MINERALOGY. 



475 



Gsoznottic Situation. \ t occurs as an efflorescence on 

 the surface of soil, on decomposing rocks of particu- 

 lr kinds, on the sides and bottoms of lakes that be- 

 come dry during the summer season, also on the 

 walls and bottoms of caves, and dissolved in the water 

 of lakes and springs. In Hungary, according to Ruck- 

 ert and Pazmand, there are so many natron lakes, that 

 0,000 quintals of soda could be obtained from them 

 annually. In some places of the same country, it efflor- 

 esces on the surface of the soil, heath, &c. It abound* 

 in th natron lakes of Egypt. 



Geographic Situation. Europe. It occurs in Bohe- 

 mia, Hungary, Switzerland, in the Phlegrean Fields, 

 Monte Nuovo, near Naples, and Mount ./Etna in Sicily. 



Africa. It occurs in considerable quantity in 



Egypt. 



A*ia. In the vicinity of Smyrna, and the ancient 

 city of Ephesus ; in Bengal ; near Bombay ; Persia : 

 Natolia; district of OchoUk, in the government of 

 Irkutsk ; and in the Crimea. 



America. Dissolved in the lakes of Mexico. 



SECOND SUBSPECIES. 

 Radiated RADIATED NATROW, Jameto*. Strahliche* Natron, 



N<tron. Klaprolh. 



External Character*. Colours greyish and yellowish 

 white. Occurs in crusts, in radiated distinct concre- 

 tions, and crystallized in capillary or acicular crystals, 

 which are aggregated on one another. The lustre is 

 glistening and vitreous. It is translucent. 



Chemical Characters. Same a* those of common 



Cotutit. Parti. Water of crystallization, 82.50 

 Carbonic acid, . SS.OO 

 Pure soda, . 37-00 



Sulphate of soda, . 2.50100.00 

 Klaprolh, Beit. b. iii. *. 87. 



Geognotlic and Geographic Situations Mr. Bagge, 

 Swedish Consul at Tripoli, gives the following in- 

 formation respecting this interesting subspecies of 

 natron. " The native country of this natron, which 

 it there called Trona, is the province Sukena, two 

 days journey from Fezzan. It is found at the bot- 

 tom of a rocky mountain, forming crusts, usually 

 the thickness of a knife, and sometimes, although rare- 

 ly, of an inch, on the surface of the earth. It u always 

 crystalline : in live fracture it consists of cohering, 

 longuh, parallel, frequently radiated crystals, having 

 the aspect of unburnt gypsum. Besides the great 



rintity of trona which is carried to the country of 

 Negro* and to F.gypt, fifty tons are annually car- 

 ried to Tripoli. It is not adulterated with fait. The 

 salt-mines are situated on the sea-shore ; but the trona 

 occurs twenty-eight days journey up the country." 

 According to the accounts of Mr. Barrow, it would 

 appear also to occur in the district of Tarka, in Bosbie- 

 man's Land, in Southern Africa. 



I'tei. It is principally employed in the manufac- 

 ture of glasa and soap, in dyeing, and for the washing 

 of linen. It is sometimes purified before it is used, 

 but more frequently (particularly that from Egypt) 

 it U used in its natural state. 



I. NITRE. 



NITBE. Three axes. Cleavage, prismatic. Taste, cooling and 



ssline. Hardness = 2.0. Specific gravity = 1.9, 2.0. 



rH.m-.iic 1. PRISMATIC NITRE, Jameson. PriaoMttfches N- 

 ttirlicher Saltpeter, Mohs. Naturlicher Salpeter, Werner. 



Prism = . Cleavage prismatic, and in the direc- Oryctogno. 

 tion of the smaller diagonal of the prism. *j-_ 



Description. External Characters. Colours grey- > *^"Y"" 1 *' 

 ish-white, yellowish-white, and snow-white. Occurs 

 in flakes, crusts, and in capillary prismatic crystals. 

 Dull, glimmering, or shining, and the lustre vitreous. 

 Alternates from translucent to transparent. Brittle, and 

 easily frangible. 



Chemical Characters. Deflagrates when thrown on 

 hot coal. 



Constituent J'</r/j. The natural nitre of Molfetta, ac- 

 cording to Klaprotli : Nitrate of potash, 42.55 

 Sulphate of lime, 25.45 

 Carbonate of lime, 30.40 

 Muriate of potash? 0.20 

 Loss, . . 1.40 



100.00 



Klaprolh, Beit. b. i. s. S20. 



Geognotlic Situation. It is usually found in thin 

 crusts on the surface of soil, and sometimes also co- 

 vering the surface of compact limestone, chalk, and 

 calc-tufF. In many countries it germinates in certain 

 seasons out of the earth, and when this earth is accumu- 

 lated in heaps, so as to expose a large surface to the 

 atmosphere, it is found to produce it annually. 



Geographic Situation. Europe. It is found in great 

 quantities in many plains in Spain; very abundantly in 

 the plains of Hungary, the Ukraine and Podolia; and 

 also in France and Italy. 



Alia. Nitre is very abundant in India; also in Per- 

 sia ; and in the valley between Mount Sinai and Suez, 

 in Arabia. 



Africa. T\\\s talt is abundant in Egypt ; also at LH- 

 dainar, in the interior of Africa ; and in the Karoo De- 

 sart, to tlte east of the Cape of Good Hope. 



America. The nitre used for the manufacture of gun- 

 powder in the United States of America, is obtained 

 from an earth collected in the limestone caves of Ken- 

 tucky. Nitre effloresces in considerable abundance on 

 the soil near Lima; and in Tucuman in South America. 



Uses. In Hungary, Spain, Molfetta, and the East 

 Indies, considerable quantities of natural nitre are col- 

 lected ; but the greatest proportion of that used in com- 

 merce, is obtained by working artificial nitre beds. These 

 consist of the refuse of animal and vegetable bodies, 

 undergoing putrefaction, mixed with calcareous and 

 other earths. Its principal use is in the fabrication of 

 gunpowder: it is also used in medicine, and many of 

 the arts. 



GENUS III. GLAUBER SALT. 



Three axes. Cleavage prismatic. Taste first cooling, Gtnai 

 and then saline and bitter. Hardness = . Sp. SALT - 



gravity = 2.2, 2.3. 



1. PRISMATIC GLAUBER SALT, Jameson. I'risma- p,.;,^,^ 

 tisches Glauer Salz, Moks. Natiirliches Glauber Salz, Glauber 

 Wrner. Salt. 



Prism unknown. Cleavage not accurately ascertained. 



External Characters. Its colours are greyish and 

 yellowish white j seldom snow or milk white. It oc- 

 curs in the form of mealy etflore^-rm'fs; in crusts; 

 seldom etalactitic, small botryoidal, renitbrni ; in small 

 and fine granular distinct concretions; and crystallized 

 in prisms, which are often acicular. Internally it is shin- 

 ing.and the lustre u v itroous. The fracture is conchoidal, 

 or uneven. The fragment*; arc indeterminately angular, 

 and blunt edged. It is brittle, nod easily frangible. 



Chemical Characters. Before the blowpipe, it is af- 



