NAT 



NEA 



NAPHTHA. A highly-inflammable 

 fluid, of a peculiar odour, sp. gr. 75, 

 which exudes from the earth in some 

 places. A similar fluid is distilled 

 from wood tar, and called wood naph- 

 tl a. It is used as a solvent of India 

 rubber. 



NAPHTHALINE. A white, crys- 

 talline, volatile product of the de- 

 structive distillation of pit coal. 

 Naphthalic acid, naphthalamide, &.C., 

 are derivatives. 

 NAPIFORM. Turnip-shaped. 

 NARCEIA. A vegetable alkaloid 

 from opium, producing salts of a blue 

 colour. Little is known concerning 

 its effects. 



NARCISSUS. Ornamental bul- 

 bous flowers. 



NARCOTICS. Anodynes. Drugs 

 which produce sleep, drowsiness, and 

 allay pain. Opium, henbane, tobac- 

 co, camphor, stramonium, &c., are 

 of this kind. 



NARCOTINE. A vegetable alka- 

 loid existing in opium, to which its 

 stimulating effects is due. 

 NARES. The nostrils. 

 NASCENT. In the act of being 

 produced or evolved. A chemical 

 phrase given to the evolution of gas- 

 es from fluids, at which time they 

 are more fitted to unite with other 

 bodies. Hydrogen, nitrogen, and oth- 

 er gases, in the aeriform state, com- 

 bine only slowly with substances, 

 but when nascent enter readily into 

 union. 



NASTURTIUM. Cress, Indian. 

 NASUTA (from nasus, the nose). 

 A prolongation of the muzzle into the 

 form of a nose. 



NATANS, NATANT, NAYANT. 

 Floating or swimming. 



NATATORY. In zoology, when 

 the feet or tail are provided with a 

 membrane or hairs to repel or dis- 

 place water, and buoy up the insect 

 or animal. 



NATRIUM. Sodium. See Soda. 

 NATROLITE. A fibrous, yellow- 

 ish mineral. Silicate of alumina and 

 soda. 



NATRON. Soda. Impure, native 

 sesquicarbonate of soda, found in 

 Egypt, Fezzan, Tarlary, Hindoslan, 



in Mexico near Zacatecas, and in Co- 

 lumbia forty-eight miles from Merida. 

 That of Fezzan is called Trona, and 

 the Columbian Urao. All these lo- 

 calities are either in lakes or on the 

 sites of ancient lakes. Egyptian na- 

 tron consists of 22 44 carbonate of 

 soda, 18 35 sulphate of soda, 38.64 

 common salt, GO insoluble matter, 

 and 14 water : trona, of 65 75 car- 

 bonate, 7-65 sulphate, 2 63 salt, 24 

 water, 1 insoluble matter. 



NATURAL HI. STORY. A de- 

 scription of natural objects, as ani- 

 mals, plants, insects, fishes, miner- 

 als, fossils. 



NATURAL ORDERS OF 

 PLANTS. Natural system of Jussieu. 

 Groups of plants having a close sim- 

 ilarity in internal organization, and 

 frequently in external characters and 

 properties. 



NATURAL PHILOSOPHY. 

 Physics, mechanical philosophy. The 

 science which investigates the me- 

 chanical laws of nature ; and the rela- 

 tions of weight, movement, pressure, 

 or of mechanical forces in masses. 



NAUCA. A seed in which the 

 scar of the hilum occupies a third of 

 the surface. 



NAUSEA. A feeling similar to 

 that preceding the act of vomiting. 



NAVE OF A WHEEL. The hub, 

 the block in the centre of the spokes, 

 which receives them. It is bound by 

 two jiave-bands of iron on the outside, 

 and contains in the inside an iron box 

 or washer, to save the friction of the 

 axle. 

 NAVEL ILL See Calf. 

 NAVEL-WORT. The American 

 plant is Hydrocotyle umbellaia, and a 

 water weed. 



NAVE W. Brassica campestris. 

 The wild plant is a native of Eng- 

 land : in the cultivated form it is 

 known as colza and rape. 



NAVICULAR (from navis, a ship). 

 Having the figure of a ship's body. It 

 is applied to the nut bone of the foot, 

 as well as to the form of seeds, &,c. 

 NEAT CATTLE. Horned cattle, 

 oxen. 



NEAT'S-FOOT OIL. The fat oh 

 taiaed by boiling calve's feet. 



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