country by fire and sword, and the extirpation of the people, or it will still continue great and flourishing; but it has oftener happened that the conqueror has assimilated with such a country,* as in the case of the Tartars and Chinese; and how often have the Netherlands been overrun by hostile armies, yet they are still a prosperous country, by means of the fertility of the soil and the industry of the people. The improvement of the land, and internal industry, may therefore be held preeminent to foreign commerce and the other pursuits of mankind; and that nation must be great and powerful which directs its exertions to such objects.

ACCOUNT OF MAKING SPANISH WHITE AND PARIS WHITE.

[By a Manufacturer.]

SPANISH White is nothing but chalk, ground generally in tubs, the bottom of which is paved with small stones of a hard quality, or has one large hard bed-stone instead thereof, and a stone on edge is fixed to an upright axle, both which go round by the means of a water-wheel, steam-engine, or horses.

The chalk is broke into small lumps about four ounces each, and thrown into the tub in which it is ground, but the tub is previously charged with a large quantity of water, and as the grinding operation commences, the chalk unites with the water, its finer particles rise to the surface, and as a small stream of water is constantly running into the tub, and fresh quantities of chalk

Many thousands of the soldiers of the Prince of Hesse Cassel, hired to England to assist in the reduction of America, preferred remaining here to returning home, after the revolutionary war. The case is not exactly parallel with that of the Chinese and Tartars; for the Hessians had their choice to stay or return. The Prince was not anxious for their return, as he was thus saved the expense of transportation, and he had men enough left for future contracts,

are added, the level of the mixture rises to a certain height, finds its way through an aperture of the tub near the top, and is discharged into a large reservoir, by which the two operations of grinding and washing are performed at the same time with a small expense. After the ground chalk has stood a sufficient time to subside, the water is run off, and the chalk being so stiff as to cut with a spade, is then removed to a place to dry, either by the air or by stove heat: the former of these is termed stiffening, the latter is called drying, and is the finishing process.

Chalk taken into the north coasts of England, at the chalk wharfs on the Thames, about 2s. 6d. per ton, and when made into Whiting in the North, sells from 16s. to 20s. per ton.

French Whiting, or Paris White, has not been made in England above 50 or 60 years; the manufacture of it was brought by a Dutchman, who settled in a sea-port town in Yorkshire, and who, by it, and his mode of refining and depurating rapeseed oil, and linseed oil, acquired a large fortune, and became a respecta

ble banker.

ON BLEACHING.

THERE are three methods-The Dutch, the Irish, and the new or French method.

The Dutch method is very particularly described by Lewis Cromelin, and copied by the late Dr. Home and the compilers of the Encyclopædia Britannica. As each of the methods in the first and the last parts of the process coincide, it is unnecessary to describe each at full length.

The first operation is steeping in warm water, of the temperature of 180° of Farenheit's thermometer; bran is often added to promote the fermentation brought on by the dressing used by the weavers; the fermentation appears by the air-bubbles which rise to the surface, by the swelling of the cloth, and the scum which rises to the top; this fermentation is acid, and accelerates the pro

cess of bleaching; it continues thirty-six or forty-eight hours; when the scum begins to fall, the putrefactive fermentation commences; the cloth is then drawn, washed, and laid on the grass; when dry, it is fit either for the Dutch or Irish method of bleaching.

Before we attempt to account for the effects of bleaching stuffs, and before we determine which method is to be preferred, we should ascertain the properties of the colouring matter of linen and its solvents. With this intention Mr. Kirwan took five quarts of burnt ley, in which yarn had been boiled,* added two ounces weak marine acid; this did not occasion any effervescence, but a deposition of a sediment of a greyish green colour, which was insoluble in boiling water; when dried it assumed a shining black colour, but internally it remained of a greenish yellow; it weighed one ounce and a half; it was insoluble in oil of turpentine, or linseed oil; it communicated a brownish tinge to the sulphuric and marine acids, and a greenish to the nitrous; it was not sensibly diminished by either of them.

He then dissolved one ounce of sweet barilha, Dantzic pearlash, Cunnamara kelp, Cashup and Clark's pearl-ash, in six ounces of pure water each, and digested eight grains of the green colouring matter in an ounce of ley made from each kind of those ashes in the temperature of 180° during three hours and a half. Two ounces of the barilha ley, one and a half ounces of the Dantzic, one and one-half ounce of kelp, one ounce of the Cashup, one ounce of Clark's dissolved the whole. He found that liver of sulphur is of all alkaline compounds the most powerful solvent of the colouring matter; hence, kelp which contains it, affords a ley which may be advantageously used in the first process of bleaching; so may the solutions of Cashup, and markoff, and artificial sulphu

rets.

The caustic vegetable alkali is most powerful, next to liver of sulphur; next to this, caustic mineral alkali; mild mineral and mild vegetable alkali occupy the last place. Solution of Windsor soap dissolved a very small quantity, and lime water scarce any

* Transactions of the Royal Irish Academy, vol. III.

of it; as one pound of lime water contains about thirteen grains of lime, its solvent powers must therefore be very weak.

Any ash ley may be converted into solution of liver of sulphur, by adding to it, when boiling, of sulphur one-twentieth part of the weight of pure alkali contained in it.

The DUTCH method consists in steeping the cloth in warm ley, but not boiling it, as the Irish do; this operation is performed in the following manner; different kinds of ashes, such as blue, white, pearl, markoff, Cashup, and Muscovy ashes are dissolved in water, with a few pounds of soft soap. The cloth is brought in dry from the green, and put into a large vat, the ley at a 100° is thrown on it, when it continues a few hours in this steep, the ley is drawn off, and then heated to 180°; this is repeated six or seven hours, and the degree of heat gradually increased till it is at last thrown on boiling hot; when the cloth hath remained in this three or four hours, the ley is let off and thrown away.

The cloth is then laid on the green and watered for six hours, afterwards it is allowed to lie till white spots appear on it before it is watered; next day it is watered twice or thrice, if the weather is dry; the third day it is lifted and passed through the same course of bucking as before. This alternate course of bucking and watering is repeated ten or sixteen times, before it is fit for souring. After souring, it is rinsed, mill-washed, and rubbed by women's hands, in soap and water; it is then sent to be bucked in ley rather stronger than formerly, which is gradually increased in strength till the cloth is of a uniform white, then the ley is weakened gradually, every course of bucking, till the process of bleaching is finished.*

The IRISH method commences as the Dutch, with macerating warm water, thirty-six or forty-eight hours† (the degree of heat of the water is lower when the temperature of the air is warm, higher when cold) it is then washed, grassed, and boiled alternately, till fit for the sour and the boards.

Home's Experiments on Bleaching.

If burnt ley is used in this steep, it will stain the cloth and prevent the acid fermentation of the dressing, which if encouraged, would dissolve the alkaline compound, precipitated upon the yarn, at the time of boiling.

As the extent of our manufacture prevents the practice of watering, the ley is washed out of the cloth after each boil, before it is exposed to the sun and air: this should be done with the utmost care in warm weather, else the alkali may crystallize on the cloth and make it tender.

As this is the part of the process in which the Dutch and Irish methods differ, the subject is of material importance; the improvements in the arts enable us to determine a dispute which has continued one hundred years,

We have seen that the principal part of the colouring matter of linen is a resin, which, like lac, is insoluble in water, and in oils; but can easily be dissolved in alkaline caustic leys; heat promotes the action of solvents upon lac. A high degree of temperature greatly promotes and assists the action of alkalies upon the colouring matter. This, and some other facts mentioned hereafter, are in favour of the Irish method of bleaching.

Bleaching by alkali, purified of carbonic acid by lime, assisted by a high temperature, has been long practised in secret in the Levant; it is now practised as a recent and valuable discovery, and was first published by Chaptal. In this method, a small quantity of ley is put into the bottom of a boiler. Cloth or yarn steeped in the same kind of ley is loosely thrown into the boiler, and suspended in it on racks or grates of wood; it is closed with a steamtight cover, and to prevent accidents from the violent expansion of steam in a high temperature, a safety valve is attached to it. Heat is then applied a few hours, the steam and heat are equally diffused, penetrate the fibrous texture of each thread, increase the solvent power of the alkali; the colouring matter is completely and speedily united with the ley, and easily removed by washing. As the action of soda upon cloth, even in its pure and caustic state, is less violent than the action of pot-ash, our attempts to bleach in this way, should commence with ley of soda, and our first essays should be on a small scale.

The apparatus for bleaching with caustic alkaline vapour is described by Chaptal, and improved by O'Reilly in his Essay on Bleaching; a description and drawing of it are in the 10th vol. of the Philosophical Magazine.