seven degrees, and is generally observed to be greatest when the aurora borealis is most remarkable.

This is a very curious phenomenon, and we have not been able to find any connection between this meteor and the position of a magnetic needle. It is to be observed, that a needle of copper or wood, or any substance besides iron, is not affected. We long thought it an electric phenomenon, and that the needle was affected as any other body balanced in the same manner would be; but a copper needle would then be affected. Indeed it may still be doubted whether the aurora borealis be an electric phenomenon. They are very frequent and remarkable in Sweden; and yet Bergman says, that he never observed any electric symptoms about them, though in the mean time the magnetic needle was greatly affected.

We see the needle frequently disturbed both from its general annual position, and from the change made on it by the diurnal variation. This is probably the effect of aurora boreales which are invisible, either on account of thick weather or day-light. Van Swinden says, he seldom or never failed to observe aurora boreales immediately after any anomalous motion of the needle; and concluded that there had been one at the time, though he could not see it. Since no needle but a magnetic one is affected by the aurora borealis, we may conclude that there is some natural connection between this meteor and magnetism. This should farther incite us to observe the circumstance formerly mentioned, viz. that the south end of the dipping needle points to that part of the heavens where the rays of the aurora appear to converge. We wish that this were diligently observed in places which have very different variation and dip of the mariner's needle.

For the diurnal and this irregular variation, consult the Dissertations of Celsius and of Hiorter, in the Memoirs of Stockholm; Wargentin, Philosophical Transactions, Vol. 48. Braun Comment. Petropol. Novi, T. V. VII. IX.; Graham and Canton as above.

TEMPERAMENT

OF THE

SCALE OF MUSIC.

328. WHEN the considerate reader reflects on the large and almost numberless dissertations on this subject, by the most eminent philosophers, mathematicians, and artists, both of ancient and modern times, and the important points which divided, and still divide, their opinions, he will not surely expect, in a Work like this, the decision of a question which has hitherto eluded their researches. He will rather be disposed, perhaps, to wonder how a subject of this nature ever acquired such importance in the minds of persons of such acknowledged talents as Pythagoras, Aristotle, Euclid, Ptolemy, Galileo, Wallis, Euler, and many others, who have written elaborate treatises on the subject; and his surprise will increase, when he knows that the treatises on the scale of music are as numerous and voluminous in China, without any appearance of their being borrowed from the ingenious and speculative Greeks.

The ingenious, in all cultivated nations, have remarked the great influence of music; and they found no difficulty in persuading the nations that it was a gift of the gods. Apollo and his sacred choir are perhaps the most respectable inhabitants of the mythological heavens of the Greeks. Therefore all nations have considered music as a proper part of their religious worship. We doubt not but that they found it fit for exciting or supporting those emotions and sentiments which were suited to adoration, thanks, or petition. Nor would the Greeks have admitted music into their serious dramas, if they had not perceived that it heightened the effect. The same experience made them employ it as an aid to military enthusiasm; and it is recorded as one of the respectable accomplishments of Epaminondas, that he had the musical instructions of the first masters, and was eminent aş a performer.

Thus was the study of music ennobled, and recommended to the attention of the greatest philosophers. Its cultivation was held an object of national concern, and its professors were not allowed to corrupt it in order to gratify the fastidious taste of the luxurious or the sensualist, who sought from it nothing but amusement. But its influence was not confined to these public purposes; and, while the men of speculation found in music an inexhaustible fund of employment for their genius and penetration, and their poets felt its aid in their compositions, it was hailed by persons of all ranks as the soother of the cares and anxieties, and sweetener of the labours of life. O Phœbe decus !-laborum dulce lenimen.

329. It is chiefly in this humble department of musical in fluence that we propose at present to lend our aid.

To be able to tune a harpsichord with certainty and accuracy, seems an indispensible qualification of any person worthy of the name of a musician. It would certainly be thought an unpardonable deficiency in a violin performer if he could not tune his instrument; yet we are well inform

ed, that many professional performers on the harpsichord cannot do it, or cannot do it any other way than by uncertain and painful trial, and, as it were, groping in the dark; and that the tuning of harpsichords and organs is committed entirely to tuners by profession. This is a great inconvenience to persons residing in the country; and therefore many take lessons from the professed harpsichord tuners, who also profess to teach this art. We have been present during some of these lessons; but it did not appear to us that the instructions were such as could enable the scholar to tune an instrument when alone, unless the lessons had been so frequent as to form the ear to an instantaneous judgement of tune by the same habit that had instructed the teacher. There seemed to be little principle that could be treasured up and recollected when wanted.

330. Yet we cannot help thinking that there are phenomena of facts in music, sufficiently precise to furnish principles of absolute certainty for enabling us to produce temperaments of the scale which shall have determined characters, and among which we may choose such a one as shall be preferable to the others, according to the purposes we have in view; and we think that these principles are of such easy application, that any person, of a moderate sensibility to just intonation, may, without much knowledge or practice in music, tune his harpsichord with all desirable accuracy. We propose to lay these before the reader. We might content. ourselves with simply giving the practical rules deduced from the principles; but it is surely more desirable to perceive the validity of the principles. This will give us confidence in the deduced rules of practice.

331. It is a most remarkable fact, that, in all nations, however they may differ in the structure of that chaunt which we call the accent, or tone, or twang, in the colloquial language of a particular nation, or in the favourite phrases or passages which are most frequent in their songs, all men make use of the same rises and falls, or inflections of voice

in their musical language or airs. We have heard the songs of the Iroquois, the Cherokee, and the Esquimaux, of the Carib, and the inhabitant of Paraguay; of the African of Negroland and of the Cape, and of the Hindoo, the Malay, and the native of Otaheite-and we found none that made use of a different scale from our own, although several seemed to be very sorry performers by any scale. There must be some natural foundation for this uniformity. We may never discover this; but we may be fortunate enough to discover facts in the phenomena of sound which invariably accompany certain modifications of musical sentiment. we succeed, we are entitled to suppose that such inseparable companions are naturally connected; and to conclude, that if we can insure the appearance of those facts in sound, we shall also give occasion to those musical sentiments or impressions.

If

332. There is a quality in lengthened or continued sound which we call its pitch or note, by which it may be accounted shrill or hoarse. It may be very hoarse in the beginning, and during its continuance it may grow more and more shrill by imperceptible gradations. In this case we are sensible of a kind of progress from the one state of sound to the other. Thus, while we gently draw the bow across the string of a bass viol, if we at the same time slide the finger slowly along the string, from the nut toward the bridge, the sound, from being hoarse, becomes gradually acute or shrill. Hoarse and shrill therefore are not different qualities, although they have different names, but are different states or degrees of the same quality, like cold and heat, near and far, early and late, or, what is common to all these, little and great. A certain state of the air is accounted neither hot nor cold. All states on one side of this are called warm or hot; and all on the other are cold. In like manner, a certain sound is the boundary between those that are called hoarse and those called shrill. The chemist is accustomed to say, that the temperature of a body is higher when it is