158 MADDER 



they would be generally adopted, and thought every possible endeavour should be 

 made to establish their use. The machine now described appeared to him to be one 

 of the best that had been brought forward for coal-cutting ; and he thought the prin- 

 ciple of its construction and action was more likely to prove the right one than that 

 of machines designed to work a pick in a similar manner to hand-labour. One of the 

 earliest coal-cutting-machines that he remembered had been made on the same prin- 

 ciple as a circular saw, but in that case the cutting-wheel had been literally a circular 

 saw with fixed teeth, and had consequently proved a failure in actual working. The 

 use of moveable teeth in the cutting-wheel of the present machine was an important 

 practical improvement, and this machine appeared to him to have been worked out in 

 a very ingenious way, and seemed one of the most likely to succeed that he had yet 

 met with. "Whether the air was worked expansively in the cylinders was a question 

 that should not be overlooked in regard to the economy of any coal-cutting machine ; 

 and if the expansion could be obtained without complicating the construction of the 

 machine, it was by all means desirable to have the benefit of it. If, however, it 

 involved the introduction of cams or excentrics and ordinary valve-gear, he thought it 

 would be better to waste a portion of the power than to introduce these complications, 

 as he considered the utmost simplicity of construction was an object of such essential 

 importance for the success of a coal-cutting machine ; and in working with compressed 

 air it must be borne in mind that the power was cheaply produced at the mouth ot 

 the pit, and readily conveyed to the machine. The construction of the machine now 

 described seemed to possess the advantage of simplicity, and he thought this machine 

 was very likely to prove one of the best yet introduced ; it had also another advan- 

 tage in being able to hole its own way into the coal at starting, without requiring any 

 preliminary holing to be done by hand before it could be got to work. He agreed in 

 considering that the discharge of exhaust-air from a coal-cutting machine was hardly 

 capable of producing an appreciable effect upon the ventilation of a colliery, as the 

 quantity of fresh air so discharged was insignificant in comparison with the total 

 quantity passing through the mine. 



TYZACIiE is the name given to certain spots in minerals, of a deeper hue than the 

 main substance, and differing from it. Clay-slate may be macled with Iron Pyrites ; 

 or it may be that the made spots are some peculiar form of the same mineral matter 

 supposed to proceed from some disturbance of the particles in the act of crystallisation. 



Modes are twin crystals which are united, or which interpenetrate. 



MADDER ( Garance, Fr. ; Krapp, Fdrberrbthe, Ger.), a substance very exten- 

 sively used in dyeing, is the root of the Rubia iinctorum, Linn. It is employed for 

 the production of a variety of colours, such as red, pink, purple, black, and chocolate. 



The Erythrodanum or Ereuthrodanum of the Greeks, of which Pliny says that it 

 was named liubia in Latin, and that its roots were used for dyeing wool and leather 

 red, was probably identical with the Eubia tinctorum, since the description of its 

 appearance and uses given by ancient authors can hardly apply to any other plant. It 

 was cultivated in Galilee, Caria, and near Kavenna in Italy, where it was planted 

 either among the olive-trees or in fields destined for that purpose. Another species 

 of Rubia, viz. the E. manjista, grows in the mountainous regions of Hindostan, and 

 the roots of this and an allied plant, the Oldenlandia umbellata, called by the natives 

 Chaya, have been in use in that country since the most remote period, for the purpose 

 of producing the red and chocolate figures seen in the chintz calicoes of the East 

 Indies. (See CALICO-PHINTINO.) The peculiar process by which the colour called 

 Turkey red is imparted to cotton was probably invented originally in India, but the 

 dyeing material generally employed in this process was not madder, but the chaya- 

 root. From India the art of dyeing this colour seems to have been carried to Persia, 

 Armenia, Syria, and Greece ; where it was practised for many centuries before it 

 became known in the western part of Europe. In those countries, however, the root 

 of the Rubia peregrina, called in the Levant Alizari, was the material to which dyers 

 had recourse for this purpose, and large quantities of it are at the present day 

 imported into Europe from Smyrna, under the name of Turkey roots. In the middle 

 ages, according to Beckmann, madder went by the name of Varantia or Veranticu 

 The cultivation of madder was introduced into the province of Zeeland, in Holland, 

 in the reign of the Emperor Charles V., who encouraged it by particular privileges 

 conferred on the inhabitants for the purpose. According to Macquer, however, it 

 was to the Flemish refugees that the Dutch were first indebted for their knowledge 

 of the method of preparing the plant. It is still grown very extensively in that part 

 of Holland, and large quantities are annually exported thence into other countries. 

 Until very recently indeed, the dyers of this country derived almost the whole 

 of their supply of madder from Holland ; and it was the discovery that Dutch madder 

 was incapable of producing some of the finer colours more recently introduced, that 

 first led to its being to some extent supplanted by madder grown in other countries. 





