LLAMA 135 



may be thus described, A drawing of the subject, in outline, on transfer tracing- 

 paper, is made in the ordinary way : when transferred to a stone, this drawing is 

 called the keystone, and it serves as a guide to all the others, for it must be transferred 

 to as many different stones as there are colours in the subject ; as many as thirty 

 stones have been used in the production of one coloured print. The first (-tone 

 required, generally for flat, local tints, is covered with lithographic ink where tho 

 parts should be of solid colour: the different gradations are produced by rub- 

 bing the stone with rubbing-stuff, or tint-ink, made of soap, shell-lac, &c. &c., and 

 with a painted lithographic chalk where necessary ; the stone is then washed over with 

 nitric acid, and goes through the entire process described above. A roller charged 

 with lithographic printing-ink is then passed over it to ascertain if the drawing 

 comes as desired ; and the ink is immediately afterwards washed off with turpentine : 

 if satisfactory, this stone is ready for printing, and is worked off in the requisite 

 colour ; the next stone undergoes the same process for another colour, and so with 

 the rest, till the work is complete : it will of course, be understood, that before any 

 single impression is finished, it will have to pass through as many separate printings 

 as there are drawings on stones. The colours used in printing are ground up with 

 burnt linseed-oil, termed varnish. 



XiITHOIMCARCZ!. An iron ochre ; essentially a silicate of alumina, with 6 to 7 

 per cent, of oxide of iron, in many respects resembling China clay or kaolin. It is 

 found abundantly in co. Antrim. See IEON. 



IiZTSSUS (Tournesol, Fr. ; Lackmus, Ger.) is prepared in Holland from the spe- 

 cies of lichen called Lecanora tartarea, and Roccella tinetoria. The ground lichens are 

 first treated with urine containing a little potash, and allowed to ferment for several 

 weeks, whereby they produce a purple-red ; the coloured liquor, treated with quick- 

 lime and some more urine, is set again to ferment during two or three weeks, then 

 it is mixed with chalk or gypsum into a paste, which is formed into small cubical 

 pieces by being pressed into brass moulds, and dried in the shade. Litmus has a 

 violet-blue colour, is easy to pulverise, is partially soluble in water and dilute alcohol, 

 leaving a residuum consisting of carbonate of lime, of clay, silica, gypsum, and oxide 

 of iron combined with the dye. The colour of litmus is not altered by alkalis, but is 

 reddened by acids ; and is therefore used in chemistry as a delicate test of acidity, 

 either in the state of solution or of unsized paper stained with it. 



Litmus is used in Holland to give a peculiar tint to certain kinds of Dutch 

 cheese. 



The preparation of litmus has been described by Ferber, Moreloz, and others. 



Litmus is imported from Holland, in the form of small, rectangular, light, and 

 friable cakes of an indigo blue colour. Examined by the microscope, we find sporules 

 and portions of the epidermis and mesothallus of some species of lichen, moss, leaves, 

 sand, &c. The odour of the cakes is that of indigo and violets. The violet odour 

 is acquired while the mixture is undergoing fermentation, and is common to all the 

 tinctorial lichens. It has led some writers into the error of supposing that the 

 litmus-makers use Florentine orris in the manufacture of litmus. The indigo colour 

 depends on tho presence of indigo in the litmus cakes. See LICHEN. 



IiITIVIUS-PAPER. Paper coloured with an infusion of litmus, used as a test for 

 the presence of acids. 



Faraday, in his ' Chemical Manipulation,' recommended an infusion of one ounce of 

 litmus, and half a pint of hot water. Bibulous paper is saturated with this. Prof. 

 Graham preferred good letter-paper to the unsized paper. In order to obtain very 

 delicate test-paper, the alkali in the litmus must be almost neutralised by a minute 

 portion of acid. 



ZiITTORAXi, a geological term. Belonging to the sea-shore. 



XiXVX-BXBI. Another name for Divi-divi. See LEATHEB. 



XiXXZVIATIOTJ (Lcssivage, Fr. ; Auslaugen, Ger.) signifies the abstraction by 

 water of the soluble alkaline or saline matters present in any earthy admixture ; as 

 from that of quicklime and potashes to make potash-lye, from that of effloresced alum 

 schist to make aluminous liquors, &c. 



XiXiAnXA. A genus of animals belonging to tho class Mammalia, order Ungulata, 

 family Bovida, and tribe Camelina. They are the camels of South America, to 

 which country they are confined. In the wild state the llamas keep together in herds 

 of from one to two hundred. There are two distinct species found wild in South 

 America, inhabiting the Peruvian Alps, the Pampas, and the mountains of Chili. 

 These animals are used as beasts of burthen ; cords and sacks, as well as stuffs for 

 ponchos, &c.,are fabricated from their wool ; and their bones are converted into instru- 

 ments for weaving the same. The Alpaca, which is a variety of tho llama, has 

 given its name to a cloth manufactured from its hair ; and this has become so valuable, 

 that attempts have been made to naturalise the animal in Eiirope. The success, 



