NOG 



JMOL 



the night, in contradistinction to diur- 

 nal. 



NOCTURNAL arch, in astronomy, the 

 arch of a circle described by the sun, or 

 a star, in the night. 



NOCTURNAL, semi, arch of the sun, is 

 that portion of a circle he passes over be- 

 tween the lower part of our meridian and 

 the point of the horizon, wherein he 

 arises ; or between the point of the hori- 

 2.011, wherein he sets, and the lower part 

 of our meridian. 



NOCTURNAL, or NocTufrLAamn, an in- 

 strument chiefly used at sea, to take the 

 altitude or depression of some stars 

 about the pole, in order to find the lati- 

 tude and hour of the night. Some noc- 

 turnals are hemispheres, or planispheres, 

 on the plane of the equinoctial. Those 

 commonly in use among 1 seamen are two ; 

 the one adapted to the polar star, and the 

 first of the guards of the little bear ; the 

 other to the pole-star, and the pointers c\f 

 the great bear. 



This instrument consists of two circu- 

 lar plates applied to each other. The 

 greater, which has a handle to hold the 

 instrument, is about two inches and a half 

 diameter, and is divided into twelve 

 parts, agreeing to the twelve months, and 

 each month subdivided into every fifth 

 day ; and so as that the middle of the 

 handle corresponds to that day of the year 

 wherein the star here regarded has the 

 same right ascension with the sun. If the 

 instrument be fitted for two stars, the 

 handle is made moveable. The upper 

 left circle is divided into twenty-four 

 equal parts for the twenty-four hours of 

 the day, and each hour subdivided into 

 quarters. These twenty-four hours are 

 noted by twenty-four teeth to be told in 

 the night. Those at the hours twelve, 

 are distinguished by their length. In the 

 centre of the two circular plates is adjust- 

 ed a long index, moveable upon tht, upper 

 plate. And the three pieces, viz. the 

 two circles and index, are joined by a ri- 

 vet, which is pierced through the centre 

 with a hole, through which the star is to 

 be observed. 



" To use the Nocturnal," turn the up- 

 per plate till the long tcoth, marked 

 twelve, be against the clay of the month 

 on the under plate : then, bringing the 

 instrument near the eye, suspend "it by 

 the handle, with the plane nearly parallel 

 to the equinoctial ; and viewing "the pole- 

 star through the hole of the centre, turn 

 the index about till, by the edge coming 

 from the centre, you see the bright star 

 or guard of the little bear (if the instru- 

 ment be fitted to that star) : then that 



tooth of the upper circle, under the'edge 

 of the index, is at the hour of the night 

 on the edge of the hour circle : which 

 may be known without a light, by count- 

 ing the teeth from the longest, which is 

 for the hour twelve. 



NODE, in surgery, a tumor arising on 

 the bones, and usually proceeding from 

 some venereal cause ; being much the 

 same with what is otherwise called exos- 

 losis. 



NODES, in astronomy, the two points 

 wherein the orbit of a pianet intersects 

 the ecliptic, whereof the node, where 

 the planet ascends northwards, above the 

 plane of the ecliptic, is called the ascend- 

 ing node, the northward node, and the 

 head of the Dragon, and is marked 

 thus Q ; the other node, where the pla- 

 net descends to the south, is called the 

 descending node, the southward node, 

 or the Dragon's tail, marked thus %$ . 



The line wherein" the two circles in- 

 tersect, is called the line of nodes. It ap - 

 pears from observation, that the line of 

 the nodes of all the planets constantly 

 changes its place, and shifts its situation. 

 from east to west, contrary to the order 

 of the signs ; and that the line of the 

 Moon's nodes, by a retrogade motion, fi- 

 nisKes its circulation in the compass of 

 nineteen years ; after which time, either 

 of the nodes having receded from any 

 point of the ecliptic, returns to the 

 same again ; and when the Moon is- in 

 the node, she is also seen in the ecliptic. 

 If the line of nodes were immoveable, 

 that is, if it had no other' motion than 

 that whereby it is carried round the Sun, 

 it would always look to the same point of 

 the ecliptic, or would keep parallel to it- 

 self, as the axis of the earth does. 



From what has been said, it is evident 

 that the Mot.n can never be observed 

 precisely in the ecliptic but twice in 

 every period ; that is, when she enters 

 the nodes. When she is at her greatest 

 distance from the nodes, viz. in the points, 

 she is said, to be in her limits. The 

 Moon must be in or near one of the 

 nodes, when there is an eclipse of the 

 Sun or Moon. 



NOLANA, in botany, a genus of the 

 Pentandria Monogynia class and order. 

 Natural order of Asperifoleje, or Luridse, 

 Borragineae, Jussieu. Essential charac- 

 ter : corolla bell- shaped ; style among 1 

 the germs; seeds five, berried, two-cell- 

 ed. There is but one species, viz. N. pro- 

 trasta, trailing nolana. 



NOLLE prosequi, is used where the 

 plaintiff will proceed no further in his 

 action, aucl may be as well before as after 



