5th. That these phenomena are the results of a simple motion of the particles of matter, such motion being a stream, and are independent of any other agency. 6th. That the positive and negative powers, whether magnetic, galvanic, or electric, are the inevitable consequences of a stream of fluid matter, the positive power being found at the point at which such fluid arrives, and the negative power at that which it vacates.

7th. That the supernatant atmosphere is taken in, or absorbed by a magnet, on all sides of the negative half of a magnetic bar, and most largely so at its pole or extremity, and issues from all sides of the opposite or positive half, in the same ratio in which it enters. Consequently, a magnet decreases the preexisting quantity of matter in the space from which such fluid is derived, and augments the pre-existing quantity in that space into which it is emitted. The immediate space around the positive magnetic pole becoming so much denser of fluid matter (than a corresponding space in the media beyond the influence of the magnetic action) as that surrounding the negative pole in the same space of time becomes rarer; whereby two atmospheres are formed, both differing in density to the adjacent media.

8th. That magnetic motions are generated by, and depend upon some, or any exciting cause, or impetus which is adequate to destroy the equilibrium of the fluid particles, contained in the spaces between the essential particles of metallic and other substances.

9th. That the continuation, degree of duration, and intensity of such motions, are due to the density of the body in and through which they take place; such protecting and modifying the motions of the internal particles of fluid matter, as regards the external atmospheric pressure, and preventing an equilibrium being formed between the two.

ON

INSTRU

EOLIAN, OR FREE-REED
MENTS OF MUSIC. BY MR. ALFRED
SAVAGE.

Sir,-A considerable addition to the within the last fifteen years, by the means of our enjoyment has been effected, application to musical instruments of the fact, that when the passage of air through an aperture is regularly stopped equal intervals, the aërial undulations so or impeded with sufficient rapidity at produced become audible. Many instruappeared during that period, under the ments constructed on this principle have names of eolophon, concertina, accordion, colina, seraphine, and others. Now as I am of opinion that the principle is one which promises far greater things than have yet been achieved, although the degree of excellence which has been produced is far from generally known, it may not be uninteresting to your readers to follow me through a slight sketch of the history and construction of the principal varieties of these instruments, and an examination of the causes of the various qualities of their tones.

This class of instruments is technically termed "free-reeds," in contradistinction to the reed-pipes of organs, which are constructed like the mouth-piece of the clarionet; that is, in the latter, the reed or spring valve is wider than the aperture which it partially closes, while in the former the valve or reed is not so wide and is shorter than the aperture, so that it can vibrate freely through it—whence the

name.

The earliest known musical instrument on this principle is called the Chinese organ, which has probably been in existence for two thousand years. The mode adopted of causing it to utter its sounds at the will of the performer, shows that people, on whom we have been too ready to retort the charge of barbarism, have been for ages, practically at least, acquainted with a very beautiful fact in the laws which govern the production of sympathetic sounds; for the performer, by stopping holes in the pipes connected with the reeds, causes them to become unisonous with the sounds produced by the vibrations of the reeds. And, as if to afford another proof that novelty is only the rediscovery of forgotten things, the Chinese formed the reeds out of the same material in which they vibrate, which is one of the greatest, if not the

very greatest improvement, which has been recently made in instruments of this kind.

During the latter part of the eighteenth and the earlier portion of the nineteenth centuries, several experiments were made in Germany, particularly an attempt to connect the reeds with a soundingboard or belly, and a free-reed was employed in the speaking machines constructed by Kempelen, Maelziel, and others; but I am not aware that any musical results were produced of general interest, and shall at once proceed to a notice of some of the experiments of the late Professor Robison, to whom we are indebted for the first practical suggestions for the construction of musical instruments on this principle.

For the purpose of determining the number of aërial pulsations by which a sound of given pitch is produced, the Professor caused a common stop-cock to revolve at a known rate in a tube through which air was passing, and he found the sound so produced so pleasing, particularly when the plug of the cock was filed away, so as never to shut more than two-thirds of the passage, that in his judgment it surpassed the finest female voice. Now this may be considered as the first type of the colophon, and his next experiment completely anticipated one of the modern forms of the instrument, for he "caused a circular spring plate to vibrate through a hole made in another plate, which produced a very bold and mellow sound;" which is the seraphine in every essential particular, only that the spring valve or reed is more conveniently made in the form of a parallelogram, although it may be questionable if the original circular form does not afford the best quality of tone. Professor Robison also, in some degree anticipated Mr. Wheatstone's instrument, by applying a current of air to variously formed strings, causing first a gut string, and successively a varnished silk ribbon, a flat silver wire, and a piece of watch spring, supported at both ends, to vibrate in a narrow aperture between two air chambers; but he did not employ a sounding-board or belly in connexion with the strings.

About 1827 several persons in England and on the Continent, had their attention directed to the production of a musical instrument on this principle, but I believe

nothing was effected which could be depended on for continued use except the eolophon of the late Mr. Day; at least that was the only instrument among upwards of a dozen exhibited at the Royal Institution about that time, which could be performed on. The writer first heard it shortly after, and was much struck with the superiority of its tones to those of a German instrument then in his possession. From that time to the present, this instrument, which has always been the best of its kind, and the seraphine which ranks next to it, although far behind in general utility, have been much in use; but until a comparatively recent period the seraphine was not capable of being used for the performance of very rapid music, as it does not speak so rapidly as the eolophon.

The concertina may be considered the first of these instruments, which was performed on in the same manner as the accordion, from which it differs chiefly in the more convenient disposition of the finger-keys. It is also much superior in tone; but its capabilities in this respect are not very severely tested, as its compass never extends far into the bass, and it is much easier to produce pleasing sounds in the treble than from the lower bass.

One of the principal varieties of the quality of tone in instruments of this kind arises from the scale, or in other terms, the size of the aperture of a sound of given pitch. If the aperture be very small, the tone is very recdy, weak, and disagreeable; a large aperture produces a much more powerful sound, of better quality. The accuracy with which the valve, or reed, fits its aperture, also considerably influences the tone. If the valve be fitted with great accuracy the tone is harsh, compared to that produced by a reed which has some more leakage; but the latter does not usually speak so quickly, and wastes more wind. The tone is also better in proportion to the stiffness of the reed, but it is difficult to make a very stiff reed speak quickly. It is obvious that if a given pressure of air be the moving force, it will cause a weak spring to vibrate sooner than a stiffer one. If very stiff reeds be used, great pressure of wind is necessary to cause them to speak rapidly, and this renders the quality of the tone less pleasing, unless they be made propor

tionably larger, in which case it affords the most perfect imitation of the trumpet which has yet been produced-far ex ceeding the best trumpet stops in organs.

Another cause of variety in the quality of the tones consists in the different means employed to connect the reeds with the frames in which they vibrate. If they be constructed of separate pieces of metal from the frames, some jarring inevitably occurs, and being heard with the tone, renders it impure. It will be remembered by your philosophical readers that the particles of bodies are most probably not in contact; and it is probable those of two dissimilar bodies cannot, by any force we can exert, be made to approximate so closely as the atoms of a homogeneous body naturally do. The consequence is, that however tightly the reeds may be screwed to their frames, if they be made to vibrate strongly, they jar; and this is heard most disagreeably as we descend towards the lower part of the compass. Nor was this defect cured, although much mitigated, by Mr. Day's ingenious contrivance of bending the reeds employed for the bass notes. It has, however, been entirely overcome by the re-invention of the Chinese method of forming the reeds out of the same piece of material which also forms the frame through which they vibrate. This was the contrivance of Mr. Storer, and was a very natural result of the application of that knowledge which he derived from his former profession, viz., a steel-pen manufacturer, (steel pens are almost entirely formed by pressure,) to the construction of free-reed instruments -furnishing another proof, among the many we almost daily witness, of the practical advantages of an acquaintance with more than one branch of manufacture. The tone of the instruments constructed by Mr. Myers, in this manner, is so superior to that of any with reeds removable from their frames, as to leave comparatively little to be desired; and from the material employed they stand in tune better, and speak more rapidly, than any other instruments on this principle with which I am acquainted.

The material of which the reeds are constructed also influences the quality of tone, although not very greatly. They have been made of brass and similar alloys, of silver, and even of gold. The

noble metals possess one advantage, viz., not becoming oxidated; but they are not sufficiently elastic, and to be stiff enough, require to be too heavy-the goodness of the tone depending greatly on the stiffness of the reed. A hardened steel reed of any given degree of stiffness is not half the weight of a silver, and perhaps not one-fourth the weight of a golden one. It is consequently put into a state of vibration much quicker than either, as it does not so much resist the force, viz., the pressure of air, which causes it to move. The instrument with steel reeds therefore speaks much quicker, and when the reeds are shut up inside a wind chest, they are extremely unlikely to become oxidated; besides, hardened steel is much less liable to oxidation than soft steel or brass. Metals, however, are by no means the only materials of which reeds may be constructed. piece of cane or wood, or, indeed, any substance sufficiently elastic, will answer the purpose; but nothing stands in tune so well as hardened steel.

A

The force of wind with which the reeds are blown has considerable influence on the quality and power of the tone; and I believe it is a matter of much practical difficulty to find such a scale of size as will afford an uni.. form quality of tone throughout the compass, if the pressure of wind be the same; generally the high treble requires much more force of wind than the bass, and perhaps the most equal quality of tone might be produced by. some contrivance which should afford a means of regulating the supply or emission of air to each individual reed in the compass of the instrument. A graduated pressure from two or three to about six or eight inches would, I think, be found most beneficial in a compass of six octaves, and one bellows would serve, if applied in the way proposed by Mr. Myers. This would combine the most rapid speaking of the treble with the best quality in the bass, from which I am convinced the best quality of tone is produced, when the pressure does not exceed that capable of balancing a column of water two or three inches in height; it is so smooth, indeed, as to be hardly distinguishable from the open diapason of the organ.

An announcement appeared some time