N A 



[316 ] 



N M 



Yery generally in the waters of 

 mineral springs. The king's bath, 

 at Bath, evolves 96*5 per cent, of 

 nitrogen, 3'5 oxygen, and some 

 carbojiic acid. The hot-well at 

 Bristol evolves 92 per cent, nitro- 

 gen, and 8 oxygen. The springs 

 at Buxton, Bakewell, and Stony 

 Middleton, Derbyshire, evolve ni- 

 trogen only. Those of the Spas 

 in Germany, yield various propor- 

 tions, as do the other thermal 

 springs in other parts of the globe. 

 Its specific gravity is 0*9722. 

 The combining power of nitrogen 

 is variously estimated, some chem- 

 ists making it 14*15, while others 

 consider it to be only half of that 

 number. Its symbol is N. 



NOA'CHIAN. Pertaining to the great 

 deluge related by Moses, from 

 which Noah and his family were 

 saved, and thus called after Noah. 

 Cuvier says " that if there be any 

 one fact thoroughly established by 

 geological investigations, it is the 

 certainty of the low antiquity of 

 the human race, and present state 

 of the surface of the earth, and the 

 circumstance of its having been 

 recently overwhelmed by the waters 

 of a transient deluge." 



NODE, (nodus, a knot, Lat. nodus, 

 Fr. nado, It.) 1. A hard knot or 

 swelling, a bump, or rising. 

 2. In astronomy, the nodes of a 

 satellite's orbit are the points in 

 which it intersects the plane of the 

 orbit of a planet. The ascending 

 node is the point through which 

 the body passes in rising above the 

 plane of the ecliptic, and the de- 

 scending node is the point through 

 which the body passes in sinking 

 below the plane of the ecliptic. 



NOCTI'VAGANT. j (from nox, the night, 



NocTi'vAGous. j and vagor, to wan- 

 der, Lat.) A name given to such 

 animals as wander, in search of 

 prey, during the night. 



NODOSA'BIA. A genus of orthocerata, 



found only fossil. They are poly- 

 thalamous univalves. 



NO'DTTLAR. In the form of a nodule 

 or small lump ; having irregularly 

 globular elevations. 



NO'DULAK IKON ORE. A variety of 

 argillaceous oxide of iron ; occur- 

 ring in masses, varying from the 

 size of a walnut to that of a man's 

 head. Their form is spherical, 

 oval, or nearly reniform, or some- 

 times like a parallelepiped with 

 rounded edges and angles. They 

 have a rough surface, and are essen- 

 tially composed of concentric layers. 

 These nodules often contain, at the 

 centre, a kernel or nucleus, which 

 is sometimes moveable, and always 

 differing from the exterior in colour, 

 density, and fracture. The texture 

 of the exterior is compact and solid ; 

 but the density gradually dimin- 

 ishes to the centre, which has an 

 earthy texture. Specific gravity, 

 about 2'57. Its constituents are 

 oxide of iron 77'0, silex 6-0, oxide 

 of manganese 1-0, alumine 0'5, 

 water 13*5. These nodules have 

 also been called (Etites and Eagle- 

 stones, from an opinion that they 

 were found in eagles' nests, where, 

 it was supposed, they prevented the 

 eggs from becoming rotten. 



NO'DULE. (from nodulus, a little knot, 

 Lat.) A rounded, irregular-shaped 

 mineral mass. Ironstone forms 

 regular layers of round nodules, 

 sometimes as much as a foot or 

 eighteen inches in diameter. These 

 nodules, when broken open, are 

 often found to be traversed by 

 cracks in all directions, more or 

 less filled up with crystalline spar, 

 together with crystals of galena, 

 blende, iron pyrites, and other 

 minerals. Jukes. 



NO'GBOBS. A fossil resembling a 

 belemnite. 



NOMENCLATURE, (nomenclatures, Lat. 

 nomenclature, Fr. collection des mots 

 qui sont propres aux differentes par- 

 ties d'une science ou d'un art.) The 



