possibly yield with a given weight of metal, with mathematical precision, bas been the principal work of my life; and in which I have, after great pains and expense, succeeded to such a degree of perfection, as to render it doubtful whether it be susceptible of further improvement. Some of the sweetest sounding bells I have cast, equalling in melody the finest toned instruments, have been of this improved model; and which,

with little more than half the weight of metal, are heard farther than bells in the same key, of the common make. Of course I cannot but know what relates to bells as well as clocks; and both reason and experience concur to assure me that bells are capable of affording a greater sound, which will be propagated to a greater distance, by blows from the clock hammers, than can possibly be produced by their clappers in ringing; and for which two very plain reasons might be adduced: but it is not my intention at present to point them out.

That Mr. W. might make a very great improvement in the striking of the clock he mentions, I am not inclined to doubt; but that it was effected by his "improved hammer" is what I cannot admit. It is probable the whole of the apparatus connecting the hammer with the clock was under the most disadvantageous circumstances, as is commonly the case, more or less, with church clocks. Indeed, I have known clock-makers, famed for the excellent machinery they produced, who have, nevertheless, fixed the connecting apparatus between the clock and the hammer in such an extremely disadvantageous manner, as sometimes to require three times the weight that might have sufficed for the effect produced; and some clocks, before I altered them, bave laboured under still more considerable disadvantages. In the particular instance alluded to, Mr. W. seems to have removed a great disadvantage, apparently without knowing in what it consisted, or in what particular part of the connexion it principally lay.

His "improved hammer," as he calls it, is certainly an ingenious device; but I consider it as only an ingenious device, in which I do not conceive there is any advantage, provided the counter-spring is properly fixed; and I do confidently assert the possibility of producing sound from a bell, by a clock hammer with a counter-spring, that will be heard to an equal distance as if struck with his improved hammer,