ployed in preparing the paste, and increasing the beauty of the decorations. The ware itself is not of equal fineness with the French and Saxon; though its workmanship, and ornaments, are far superior. The paintings are, in general, rich, and well executed; and the gilding and burnishing exceedingly beauti

ful.

The body of the semi-vitreous ware, called porcelain, is fine white elay, combined with different proportions of fluxing matter. The best kind is absolutely infusible, and takes for its glaze a vitreous substance, without a particle of lead: when the paste is duly prepared, by grinding, and other operations, it is consigned to the workman, whose dexterity produces a variety of beautiful forms, from the shapeless mass delivered into his hands. Round vessels are usually made by a man called a thrower, who works them on a circular block, which moves horizontally on a vertical spindle. From him they pass to the lathe, and are reduced to their proper thickness and form at the end of an horizontal spindle. Afterwards they are finished, and handled, if necessary, by other persons, and are then conveyed to a stove, where they remain till the moisture is entirely evaporated, when they become fit for baking. Oval vessels, such as tureens, teapots, &c. assume their form through being pressed into moulds of plaster, or gypsum, by hand. The saggars, or cases, in which the articles are burnt, are vaious in shape and dimensions, as best regards convenience. These are set in the kiln, or oven, one upon the other, and when piled up nearly to the top, have somewhat the appearance of piles of cheese. When

the kiln is fui, it is carefully closed, and the ware baked, by the adinission of heat through horizontal and vertical flues: this is the first baking; and the porcelain in this state is vulgarly called biscuit. It is ther dipped in glaze of about the consistence of cream, and carried to the glaze kiln, where it is again baked, but in a less intense degree of heat than before.

The ware is now delivered to the painters, who, with colours prepared from mineral bodies, ornament it with landscapes or figures, according to the required patterns. After this process, it is again conveyed to the kiln, and the colours vitrified, in order to fix and give them a proper degree of lustre. Every coat, or layer of colouring, requires a fresh burning: once or twice is sufficient for the ornaments of the common porcelain, but the more elaborate decorations render it necessary for the colours to be laid on, and undergo the action of fire several times, before they obtain their full effect and beauty. This completes the process of those articles that have no gold in their pattern; but where this addition is wanted, they are penciled with a mixture of oil and gold dissolved, or thrown down, by quicksilver, aided by heat; and once more committed to the kiln. Here the gold reassumes solidity, but comes out with a dull surface, which is quickly rendered brilliant by rubbing with . blood stones, and other polishing substances. The procelain is now ready for use; but it should be ob◄ served, that the latter part of the process requires considerable care, as the gold, when not sufficiently burnt, will separate in thin flakes; and when over fired, will not receive a proper

a proper polish. The highest finish ed ware in this manufactory is frequently returned to the enamel kiln, where the colours are fluxed six or seven times: the best only is here finished for sale.

The making of biscuit figures, or white ware, is peculiar to this manufactory; and the pieces them selves are supposed to be equal in beauty and delicacy to any others of a similar kind made in Europe. Here the lathe is of no use, the figures being all cast in moulds of plaster or gypsum, into which the materials are poured, having previously been reduced to a liquid of the consistence and appearance of thick cream. The water contained in the mixture is quickly absorbed by the plaster, and the paste hecomes sufficiently hard and tenacious to part freely from the mould. The various parts of the figures, as the head, arms, legs, &c. are cast in separate moulds, and, when dried and repaired, are joined by a paste of the same kind, but thinner than the former. The articles are then sent to the kiln, and, after undergoing a regular and continued heat, come out extremely white and delicate.

This manufactory, though of five times the extent of the original building, is insufficient for the number of workmen now wanted; as the attention paid by the proprietors to the improvement and qualities of the porcelain has been deservedly rewarded by a very considerable increase of business. Additional buildings are erecting; and a variety of alterations are projected, which, if executed according to the comprehensive plan on which they are proposed, will render this manufacture not only a source of great individual emolument, but likewise occasion it

to become an object of national importance. A steam engine is now preparing; several new glaze and biscuit kilns have been erected; and many other improvements are making, to accelerate the production, and increase the durability and beauty of the ware. The manufactory, when the proposed buildings are completed, will occupy an area equal to 6000 square yards, and afford sufficient room for the employment of between 300 and 400 workmen; the front alone will extend nearly 170 feet.

The original silk mill, erected by Mr. Crochet, and now called the Old Shop, was afterwards converted into a cotton factory, but is at present in the occupation of Messrs. Brown and son, who employ it for cutting and polishing marble, and manufacturing the Derbyshire fluor spar, or blue John, and gypsum, into a variety of beautiful ornaments, as urns, vases, columns, obelisks, &c. The machinery applied to execute these purposes is of very ingenious construction; and the lathes are so contrived, by the assistance of a reverse motion, that they can readily be made to revolve either slower or faster, as the design or quality of the substance under manufacture may require. They may likewise be stopped at pleasure, without impeding the motion of any other part of the works.

When the blue John is to be made into a vase, or any other ornamental form that renders the use of the lathe necessary, it is carved, with a mallet and chissel, into a rude resemblance of the object intended to be produced, and being afterwards strongly cemented to a plug or chock, is screwed upon the lathe. A slow motion is then given to the work :

and

treated on blights, and so many different theories have been offered to the public, that the subject may appear to many to have been already sufficiently investigated. The society, however, entertained a contrary opinion; and having expressed a wish to receive further information, I avail myself of this opportunity to lay before them some remarks, which I have at different times made during several years of rather close attention to the subject. What are usually termed blights, in the vague and extensive signification of that word, appear to me to originate from three distinct causes: from insects, from parasitical plants, and from unfavourable seasons.

The destructive effects of the aphis on wall trees are so well known, to every gardener, as scarcely to require description. The leaves curl up, the fruits drop off, and the progress of vegetation is almost to tally suspended. Much ill-applied -labour is often used by the gardener to destory these insects, though they are not very tenacious of life. Another more extensive, but less fatal disease in plants, the honey dew, is produced by this insect (as described by the abbé Boissier de Sauvages). It has, however, been contended, that the honey dew is not produced by the aphis, but that it is a morbid exudation from the plant; at least, that there are two kinds of it; because the leaves are often covered with honey on trees where the aphis is not found, and because the aphis is sometimes found without the honey dew. But to this it may be objected, that honey, not being a volatile substance, will remain on the leaves till it is washed off by the rain; and, when moistened by the dew, will have the appearance

of a recent exudation; and that the aphis certainly does not afford honey at any period of its existence. I have frequently placed plates of glass and of tale under the leaves of fruit trees, on which different species of the aphis abounded, and I have found these substances to be in a few hours covered with honey; and I have at other times distinctly seen the honey fall from the under sides of the leaves, where these insect abound, by the following means: Having placed a small branch, containing a numerous colony of insects, in the window of my study, where the sun shone strongly upon it, I closed the shutters so as to exclude all the light, but that which fell directly on the branch. In this situation the descending drops of honey became extremely visible by refraction, and appeared evidently to be emitted from the insect with considerable force. Each drop contained many minute white points, which I considered as the eggs of the aphis; but, as I knew that the modes of generation in this singular insect had much engaged the attention of naturalists, I did not examine with sufficient attention to decide that point. This species of insect appears to require a previous disposition in the tree to receive it; and its first attacks may thence be considered as symptomatic of a previous habit in the tree: for I have found that trees which have lately been transplanted, have totally escaped its attacks, when every other tree, of the same kind of fruit, growing in the same situation, has been nearly destroyed, And I can assert, from many experiments, that if every peach and nectarine tree was to be dug up once in every five or six years, and to be replanted with

some

some fresh mould round the roots (which should be as little injured as possible), a much larger quantity of fruit, and of very superior quality, would be obtained. It is unnecessary to inform the experienced gardener, that the tree should be removed early in autumn; that its branches should be considerably retrenched, and that it should not be suffered be bear a heavy crop of fruit in the succeeding season. I have never found any species amongst the numerous and prolific genus of the aphis, which was not readily destroyed on the wall tree by covering it with a sheet of canvas, and under that introduce ing the smoke of tobacco. It is, however, necessary that the fumigation should be repeated twice or thrice, with intervals of four or five days. I have often seen the addition of sulphur recommended, and have known it tried, but always with fatal consequences to the tree, as well as to the insects.

The blossoms of apple and pear trees are often said, by farmers, to be blighted, when they are destroyed by insects, which breed within them, or in their fruit; and the same term is used, when the leaves have been eaten by the caterpillar but as the insects themselves, as well as the manner in which their depredations are made, are extremely obvious, they do not properly come under our observation when treating of blights.

The species of parasitical plants which are found in the form of disease on other plants, appear to me greatly to exceed the number of those I have any where seen de scribed by botanical writers. Of these the mildew is the most common and obvious. If a branch, infected with this disease, be struck

2

by the hand in calm dry weather, a quantity of white powder will be found to fly from it; and if this be received on a plate of talc, or of glass, and examined by the microscope, it will be found to consist of very numerous oval bodies, evidently organized. There is another plant similar to this in every thing but colour (being of a tawney brown), which is not unfrequently found on the leaves of young apple trees. Both these plants appear to me to be evidently species of mucor; and as much the greater number of species of this genus of plants is found to flourish in damp air, and in situations deprived of light, it may be supposed that the foregoing diseases might be prevented or removed, by placing the plants at proper distances; but I have not found this to be the case. They, however, abound most in low and sheltered situations; but they are not unfrequently seen in those of an opposite kind. The red and white mould on hops, and the black spots on stalks of wheat (the rubigo of Virgil), and many other diseases of plants, will, I think, be found to arise from the attacks of minute plants of this genus, which appears to me to possess qualities somewhat similar to the digestive powers of animals.

The most common and extensive causes of what are termed blights remain still to be described, and evidently exist in the defects and sudden variations of our unsteady climate. Whatever be the cause by which the sap is raised and propelled to the extremities of trees, it is well known, that its progress is accele rated by heat, and that it is checked, or totally suspended, by cold; and it has been ascertained by others, as well as by myself, and indeed is

known