But a dyer in the _country_, whose business is barely sufficient to keep a vat going, will find more difficulty in this respect. If, therefore, he does a small batch of work on Monday, but has not half worked down his vat, and has no prospect for two or three days of doing any more work, he may possibly try to keep it with lime for a day or two: he may do so, and in the issue, in some instances, _too much lime_ is the consequence. We consider, however, that when the vat can be worked daily, and replenished as it is worked down, as is the case in London, with care and attention, there is no danger of the loss of a woad vat: in London, such an accident now seldom happens. The author is, notwithstanding, persuaded that all the art of man cannot always keep a vat from the state of having either too much or too little lime, _when heated but seldom_, under a short course of work: for when a vat is in order, it is like a ripe vegetable; you must gather it, or it passes the time of its perfection; it may even be rotten ripe. We say, therefore, WORK THE VAT: withdraw from it, upon your cloth, its colour, which, as soon as you expose it to the atmosphere, will combine with its oxygen,—the oxygen with the carbon of the indigo and the woad. If you play with it too long, the putrid fermentation will begin, and the vat will be spoiled. The smell of rotten eggs always proclaims the approach of the mischief. No one, therefore, should attempt to have a woad vat or vats, unless he can keep them nearly always at work. When worked down in a moderate time, and replenished with lime, woad, indigo, &c., working out and replenishing in, there can be no danger. On the other hand, in proportion as the vat is out of condition, although partially recovered, it must always be with more or less loss. _Methods of dyeing_ BLUES. Whether the goods be cloth, or skeins of yarn, they must, in all cases, be first wetted out and wrung, and then put into the vat, worked in it, taken out and aired, that they may turn from green to blue; and, if necessary, they must be put in again. There is no difficulty in dyeing _dark blues_, by repeated dippings; but if _light blues_ be dyed in vats which are nearly exhausted, they will not be bright. Blue vats, upon a large scale, are now mostly heated by steam; they are then, with little trouble, always in a state for working, without the necessity of re-heating. They are very convenient for light colours, even after they become very weak. In some instances, in order to dye light colours to the best advantage, it would be advisable to set a vat on purpose, which should be strong in woad and weak in indigo; because the colour would be given more slowly, and the light colour obtained from them with much more facility. _To dye wool with lac-dye,_ SCARLET _and_ CRIMSON.