It is remarkable that although the process of _rouissage_ or watering is felt to be one of the utmost nicety and importance, the ultimate value of the flax being mainly dependent upon it, no uniform system prevails throughout the various provinces of Belgium. In Hainault and around Namur, where an impression is held that the effluvia of the flax, whilst undergoing the _rouissage_, is injurious to health, it is interdicted by the police, and it is consequently dew-riped, simply by spreading it upon the grass, and turning it from time to time, till the mucilaginous matter, by which the fibre is retained around the stem, is sufficiently decomposed to permit of its being readily separated from the wood. In the Pays de Waes, the flax is steeped in still water as in Ireland, except that in the latter country, a small stream is contrived, if possible, to pass in and out of the pit during the process.[23] The system of the Pays de Waes is that which has met with the most decided approbation in Belgium; it is recommended officially to the farmers in the instructions published by the Société Linière, an association instituted for the purpose of promoting the cultivation of flax, and its various manufactures.[24] The system at Courtrai, consists in immersing the flax, after being dried and stored for twelvemonths, in the running water of the Lys; an operation, which in their hands, is performed with the utmost nicety and precision, and for which it is so renowned that the crops for many miles, even so far as Tournai, are sent to the Lys to undergo the _rouissage_. The flax, tied up in small bundles, is placed perpendicularly in wooden frames of from twelve to fifteen feet square, and being launched into the river, straw and clean stones are laid upon it till it sinks just so far below the surface of the stream as to leave a current both above and below it, which carries away all impurities, and keeps the fibre clean and sweet during the period of immersion. This continues for seven or eight days, according to the heat of the weather and the temperature of the water, and so soon as the requisite change has taken place in the plant, the frames are hauled on shore, and the flax spread out upon the grass to sun and dry it previously to its being removed to undergo the further processes. The _rouissage_ at Courtrai is usually performed in May, and again in the months of August and September; after which the flax merchants of Brabant and the north send their agents amongst the farmers, who purchase from house to house, and, on a certain day, attend at the chief town of the district to receive the “deliveries,” when the qualities of the crop and the average prices are ascertained and promulgated for the guidance of the trade.