LIAS 107 



fine masses on Mount Hradisko, near Rosna, in Moravia. It is remarkable for the 

 large quantity of lithia -which it contains, and also for its containing the newly- 

 discovered metal rubidium. See SPECTRUM ANALYSIS. 



LEPIDOMEIiAIffE. An iron-potash mica, of black colour. 



ZiETTSOlTCITE. A beautiful blue velvety mineral, from the Banat, first de- 

 scribed by Dr. J. Percy. It is a hydrqus sulphate of copper, of rare occurrence. 



LETTUCE. The Lactuca sativa, cultivated as a salad. 'Lettuce opium' is 

 prepared from this species, and from L. virosa, a more highly narcotic species. 



XiETTCAXTXXiXN'E. If a solution of rosaniline is left in contact with metallic 

 zinc, or treated with sulphide of ammonium, it is rapidly decomposed. The rosani- 

 line disappears, and is transformed into a remarkable base, which has received the 

 name of leucaniliiie, and which may be obtained in completely colourless needles 

 scarcely soluble in water, very soluble in alcohol. Its formula is : 



CtojpiNi (C'WH 1 ). 



The salts of leucaniline are also colourless, easily crystallisable, and very soluble 

 in water, from which they may be precipitated by the addition of an excess of 

 acid. 



There exists an extremely remarkable relation between the composition of leu- 

 caniline and that of rosaniline : 



Rosaniline C 2 H 19 N S (C 1() H lfl r 3 ). 



Leucaniline . . . . . C 20 E 2I N 3 (C 10 H 2 'IT 3 ). 



Leucaniline differs therefore from rosaniline simply by containing two atoms more 

 of hydrogen. 



The two bases bear to each other the relation which exists between blue and white 

 indigo : 



Blue indigo CH'*N0 (C 8 H IO r 2 O). 



White indigo .... C 16 H 12 N 2 2 (C 8 H I2 W 2 O). 



Leucaniline, as might have been expected from this interesting relation, may be 

 reconverted into the red colouring matter by oxidising agents. On gently heating 

 the colourless solution of hydrochlorate of leucaniline with peroxide of barium, per- 

 chlorides of iron or platinum or chromate of potassium, the liquid at once re-assumes 

 the splendid colour of the rosaniline salts. (Hofmann.) 



LETTCITE. A mineral found in volcanic rocks, containing usually 56'10 of 

 silica, 23'10 of alumina, and 21'15 of potash. The finest and most beautiful crystals 

 are found in the older lavas of Vesuvius and Rocca Monfina, and in the neighbour- 

 hood of Rome. It is sometimes called the white garnet, from the similarity of its 

 crystallisation to that of the common garnet. Kirwan calls it the white garnet of 

 Vesuvius. It was always supposed that leucite crystallised in the cubic system 

 until Vom Rath showed, in 1872, that the crystals belonged to the tetragonal 



A synonym of LETTKOI. 



IiEUCOPYRITE. An arsenide of iron, resembling Lolingite. 



IiETTXOXt. See CHINOLINE. 



XiEVEIi (a mining term). An adit gallery or horizontal working in a mine. 



LEVIGATION is the mechanical process whereby hard substances are reduced 

 to a very fine powder. 



IiEViriiOSE. A kind of sugar which turns the plane of polarisation of a ray of 

 light towards the left hand. 



LEWIS is the name of one kind of shears used in cropping woollen cloth. 



IiZAS. Under this term are comprehended the strata which intervene between the 

 Trias, or New Red Series, and the Inferior Oolite. In the aggregate they are of 

 considerable thickness, and occupy a large area" in this country, stretching in a 

 north-easterly direction from the sea west of Lyme Regis, in Dorsetshire, to Red- 

 car, on the coast of Yorkshire. The strata which compose the Liassic series 

 consist, in the lower part, of compact argillaceous limestone, alternating with or 

 forming layers in clay, to a provincial pronunciation of which word the name 

 lias probably owes its origin. This limestone forms the base of a thick deposit of 

 blue clays and marls, which are overlaid by a series of sands and sandstone, called 

 Marlstone ; these in tl:oir turn are separated from another mass of sands, which 

 form the uppermost member of the group, by a stratum of clay, known as the 

 Upper Lias Clay. 



