CUR 



CUR 



is taken off from hides designed for these 

 purposes. Hides for the roofs of coaches, 

 &c. are shaved nearly as thin as shoe 

 hides, and blacked on the grain side. 



The oil used in the first operation of 

 stuffing, or dubbing, is called spent oil, 

 and contains a portion of alkali. It has 

 latterly been made up expressly for the 

 curriers. A fact worthy of remark is, 

 that it is imbibed more uniformly and ef- 

 fectually by wet than by dry leather; 

 and this no doubt arises from the gradual 

 evaporation of the water, which gives 

 place to the introduction of the oil by 

 capillary attraction, whereas the air, if in- 

 terspersed in the pores, would resist it. 



CURSITOR, a clerk belonging to the 

 Court of Chancery, whose business it is to 

 make out original writs. In the statute 

 18 Edward III. they are called clerks of 

 course, and are twenty -four in number, 

 making a corporation of themselves. To 

 each of them is allowed a division of cer- 

 tain counties, into which they issue out 

 the original writs required by the subject. 



CURSOR, in mathematical instruments, 

 is any small piece that slides, as the piece 

 in an equinoctial ring-dial that slides to 

 the day of the month ; the little label of 

 brass divided like a line of sines, and 

 sliding in a groove along the middle of 

 another label, representing the horizon 

 in the analemma; and likewise a brass 

 point screwed on the beam-compasses, 

 which may be moved along the beam for 

 the striking of greater or less circles. 



CURTATE distance, in astronomy, the 

 distance of a planet from the sun to that 

 point where a perpendicular let fall from 

 the planet meets with the ecliptic. 



CURTATION, in astronomy, is the in- 

 terval between a planet's distance from 

 the sun and the curtate distance. 



CURTIN, CITHTATN, or COURTIN, in for- 

 tification, is that part of the rampart of a 

 place which is betwixt the flanks of two 

 bastions, bordered with a parapet five feet 

 high, behind which the soldiers stand tofire 

 upon the covered way, and into the moat. 



CURTISIA, in botany, so named from 

 William Curtis, teacher of botany in Lon- 

 don, author of " Flora T.omlinensis," a 

 genus of the Tetrandria Monogynia class 

 and order. Essential character: calyx 

 four-parted ; petals four ; drupe superior, 

 roundish, succulent, with a four or five- 

 celled nut. There is but one species, 

 viz. C. faginea, beech-leaved Curtisia, or 

 hassagay-tree. This is one of the largest 

 trees in the African woods, with very di- 

 minutive flowers. The Hottentots and 

 Caffres make the shafts of their javelins, 

 or assagays, from the wood of this tree. 



They always carry one or two of these 

 with them on their journies. They con- 

 sist of an iron spear hollowed out on each 

 side, about six inches long, with an iron 

 shaft. It is fastened wi*h thong? of lea- 

 ther to a slender round stick, five feet 

 long, tapering towards the end. With 

 these lances, which they throw with great 

 dexterity to the distance of a hundred 

 paces, the Hottentots and Caffres defend 

 themselves, and kill buffaloes and other 

 wild animals. 



CURVATURE of a line, is the peculiar 

 manner of its bending or flexure, by which 

 it becomes a curve of such and such pe- 

 culiar properties. Any two arches of 

 curve lines touch each other, when the 

 same right line is the tangent of both at 

 the same point ; but when thev are ap- 

 plied upon each other in this manner, 

 they never perfectly coincide, unless they 

 are similar arches of equal and similar 

 figures: and the curvature of lines admit 

 of indefinite variety. Because the curva- 

 ture is uniform in a given circle, and may 

 be varied at pleasure in them, by enlarg- 

 ing or diminishing their diameters, the 

 curvature of circles serves for measuring 

 that of other lines. 



Of all the circles that touch a curve in 

 any given point, that is said to have the 

 same curvature with it, which touches it 

 so closely, that no circle can be drawn 

 through the point of contact between 

 them. And this circle is called the circle 

 of curvature ; its centre, the centre of 

 curvature ; and its semidiameter, the ray 

 of curvature belonging to the point of 

 contact. As in all figures, rectilinear 

 ones excepted, the position of the tan- 

 gent is continually varying, so the curva- 

 ture is continually varying in all curvi- 

 linear figures, the circle only excepted. 

 As the curve is separated from its tangent 

 by its curvature, so it is separated from 

 the circle of curvature in consequence of 

 the increase or decrease of its curvature ; 

 and as its curvature is greater or less, ac- 

 cording as it is more or less inflected 

 from the tangent, so the variation of cur- 

 vature is greater or less, according as it 

 is more or less separated from the circle 

 of curvature. 



When any two curve lines touch each 

 other in such a manner that no circle can 

 pass between them, they must have the 

 same curvature ; for the circle that 

 touches the one so closely that no circle 

 can pass between them must touch the 

 other in the same manner. And it can 

 be made appear, that circles may touch 

 curve lines in this manner; that there 

 may be indefinite degrees of more or less. 



