BULL-DOG 549 



quantity of a yellow colouring matter, which may very easily be obtained from it. 

 This colouring matter crystallises is small primrose-yellow needles. It is very little 

 soluble in cold water, but soluble in boiling water, and still more soluble in alcohol. 

 Muriatic and sulphuric acid change its colour to a deep orange, the colour disappearing 

 on the addition of a large quantity of water. It dissolves easily in caustic alkalis, 

 forming solutions of a beautiful deep yellow colour, from which it is again deposited 

 in crystalline needles on adding an excess of acid. It is, however, decomposed when 

 its solution in alkali is exposed for some time to the air, being thereby converted into 

 a yellowish-brown amorphous substance, resembling givm. Its compound with oxide 

 of lead has a bright yellow colour, similar to that of phromate of lead. The com- 

 pounds with the oxides of tin are of a pale but bright yellow colour. On adding 

 protosulphate of iron to the watery solution, the latter becomes greenish, and, on 

 exposure to the air, acquires a dark greon colour, and appears almost opaque. The 

 watery solution imparts to printed calico, colours, some of which exhibit considerable 

 liveliness. Silk and wool do not, however, acquire any colour when immersed in the 

 boiling watery solution, unless they have previously been prepared with some mordant. 

 The composition of this substance in 100 parts is as follows: carbon 50'00, hydro- 

 gen 5-55, oxygen 44-45. Its formula is probably C^H^O 20 [C 15 H M O 10 ]. It appears 

 to be identical with Eutine, the yellow colouring matter contained in the Euta 

 graviolens, or common rue, and in capers ; and with Eixanthim, a substance derived 

 from the leaves of the common holly. From 1,000 parts of fresh buckwheat leaves, a 

 little more than one part of the colouring matter may bo obtained. As the seed of 

 the plant is the only part at present employed, it might be of advantage to collect 

 and dry the leaves, to be used as a dyeing material. E. S. 



The Tartarian Buckwheat (Potygonum Tartarium) differs from the former in having 

 the edges of its seeds twisted. It is not considered so productive, but it is more 

 hardy ; and better adapted for growing in mountainous situations. 



The Dyer's Buckwheat. (Potygonum tinctorium.') This plant was introduced to tho 

 Eoyal Gardens at Kew by Mr. John Blake, in 1776. Authentic information as to 

 its properties as a dye-yielding plant was only received at a comparatively recent 

 period, from missionaries resident in China, where it has always been cultivated 

 for its colouring matter. In Europe, attention was first directed to its growth by 

 M. Delille, of the Jardin du Eoi at Montpellier, who in 1835 obtained seeds from tho 

 Baron Fischer, -Director of the Imperial Gardens at St. Petersburg. It has since that 

 time become sufficiently valuable to render its cultivation as a dye-drug of sufficient 

 importance. The Japanese are said to extract blue dyes from Polygonum Chinensis, 

 P. barbatum, and the common roadside weed, P. aviculare. Lawson. 



BUDDLE. See DRESSING ORES. 



BUBBLING. A mining term. The process of separating the metalliferous ores 

 from the earthy matters with which they are associated, by means of an inclined 

 hutch, called a buddle, over which water flows. It is indeed but an arrangement for 

 availing ourselves of the action of flowing water to separate the lighter from the 

 heavier particles of matter. See DRESSING OHES. 



BT7DE XilCHT. A highly illuminating flame invented by Sir Goldsworthy 

 Gurney, of Bude, in Cornwall. Oxygen gas is driven through the centre of an 

 argand flame of ordinary coal-gas, .by which an intense combustion is established, 

 and hence the high illuminating power is obtained. 



BUFF LEATHER. A leather prepared with some albuminous substance and 

 oil. See LEATHER. 



BUFF STICKS. Pieces of wood upon which buff leather is fastened ; they are 

 used for polishing. 



BUGLE. A kind of bead used for ornamenting dresses. 



BUHL Buhl-work consists of inlaid veneers ; and differs from marquetry in being 

 confined 'to decorative scrollwork, frequently in metal, while the latter is more com- 

 monly used for the representation of flowers and foliage. Boule, or Buhl, was a 

 celebrated cabinet-maker in France, who was born in 1642 and died in 1732. He 

 was appointed ' Tapissier en titre du RQJ,' and he gave his name to this peculiar 

 process of enlaying wood with either wood or metal. See MARQUETRY, PARQUETRY. 



BUHR-STONE is a cellular flinty quartz rock, constituting one of the jaspery 

 varieties of the quartz family. It forms a celebrated grit-stone, much used in Franco 

 and other parts of the Continent for grist mills. Those of La Ferte-sous-Jouarre 

 (Seine-et-Marne) are regarded as superior to all others. In consequence of tho 

 necessity for carefully piecing these stones together, they are naturally expensive ; 

 yet the demand for buhr-stones continue* great. Written also BURR and BURRH. 



BUKE or BUCK MUSLIN". A clear muslin woven for tambour working, and 

 used principally for ladies' dresses. It is often called ' book ' muslin. 



BULL-BOG. A name given to an iron slag. See IBOK. 





