\section{Instructions for Playing on the Musical Glasses}

As the tones of the musical glasses are, from their similitude, more like the human voice, than any musical instrument, that ever was, or, perhaps, ever will be invented; there is much reason to suppose, these glasses will, in a short time, become as common a piece of furniture as an harpsichord; and that every lady, who can play or sing, (but more particularly the latter) will be furnished with an instrument, in itself of no great expence; an instrument, that not only sets off the voice with greater advantage than any other; and if I was to say, will assist and improve a voice, I do not think I should say more than is due to the exquisite tone it produces; a tone superior to every other instrument, and perhaps, the only one from which you hear the effect without the cause. But as those few, in whose profession the musical glasses now are, may make a mystery of the matter, I shall here lay down such plain directions for providing the glasses, and performing on them, when they have so done, that will shew there is no great difficulty either in procuring the proper glasses, or performing on them, when they are suitably chosen and properly fixed.

In order, therefore, to furnish a compleat set of glasses, you must give directions to have three or four blown of each size; for though a glass be of the same circumference and depth, the tone will be very different, either flatter or sharper, in pro-$<$2$>$portion as the glass is either thinner or thicker near the upper edge; and therefore you cannot, unless by accident, get a regular succession of the notes without ordering three or four glasses of each size; i.e. four of an inch and an half diameter, four of an inch and three quarters, and so increase a quarter of an inch, down to four inches, from which number any person, who has an accurate ear, will be able to pick out a regular succession of notes in the natural key; from (a) in Alt, down to (a) double Octave, which is fifteen glasses. Care must, however, be taken not to put in any notes that are too flat, because they cannot be corrected; but those which are half, or a quarter of a note too sharp, can be easily made flatter with water. It must be also observed, that the tone of those glasses which have none, or very little water, are much the clearest and best; and therefore, the nearer they are brought in tune without water, the more perfect and compleat they are.

In the copperplate [illustration] you will find the middle range representing the glasses in their proper order, and in the natural key of (c): in the front row, opposite the natural notes, are placed some flats and sharps; and all the rest may be fixed there, at the discretion of the performer. On the row behind, may be placed as many triple octaves as the stage will hold; and such may be chosen as are most likely to be wanted to open any particular part of the performance; and when this is done, and your glasses properly fixed, at about a quarter of an inch distance from each other, and regularly laid, i.e. to go gradually down from the left to the right, the greatest part of the difficulty is over. For I would engage to teach a moderate genius to play a tune in a few hours; or rather be surprised that one, who knows the succession of notes, did not do it untaught the first time of attempting it.

The vibration and tone is produced by means of a certain degree of moisture, by wetting the balls of the middle fingers; which, however, will not produce a clear tone, till the fingers have imbibed part of the water, or have been wet for some time, unless you rub them with the pulp of a unripe Gripe [sic]; and with that assistance the tone is $<$3$>$instantly produced, by pursuing the circular motion of the glass; for if you scribe strait across the glass, it I occasions an harsh and unpleasing tone.

From the short practice I have had, it being not above four weeks since I first heard them, and little more than a fortnight since I made my first attempt to play, I have not had sufficient time to examine what improvements the musicall glasses are capable of; but I am confident, some Grace, never yet attempted, may be executed with advantage. I can at present make a tolerable shake and beat, which may be easily acquired by seeing it once done.

In order to produce the tone clearly and properly from the smaller treble glasses, the ball of the middle fingers, or the prominent part between the first and second joint, being wet, must be flatly, and regularly moved, in a circular motion, on the top of the glasses; but this touch will not do for the large triple octaves, which are apt (from their great vibration) to give false tones, of so touched; and therefore these are to be touched with the ball of the fore, or middle finger, about half an inch below the rim on the outside; and by a very little practice, the glasses will, by their greater or less vibration, inform the practitioner how the touch is to be applied to produce the true tone. One of the principal inconveniencies attending these tones, is, that the vibration (especially on the large glasses) continues too long; but by a little practice, the performer may, in a great measure, remove it; for the slightest touch, or dot with the finger, on the outside of any of the glasses, will instantly take it off. Whoever undertakes to pick out the succession of notes, should not only have a proper attention to the exact order of the notes, but also that the glasses increase in size gradually, down from a, the upper octave, to a, the lower double octave; otherwise there will not be an uniformity of tone, which ought to be attended to; for in chusing [sic] and trying the glasses, you will frequently find the larger glass much sharper than a size less.

$<$4$>$From the above information, I am confident, any person, of a musical turn and genius, will be able to furnish themselves with this extraordinary instrument, if it may be so called; and therefore I shall conclude with giving a hint, that, perhaps, some mechanical genius may improve to his own advantage, and render this music much more perfect and compleat, than it now is. It may be observed, that those glasses which have half, or one third water in them, will, if held in the hand steady and upright, have a clear and uninterrupted tone; but if by humouring your hand, you cause the water to roll round the side, so as to rise higher than its real quantity, it instantly falsifies the true note, and produces a very fine chromatic; which is reduced again to the true note, by letting the water become quiet, and the glass be upright. Now suppose every glass was fix'd in a brass ball, that turned in a concave socket, as presented in the copper-plate, I apprehend they might be steady enough to produce the true note, and yet, by a dextrous performer, and a little practice, the note might be falsified, and corrected by the address of the performer, with a little practice.

I have consulted an ingenious organ-builder, who is very confident he can give the same touch to these glasses, and cause it to be done by the keys, as on an harpsichord; and I have employed him to make me an organ with glass notes, instead of pipes, which I have some reason to believe I shall soon produce before the public; and which, if it answers what the workman seems confident it will, may be an instrument that will astonish and delight more than any ever yet performed on.

Mr. Ardesoif, jeweler and toy-man, next door to Mr. Drummond's, the banker, at Charing-Cross, has some sets of musical-glasses to dispose of, that are perfect in tune, and to be sold cheaper than any person can provide a single set; because four or five times the number of glasses wanted, must be blown, in order to pick out a regular succession; but one who sells many sets, may, in time, bring them all into use; and therefore it is cheaper, and less trouble, to be at a certainty in the first price, than to attempt providing them in any other way.

$<$5$>$When the glasses are fixed on the three stages, they may be either fastened down to a table, or a case made for them, according to the fancy of the performer; and such, whose ear is not accustomed to tune instruments, may have them properly and correctly tuned by a professor, and then mark, with a diamond, on the outside of the glass, the exact heighth of the water; by which mark you may be quite certain of the true tone, whenever the water is changed. It must also be remembered, that if you continue to play any time, those glasses that have water, will become flatter, by the additional water that drips, from the wetting the fingers so frequently; and therefore, that must, now and then, be attended to; and the dry notes sponged out, and the wet ones corrected.

FINIS.


