NATURE-PRINTING 403 



potash, etc. Naphthaline yellow, known also as Manchester yellow, Martins yellow, and 

 Jaime d'or, is prepared by adding nitrite of soda to a solution of hydrochlorate of naph- 

 thylamine, -when diazonaphthol is formed. On heating this with nitric acid, binitro- 

 naphthylic acid is produced, and the lime or soda compound, of this acid forms 

 naphthaline yellow. This pigment is used for dyeing wool and silk, without the aid 

 of a mordant, and for modifying the tint of magenta. The naphthaline dyes are 

 fully described in Crookes's ' Practical Handbook of Colours,' and in Watts's ' Dic- 

 tionary of Chemistry.' 



NAPHTHYXiAMINE. C 20 H 9 N (C 10 H 9 N). An organic base, isomeric with 

 cryptidine, produced from nitronaphthaline by the action of reducing-agents, such 

 as sulphide of ammonium, or protacetate of iron. 



KTAPX.ES VEXi&OW. (Jaunc mineral, Fr. ; Neapelgelb, Ger.) This is a fine 

 yellow pigment prepared from antimony. It is said to be prepared by calcining 

 about 12 parts of metallic antimony with 8 parts of red lead and 4 parts of oxide of 

 zinc in a reverberatory furnace. The mixed oxides are to bo well rubbed together 

 and fused ; after this, the fused mass is to be reduced to a very fine powder. This 

 colour is principally prepared in Italy ; but the chrome yellows have almost entirely 

 superseded it. See YELLOW COLOURS. 



NA5SCOTIISTE. C 14 H 23 NO U (C 22 H 23 NO 7 ). An alkaloid contained in opium. 

 It may be obtained in large quantities from the coloured and uncrystallisable 

 mother-liquors obtained in the preparation of morphine by Gregory's process. 



NATIVE AXiIiOlT. A name sometimes given to OsMruM-lBiDruM, which see. 



NATIVE METALS. See the respective metals, as COPPER, &c. 



UATKOIiITE, from the Latin natron, soda. This mineral occurs reniform, 

 botryoidal, and massive ; it has a splintery fracture ; is, on the edges, translucent, 

 and of a pearly lustre. It consists of soda, alumina, silica, and water ; it is found in 

 Scotland, Switzerland, Saxony, and Nova Scotia. Natrolite receives a high polish, 

 and it has, therefore, been used for rings and other ornaments. 



NATRON is the name of the native sesquicarbonate of soda, which occurs as a 

 deposit on the sides of several lakes to the west of the Delta of Egypt ; also as thin 

 crusts on the surface of the earth, rarely an inch in thickness, at the bottom of a 

 rocky mountain, in the province of Sukena, near Tripoli, and two days' journey from 

 Fezzan, and is called by the Africans Trona. The walls of Cassar (Qasrr), a fort now 

 in ruins, are said to have been built of it. At the bottom of a lake at Lagunillas, 

 near Merida in Venezuela, is found a substance called by the Indians Urao, which is 

 tolerably pure sesquicarbonate of soda. It is collected every two years by the natives, 

 who, aided by a pole, plunge into the lake, separate the bed of earth which covers the 

 mineral, break the urao, and rise with it to the surface of the water ; it is then 

 removed to the magazine, and dried in the sun. Natron is also found near Smyrna, 

 in Tartary, Siberia, Hungary, Hindostan, and Mexico ; in the last country there are 

 several natron lakes, a little to the north of Zacatecas, as well as in many other 

 provinces. 



These deposits are never pure sesquicarbonate of soda, but contain generally some 

 sulphate of soda, chloride of sodium, and earthy matters. 



NATURE-PRINTING. (Naturselbstdruck, Ger.) The following description 

 of this very beautiful process is an abstract of a lecture delivered by Mr. Henry 

 Bradbury at the Eoyal Institution : 



Nature-printing is the name given to a technical process for obtaining printed 

 reproductions of plants and other objects upon paper, in a manner so truthful, that 

 only a close inspection reveals the fact of their being copies ; and so distinctly 

 sensible to even touch are the impressions, that it is difficult to persuade those 

 unacquainted with the manipulation that they are an emanation of the printing- 

 press. 



The distinguishing feature of the process consists : first, in impressing natural 

 objects such as plants, mosses, seaweeds, and feathers into plates of metal, causing, 

 as it were, the objects to engrave themselves by pressure ; secondly, in being able to 

 take such casts or copies of the impressed plates as can be printed from at the ordi- 

 nary copper-plate press. 



This secures, in the case of a plant, on the one hand, a perfect representation of its 

 characteristic outline, of some of the other external marks by which it is known, and 

 even in some measure of its structure, as in the venation of ferns and the ribs of the 

 leaves of flowering plants ; and, on the other, affords the means of multiplying copies 

 in a quick and easy manner, at a trifling expense compared with the result and to 

 an unlimited extent. 



The great defect of all pictorial representations of botanical figures has consisted 

 in the inability of art to represent faithfully those minute peculiarities by which 

 natural objects are often best distinguished. Nature-printing has therefore come 



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