cus 



oient to describe the cubic parabola once. 

 When the equation to be constructed, 

 by omitting the two last terms h x and k, 

 is reduced to 7 dimensions ; the other 

 curve by expunging m, will have the 

 double point in the beginning of the ab- 

 scisse, and may be eas>ily described as 

 above: if it be reduced to six dimensions, 

 by omitting the last three terms g&-\- 

 /i.r-f-Ar/ the other curve by expung- 

 m f> w 'iH become a conic section. And 

 if, by omitting the last three terms, the 

 equation be reduced to 3 dimensions, we 

 shall fall upon Wallis's const ruction by the 

 cubic parabola and righfline. 



CrnvEs, family of, according to Wol- 

 h'us, is a congeries of several curves of 

 different kinds, all defined by the same 

 equation of an indeterminate degree ; 

 but differently, according to the diversity 

 of their kinds. For example, let the 

 equation of an indeterminate degree be 

 a m 'x=ym : If i=2, a A- will be equal 

 to y2. If m = 3, then will a*x = yi. 

 If m = 4, then will a3 x r= y+, 8tc. ; all 

 which curves are said to be of the same 

 family. The equations, however, by 

 which the families of curves are de- 

 fined, must not be confounded with tran- 

 scendental ones ; though with regard to 

 the whole family they be of an indetermi- 

 nate degree, yet with respect to each 

 several curve of the family they are de- 

 terminate ; whereas transcendental equa- 

 tions are of an indefinite degree with re- 

 spect to the same curve. 



CUSCUTA, in botany, a genus of the 

 Tetrandria Digynia class and order. Na- 

 tural order of Convolvuli. Essential cha- 

 racter: calyx four-cleft ; corolla one pe- 

 talled ; capsule two-celled. There are 

 four species. These are parasitical plants, 

 fastening themselves to, and drawing 

 their nourishment from, others. C. Eu- 

 ropza, common dodder, is a native of 

 Europe, in the hedges, &c. usually on 

 bushes and the loftier plants, as hops, 

 brambles, woody nightshade, fern, thistles, 

 hemp ; also on flax, nettles, clover grass, 

 Sec. flowering in July and August. Cus- 

 cuta Americana is the species indigenous 

 in the United States; it is found on plants 

 growing on the borders of creeks, rivu- 

 lets, fountains, and other damp places, at- 

 taching itself to Impaticus, Chephalan- 

 thus, &c. 



CUSPIDATE, in natural history, termi- 

 nating in a sharp point. 



CUSSOMA, in botany, so called in me- 

 mory of Cusson, a celebrated botanist ; 

 genus of the Pentandria Digynia class and 

 order. Natural order of Aralisc. Essen- 



cus 



tial character : petals three-cornered ; 

 margin of the receptacle dilated into a 

 five-toothed calyx. There are two spe- 

 cies, vis. C. thysifloraand C. spicata, both 

 natives of the Cape of Good Hope. 



CUSTOM, a very comprehensive term, 

 denoting the manners, ceremonies, and fa- 

 shions of a people, which, having turned 

 into a habit, and passed into use, obtains 

 the force of laws; in which sense it im- 

 plies such usages as, though voluntary 

 at first, are yet, by practice, become ne- 

 cessary. 



Custom is hence, both by lawyers and 

 civilians, defined lex non scripta, a law, 

 or right, not written, establish od by 

 long usage, and the consent of our an- 

 cestors ; in which sense it stands op- 

 Eosed to the lex scripta, or the written 

 iw. 



As no law can bind people without their 

 consent, so, wherever that is had, and a 

 certain rule used as a law, such rule gives 

 it the force of a law; and if it be univer- 

 sal, then it is common law ; but if restrain- 

 ed to this or that particular place, it is 

 custom. 



Custom had its beginning, and received 

 the sanction of the law, thus ; when a 

 reasonable act, once done, was found 

 to be beneficial to the people, then they 

 had frequent recourse to it ; and by re- 

 petitions thereof, it became a custom, 

 which being 1 continued ultra tritavittn, time 

 out of mind, without any interruption, it 

 obtained the power of a law, and binds 

 the places, persons, and things, concern- 

 ed tlierein. 



All customs ought to have a reasona- 

 ble commencement, be certain, not am- 

 biguous, have uninterrupted continuance, 

 and not be against the King's preroga- 

 tive : these are incidents inseparable : 

 yet a custom is not unreasonable for be- 

 ing injurious to private persons and in- 

 terest, so as it tends to the general ad- 

 vantage of the people : but if any custom 

 be contrary to the public good, or if it in- 

 jures a multitude, and benefits only some 

 certain persons, such a custom is repug- 

 nant to the laws of reason, and conse- 

 quently void. Custom must always be 

 alleged in many persons ; and so it may 

 be claimed by copyholders, or the inhabi- 

 tants of a place, as within such a county, 

 hundred, city, borough, manor, parish, 

 &c. but regularly they shall not allege a 

 custom against a statute : nor may custom 

 be pleaded against custom ; though acts 

 of parliament do not always take away 

 the force of customs. The general cus- 

 toms used throughout England, being the 



