muscles, and a total inability to extend the leg is generally observed. The muscles should be relaxed, by extending the knee, and bending the thigh on the pel vis: they may also be surrounded with a roller, a compress being placed just above the upper portion of the broken bone. The newly-formed substance which unites the broken ends is of a ligamentous or cartilaginous nature, and not bony.

Fractures of the leg. If they affect both bones, there can be no doubt of the nature of the case; but the symptoms are more uncertain, when the fibula alone is broken. The limb should be laid on its outside, with the knee moderately bent. Japanned iron, or wooden splints shaped to the part, and covered with soft pads, are employed. The leg having been placed in the above mentioned position, extension is made, if necessary; and the under splint, covered with its pad, and having an eighteen-tailed bandage laid on it, is passed under the limb. Having observed that the ends of the bones are in exact contact, the surgeon places his soap plaster over the fractured portion, and lays down the bandage. Another soft pad is then put over the upper surface of the leg, and the other splint applied. The leather straps attached to the splints are fastened with sufficient tightness, to prevent any motion of the fractured part. When the pressure of the splints is painful, soft pads are necessary.

Ruptured tendo Achillis. The large tendon of the muscles of the calf of the leg is sometimes torn asunder by the violent exertion of those muscles. An inability to extend the ankle, and a consequent impaired power of progression, follows. The ends of the tendon may be approximated by straightening the ankle and bending the knee. The foot may be kept in this position by the assistance of bandages. The case requires about the same degree of confinement as a fracture. Some persons have not kept their bed for this accident, but have walked about with a high-heeled shoe. The tendon of the plantaris muscle is sometimes rupured, and the accident is attended with the symptoms as if the tendo Achillis were torn.

PARTICULAR DISLOCATIONS.

Lower jaw. This bone can only be lux ated forwards, when the condyloid processes advance beyond the eminentiæ articulares. In this case the mouth remains

open, and cannot be shut; there is pain; impaired and almost destroyed articulation and deglutition, &c. One or both condyles may be displaced. To reduce it, the thumbs, well covered, should be introduced as far backward as possible along the grinding teeth. The surgeon then elevates the front of the bone with his fingers, and the palms of his hands, while he depresses the condyles with his thumbs; and the latter prominences are thus forced back into the glenoid cavities of the temporal bones.

Dislocations of the head and vertebræ are probably imaginary occurrences, as we know hitherto of no well-attested example of their occurrence.

The os humeri is probably luxated more frequently than any other bone. It may be displaced downwards, forwards, and backwards. In all these cases a vacancy is distinguishable under the acromion, in consequence of the absence of the head of the humerus from the glenoid cavity of the scapula. The head of the bone forms a preternatural tumour in some situations. The elbow cannot be carried close to the chest, nor can the limb be elevated, without extreme pain, to a line with the acromion. Great pain is caused by the pressure of the head of the bone in its unnatural position, particularly when it lies in the axilla. Our object is to dislodge the head of the os brachii from its unnatural situation, in order to bring it on a level with the glenoid cavity of the scapula. To accomplish this purpose, extension must be made; that is, the limb must be drawn forcibly outwards; and the bone itself should be made to operate as a lever, which can be best ef fected by the surgeon's knee placed under it towards the head, while he depres. ses the elbow at the proper time, so as to raise the head towards the glenoid cavity. The patient's body should be fixed, by placing a broad towel round the chest, and tying it to some immoveable point. The extension should be gradual, and kept up unremittingly, which can be best effected by means of pullies. The elbow should be bent, and the extending power applied just above the condyles of the humerus. When the surgeon finds that the head of the bone is drawn out of its unnatural position, he may allow the extension to be remitted, and depress the elbow. The arm should afterwards be kept quietly in a sling, a piece of soap plaster, and a spica bandage, being applied to the shoulder.

Elbow. Dislocations at this joint are

very difficult to discover, from the swelling, which comes on so quickly. The radius may be displaced forwards; and here the flexion of the elbow is almost entirely destroyed. The ulna may at the same time be driven backwards: it may also be pushed inwards, so as to occupy the place of the radius. All these are easily reduced, when they are ascertained. Leeches and cold washes should be employed afterwards.

Wrist. The distortion consequent on a displacement of the carpus is so considerable, that the nature of the case is rendered immediately obvious. The reduction is easy; and after it has been accomplished, the hand and fore-arm should be bound on a splint, and supported by a sling.

Thigh. The os femoris may be displaced downwards and inwards, so that the head rests on the obturator foramen; upwards and outwards, when the head is towards the sacro-ischiatic foramen, and the trochanter forwards; and upwards and forwards, so that the head rests upon the os pubis. In the first case, the toes are turned out, and the limb elongated. In the second, the limb is shortened, the foot turned inwards, and the buttock more prominent. Great pain is excited by attempting to move the limb in all cases of luxation, and a vacuity is discernible in the natural situation of the head of the bone. The patient should be placed on the side opposite to the accident, and his pelvis should be fixed by means of a sheet passed under the perineExtension may be made by fixing a broad towel, or the pullies, just above the condyles. When the head of the bone is on the dorsum ilii, the extension is to be continued until it has been brought to the acetabulum, into which the surgeon must guide it. In the dislocation on the obturator foramen, we should make a lever of the bone, by passing a towel under the thigh, near the trochanter, and elevating it after a slight extension has been made, the condyles being at the same time depressed.

um.

The patella may be dislocated either inwards or outwards. Its reduction is very easy, when the muscles inserted into it have been relaxed.

The knee hardly admits of complete luxation, without such injury of the parts as would render the loss of the limb necessary. The nature of the accident must be obvious from the altered figure of the parts, and replacement is perfectly easy. Inflammation must be guarded against afterwards.

The ankle may be dislocated outwards, the fibule being at the same time broken. This is generally a compound luxation; the extremity of the tibia, when displaced from the astragulus, very often penetrating the integuments. Formerly this accident was considered as a cause of amputation; and many practitioners have been in the habit of sawing off the projecting portion. Yet by replacing the bone, closing the wound, keeping the parts quiet, &c. the injury has been often recovered. Luxation may also occur in the opposite direction, and forwards. The latter is very difficult to retain in place, as the muscles of the calf are so apt to move the foot.

SURIANA, in botany, so named in honour of Joseph Donat Surian, a genus of the Decandria Pentagynia class and order. Natural order of Succulentæ. Rosaceæ, Jussieu. Essential character: calyx fiveleaved; petals five; styles inserted into the inner side of the germs; seeds five, naked. There is but one species, viz. S. maritima, a native of the sea coast of South America, and the islands, of the West Indies.

SURRENDER, in law, a deed or instrument, testifying that the particular tenant of lands or tenements for life, or years, doth sufficiently consent and agree, that he which has the next or immediate remainder, or reversion thereof, shall also have the present estate of the same in possession; and that he yields and gives up the same unto him; for every surrenderer ought forthwith to give possession of the things surrendered. Where a surrender is made in consequence of a fresh lease, and that lease turns out invalid, the surrender is considered as not valid, and the former lease is established. Surrender into the hands of the lord is the mode of passing copyholds, and a surrender to the use of a will is necessary, in order to pass them by a will.

SURROGATE, one who is substituted or appointed in the room of another; as the bishop or chancellor's surrogate.

SURSOLID, in arithmetic and algebra, the fifth power, or fourth multiplication of any number or quantity, considered as a root. See RooT.

SURSOLID problem, in mathematics, is that which cannot be resolved but by curves of a higher nature than a conic section, v. gr. in order to describe a regular endecagon, or figure of eleven sides in a circle, it is required to describe an isosceles triangle on a right

AB. Now the triangle BEC being equal to the triangle DFA, and likewise similar thereto, it is evident that, by transposing the former from the right to the left of the figure, would make it rectangular, as shown by the dotted line: therefore multiply the base DC, say 100 yards, by the altitude CE, say 80 yards, and the area will be found to contain 8,000 square yards.

Proposition IV. "To survey the irregulars, fig. 4." Here AC and BD are parallel, but neither CD nor AB are perpendicular thereto, nor parallel between themselves. We must, therefore, cut off the triangles AEB and CFD; whose areas will be found by multiplying half their respective breadths by their whole depths; or their whole breadths by half their depths: the centre part, ECBF, treated as a parallelogram, already described. The whole of the calculations being added together, give the area of the entire figure ACBD.

is

Proposition V. "To ascertain the area of the trapezium, ABCD." This figure is no where parallel, and has all its sides of unequal lengths. The easiest mode of surveying it is, by drawing a diagonal between the two most distant points, C and B; and making off-sets, rectangular to that diagonal, from E to A, and from F to D. These off-sets give the altitudes; EA being the altitude of the triangle CAB, say 40 yards; and FD being the altitude of the triangle BDC, which we will take at 80 yards. Now the diagonal, CB, becomes a base common to both triangles; therefore add the two altitudes together; namely, 40 to 80, which make 120; take their half 60, and multiply by the base, which we will call 140: the area will contain 8,400 square yards. It will be seen that this proposition is, in a great measure, the foundation of all horizontal computation; and the student should remark that all figures, having many sides, may be divided into trapezia, and those again into triangles: each figure will have two sides more than the numbers of triangles it contains: thus, fig. 5 has four sides, and contains two triangles; fig. 6 has five sides, and contains three triangles.

Proposition VI. "To survey the pentagon, or five-sided field, ABCDE, fig. 6." Divide it into the three triangles, ABC, DAC, EAD, and having found their respective altitudes, as already shown, by perpendiculars drawn to their summits from their respective bases, multiply half those altitudes by those bases, and the three products will

amount to the whole area of the pentagon.

Proposition VII. "To ascertain the area of the irregular six-sided figure, or hexagon, (fig. 7) ABCDEF." In this, some of the angles point inward. First draw the line ČE, which will divide the figure into two trapezia; viz. CEBA and CEFD, next divide each of these trapezia by the diagonals BE and CD, into two triangles respectively: the areas of the four triangles, BAE, BCE, FCD, and CED, will, when added together, exhibit the contents of the whole figure.

Proposition VIII. "To measure the irregular field ABCDE, fig. 8." The figure here given has two curved sides, one of which projects, the other of which inflects: the ordinary parts which can be divided into triangles are worked in the manner already shown; but the curved parts must be measured in the following mode: Draw the line ED, and from it make three, or more, off-sets to the curv ed part; take from E to 1, as a base, and half the depth of the off-set 1, as an altitude; multiply them together: then take from 1 to 2, as a base, and the mean of the depths of the off-sets 2 and 3, for the altitude; multiply these also together: do the same for the space between 2 and 3, and calculate the end, between 3 and D, as was done from E to 1; the sum of their several products, added together, will show the area of the curve. As the other curve bends inward, draw the line AE, and treat it the same as was done regarding ED: then considering the entire triangle, AED, as a part of the field, compute its contents, and deduct from it the measures taken by means of the off-sets 4, 5, 6,: the residue, added to the contents of the curve from E to D, and the triangles, ABC and ACD, will show the area of the whole figure ABCDE. It is obvious that, in this manner, the extent of water may be deducted from the area of any field.

The next figure, No. 10, shows the method of surveying with a plain-table, which usually stands upon three legs, and has a compass attached to one side. There is a box-wood frame that fits on the board of the plain-table, and is graduated with 360 degrees. This serves to show the direction of any line from the centre of the board, where there is a brass stud, or plate, let in; and it also compresses the paper so as to prevent its shifting. To this instrument there is a brass rule of two feet long, with ends turned up at right angles, in which are

slits, or sights, to direct the surveyor's eye. He places the rule so as to touch the brass centre, and directing it to any particular point, observes the angle it makes, according to the index on the box-wood frame; while an assistant measures the distance, from the centre under the plain-table to the point observed. The surveyor draws a line on the paper, in the direction of the brass rule, from the exact centre of the plain-table, and notes down at the side of that line, what its length may be in chains, links, &c. according to Gunter's scale; or else in yards and feet, as in familiar measurement. Thus, in fig. 10, A represents the plain-table, placed in the centre of the field BCDE: fg is the rule with sights: the figures written on the sides of the lines proceeding to the four corners, express their several distances from the centre of the plain-table. This mode of surveying is peculiarly suited to small surveys: especially to the interiors of enclosed places; and has the advantage of forming the plan on the paper, as the survey proceeds: for the number of yards, &c. being set off, from the scale on the brass rule, on the several directing lines, as from the centre A to B, C, D, and E, respectively; and their lengths being determined by their several due measures, the lines BC, CD, DE, EB, will give a true fac-simile of the shape of the field. The contents must be ascertained by dividing the field, as before explained, into triangles, whose conjoint measurements will amount to its contents.

Although the plain-table is not a sufficient instrument for general purposes, it is in the foregoing instance extremely convenient: its use may be extended, under due precaution, to ascertaining the distances of remote, or of inaccessible, objects, situated on the same level with itself. But for such purposes a theodolite, standard-triangle, circumferentor, or some instrument capable of taking heights as well as levels, is ordinarily employed. The following proposition will illustrate the above point.

Proposition XI. "To ascertain the distance of an object at C, from the point B, fig. 11." Draw the base line, BA, in any convenient direction, and from each station (commonly marked by surveyors

) observe what angle is made; viz. at B, ascertain the value (or extent) of the angle CBA, and at A, the value of the angle CAB take care to be very correct as to the measurement of your base line; which we will take at 120 yards. Now,

the points A and B being established at a certain distance, and the two angles they mutually form with C being ascertained by the graduated edge of the instrument, it follows that the intersection of the two sights, from B to C, and from A to C, will determine the exact locality of C: let the line BC be measured on the same scale from which BA was taken, and it will show the distance of C from B. In this manner the whole horizon may be surveyed from the base line AB; except such parts as may lay in, that is, occupy the same direction therewith. And it is to be observed, that in laying a base line, the nearer the angle of intersection, as at C, is to a right angle, the more exactly will the distance be denoted. Hence a great extent of base line is to be preferred, when at command; and if practicable, no angle under twenty degrees should be made it is always better to take a new station than to make acute angles with the object to be surveyed; which may, for the most part, be easily avoided in horizontal sights; but in verti cal observations, very acute angles will ordinarily occur.

Thus, in Proposition X. "which relates to ascertaining the heights of P and Q, (fig. 12) from the level of C, and the distance of C from B, cannot be effected but by acute angles." Here, in lieu of laying the base line, AB, as nearly as possible square with the point C, we place it in the exact direction therewith. Then, after taking the angles of elevation from the horizon at the station B, to the two points O and P, and measuring the exact length of the base line AB, the instrument is removed from B to A; where two more sights are taken to O and P. We have thus the two angles, PBA and PAB, determining the locality of P; and the two angles, OBA and OAB, determining the locality of O. Now the line BA being prolonged, and the perpendicular, PO, being likewise continued, will intersect in C. The lines, PB, OB, and CB, being measured on the same scale whence the base line AB, was taken, the altitudes of P and of O, with their intermediate distance, will be given; while the distance of C from B will be exhibited.

We shall conclude this article with a

few words on the manner of carrying a line of sight over a hill, as is often done for the formation of a road, or for the conducting a canal over a rising ground; in which case the level must be preserved