1074 VERMILION 



stronger ; and the whole distributed as before, into four casks ; composing in all 670 

 pound measures of a green liquor, of 1 '151 spec. gray. 



Meanwhile, a magma of lime is to be prepared as follows : 100 Ibs. of quicklime 

 are to be mixed up with 300 Ibs. of water, and the mixture is to be passed through a 

 wire-gauze sieve, to separate the stony and sandy particles, and then to be ground in 

 a proper mill to an impalpable paste. About 70 or 80 Ibs. of this mixture (the beauty 

 of the colour is inversely as the quantity of lime) are to be distributed in equal por- 

 tions between the four casks, strongly stirring all the time with a wooden spatula. It 

 is then left to settle, and the limpid liquor is tested by ammonia, which ought to occa- 

 sion only a faint blue tinge : but if the colour be deep blue, more of the lime-paste 

 must bo added. The precipitate is now to be washed by decantation, employing for 

 this purpose the weak washings of a former operation ; and it is lastly to be drained 

 and washed on a cloth filter. The proportions of material prescribed above furnish 

 from 500 to 540 Ibs. of green paste. 



Before making further use of this paste, the quantity of water present in it must be 

 determined by drying 100 or 200 grains. If it contain 27 per cent, of dry matter, 12 

 Ibs. of it may bo put into a wooden bucket (and more or less in the ratio of 12 to 27 

 per cent.) capable of containing 17i pints ; a pound (measure) of the lime-pasto is 

 then to be rapidly mixed into it ; immediately afterwards, l pint of a watery solution 

 of the pcarlash of commerce, of spec. grav. 1-114, previously prepared ; and the whole 

 mixture is to be well stirred, and immediately transferred to a colour-mill. The 

 quicker this is done, the more beautiful is the shade. 



VERJUICE, ( Verjus, Fr. ; Agrest, Ger.) A harsh kind of vinegar, containing 

 much malic acid, made from the expressed juice of the wild crab apple. 



VEROTXCEXiIiI, a paste of wheat-flour, drawn out and dried in slender cylinders, 

 more or less tortuous, like worms whence the Italian name. The flour of Southern 

 countries is best suited for its manufacture. 



It may be made economically by the following prescription : 



Vermicelli, or Naples flour . . . . .21 Ibs. 



White potato-flour 14 



Boiling-water 12 



Total 47 Ibs. 



Affording 45 Ibs. of dough and 30 of dry vermicelli. 



VERlVTICUIiITES. A group of minerals resembling the chlorites, remarkable 

 for their exfoliation before the blowpipe. 



VEXUraiXtXOXr, or Cinnabar, is a compound of mercury and sulphur in tlio pro- 

 portion of 100 parts of the former to 16 of the latter, which occurs in nature as a 

 common ore of quicksilver, and is prepared by the chemist as a pigment, under the 

 name of Vermilion. It is, properly speaking, a bisulphide of mercury. This artifi- 

 cial compound being extensively employed, on account of the beauty of its colour, in 

 painting, for making red sealing-wax, and other purposes, is the object of an import- 

 ant manufacture. When vermilion is prepared by means of sublimation, it concretes 

 in masses of considerable thickness, concave on one side, convex on the other, of a 

 needle-form texture ; brownish-red in the lump, but when reduced to powder it is of 

 a lively red colour. On exposure to a moderate heat, it evaporates without leaving a 

 residuum, if it be not contaminated with red lead ; and at a higher heat, it takes fire, 

 and burns entirely away, with a blue flame. 



The English vermilion is now most highly prized by the French manufacturers of 

 sealing-wax. 



The humid process of Kirchhoff has of late years been so much improved, as to 

 furnish a vermilion quite equal in brilliancy to the Chinese. The following process 

 has been recommended: Mercury is triturated for several hours with sulphur, in the 

 cold, till a perfect ethiops is formed ; potash-lye is then added, and the trituration is 

 continued for some time. The mixture is now heated in iron vessels, with constant 

 stirring at first, but afterwards only from time to time. The temperature must be 

 kept up as steadily as possible at 130 Fahr., adding fresh supplies of water as it 

 evaporates. When the mixture, which was black, becomes, at the end of some hours, 

 brown-red, the greatest caution is requisite to prevent the temperature from being 

 raised above 114, and to preserve the mixture quite liquid, while the compound of 

 sulphur and mercury should always be pulverulent. The colour becomes red, and 

 brightens in its hue, often with surprising rapidity. When the tint is nearly fine, 

 the process should be continued at a gentler heat, during some hours. Finally, the 

 vermilion is to be elutriated, in order to separate any particles of running mercury. 



