ations of atmospheric temperature, and the intonation is preserved almost as perfectly as if the sounds were produced by as many tuning forks.

The mention of tuning forks has reminded me that a musical instrument has been constructed, which consists of a series of such forks made to vibrate by a rosined silk band brought in contact with the prongs by means of a lever, at one end of which is a small pulley, the other being connected with the finger key. I think Mr. Goldsworthy Gurney, of steam locomotive notoriety, constructed an instrument of this kind, as well as his piano, in which heavy steel springs are substituted for strings, neither of which are much more novel than the arrangements of his steam carriage, which resembles Trevethick's, for I have seen a piano-forte of this kind thirty years old. Both instruments labour under the great defect of requiring much power to put the heavy springs into a state of vibration, which causes the bowing in one, and the blow of the other to be too much heard, a defect which does not exist when the vibrating parts are not heavier than the steel or gut strings of a piano or violin.

Nearly allied to the instrument consisting of tuning-forks is the terpodian, and what is nearly the same the cedephon; but instead of the vibrating springs being in the form of forks, they are cylindrical rods of metal, from which depend thin pieces of brass, on the fronts of which are affixed pieces of felt. The action brings the thin piece of brass, or rather its covering of felt, against a revolving cylinder of metal, or more properly a number of cylinders on one axis, whose surfaces are coated with rosin. The bowing action of the cylinders is communicated by the depending pieces of brass to rods above, causing them to vibrate. The tones thus produced are most delightful in the middle part of the compass, and the swell produced by the pressure of the finger, is perhaps superior to that of any other keyed instrument; but it is difficult to keep in order, and the quality of tone varies much at the extremities of the compass; but this I attribute to a strange error of the maker, who has put the largest cylinder to act on the bass rods, and the smallest to the treble; and all the cylinders being on the axis, the rates of motion of their surfaces are just contrary to what they should be: an evil not con

fined to the dephon, for it exists to a greater degree in that delightful instrument, the harmonicon of Dr. Franklin, in which the glass bells are all fixed on one spindle or axis; and, consequently, the larger ones, which produce the bass sounds, perform the same number of revolutions per minute as the small bells which utter the highest treble, though their peripheries being so much larger, the motion of the surfaces is much quicker. This evil might be avoided by putting each octave of bells on to a separate axis, and if the axes were made tubular, and one allowed to revolve within the other, any required speed might be communicated to each, and the quality of the tone be rendered equal throughout the compass. The harmonicon is subject to the very disagreeable accident of the glass bells breaking in use, by which the fingers of the performer are liable to be severely cut, if applied directly to the glass bells. Those made to play with keys are not so dangerous, but the tone is not so good. Perhaps some of your musical readers can inform me if a harmonicon has yet been constructed with metal bells; they would possess the advantage of not being liable to fracture, and the compass might be carried lower in the bass with more facility; they would also be very easy to tune, which glasses certainly are not, as any one who has made the attempt can testify. The tone and power of expression on this instrument are so delightful that it deserves some labour should be bestowed on the attempt to diminish its defects.

When describing the claviol I ought to have mentioned what should perhaps be termed a humble imitation of that instrument, which was exhibited to the musical public under the title of euphonon. In this instrument the strings are of steel wire, excepting the bass, and they are put into vibration by an endless band, acting as a bow, one band to each string. It is less expensive in construction than the claviol, but its tone is far inferior in power and quality, and from the great number of bows or bands is more difficult to keep in order; besides, it has no contrivance for insuring a nearly equal straining force on its strings, and consequently does not stand in tune better than an ordinary piano, which it much resembles in its construction, excepting the action. Instruments of this kind, I

believe, are not very modern. I saw one ten years ago, perhaps thirty or forty years old, which was of German manufacture, but they underwent some improvements by Mr. Pinnock, and also I believe by Mr. Hawkins. In the old one, before mentioned, the bows or endless bands all moved with the same velocity, but I believe this great error was corrected in some of the more modern instruments. The same contrivance of bands or bows has been applied in America to continue the sounds of the pianoforte. See article Piano, Herbert's Cyclopedia.

The late Mr. Walker, whose Lectures on Astronomy are amongst the memorabilia of our immediate progenitors for many years, used to perform "the music of the spheres" on an instrument he termed the celestina, and much speculation existed as to how its delicate tone was produced; but as all human secrets are in time discovered, it was found to be nothing but that much underrated instrument the harpsichord; and as the action is of easy construction, and the effects of the instrument very pleasing, I may, Mr. Editor, should you think it would be acceptable, at some future period describe it more fully for the benefit of such of your readers who, being both mechanical and musical, may desire to construct it for themselves; but the length of this communication already warns me that I must say no more at present than that it consists of an endless band of silk, rosined, which is made to rub against the strings by being brought, while in motion, between the two strings, which are turned in unison by small pullies which are affixed to the ends of levers connected with the finger-key. It is obvious that in the celestina the friction of the endless band may be used either originally to excite the vibration of the strings, or to continue their vibrations after being struck by the plectra, and of course the sound is very perfectly swelled by increasing the pressure of the finger on the key and moving the pedal quicker, having the general defect of raising the pitch thereby. This evil is very perceptible in the swell of all instruments with metal strings which are sounded by friction. The pitch of a gut string does not rise so much, but still it is sensible when the two points to which the strings are affixed are immovable. In the claviol one of

these points is not absolutely fixed, it being the end of a very long helical spring, which might be stretched perhaps the twentieth part of an inch without greatly increasing the straining force. This, I believe, is the cause of the pitch of that instrument not rising when the sound is swelled to any very appreciable

extent.

I feel this very long article ought to be concluded, but cannot find the heart to do so without adverting to the sostinente pianoforte of the ingenious Mr. Mott. This instrument, which com bines the rapidity of the most brilliant pianoforte execution, with the power of sustaining and swelling the sounds and varying their quality at the pleasure of the performer, must, I think, stand A 1 in the scale of excellence of instruments with keys. Its power of sustaining its sound is due to an interesting fact in physical science, viz., that if an exciting cause of vibration (as for instance the action of a bow) be applied to an elastic body, the motion so imparted will be communicated to another elastic body in contact with the first. The talented inventor applied this principle by making this substitute for a bow act not immediately on the strings of the piano, but on a series of pieces of silk or hair attached to them, and by this happy thought obviated the evils which would ensue from want of elasticity in the cylinder, thereby greatly improving the tone and producing a touch which enables the fingers of the performer to do that his mind willeth to do; but I need not go into further details of the construction of this instrument, as we may congratulate ourselves on living in an age when it is procurable for love or lucre, which is not the case with the claviol, celestina, aedophon, and some others, which, like the tones of Paganini's fiddle and Malibran's voice, are heard no more in the land. Yours most respectfully, ALFRED SAVAGE.

16, Garlick Hill.

COLD-BLAST ANTHRACITE IRON.

The Ystalyfera Iron Company beg to hand to the Editor of the Mechanics' Magazine a copy of Mr. Mushet's elaborate trials on their cold-blast anthracite iron, which they hope he will think of sufficient importance and interest to deserve insertion in his next