TUNING-FORK. A steel instrument with two prongs springing out of a handle, and so adjusted as to length that when struck a certain fixed note is produced, by which the pitch of the voice or of musical instruments is regulated. In England the tuning-fork is made with parallel prongs, and is vibrated by striking one of the prongs when both unite and reinforce each other ; the note becomes much more resonant by placing the handle on a sounding-board, or even on a table. In France, where the instrument is called a diapason, and in Germany a diaspason, the prongs are bent intD•the form of an exag gerated horse shoe, and a cylinder of wood being placed in the widest part of the opening, is moved quickly upwards so as to separate the prongs further apart, and they continue to vibrate for some time. The fork Is usually tuned to A or o in the tenor, a separate fork being provided for each pitch required. Mr. Klein has, however, introduced a fork which admits of adjustment for pitch by means of a small braes clamp, which slides on one of the prongs, and can be fixed in certain positions by means of a clamping screw. By varying the place of the clamp upon the prong the pitch of the fork can be raised or lowered, and certain marks are engraved upon the prong, showing the position for the clamp for giving the pitch adopted by each of the principal orchestras in Europe.
It would be very desirable If a uniform pitch could be agreed on in the musical world ; but so long as each nation continues to use its own weights and measures, it will naturally claim the privilege of regulating its own musical pitch. Under ACOUSTICS, CONCERT PITCH, and TEmesaAnsar and Turirso, some remarks arc made on this sub ject, by which it appears that for many years past the pitch has been rising, to the Injury of the voices of our public singers. Messrs. Broadwood, the well-known pianoforte makers, employ three tuning forks. all of different pitch : the first is the philharmonic standard of thirty years ago, and is used for tuning pianos which give the accompaniments at vocal concerts ; secondly, a fork higher in pitch, used for tuning pianos that take part in orchestral compositions; and thirdly, a fork of still higher pitch, used as the opera and philharmonic standard of the present day. Indeed there is a difference of about a semitone between the first and third of these forks.
It is stated that the middle c-fork used In Paris in 1699 was equal to 489 vibrations per second, while in 1859 it had increased to 588. In the last-named year the opera standard fork used In London, St. Petersburg, and Berlin, was even somewhat higher than that of Paris ; and cases have frequently occurred in which a band intended to take part with a cathedral organ, such as that of St. Paul's, London, found it impossible to tune down all their Instruments to the pitch of the organ. The object of thus raising the pitch has been to improve the brilliancy of the Instruments. Opera bands and military bands have both raised their pitch. The conductor of the band of the °elides of Brussels employs two forks, one which is too high for vocal music, being used to give brilliancy to military Instruments.
Attempts have been made at various times to settle the standard of pitch by reference to scientific principles. Fischer's experiments, or rather their results, obtained in 1823, are noticed under AcousrLcs. About thirty years ago the Philharmonic Society adopted a fork of a certain pitch, which for a time seemed to check the tendency to rise in the standard. The maker informed us that this fork was entirely settled by ear, and that Sir George Smart directed him to make it a little sharper or a little flatter until in the course of about half an hour, a pitch was hit upon which satisfied Sir George's mnsieal ear. In 1834 some of the leading musicians of Germany met at Stuttgard, and agreed upon an A-fork of 880 vibrations per second, corresponding with 528 for the tenor c. The next attempt to secure a uniform standard was made by Mr. Mullah, In 1842. When this gentleman introduced the system of teaching singing on the Wilhem method, under the sanction of the Committee of Council on Education, it was quite necessary to secure a common standard of pitch for the sake of uniformity in the various classes, and among the teachers iostructed by Mr. Hullah, who themselves had classes in various parts of the kingdom. The great and successful gatherings in Exeter Hall, where 1500 or 2000 pupils under this method united their voices, would evidently have been impassible unless a standard of pitch had been adopted. Accordingly, Mr. Mullah and his publisher, Mr. Parker, applied to Mr. Tomlinson to prepare a new fork ; the necessity for which will be further apparent when it is considered that the A-fork or the c-fork of one maker did not by any means imply the same A fork or c-fork of another maker ; nay, even forks of the same name, and bought at the same shop, were not, as a rule, in unison. Mr. Iiullah expressed great anxiety that the pitch should be kept down as much as possible, but he left it to Mr. Tomlinson to decide what number of vibrations per second should be assigned to the note which it was agreed should be the middle o of the pianoforte. In a letter addressed to Mr. Hullah on April 18, 1812, Mr. Tomlinson stated his reasons why
the number 512 should be adopted. We will quote a few remarks from the printed description which was written when this fork was issued, and which has been given with every fork that has been sold, ever since:— " The tuning-forks now in use are themselves regulated—not upon any definite principle—but by the imperfect system of copying ; each one being attuned in (apparent) unison with others. The workman, having no test but his ear to depend upon, is liable to fall into inac curacies, the precise amount of which he has no means of determining hence the standard itself may vary from time to time ; and indeed It. is known to musicians that the standard of musical pitch is higher in this country at the present time than formerly, any given note being now a little sharper than the almllarly-named note in the times of our earlier composers. And not only so, but different vocalists of dis tinction, instrumental performers, stud musical instrument makers, adopt certain standards of their own, which often differ considerably one from another. These discrepancies, and the rapid extension of vocal music in England under the auspices of the Committee of Council on Education, have led to the opinion that the present is a favourable time to attempt the formation of a rigorous standard of pitch; one which, by depending on an unchanging scientific prinoiple, will be independent of local and temporary usages. The priuciple here alluded to is that on which the pitch wholly depends—namely, the number of vibrations per second which produces the given note. The great rapidity of these vibrations renders the determination of the number a point of much difficulty : but seleoce furnishes many resources whereby this determination can be made with great nicety. Any note might be chosen as a standard, but the note " Do " or 0, represented musically thus, has been selected as the one most gene rally useful: This note in the new standard tuning-forks, is produced by 511 vibrations per second, a number, the simplicity of which renders it peculiarly valuable. It forma part of the geometrical series, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048 ; each term of which thus becomes a representative of the natural note " Do" (except the first five terms, which vibrate too slowly to produce musical sounds); every term being the octave of the next below it. Under such a system the lowest c on a grand pianoforte would be due to 32 vibrations per second; the highest c to 2048, and the highest note of the instrument to 2730. By careful experiments, made expressly for the present object, it has been recently determined, that the philharmonio C, the most authoritative standard in this country, vibrates a smaller number of times per second than 512; while Fischer, of Berlin, found, a few years ago, that the average of the pitch note A, In four celebrated Continental orchestras, gave a number which would raise the c to about 516 vibrations per second. Thus the numbers of vibrations per second of the pitch-note A at the principal. Berlin and Paris theatres were as follow : " In selecting, therefore, the number 512, we not only obtain that which is theoretically most correct, but one which is also a convenient mean between various existing standards ; it gives a very trifling elevation to the general English pitch, and furnishes a standard, which, for the first time in this country, can be numerically expressed in connection with the tuniug-fork." It is further stated that " every fork is tested by an uniform standard, and stamped with a device expressive of the velocity of its vibrations =512 per second." It is remarkable that this fork should have been almost entirely confined to the use of Professor Mullah's singing-classes, and that when the Society of Arts committee was appointed the existence of a stan dard for nearly twenty years, of which many thousands had been issued to the public, should have been known only to a few of the members of that committee. This committee seems to have been appointed in consequence of the imperial government of France having in 1858 appointed a commission to inquire into the best mode of settling a diapason normal. The commissioners, among whom were some eminent composers, as well as men of science, preseuted their report early in 1859, in which it was admitted that the standard of pitch differs in different countries ; that it differs among different musical establishments in the same country ; that there is a tendency every where to an elevation in pitch ; and that great confusion arises from these circumstances. It was agreed that the Paris Opera standard ought to be lowered; and in order that existing musical instruments' might be readily adapted to a lower pitch, about half a semitone of diminution was recommended : !ninety, that the Opera A fork should ho lowered from 896 to 870 vibrations per second, equivalent to a lowering of the tenor o from 538 to 522. A decree of the Emperor sanctioned this standard, and made it compulsory on all musical establishments in any way supported by the state to adopt this stan dard at. Paris from the 1st of July, 1859, and in the provinces from the 1st of December following.