a turf to enjoy themfelves on. Young lambs, in whatever cafe, confined with hurdles on an arable field, are feldom known to do well. The most eligible method of any I have an idea of, would confift in hauling the roots, fome time in April, entirely off from the field whereon they grow, and throwing them promifcuously about on fome adjoining pafture, or field of rye-grafs, clover, &c. (to be fown with wheat the enfuing feafon); in either of these fituations to let the fheep be regularly introduced to them, with hurdles, as they would otherwife have been on the arable.

The

and other arts, have been found by chance to be neceffary, yet fufficient pains have not been taken to afcertain the principles upon which they act of this number is verdigris; and as this article was imported to us, at a very great expence from France, I was induced fome years ago to under. take a courfe of experiments to inveftigate the manner of its ope. ration, and from thence to find, if poffible, an effectual substitute, cheaper and nearer home. On adding verdigris to the common ingredients of the black dye, (viz, aftringents and martial vitriol) the first thing remarkable is, that a quantity of iron is precipitated; for the pieces of verdigris will be covered over with the crocus of iron, almost instantly, and a quan. tity of the copper of the verdigris is at the fame time taken up by the difengaged acid; as appears by the copper coat a knife receives on being held in the liquor fo that the vitrolic acid leaves the iron, with which it was combined in martial vitriol, and unites with the copper of verdigris, and again leaves the copper to unite with iron in its metallic ftate. The fame decompofition happens with lead, if faccharum faturni be made ufe of instead of verdigris, though lead, according to the received doctrine of elective attractions, has a ftill lefs affinity with iron, than copper has. In fact, I find that faccharum faturni will anfwer nearly the end of verdigris, and though, as a fubftitute to it, we could reap no advantage from it, yet I think it gives us an infight into the principle upon which vetdigris is of ufe in the black dye, viz. by uniting with part of the acid of the vitriol, and giving the

aftringen

aftringent matter of the vegetable an opportunity of forming an ink with the precipitated iron in greater abundance, and more expeditioufly, than it could other wife do. Believing this to be the true manner of its operation, I went to work upon this principle, and fubftituted alkaline falts in the room of verdigris, as I ima gined these would be a much more innocent as well as cheaper ingre. dient; for the acid, or the corro. five metallick falts, are the only hurtful ingredients in the dye, and the alkali in proper proportion will unite with the fuperabundant acid, and form an innocent neutral falt, vitriolated tartar. Upon the first trials, I was fatif. fied of the truth of my conjectures; for in all the experiments which I made in the final way, the afhes anfwered at leaft as well as the verdigris: but in real practice, in the large, I found my. felf deceived; for upon dying a kettle of hats of twenty-four dozen, though the colour came on furprizingly at first, yet the liquor foon became weak. I made many experiments, which it is ufelefs here to relate, until I united vitriol of copper with the alkali, which, upon repeated trials, has been found to anfwer perfectly the end of verdigris. The following, I believe, will be found to be the juft proportions, though there is fome difference in the practice of different dye. houses.

Saturate two pounds of vitriol of copper, with a ftrong alkaline falt (American pot-afhes, when to be procured, are recommended). The vitriol will take about

an equal weight of dry afhes. Both the vitriol and the afhes are to be previously diffolved apart. When this proportion is mixed, well ftirred, and fuffered to stand a few hours, a precipitate will fubfide. Upon adding a few drops of the folution of afhes, if the mixture be faturated, the water on the top of the veffel will remain colourlefs; but if not, a blue colour will be produced; upon which add more afhes; there is no danger in its being a little over faturated with afhes. Take care to add the folution of afhes to that of vitriol by a little at a time, otherwife the effervefcence which enfues will caufe them to overflow the veffel: these four pounds of vitriol of copper and afhes, will be equal to about the fame weight of verdigris; and fhould be added to the other li quors of the dye, at differe.3 times, as is ufual with verdigris,

The black, thus dyed, will be perfectly innocent to the goods, rather tending to keep them soft, than corrode them, particularly hats, in which there is the greatest confumption of verdigris.

For those who are conftantly ufing verdigris, it would be proper to have a veffel always at hand, containing a faturated folution of vitriol of copper; and another, with a faturated folution of afhes, ready to mix as they are wanted; for I find they do not answer fo well if long kept.

JAMES CLEGG.

Manchester, Dole Fields, January 14, 1762.

An Account of Cloth made from the Refufe of Flax, and Backings of

Tow.

I

SIR,

HAD the pleasure of your letter yesterday by Doctor Halliday. Lord Moira and I, with much fatisfaction, defire to be both ranked as fubfcribers to the Sylva, which is to be republifhed by Doctor Hunter, whofe Georgical Effays have ben greatly admired beneath this roof.

As to the factitious cotton I have attempted to introduce the to introduce the ufe of, I flatter my felf that it is beginning to answer that purpofe I had at heart, fome alleviation to the miferies of the unhappy beings that furround me, the excess of poverty that reigns here being fuch, that in my native land I am perfuaded it would not be ima gined to exift. The very refufe of the flax, which is called the backings of tow, produces a material that can be manufactured into a coarse but comfortable clothing of the fuftian and cotton kind, and this kind of cotton was offered to me laft week for fale, at three-pence per pound; it is there fore plain how little pains and expence the manufacturing of it softs. Wool is here almoft con.

backings are all I employ, except fired or mildewed flax, both of which (from being ill-flaked) be. ing improper for the linen cloth, I have made ufe of; hemp will alfo produce a fort of cotton, but it requires infinitely more boiling, and bears a nearer refemblance to wool. It was the codilla that I tried; the backings of that come amazingly cheap, and I believe it will take a better dye than flax.

The main purport in view feemed to me, the divesting the flax of its oil. I tried foap. boiler's lye with very good fuc cefs, fcouring it afterwards to take off any bad effects of the lime ufed therein. I then had it tried to be fcoured like wool, but found it required that the fer. mented urine in that cafe fhould not be mixed with water, and that kelp and common falt were necel. fary to be added to it. Either of these methods do. The boil. ing of it might, I am fure, be expedited, by having a cover to the iron pot, which might keep in the fteam; and care must be taken, as the liquor diminishes, to replenish it conftantly. I have boiled fome in a mixture of lime water and falt; this had a harthnefs in it that more resembles the crifpness

of

of cotton, but the fcouring of it would certainly deprive it of that quality, and leaving the line in, it is confidently afferted here, would rot it. I own I doubt that effect, as I imagine that lime, after it is flacked by water, no longer retains its corrofive quality. In India and China they ufe it in their washing of linen as regularly as we do foap.

The tow is heckled and boiled in fmall faggots, tied up by a thread or bit of tow. The back ings are carded in thin flakes, rolled up likewife, and tied. After boiling, they open in the fame flakes they were carded into, and are washed out, and laid to whiten in that form. I fend you, however, a fample of the back. ings of white flax, that was only boiled four hours, and 'never laid down to whiten. In the courfe of this fhort procefs, you will fee that the materials of which fack ing is made, is confiderably mended, though I think it wants another hour's boiling, and that a week's whitening would hive taken off that harshness of the flax it ftill in fome degree poffeffes. It requires being beat, or put into a prefs, before it is carded on cotton cards, to feparate the fibres, which feem to be fet at liberty from each other, by a diffo. lation of fome refinous fubftance in the flax, at the fame time that the oil of that plant is converted into a kind of foap. When I mention white flax, I do it in oppofition to that, which being freeped in the bags, has the ap. pellation of blay; this getting a tincture from the heath, has its colour rather fixt than difcharged, by being made into cotton.

You

enquire into the refult of my pur. fuits concerning fixing lafting tinctures on linen. The tedious fick nefs, and at length death, of a friend, kept my mind for many months this fummer, in a fitua tion of languor that is a total enemy to the bufy occupations of curiofity, and when I refolved to engage myself therein, to keep off unavailing reflections, I found it too late for many herbs 1 had fet down in a lift, and that a plat of weld I had planted the autumn before, had never come up. I then employed myfelf with the purple fith found on the Newcaftle fhore. They answered all the fmaller experiments mentioned by Reaumur and Templeman, but thofe Dr. Holland has given, in his tranflation of Pliny, the naturalift, they in no degree correfponded to; with all the boiling in lead and falt prefcribed by him, they only produced a very ill-looking foap. Though there appears no doubt but the purple wilk found here is the buccinum of the antients, it however appeared to me that it was probable they got their colour from fome mofs they fed upon. It could not be the archil, which (as I am td) grows much higher on the rocks than where they lie. I therefore employed a perfon to fearch about the places in which the wilks or buccina lie, and to get me fome of the mofs and feaweeds that grew near them. My fmail collection is but juft arrived, and I have not had time as yet to try whether my conjecture is true or falfe. To the purple yielded by the archil, I owed my fufpicion, that there might be other moffes that would produce ftronger G 3

and