SLEEP

ing countries are Cuba, Por to rico, and Brazil. Publications on the slave trade are so numerous, that it is difficult to make a selection for purposes of reference. Perhaps (after Clark sori's History) the student could not find the account of its progre better given than in succe ive numbers of the Edin. Review, especially vols. xxi. xxiii. xxiv. xxxvi.; though it must be admitted that there is in these, and most works on the subject, a strong tendency to exaggeration. There is a good article on the international law of the slave trade in the Law Magazine for August, 1841. SLEEP. (Germ, schlaf.) That state of the body in which the functions of sensation and volition are suspended, while the vital functions retain their usual activity: the operations of the mind, if not at perfect rest, are disconnected with external objects. Healthy or natural sleep usually comes on with a peculiar sense of muscular la itude, gaping, and desire of repose; the eyelids fall, and there is general muscular relaxation. The sense of hearing is that which is longest retained; and we generally hear what is going on about us, and even feel inclined to take occasional part in conversation, long after the eyes are closed. The quantity of sleep required by different individuals is various, from six to nine hours being the average proportion. Indolent listle persons, and especially those who indulge in the luxuries of the table, and a|re in good health, will often slumber away from eight to ten hours daily; while others of active dispositions, and who live abstemiously, will be satisfied with four or five hours of sleep: and such persons are generally more disturlied by dreams than the former. Very young children sleep away much of their time, and so also do many old persons. Sleep is often prevented by intense thought, by anxiety, and other mental affections; and also by hunger, and by the application of cold to a jjart of the body. When a person has been over-fatigued by bodily exertion, sleep is also often courted in vain; and there are many stimuli by which its acce ion at the usual times is prevented or retarded, such as strong tea,coffe^, small doses of opium, and several other articles of medicine and diet. Bodily exercise and mental tranquillity, a full meal, the absence of light, noise, and other disturbing causes, are circumstances generally favourable to sleep; but in all these respects various habits often greatly interfere, and persons accustomed to very active lives when suddenly deprived of their usual occupations often sleep worse than before, indolence becoming an apparent stimulant. A ■ distended stomach keeps some individuals awake; and others cannot sleep in a dark room, or in the quiet of the country, who have been used to a night lamp, and to the rumbling of carriages over a London pavement. The proximate cause of sleep has been discu ed by several eminent physiologists, but without any very satisfactory results: it is, in fact, as entirely beyond our grasp, as are the other functions of the nervous system. See Dreams. SLEEPER. In Architecture, a piece of timber whereon are laid the ground joists of a floor. Sleepers are also pieces of timber, now rarely used, in foundations cro ed by planks, ., and at right angles to them, where the soil is bad. Formerly the term was used to denote the valley rafters of a roof. SLI'CKENSIDE. A provincial term applied by the Derby shire miners to a species of galena, or sulphuret of lead. SLIDE. In Music, a grace used in the German school, and consisting of two small notes moving by degrees. SLI'DING KEEL, is a narrow oblong frame or platform, let down vertically through the bottom of a small ve el, like a deepening of the keel throughout a portion of hor length. Its use is, like that of the leeboard, to sustain the ve el against the lateral force of the wind. SLI'DING RULE. A mathematical instrument or scale, consisting of two parts, one of which slides along the other, and each having certain sets of numbers engraved on it, so arranged that when a given number on the one scale is brought to coincide with a given number on the otiier, the product or some other function of the two numbers is obtained by inspection. The numbers may be adapted to answer various purposes; but the instrument is chiefly used in gauging, and for the mensuration of timber. SLING. (Ger. schlinge.) A weapon made of a strap and two strings, by means of which a stone or other mi ile is projected with much greater velocity than could be given to it by the hand without such a istance. The velocity with which the projectile is discharged is the same as that with which it is whirled round in a circle having the string for its radius, and may therefore be computed when the time of revolution and the length of the string are given. The sling was known as a weapon of offence in the earliest ages. SLIPS. In Geology, ma es of strata separated vertically or aslant. SLO AM. Layers of clay between those of coal..SLOOP. A ve el with one mast like a cutter; but 1123 SMALT. having a jib stay, which a cutter has not. Also the general name of ships of war below the size of frigates. SLOPS. Clothes and bedding supplied from the ship's stores to the seamen, but at their expense. SLOUGH. A Surgical term applied to the separation which ensues between dead and living parts. SLUE. In Naval language, to slue is to turn a cylindrical piece of timber, as a mast or boom, about its axis, without moving it out of its place. SLUICE. (Lat. clausus, a-Am/ Mjo.) In Hydraulics, a frame of timber, stone, or other solid substance, serving to retain and raise the water of a river or canal, and, when nece ary, to give it vent. SLUR. In Music, an arch /""N connecting two or more notes not on the same degree, indicating to the performer that in playing they are to be united as much as po ible. SMACK. A ve el with one mast, commonly rigged as a sloop, and used in the coasting trade, or as a tender in the royal navy. The ve els of this name that have long plied between Leith and London are well known, and have always been noted for their security. SMALLPOX. Called also Variola, from varius, changing colour; because it changes and disfigures the skin. There are two forms of this disease, generally called by medical men the distinct and the confluent; in the former the pustules are separate, in the latter they coalesce. Distinct smallpox begins with the usual symptoms of inflammatory fever; that is, pains in the back and loins, sickne , drowsine , lieadach, pain upon pre ure about the region of the stomach, and in infants one or more epileptic fits. About the end of the third day little red spots, much resembling flea-bites, make their appearance upon the face and head, which spread during the fourth day over the breast, body, and limbs; about the fifth day a small circular vesicle forms upon each little point, depre ed in the centre, surrounded by an inflamed margin, and containing a colourle fluid, and at this time the eruptive fever disappears; about the sixth day the throat becomes sore, and the saliva viscid; and about the eighth day the face is swollen, and the pustules round, prominent, and prevalent; about the eleventh day the pustules attain their full size (about that of a pea), and the matter which tliey contain becomes opaque and yellow, and a dark central spot appears on each; the swelling of the face subsides, and is transferred to the hands and feet, and more or le secondary fever now ensues. After this the pustules become rough, break, and scab over, and a dark brown spot remains for some days; and if the pustules have been large an indentation is left: the remaining symptoms gradually subside, and about the seven teeth or eighteenth day the secondary fever disappears. Confluent smallpox is ushered in by a lever of a typhoid rather than of an inflammatory character; all the incipient symptoms are aggravated; delirium or coma attends them^ and in infants there is diarrhoea,.and in adults salivation. The eruption is very irregular in its progre and appearance, and usually preceded by red patches upon the face, from which the pustules emerge on the second day in the form of clusters somewhat resembling measles. Their progre is rapid; but instead of being circular and well defined, they are flat and irregular in shape, and contain a brownish fluid very unlike pus: the intermediate spaces between the clusters are generally pale and flaccid. The tumefaction of the face and runnmgof saliva are greater than in the distinct species; and the fever does not cease upon the appearance of the eruption, but about the ninth day it generally becomes aggravated, the eruption livid, and accompanied by pete chias or purple spots; and about the eleventh day from the commencement of the disease it often terminates fatally. This disease is the effect of a specific contagion, and is produced either by inoculation, or by exposure to the effluvia from persons suffering under it: in the latter case it is usually called the natural smallpox. When the distinct smallpox goes regularly through the stages above described it is rarely dangerous, except from mismanagement; but it often leaves a tendency to inflammatory disorders, and in a scrofulous habit it excites that disorder into activity. Any of the symptoms which have just been described as characterizing confluent smallpox are alarming; so is a sudden disappearance of the eruption, or change in its appearance, followed by depre ion or dehrium. In treating the distinct smallpox the febrile symptoms are to be moderated by cool air, saline and mild acid and diluting drinks, and very gentle aperients. Bleeding and purging are in almost all cases to be decidedly avoided. Great irritability may occasionally be allayed by small doses of opium and campi i or, or, which is preferable, by muriate of morphia: this will also check diarrhoea, should it; supervene. The confluent form generally requires more or le of the treatment which is adopted in low or putrid fever. Obstinate vomiting, which is sometimes not only a troublesome but alarming symptom, is best encountered by the saline draught in the act of effervescence, with a few grains of aromatic confection, and a feiv drops of tincture of opium. SMALT. (Germ, schmalz.) A fine blue colour used 4C 2 Page 1137