probably never would have done it, had they not in a manner compelled him to do so by their outrageous behaviour, their acts of public violence, in defiance of the laws, and their extensive compiracies against his life.

Mons. Ennio Quirino Visconti has begun to publish an ancient iconograpy, or collection of authentic portraits of emperors, kings, and illustrious persons of antiquity. The first part, containing the Greeks, was published in 1808, in three vols. atlas size. All the drawings have been taken from authentic originals, except about twelve; many were never before published; and an historical account of each portrait is given. To say, that this highly interesting work abounds with remarks, exhibit ing a profound erudition, on all parts of archaeography; that the history, literature, and biography of Greece, receive much illustration from it; that various points of chronology are discussed and settled in it; and that the philological, paleographical, and numismatic observations are numerous and interesting; is no more than might be expected from its celebrated author.

An edition of Juvenal has lately issued from the press of Didot, corrected from thirty six manuscripts in the imperial library. At the foot of the page is a perpetual commentary by the Editor, Mons. N. L. Achain

tre; and in a second volume are given a life of Juvenal, the unpublished notes of Hadrian and Charles de Valois, the ancient scholia annexed to the first Paris edition by Pithou, various readings, catalogues of editious and versions of Juvenal, and an index verborum. A third volume is to give the satires of Persius in a similar manner.

A French translation of Daphnis and Chloe has been published by Mons. Courier. It is chiefly a copy of the translation by Amyot, except where correction was necessary; but it is valuable for the addition of a passage of some length from a manuscript in the abbey at Florence, which was wanting in the copy translated by Amyot. When Mons. Courier had finished his translation, he unfortunately let fall his pen on the original Greek, which has blotted this passage in such a manner, that it is for the most part unintelligible. Mons. Furia, the librarian, has in consequence inserted a very angry article in the Collezione d'Opuscoliscientificie letterari, X. 49, with a fac simile of the blotted page. Mons. Renouard, who considered himself as implicated in the charge against Mons. Courier has published a little tract in his justification: Mons. Furia has again spoken of the circumstance in the Giornale Ciclopedico of Florence: and Mons. Courier has since written a pamphlet against Mons, Furia.

tion.

Mons. Daubuisson de la Feuillade has exhibited on a piece of water near Paris, a model of a vessel invented by him. it was 25 feet long, 4 feet, 4

of water, was deep waisted, and had four masts. Its sails turned quite round, and both ends were alike, so that either might be made stem or stern at pleasure. The inventors ob

ject in this was to supersede the necessity of tacking, a purpose evidently not to be answered by it. In a dead calm the vessel is to be impelled by what he calls a rume aspirante (perhaps the oars invented by Barnoulli, to be drawn backwards and forwards und water). He proposes to build a vessel on this model 200 feet long, to carry 66 guns, and two thousand men, which, with victuals and stores for 50 days, would draw only 9 feet of water. He supposes it would sail faster, and lie nearer the wind, than any vessel now in use. (No doubt it would sail fast going large, but it could not work well to windward.) It is to be rendered incapable of being sunk by means of cop per airvessels, and a cork sheathing. Its design is to surprise an enemy's harbour.

On the processes employed to obliterate writing, methods of detecting frauds of this kind, the improvement of common ink, and a new ink that resists the action of chemical agents, by Dr. B. H. Tarry.

Writing is obliterated either by the application of some acid, or by scratching it out with a knife When ever the latter method is employed for a fraudulent purpose, as some other writing will be substituted, commonly pounce, or size, is applied to the paper, that the fresh ink may not run In general close inspection with a good lens will show where writing has been scratched out, by the appearance of loose or ragged filaments. If pounce have been applied, spirit of wine will dissolve it, and wash it away: if size, immersion in warm water for a few minutes will have the same effect. After the application of either of these, the paper should be dried slowly; at first in the shade, till three parts dry, and afterwards between several sheets of paper,

and while it is drying the ink last used, will spread and sink into the paper more or less. It may be remarked too, that the strokes of a pen will be more generally slender, where pounce has been applied, and more full, where size has been used, than in the other parts of the paper.

In some cases the original writing, that has been obliterated, may be made to reappear. If the whole of the iron that was in it be removed; this is impracticable. If it be not, infusion or decoction of galls will render it visible, in cases where nitric or oxymuriatic acid was employed to destroy it. The liquid prussiat of potash, or of lime, which is better, will restore letters obliterated by oxalic acid, or salt of sorrel, making them appear of a reddish brown. If oxymuriatic acid were used, it will render them visible, of a light greenish blue as long as the paper continues wet.. If nitric or sulphuric acid were employed, the prussiat of lime will show this by tinging the paper blue, but it cannot restore the writing.

The hydroguretted sulphurets of the alkalis, or of the alkaline earths, will restore writing obliterated by the oxalic, oxymuriatic, or nitric acid, rendering it of a green black, brown red, or a pale rust colour. The sulphurets should be diluted with halfor two thirds their quantity of water. When the action of the nitric acid has been so powerful, or so long continued, as to prevent the writing from being restored, sulphuretted hydrogen will produce wavy lines of a green black on the paper. When the nitric acid has been employed alone, and not to this extent, on holding the paper to the fire, the writing will reappear of a rust colour.

The goodness of ink depends on its containing the principles essential to its composition in due proportion, and the absence of those foreign to it.

The following are Dr. Tarry's directions for accomplishing these pur

poses.

In a wine quart of rain or river water, infuse four ounces, troy weight, of bruised galls, letting them stand in the sun four hours in summer, or six in winter. Strain off the liquor, and let it stand five or six months, Occasionally removing the mother that forms on the top, and finally separating both this and the sediments by filtering through paper. In the filtered liquor dissolve a troy ounce of powdered gum arabic. After this is completely dissolved, and a troy ounce of sulphat of iron, commonly called green vitriol,, which has been first calcined till it grows reddish, and finely powdered. Continue shaking the mixture, till the vitriol is entirely dissolved. Care must be taken in calcining the vitriol, which may very conveniently be done in an iron ladle, or in a fireshovel, that it is not brought to a full red, as in this state a great portion of it will be insoluble.

With regard to the composition of the indelible ink we are sorry to say, that Dr. Tarry has thought proper to keep it secret. He only informs us that it contains neither galls, nor logwood, nor brazil, nor gum, nor any preparation of iron; that it is entirely vegetable; and that it resists the action of the most powerful acids, of alkaline solutions in their most concentrated state, and of all solvents. He sells it in a solid form; and for use it is to be mixed accurately in a mortar with eight parts of water, and then put into a bottle, left at least one third empty for the purpose of shaking it, which is to be done every six or eight hours for a couple of days. It soon softens quills, but metallic pens are well adapted to it, as it contains no acid. It contains nothing deleterious. The action of nitric acid on it is very trifling. Oxy

muriatic acid changes any thing written with it to the colour of goose dung; and often this caustic alkali renders it of a steel gray: but to produce these effects it must be steeped in them a long time, and the form of the letters then remains unchanged.

but

The ink has been examined by a committee of the French Institute, who confirm the report of Dr. Tarty with respect to its qualities; they add, that it requires to be shaken every time it is used, as the colouring matter soon subsides to the bottom. I

Account of a preservative Stucco, invented by the late Mr. Bachelier.“

The speedy alteration of the stones employed in the principal buildings at Paris, and the inconveniences of renewing their surfaces from time to time by scraping them, induced Mr. Bachelier to propose to the superintendant of the royal buildings to make trial of a preservative stucco. In consequence, three pillars in the court of the Louvre were coated with this stucco to half their height, in 1755; and the parts coated remain in the highest preservation to the present day, being strikingly distinguished by their uniform tint, contrasted with the dull, grey, and earthly aspect of the contiguous parts.

As the alterations making in the Louvre would necessarily destroy every trace of this experiment, some of the members of the Institute conceived it a matter of importance, that an investigation of it as far as possible should take place before it was too late, and accordingly a committee was appointed for the purpose.

On enquiry it was found, that Mr. Bachelier had no where left any ac, count of his process in writing; but his son gave the committee all the information he could from memory, having seen his father prepare it;

and presented them with some sheets of paper, coated with the same preparation, which had been made for the purpose of receiving writing, that could be effaced with a sponge. The coating of this paper, and what could be scraped from the pillars, were analysed; and from the results of these analyses, the account given by the son, and various experimental trials subsequently made, the following appears to be an accurate description of the preparation, except perhaps with respect to the proportion of the ingredients, and in these Mr. Bachelier himself probably followed no precise rule.

The quantity of lime to be used at once, being determined on, this is to be slaked in as little water as possible, but enough to enable it to pass through a sieve not very fine, in order to separate the parts that will not slake. This is to be triturated with skimmed-milk cheese, to the consistence of a soft, smooth, and coherent paste; when calcined gypsum, equal to about two-fifths of the weight of the lime, and pure -white lead equal to about one third, are to be added; and by farther grinding on the stone, with the addition of a little water, the whole is to be reduced to a pap, rather thick than fluid. Lastly, it is to be diluted with common water the moment of using it, which is to be done with a painters or varnishers brush. Mr. Bachelier used oystershell lime, but good stone lime is probably not less efficacious. Care must be taken, that the white lead is not adulterated with whiting, as this would render the composition less adhesive. Indeed I am inclined to think, from the account given by his son, that he did not use ceruse, but employed a strong solution of sugar of lead instead of the water here directed. All the whey must be well pressed out of the cheese; and, if it be

not fresh made, it should be left some time exposed to a moist air to soften. When used fresh, about a fourth of the weight of the other three ingre dients will be a sufficient quantity. The coating laid on should be so thin, as not to injure the delicacy of the edges or indented angles of the finest sculpture.

On the Culture of the Potato in Hotbeds; ty Thomas Andrew Knight, Esq. F.R.S., &c.

THE potato being now very ex

tensively cultivated under glass, and with artificial heat, any improve ment of its culture will probably prove acceptable to many readers of the Horticultural Transactions; and I am therefore induced to send the following account of some methods which I have practised with success, and which will, I believe, be found better than any at present generally known.

The varieties of potatoes, which are well calculated for early forcing, begin to vegetate before Christmas; and it is of consequence to preserve the germs and roots first emitted, from injury, where a crop of good potatoes is required before the end of May. I therefore plant my potatoes in pots of about six inches diameter, in January (a single potato in each), and the pots are then placed in the ground, and covered with litter, to protect them from frost; and in this situation they remain till the hot-bed is ready to receive them. In the mean time, the roots extend themselves through the mould within the pots, and the germs reach its surface; whilst the excita bility of the plants is not at all expended, on account of the low tem perature in which they vegetate and, therefore, when plunged into the hot-bed, they instantly shoot with excessive rapidity, and in a few days begin to generate tubers.

One

stem alone should be suffered to grow in each pot; for where more remain, the tubers are smaller, and the crop is not increased in weight. When the plants grow in small pots, the gardener will have apparently the advantage of being able to take out the largest potatoes, by inverting the pots, without materially injuring the fibrous roots; but this practice will rarely be found eligible, because the plants, having the range of their roots confined to the limits of the pot, soon occupy the whole of their pasture, and therefore do not produce their tubers in succession as they will under common circum

stances.

The lights should be drawn off during the day, when the Spring is far enough advanced to permit this to be done without injury to the plants; and early in May the pots may be taken out of the hotbed, which may be employed for other purposes; and as it must necessarily have been kept very dry during the latter period of the growth of the potatoes, it will generally afford a strong heat on being well watered.

I confine my plants (which are naturally of very dwarfish growth) to small pots, because under this mode of culture the tubers acquire maturity sooner, and are better; but the crop is not so heavy as when their fibrous roots are permitted to extend more widely: and therefore, where a larger, but rather later crop, 3 required, the best plan is to put the tubers to vegetate in small pots, nd from these to remove them, with their roots and gerins uninjured, o the hot-bed.

I tried the effect of placing a few ibers (half a dozen only) on the loor of my cellar, disposing them st in contact with each other;

and as soon as the germs were about four inches long, a hot-bed was made ready to receive them. This experi ment succeeded perfectly; and as it is not attended with so much expense and trouble as either of the preceding methods, it will be found, in many cases, the most eligible. All that appears necessary to obtain an early crop, is to advance the growth of the plant, as much as convenient, under a low temperature, so as to avoid all unnecessary expenditure of its excitability; and, subsequently, to preserve its germs and roots as much as possible uninjured in transplantation.

Were the potato incapable of being raised by forcing in greater perfection, than it is found in the markets of the metropolis, I should think the labour and expense of propagatiug it very ill applied: but the yellow variety, which is now very generally cultivated round London, and which is known in other parts of the kingdom under the name of For's Seedling, has no other merits, whilst young, than its earliness, and a moderately large produce, for in every other respect it is below mediocrity; and even when full grown, it is never excellent indeed, a good potato for forcing, does not appear to me to be at present in the possession of the market gardeners of London.

I hoped to have sent this year to the Horticultural Society, samples of two or three very early new varieties of potatoes, which I have obtained from seed by the process detailed in their Transactions of 1807; and for that purpose I had planted a considerable quantity. But, unfortunately, I planted them in a field at a considerable distance from my house, for the advantage of fresh soil, where the rooks, frein a rookery in the neigh