In summer, on the contrary, when the leaves are out, the sap is rapidly expended; and in winter, when the roots are dormant, it is sparingly produced; so that no surplus of this fluid apparently exists. From reasoning a priori, it would seem that no treatment would be so effectual in getting rid of the greatest quantity of sap as to girdle the tree, by cutting away a ring of alburnum, in the early part of summer, thus putting a stop to the further ascent of the sap, and then to suffer it to stand until the leaves should have expended, by their growth, or transpiration, all the fluid which could be extracted by them, previously to the death of the tree. The wood would thus, probably, be found in the driest state, to which any treatment could reduce it in the living state. Buffon has recommended stripping the trees of their bark in spring, and felling them in the subsequent autumn. This method is said to harden the alburnum; but the cause is not very apparent, nor is the success at all certain.-Seasoning. At what ever period timber is felled, it requires to be thoroughly seasoned before it is fit for the purposes of carpentry. The object of seasoning is partly to evaporate as much of the sap as possible, and thus to prevent its influence in causing decomposition, and partly to reduce the dimensions of the wood, so that it may be used without inconvenience from its further shrinking. Timber seasons best when placed in dry situations, where the air has a free circulation round it. Gradual drying is considered a better preservative of wood than a sudden exposure to warmth, even of the sun; for warmth, abruptly applied, causes cracks and flaws, from the sudden and unequal expansion produced in different parts. Two or three years' seasoning is requisite to produce tightness and durability in the wood work of buildings. It must be observed that seasoning in the common way only removes a portion of the aqueous and volatile matter from the wood. The extractive, and other soluble portions, still remain, and are liable to ferment, though in a less degree, whenever the wood reabsorbs moisture. Such, indeed, is the force of capillary at traction, that wood, exposed to the atmosphere in our climate, never gives up all its moisture.-Preservation of Timber. When wood is to be kept in a dry situation, as in the interior of houses, no other preparation is necessary than that of thorough seasoning. But when it is to be * See McWilliam on the Dry Rot, pp. 151 and 158. exposed to the vicissitudes of weather, and, still more, when it is to remain in a warm and moist atmosphere, its preservation often becomes extremely difficult. Numerous experiments have been made, and many volumes written, upon the preservation of timber, and the prevention of the dry rot; but the subject is not yet brought to a satisfactory conclusion. The methods which have hitherto been found most successful, consist in extracting the sap, in excluding moisture, and in impregnating the vessels of the wood with antiseptic substances. For extracting the sap, the process of water seasoning is rec ommended. It consists in immersing the green timber in clear water for about two weeks, after which it is taken out, and seasoned in the usual manner. A great part of the sap, together with the soluble and fermentable matter, is said to be dissolved or removed by this process. Running water is more effectual than that which is stagnant. It is necessary that the timber should be sunk, so as to be completely under water, since nothing is more destructive to wood than partial immersion. Mr. Langton has proposed to extract the sap by means of an air-pump, the timber being enclosed in tight cases, with a temperature somewhat elevated, and the sap being discharged in vapor by the operation of the pump. It appears extremely probable, that if trees were felled in summer, and the buts immediately placed in water without removing the branches, a great part of their sap would be expended by the vegetative process alone, and replaced by water. It is well known that branches of plants, if inserted in water, continue, for some days, to grow, to transpire, and to perform their other functions. This they probably do at the expense of the sap, or assimilated fluid, which was previously in them, while they replace it by the water they consume. This state of things continues until the juices are too far diluted to be capable of any longer sustaining life.-The charring of timber, by scorching or burning its outside, is commonly supposed to increase its durability; but, on this subject, the results of experiment do not agree. Charcoal is one of the most durable of vegetable substances; but the conversion of the surface of wood into charcoal does not necessarily alter the character of the interior part. As far, however, as it may operate in excluding worms, and arresting the spreading of an infectious decay, + Repertory of Arts, 1826. Franklin Journal, ii. and vi. like the dry rot, it is useful. Probably, also, the pyroligneous acid, which is generated when wood is burnt, may exert a preservative influence. The exclusion of moisture, by covering the surface with a coating of paint, varnish, tar, &c., is a well-known preservative of wood which is exposed to the weather. If care is taken to renew the coat of paint as often as it decays, wood, on the outside of buildings, is sometimes made to last for centuries. But painting is no preservative against the internal or dry rot. On the contrary, when this disease is begun, the effect of paint, by choking the pores of the wood, and preventing the exhalation of vapors and gasses which are formed, tends rather to expedite than prevent the progress of decay. Paint itself is rendered more durable by covering it with a coating of fine sand. Wood should never be painted which is not thoroughly seasoned. The impregnation of wood with tar, bitumen, and other resinous substances, undoubtedly promotes its preservation. It is the opinion of some writers, that "woods abounding in resinous matter cannot be more durable than others;" but the reverse of this is proved, every year, in the pine forests of this country, where the lightwood, as it is called, consisting of the knots and other resinous parts of pine trees, remains entire, and is collected for the purpose of affording tar, long after the remaining wood of the tree has decayed. A coating of tar or turpentine, externally applied to seasoned timber, answers the same purpose as paint in protecting the wood, if it is renewed with sufficient frequency. Wood impregnated with drying oils, such as linseed oil, becomes harder, and more capable of resisting moisture. It is frequently the custom, in this country, to bore a perpendicular hole in the top of a mast, and fill it with oil. This fluid is gradually absorbed by the vessels of the wood, and penetrates the mast to a great distance. Animal oils, in general, are less proper for this purpose, being more liable to decomposition. The preservative quality of common salt (muriate of soda) is well known. An example of its effect is seen in the hay of salt marshes, which is frequently housed before it is dry, and which often becomes damp afterwards, from the deliquescence of its salt, yet remains unchanged for an indefinite length of time. In the salt mines of Poland and Hungary, the galleries are supported by wooden pillars, * Tredgold's Elementary Principles of Carpentry, page 166. which are found to last unimpaired for ages, in consequence of being impreg nated with the salt, while pillars of brick and stone, used for the same purpose, crumble away, in a short time, by the decay of their mortar. Wooden piles, driven into the mud of salt flats and marshes, last for an unlimited time, and are used for the foundations of brick and stone edifices. In canals, which have been made in the salt marshes about Boston, and other places, trunks of oak trees are frequently found, with the heart wood entire and fresh, at a depth of five or six feet below the surface. At Medford, Massachusetts, the stumps of trees are found standing in the gravelly bottom of the salt marsh, where the tide rises in the canals four or five feet above them. This bottom must originally have constituted the surface of the ground, and must have settled long enough ago for the marsh mud to have accumulated, as it has done for miles round, apparently since that period. The application of salt, in minute quantities, is said rather to hasten than prevent the decay of vegetable and animal bodies. Yet the practice of docking timber, by immersing it, for some time, in sea water, after it has been seasoned, is generally admitted to promote its durability. There are some experiments which appear to show, that, after the dry rot has commenced, immersion in salt water effectually checks its progress, and preserves the remainder of the timber.† In some of the public ships, built in the U. States, the interstices between the timbers, in various parts of the hull, are filled with dry salt. When this salt deliquesces, it fills the pores of the wood with a strong saline impregnation; but it has been said, in some cases, to render the inside of the vessel uncomfortably damp. If timber is immersed in a brine made of pure muriate of soda, without the bitter deliquescent salts which sea water contains, the evil of dampness is avoided. A variety of other substances, besides common salt, act as antiseptics in preventing the dry rot, and the growth of the fungus which attends it. Nitre and alum have been recommended for this purpose; and some The British frigate Resistance, which went sunk in Plymouth sound, were both affected with down in Malta harbor, and the Eden, which was dry rot. These ships, after remaining many months under water, were raised, and it was found that the disease was wholly arrested. Every vestige of fungus had disappeared, and the ships remained in service afterwards, perfectly sound from any further decay. (Supplement to the Encyclopedia Britannica, iii. 682.) of the metallic salts are considered still more effectual. Of these, the sulphates of iron, copper and zinc have the effect to harden and preserve the timber. Wood boiled in a solution of the former of these, and afterwards kept some days in a warm place to dry, is said to become impervious to moisture. Corrosive sublimate, which is recommended by sir H. Davy, is a powerful preservative of organized substances from decay, and proves destructive to parasitic vegetables and animals; but its safety, in regard to the health of crews, if used in large quantities about the wood of a ship, may be considered as doubtful. An opinion has been supported, in this country, that the decay of timber in ships, by dry rot, is owing to the impure atmosphere generated by bilge water, and that it is to be remedied by constructing ships with a view to their free and effectual ventilation. (Bigelow's Technology.) TIMBREL. (See Tambourine.) TIMBUCTOO, OF TOMBUCтOO; a city of Africa, for many centuries the great emporium of the interior trade of that continent, situated eight miles to the north of the Niger. (q. v.) This city has excited much interest, and has only recently been visited by any European traveller; and the information as yet possessed respect ing it is exceedingly vague. Leo Africanus gives a description of this city, which he had visited twice. According to him, Timbuctoo was founded in the year of the Hegira 610 (1218, A. D.), and, having extended its dominion over all the neighboring states, acquired that commercial prosperity for which it has ever since been distinguished. At the time when he visited it, it contained many persons of great opulence, particularly foreign merchants. The king held a splendid court, and had an army consisting of 3000 cavalry, and a numerous infantry. The royal palace and principal mosque were built of stone, but the houses of the ordinary inhabitants were constructed in the form of bells -the walls composed of stakes or hurdles, and the roofs of reeds. In 1811, Robert Adams, an illiterate American sailor, was, according to his own account (see his Narrative, London, 1816, the misstatements of which are pointed out in the North American Review, vol.5 and 22), after being shipwrecked near cape Blanco, carried as a slave to Timbuctoo, and detained there six months. A more recent account was given by captain Riley, an American, who suffered shipwreck on the coast of Sahara, in 1815. The account was given to Riley by Sidi Hamet, an intelligent Arab merchant, by whom he was purchased and carried to Mogadore. (See Riley's Narrative of his Shipwreck and Captivity, New York, 1817.) In 1826, major Laing reached Timbuctoo, where he remained for upwards of a month. Several letters were received from him while there, stating that, in point of extent, it did not exceed four miles in circuit, but that in other respects it answered his expectations. He was soon after obliged to leave the city, and was murdered three days after quitting it: his papers have not been recovered. (See Laing.) In 1828, Caillié visited Timbuctoo (or Temboctoo, as he calls it), and resided there above a fortnight. According to him, it consists of ill-built earthen houses, situated in the midst of deserts of moving sand, and containing seven mosques. He estimates the population at only 10,000 or 12,000, chiefly negroes, who are Mohammedans. It is entirely supported by commerce, being the depot of salt from the Taudeny mines, and of European goods brought by the caravans from Morocco, as well as those from Tunis and Tripoli, which go by the way of Ghadamis. These goods are embarked for Jenne (q. v.), to be exchanged for the gold, slaves, and provisions, with which that city exclusively supplies Timbuctoo. We may expect more full accounts of this part of the country from the expedition now (1832) ready to sail from England, under the direction of the Landers. (q. v.) Lon. of Timbuctoo, according to Rennell, 2° 30′ E.; lat. 16° 30′ N.; according to the map prepared by Jomard, from Caillie's notes, lat. 17° 50' N.; lon. 3° 34′ W. (See Caillie's Travels to Timbuctoo, from the French, Lond., 1830.) TIME is the general relation in which all things perceptible stand to each other, in regard to their origin, continuance and dissolution. It is a form necessary to enable the mind to unite successive existence. It is not an external object, nor 8 mere relation of individual things to each other, but is infinite, like the phenomena which are submitted to this form in our perceptions. (See Kant, volume vii, p. 304.) We speak of a distinct period of time (relative time) only in reference to that which fills time. Accordingly, we also distinguish the past, present and future as its component parts, which pass continually each into the succeeding. In order to measure the succession and duration of particular things and events, the great motions of the heavenly bodies, which always remain the same, particularly of those bodies which are most closely connected with the earth, have been taken as standards; hence the physical or astronomical time. Such a measure of time is afforded, by nature herself, in the apparent daily revolution of the heavenly arch, i. e. the rotation of the earth on its axis. This gives rise to the sidereal time. (q.v.) But as the sidereal time will not serve for the purposes of common life, it was necessary to resort to the solar time. (q.v.) The latter, indeed, is unequal, and neither agrees accurately with the sidereal time, nor with that indicated by a clock; but this evil is remedied by the equation of time (q. v.), through which the true solar time is changed into mean time. Time, in music and rhythm; the measure by which a series of tones or sounds is uniformly divided; next, the various modes of this division, and the division itself (as when we say, This singer does not keep time). Time has nothing to do with the height or depth of the tones, and can exist without these distinctions, but not without a variety of duration and accent, since without such variety we cannot conceive a connected series of tones or motions (for in dancing, too, we speak of time) as constituting a whole. In order to do this, it is necessary that the successive sounds or motions should appear to us as portions of divisions recurring periodically, because in this uniform recurrence we perceive that uniformity in variety which is essential to time. Time, therefore, in music, corresponds to symmetry in those objects which occupy space. But it is not only necessary to perceive that each division of the series of tones or motions, which is called in music a bar, is of equal duration with the others; all the bars must also be perceived to correspond with each other as to the parts of which they are composed. Otherwise, the perception of uniform progress would be destroyed; if, 4 3 for instance, time and should con4 4 tinually and regularly follow each other in such a way that each bar should occupy precisely the same time, the parts of one bar would be at variance with those of the other; the accent would not be the same; the feeling of symmetry and a wellordered whole would be destroyed. As symmetry delights through the eye, so ⚫ time does through the ear. (See Rhythm, Music, Dancing.) Time, again, varies according to its component parts; hence the different kinds of time. It varies according to the number of the parts which greater variety, can be reduced to the 4 time. A shorter duration of the three equal parts gives rise to the 3 longer duration to the time. 2 3 8 time; a By multi6 plying the three, we obtain the heavy 2' and the 12, 6 699 and the easy time, 4' 8' 4' 8' 8 which form the rest of the uneven kinds of time. The two latter are not often used. Beyond twelve uneven parts, there would, again, be no distinct perception; therefore the time could not be distinguished. Other uneven numbers, as 5 and 7, do not form kinds of time, because, according to Apel, they consist of even and uneven numbers. Therefore all uneven times were formerly called triple times; as only those uneven times which originate from three parts, are natural to the ear. A time consisting of one portion only would be impossible, as time requires a uniformity of the various, a periodicality. From all this it appears that the kinds of time are not arbitrary inventions, as Rousseau seems to think. Uneven time is considered livelier than even. As to the parts of time, they derive different values from the accent. Accordingly we distinguish good and bad notes (notes being the parts of divisions of time, or bars, in music), nota buona, and nota caltiva, thesis and arsis. A good or heavy note is that which has the accent, and in vocal music requires a long syllable; a bad one has a short syllable. Good notes, in the even species of time, are the first (thesis), which has absolutely the greatest stress, because it decides the beginning of the bar. If the half bars of time are changed into quarters, the first and third quarters receive the accent, the latter, however, a weaker one. A still weaker accent is given to the third and sixth eighth, if the quarters are changed into eighths. In the uneven time, the first has again the accent in 3 6 the time, and in 2 1 4' 2 4 the first and fourth have the greatest stress, the second and fifth a proportionably weaker stress, and so on. That the various species of time are distinguished by variety of accent, even if the notes are of equal value, we see, e. g. by a comparison of 3 6 3 and also of and 4' is accentuated thus, time; because This the composer has to refer to the words which he intends to set to music. Franco of Cologne is considered the inventor of modern time. (See Music, History of.) With the Greeks, the time was indicated at the beginning of the chorus, originally by wooden shoes (povnia), at a subsequent period by iron ones; with the Romans by the scamillum, or scabillum. It is of the greatest importance, for the performance of musical pieces, to ascercain the precise duration of the notes, i. e. the tempo. (q. v.) The usual expressions, andante, adagio, allegro, &c., are too vague. Various attempts, therefore, have 23 VOL. XII. It been made, at different times, in London and Paris, to invent a machine which would enable the composer to indicate, with the greatest accuracy, the duration of the unit of the bar. Some of these have been commended by the academy of arts and sciences at Paris. These inventions have not met with much favor in Germany till lately, when one of the most successful has been made by Stöckel, nometer is a machine of the form of a at Burg, Germany, whose musical chrocommon-sized clock. It has a dial, with numbers, to which the hand is turned, according to the directions given by the composer at the beginning of the piece. A pendulum, now put in motion, determines exactly the duration of the unit note. Mälzel of Vienna has brought this machine to great perfection. is used in orchestras; and distinguished composers, as Beethoven, have determined the time of their compositions by this instrument. It can be bought in every considerable music shop in Leipsic and Vienna. But a very simple and efficient way of determining the time accurately is laid down, by Gottf. Weber of Mayence, in the Leipsic Musical Gazette. He says, "The simplest and surest measure of time is a simple pendulum, i. e. a thread with a leaden bullet at one end. is well known that a pendulum swings quicker the shorter it is. It is, therefore, only necessary to write, at the beginning of a musical piece, the length of a pendulum, the vibrations of which correspond to the desired duration of the unit note. Thus, allegro 8" would signify 1 that in this allegro the unit note is to 4 2 It |