232

DYEING AND CALICO PRINTING.

down to a powder, but it undergoes some previous operations to fit it forgrinding. The root when first dug out is very brittle, and is hence left on thefields for twenty-four hours after being dug up, in order to grow tough. Inthe Caucasus the root is washed in water, to remove adhering soil,—a processwhich in Europe has been condemned as injurious without trial, and whichmight be advantageously tried. After washing it is. next placed in pits dug inthe ground, similar to those used by farmers for storing potatoes during thewinter. In these some brushwood is burned, probably to fill the pit withempyreumatic vapours, whereby the possibility of fermentation and decay ofthe madder is prevented.. The roots are then covered over with soil, and leftin the pits for some five or six months. After this lapse of time the madder isfound to have lost all its sugar and the other inert vegetable matters itcontains. It is next dried in the sun, and after this treatment is known asMarina. Its tinctorial power is greatly enhanced by this process. In Alsaceand Zealand the root is dried artificially in kilns. In Zealand peat is gene-rally used as fuel, and in the kilns the smoke and gaseous products of com-bustion are let pass through and over the roots. In the more improvedestablishments steam or hot air is employed with advantage. By this dryingthe root is enabled to keep, and rendered more marketable. A second dryinghas to be performed to fit it for grinding.

The fresh root contains from 70 to 80 per cent of water. That from Alsaceand Zealand, and indeed from any clay soil, is rich in sugar and othersubstances, which render the drying more difficult. After drying, the rootstill retains 15 to 19 per cent of water, which can only be got rid of byexposure for twenty-four to thirty-six hours to a temperature of 50° to 6o° C.

A higher heat is injurious, and even at this temperature combustion some-times ensues. After drying, the roots are beaten with thrashing-machines, toremove sand, clay, and rootlets. The latter, along with some of the bark ofthe roots, are separated by means of sieves, and sold for dyeing. TheLevantine, Spanish, and Neapolitan roots generally find their way to Avignon,to be there ground up. These contain only 12 to 14 per cent of water, andare easily dried. The alizaris (unground roots) are met with in commercepacked in bags or casks, weighing, for the countries, above 9 to 10 cwts. TheVaucluse alizaris are packed in coarse canvass bags, and weigh from if to 2cwts. Zealand roots were formerly very rarely met with unground. Theresult was that it was rare to find even 25 casks (weighing about 12 cwts. each)of ground Dutch madder exactly alike. A recent improvement is that inZealand, as well as in the Vaucluse, large works have been established, whoseowners buy the roots from the small growers. Hence a quite uniform produdis obtained in quantity. A very large proportion, both here and in theVaucluse, is at once converted into garancine and other preparations. Whenthe dry root has been stored a second time it is broken up and ground byedge-stones. The stones used in France are made of a kind of hard lime-stone. The excellent stone got from Belgium has been found to answer well.When ground the madder is carefully mixed, and packed in strong casks.Those from Zealand contain about 12 to 14 cwts., and those from Vaucluse20 to 22 cwts. In Zealand adulteration is repressed by heavy penalties, andthe maufadlories are placed under proper inspe&ion, so as to secure the purityof the article. This regulation has tended to support the Zealand madder in itssevere competition with that of Avignon, where adulteration is not uncommon,