pounded and sifted very fine, to rub on paper, in order to prevent the ink from spreading on the surface of the paper, and to render the writing clear and distinct.

PREMIUM denotes that sum of money, or percentage, which is given to an insurance office for insuring the safety of a ship or other property.

PRICE-CURRENT: a list or enumeration of various articles of merchandise, with their prices, and sometimes the duties payable thereon, and the drawbacks allow ed upon particular sorts of goods. Lists of this description are published periodically, generally once a week, in our great commercial cities.

PRIMAGE: a certain allowance paid by the shipper or consignee of goods, to the mariners and master of a vessel, for loading the same.

PRIVATEERS: ships of war fitted out by private individuals, "to annoy and plunder the public enemy. But before commencing their operations, it is indispensable that they obtain letters of marque and

reprisal from the government to which they are subject, authorizing them to commit hostilities, and that they conform strictly to the rules laid down for the regulation of their conduct. All private individuals attacking others at sea, unless empowered by letters of marque, are to be considered pirates; and may be treated as such, either by those they attack, or by their own government.

PROA, in navigation, is a name given to a vessel used in the South Seas, because, with a brisk trade wind, it sails near twenty miles an hour.

PRODUCE, in mercantile affairs, is a term applied to the indigenous merchantable commodities of any territory. Thus we call sugar, coffee, cotton, and the like, "West India produce;" hemp, flax, &c. "Russia produce," &c.

PROMISSORY NOTE: a note of hand, purporting the payment of a certain sum, at a stated period. Form of a Promissory Note.

New York, 6th July, 1837. Three months after date, I promise to pay to John Johnson, Esq., or order, the sum of three hundred and fifty dollars, with interest, for value received.

PRUNES: dried plums, of which there are many varieties. The best are imported from France, in the south of which this fruit is very abundant.

PRUSSIAN BLUE: a beautiful deep blue powder, accidentally discovered at Berlin in 1710. It is of considerable importance in the arts, being much used by painters. It cannot be used in the dyeing of cottons, or any sort of stuff that is to be washed with soap, as the alkali contained in the soap readily dissolves and separates the coloring

matter.

noes.

PUMICE-STONE : a light, spongy, vitreous stone, found usually in the neighborhood of volcaIt is used for polishing metals and marble, and smoothing wood and pasteboard. The lighter pumice-stone floats on water. The island of Lipari, in the Mediterranean, is chiefly formed of pumicestone, and may be said to be the magazine whence all Europe is supplied with this useful article.

PURSER: an officer on board frigates and other public ships, who is entrusted with the purchase and care of the provisions, beer, water, casks, &c. of the ship, and all the stores thereto belonging.

PUTTY: a kind of paste, compounded of whiting and linseed oil, worked together to the consistence of a thick dough. It is used by glaziers for fastening in the squares of glass in sash windows, and by painters for stopping up the crevices and clefts in timber and wainscots, &c.

PYROPHORUS. By this name is denoted an artificial product, which takes fire or becomes ignited on exposure to the air. It is prepared from alum by calcination, with the addition of various inflammable substances.

PYROTECHNICS: the art of making fireworks.

Q.

QUADRANT: a mathematical instrument of great use in astronomy and navigation.

QUARANTINE: a regulation, by which all communication with individuals, ships, or goods, arriving from places infected with the plague, or other contagious disease, or supposed to be peculiarly liable to such infection, is interdicted for a certain definite period. The term is derived from the Italian quaranta, forty; it being generally supposed

that if no infectious disease break out within forty days, or six weeks, no danger need be apprehended from the free admission of the individuals under quarantine. During this period, too, all the goods, clothes, &c. that might be supposed capable of retaining the infection, are subjected to a process of purification. This last operation, which is a most important part of the quarantine system, is performed either on board ship, or in establishments denominated lazarettos. The lazarettos at Leghorn, Genoa, and Marseilles are the most complete of any in Europe. The facilities they afford to navigation are very great; for as ships from suspected places may discharge their cargoes in the lazaretto, they are not detained longer than they would be were there no quarantine regulations. The goods deposited in the lazaretto, being inspected by the proper officers and purified, are then admitted into the market.

The period of quarantine varies, as respects ships coming from the same place, according to the nature of their bills of health. These are documents, or certificates, signed by the consul or other competent authority in the place which the

ship has left, describing its state of health at the time of her clearing out. A clean bill imports that, at the time of her sailing, no infectious disorder was known to exist. A suspected, or, as it is more commonly called, a touched bill, imports that rumors were afloat of an infectious disorder, but that it had not actually appeared. A foul bill, or the absence of clean bills, imports that the place was infected when the vessel sailed. The duration of the quarantine is regulated by the nature of these instruments.

QUARTO: a book, in which every sheet, being twice doubled, makes four leaves or eight pages.

QUASSIA: a beautiful tall tree, growing in North and South America, of which there are several varieties. The wood is of a pale yellow color, and its taste is intensely bitter.

quills being the best. Crow quills are chiefly used for drawing. The goodness of quills is judged partly by the size of the barrels, but more by the weight. Particular attention should be taken in purchasing quills, that they be not left-handed, that is, out of the left wing. A method of hardening quills is by setting water and alum over the fire, and while it is boiling putting in a handful of quills, the barrels only, for a minute, and then laying them by.

R.

RAGS: shreds or fragments of linen, woollen, or cotton cloth. Though commonly held in little estimation, rags are of great importance in the arts, being used for various purposes, but especially in the manufacture of paper, most of which is entirely prepared from them. Linen rags are imported into this country in considerable quantities from Italy, Sicily, and other parts of Europe. There is considerable variety in the appearance of rags from different ports; but, in general, those from the north of Europe are darker and stronger than those from the Medi

terranean ports. Most of the rags collected in the Tuscan states, to the extent of 10,000 or 12,000 bags a year, go to America.

RAGWORT: a perennial plant, growing by road-sides, and flowering from July to August. It imparts a fine green color to wool.

RAILROAD: a species of road, having tracks or ways formed of iron, stone, or other solid material, on which the wheels of carriages passing along it run. The object in constructing such roads is, by diminishing the friction, to make a less amount of power adequate either to impel a carriage with a greater velocity, or to urge forward a greater load.

The friction on a perfectly level railroad, properly constructed, is estimated to amount to from one tenth to one seventh only of the friction on an ordinary level road; so that, supposing the same force to be applied in both cases, it would move a weight from ten to seven times as great on the former as on the latter. But if there be a very moderate ascent, such as one foot in fifty, which in an ordinary road would hardly be perceived, a great increase of power on the railroad is required to overcome the resist

ance that is thus occasioned. The reason is that the ordinary load on a level railroad is about seven times as great as on a common turnpike road; so that when the force of gravity is brought into operation by an ascending plane, its opposing power, being proportioned to the load, is seven times as great as on a common road. Hence the vast importance of having railroads either level, or as nearly so as possible.

It is also of great importance that railroads should be straight, or, at least, free from any abrupt curves. Carriages being kept on the road by flanges on the wheels, it is obvious that, where the curves are quick, the friction on the sides of the rails, and consequent retardation, must be very great. Railroads are either made with double tracks, one for going and one for returning, or they are made with sidings, where the carriages may pass each other.

The application of locomotive engines as a moving power on railroads must be regarded as of the highest importance. These engines were first brought into use in England in 1825, and now they are in general use both there and

in this country. Carriages full of passengers, attached to these engines, may be safely impelled along a perfectly level railroad at a speed of twenty or thirty miles an hour.

RAISINS: the dried fruit of the vine. They are produced from various species of vines; deriving their names partly from the places where they grow, as Smyrnas, Valencias, &c., and partly from the species of grape of which they are made, as muscatels, blooms, sultanas, &c. Their quality appears, however, to depend more on the method of their cure than on anything else. The finest raisins are cured in two ways: either by cutting the stalk of the bunches half through, when the grapes are nearly ripe, and leaving them suspended on the vine till the watery part be evaporated, and the sun dries and candies them; or by gathering the grapes when they are fully ripe, and dipping them in a lie made of the ashes of the burnt tendrils; after which they are exposed to the sun to dry. Those cured in the first way are most esteemed, and are denominated raisins of the sun. The inferior sorts are very often dried in ovens.

Raisins are imported in casks,