The islands of Guernsey, Jersey, Alderney, and Sark, the Scilly Islands, and the Isle of Man, were not comprised in the enumeration; the total population of these islands has been usually estimated at about 80,000. The number of houses in Ireland has been nearly ascertained, by the collection of a hearth-money tax, from whence it has been computed, that the population of that part of the united kingdom somewhat exceeds four millions of persons. Therefore, with a very moderate allowance for those places from which no returns were received, and for omissions in others, the total population of the united kingdom of Great Britain and Ireland amounted to 15,100,000 persons.

At the beginning of the preceding cen. tury, Dr. Davenant published an account of the total number of houses in England and Wales, according to the hearth-books of Lady-day, 1690; this account was probably as correct as the above, and a comparison of them shows an increase from 1690 to 1801 of 261,708 houses, which, at 53 persons to a house, makes an increase of 1,465,563 persons. This appears to be the least increase that can have taken place; but it has certainly been greater, on account of the number of soldiers and seamen far exceeding those employed in 1,690.

A circumstance, which caused considerable disagreement in the estimates, which, previously to the enumeration, had been formed on this subject, was the want of sufficient accounts to determine the

proportion of persons to a house. Dr. Davenpant and Dr. Brakenridge reckoned six persons to a house; while Mr. G. King allowed rather more than 4 in London, 43 in the cities and market towns, and four in the villages. Dr. Price asserted, that six persons to a house for London, and five to a house for all England, was too large an allowance; but the fact now appears to be, that in England and Wales the proportion is 53 persons to a house, and in Scotland 52.

The proportion of inhabitants to a house differs very considerably in some of the counties of England; the chief cause of this difference is the large towns, and particularly the sea-ports, which some of them contain, as in such places the inhain moderate sized inland towns. The dif bitants live more crowded together than ference, in this respect, between large towns and those of less extent will be shown, with tolerable accuracy, by the following statements.

The enumeration has not only ascertained with precision the proportion of inhabitants to the houses, but likewise the proportion of males and females. It has been long known, that more male children come into the world than females, of which additional evidence is furnished by the registers of baptisms collected on this occasion, the total of the twenty-nine years for which returns were required, being 3,285,188 males, and 3,150,922 females, or 104 males born to 100 females. This approaches much nearer to equality, than the proportion which previous accounts had appeared to establish, and will probably be found nearer the truth. It has been asserted, that although more males are born than females, there are more females living than males. This opinion appears to have been formed from accounts of places of small extent, or in which the males belonging to such places, who at the time were employed in the army and sea-service, were not included; and if only the resident population is considered, there certainly will appear an excess of females in almost every part of Great Britain. In the ma

ritime counties there appears to be on an average 110 females to 100 males, and in the inland counties 104 females to 100 males. There can be no sufficient reason. assigned for a greater proportion of females residing in the counties which contain sea-ports, but their connection with males engaged in a seafaring life; and in reality the proportion of females is not greater in these counties than inthe others, but it unavoidably appears so, in consequence of persons in the navy and merchants' service having been accounted for in a body, and therefore not being included in the returns of the parishes to which they belong. Of the total number of males in Great Britain, it appears that one in twenty-seven, or nearly four in 104, are in the army and militia, which corresponds with the appearance of an excess of females in the inland counties, whence most of our soldiers, but scarce any sailors, are supplied; and of the total number of males in Great Britain, the army, navy, and seamen in the merchants' service, amount together to one in 11, or somewhat less than 10 out of 110; which agrees so nearly with the average excess of females in the maritime counties, that little doubt can remain, that the appearance of an excess of females has been caused merely by soldiers and seamen not being included in the parochial re

turns.

The total number of males, including the army, navy, &c. was 5,450,292; the total of females 5,492,354, exceeding the males by 42,062, which difference, of less than one in 100, may be accounted for by emigration from this country to the East and West Indies, America, &c. very few females going from hence to reside in foreign parts, in comparison with the number of males who are continually leaving the country in commercial pursuits, or from other motives. The result of the enumeration, therefore, strongly proves that the number of males and females living is as nearly equal as in a subject of this nature could be expected; and the circumstance, of a greater proportion of males being born, appears a necessary provision for maintaining this equality, as providing against the greater adventitious mortality among males, in consequence of the casualties to which they are exposed, and particularly from war and navigation.

An attempt was made to ascertain the population of France, by command of the government, in the tenth year of the Republic, but the account does not appear to

have been very accurately taken. The total population of the 102 departments, into which France was then divided, was stated at 33,104,343 persons, over an extent of about 185,600 square miles. This account included thirteen departments incorporated with the north of France, four departments in the south, and some smaller acquisitions, comprehending, in the whole 23,790 square miles, containing 5,114,419 inhabitants.

POPULUS, in botany, poplar, a genus of the Dioecia Octandria class and order. Natural order of Amentaceæ. Essential character calyx of the ament a flat scale, torn at the edge; corolla turbinate, oblique, entire: female, stigma four-cleft; capsule two celled; seeds many, pappose. There are eleven species; among which we shall notice the P. tremula, trembling poplar-tree, or asp, as it is called from the German espe, which is the general name of all poplars; it has a green smooth bark; the leaves at first breaking out are hairy above, and cottony underneath, but when full grown are smooth. Linnæus observes that they are rolled inwards at the edge, having two glands, running one into the other, on the inner side above the base; he also observes that the leaf-stalks are flatted towards the end, which occasions the perpetual trembling of the leaves with every breath of wind; the petioles being flat in the white and black poplars, as well as in this. Dr. Stokes accounts better for the phenomenon, from the plane of the long leafstalks being at right angles to that of the leaves, allowing them a much freer motion than could have taken place had their planes been parallel. The highlanders of Scotland account for it from a superstitious notion that our Saviour's cross was made of this tree, and that therefore the leaves can never rest.

PORANA, in botany, a genus of the Pentandria Monogynia class and order. Essential character: calyx five-cleft, in the fruit larger; corolla bell-shaped; style semibifid, longer, permanent; stigmas globular; pericarp two valved.There is only one species, viz. P. volubilis, a native of the East Indies.

PORCELAIN, a fine sort of earthenware, chiefly manufactured in China, and thence called china-ware.

The combination of silex and argil is the basis of porcelain: and, with the addition of various proportions of other earths, and even of some metallic oxides, forms the different varieties of pottery, from the finest porcelain to the coarsest

earthenware. Though silicious earth is the ingredient which is present in largest proportion in these compounds, yet it is the argillaceous which more particularly gives them their character, as it communicates ductility to the mixture when soft, and renders it capable of being turned into any shape on the lathe, and of being baked.

The clays are native mixtures of these earths; but they are often rendered unfit for the manufacture of at least the finer kinds of porcelain, from other ingredients which they also contain.

The perfection of porcelain will depend greatly on the purity of the earths of which it is composed; and hence the purest natural clays, or those consisting of silex and argil alone, are selected. Two substances have been transmitted to Europe, as the materials from which the Chinese porcelain is formed, which have been named KAOLIN and PETUNSE, which see; it was found difficult to procure, in Europe, natural clays equally pure, and hence, in part, the difficulty of imitating the porcelain of the east. Such clays, however, have now been discovered in different countries; and hence the superiority to which the European porcelain has attained. The fine Dresden porcelain, that of Berlin, the French porcelain, and the finer kinds which are formed in this country, are manufactured of such clay, which, from the use to which it is applied, has received the name of porcelain earth, and which appears, in general, to be derived from the decomposition of the felspar of granite. It appears, also, that the natural earths, containing magnesia, are used with advantage in the manufacture. The proportion of the earths to each other must likewise be of importance; and from differences in this respect arise, in part, the differences in the porcelain of different countries, as well as the necessity frequently of employing mixtures of natural clays. The argil communicates tenacity and ductility to the paste, so that it may be easily wrought; the silex gives hardness and infusibility; and on the proper proportion of these depends, in a great measure, the perfection of the compound. The proportion of silex in porcelain of a good quality is, at least, twothirds of the composition; and of argil, from a fifth to a third. Magnesia is of utility, by lessening the tendency which the composition of silex and argil alone has to contract in baking, and which is convenient in the manufacture. In the

manufacture of the finer kinds of porcelain, the ingredients are carefully washed, dried, and ground by a mill to a very fine powder, which is passed through a sieve. This is made into a paste with water, which is well kneaded, so as to be uniform in composition. The vessels shaped from this paste are baked in earthen pots, to render them tolerably hard and compact: they are then covered with the materials for glazing, which, in the better kinds of porcelain, consist of a mixture of earths, which form a compound more vitrifiable than the porcelain itself.

These materials are diffused in a very fine powder in water, into which the baked vessels are dipped: the surface is thus covered with a thin crust, the water being absorbed. When dry, they are again placed in the earthen pots, and exposed to a very intense heat. The solid matter of the porcelain undergoes a semivitrification, whence it possesses all the hardness of glass, and has an additional value, in being less brittle, and much more able to bear sudden alterations of temperature: it derives also much beauty from its semi-transparency and white colour. The glazing on the surface is, from its greater fusibility, more completely vitrified, and is, of course, more smooth and impervious. See GLAZING, ENAMELLING, &C.

PORCH, in architecture, a kind of vestibule supported by columns; much used at the entrance of the ancient temples, halls, churches, &c. See ARCHITEC

PORCUPINE. See HISTRIX.

PORE, in anatomy, a little interstice or space between the parts of the skin, serving for perspiration. See CUTIS and PHYSIOLOGY.

PORES, are the small interstices between the particles of matter which compose bodies, and are either empty, or filled with some insensible medium.

Condensation and rarefaction are only performed by closing and opening the pores. Also the transparency of bodies is supposed to arise from their pores being directly opposite to one another. And the matter of insensible perspiration is conveyed through the pores of the cutis. Sir Isaac Newton shows, that bodies are much more rare and porous than is commonly believed. Water, for exam

ple, is nineteen times lighter and rarer than gold; and gold itself is so rare, as very readily, and without the least opposition, to transmit magnetic effluvia, and easily to admit even quicksilver into its pores, and to let water pass through it for a concave sphere of gold hath, when filled with water, and soldered up, upon pressing it with a great force, suffered the water to ooze through it, and stand all over its outside, in multitudes of small drops, like dew, without bursting or cracking the gold. Whence it may be concluded, that gold has more pores than solid parts, and consequently that water has above forty times more pores than solid parts. Hence it is that the magnetic effluvia passes freely through all cold bodies that are not magnetic; and that the rays of light pass, in right lines, to the greatest distances through pellucid bodies.

PORISM, in geometry, has been defined a general theroem, or canon, deduced from a geometrical locus, and serving for the solution of other general and difficult problems. But Dr. Simson defines it a proposition, either in the form of a problem or theorem, in which it is proposed either to investigate or demonstrate. Euclid wrote three books of Porisms, which are lost; and nothing remains in the works of the ancient geometricians on this subject, besides what Pappus has preserved in his mathematical collections. Dr. Simson, among the moderns, left behind him a considerable treatise on the subject of Porisms, which was printed at the expense of the late Earl Stanhope, who was himself a very able mathematician, and the patron, of several persons who had distinguished themselves, in that branch of science.

POROSTEMA, in botany, a genus of the Polyadelphia Polyandria class and order. Natural order of Lauri, Jussieu. Essential character: calyx six-parted, unequal: corolla none : filaments nine, with four anthers on each; capsule covered, four or six-celled, many-seeded. There is but one species, viz. P. guianensis, a native of the woods of Guiana.

PORPHYRY, in mineralogy, a name appropriated to that rock where grains or crystals of felspar are imbedded in a certain basis, as in horn-stone, pi'ch-stone, or indurated clay. There are five species of rocks belonging to the porphyritic formation, viz. 1. Horn-stone porphyry; the horn-stone, which serves as the base of this substance, is generally red or green, and incloses crystals of quartz and fel

spar. 2. Felspar porphyry; the base of this is red compact felspar, inclosing crystals of felspar and quartz. 3. Scenitic porphyry; containing crystals of hornblende, in addition to the other ingredients. 4. Pitch-stone porphyry; the base of which is red, green, brown, or black. 5. Clay porphyry; the base of which is indurated clay passing into horn-stone, it is of a reddish colour, and contains crystals of quartz and felspar. Horn-stone porphyry is the oldest of the class; and clay porphyry the most recent. The red porphyries are employed in ornamental architecture for columns.

PORT, a commodious place situated on the sea-coast, or at the mouth of a river, screened from the wind and the enterprises of an enemy, with depth of water sufficient for ships of burden, and where vessels lie by to load and unload.

Ports are either natural or artificial; the natural are those formed by Providence, and the artificial such as are formed with moles running into the sea. The city of Constantinople is called "The Port," from its having one of the finest ports in Europe. All the ports and havens in England are within the jurisdiction of the county; and the Court of Admiralty cannot hold jurisdiction of any thing done in them. 30 Henry VI.

PORT holes, in a ship, are the holes in the sides of the vessel, through which are put the muzzles of the great guns. These are shut up in storms, to prevent the water from driving through them. The English, Dutch, and French ships, have the valves, or casements, fastened at the top of the port holes, and the Spanish vessels aside of them.

PORTAL, in architecture, a little gate where there are two gates of a different bigness; also a little square corner of a room cut off from the rest by the wainscot, and forming a short passage into the room. The same name is also sometimes given to a kind of arch of joiners'

work before the door.

PORTCULLIS, in fortification, is an assemblage of several large pieces of wood, joined across one another like a harrow, and each pointed with iron at the bottom. They are sometimes hung over the gateway of old fortified towns, ready to let down in case of surprise, when the gates could not be shut.

PORTER, a kind of malt liquor, which differs from ale and pale beer in its being made with high-dried malt.

PORTGREVE, or PORTGRAVE, anciently the principal magistrate in ports and other maritime towns. The word is

formed from the Saxon "port," and 66 geref," a governor. It is sometimes also written "portreve." It is said by Camden, that the chief magistrate of London was anciently called port-greve, which was exchanged by Richard I. for two bailiffs and these again gave place, in the reign of King John, to a mayor, who was annually elected magistrate.

PORTICO, in architecture, a kind of gallery on the ground, supported by columns, where people walk under covert.

PORTLAND-STONE, is a dull whitish species of stone, much used in buildings; it is composed of a coarse grit, cemented together by an earthy spar: it will not strike fire with steel, but makes a violent effervescence with nitric acid.

PORTLAND vase, a celebrated funeral vase, which was long in the possession of the Baberini family; but which was some years since purchased for 1000 guineas by the Duke of Portland, from whom it has derived its present name. Its height is about ten inches, and its diameter, where broadest, six. There are a variety of figures upon it, of most exquisite workmanship, in bas relief, of white opaque glass, raised on a ground of deep blue glass, which appears black, except when held against the light. It appears to have been the work of many years, and there are antiquarians who date its production several centuries before the Christian era; since, as has been said, sculpture was declining in excellence in the time of Alexander the Great. Respecting the purpose of this vase, and what the figures on it were meant to represent, there have been a variety of conjectures. We shall, therefore, give a short account of the several figures, without noticing any of the theories or conjectures that have been made about them. In one compartment three exquisite figures are placed on a ruined column, the capital of which is fallen, and lies at their feet among other disjointed stones; they sit under a tree on loose piles of stone. The middle figure is a female, in a reclining and dying at titude, with an inverted torch in her left hand, the elbow of which supports her as she sinks, while the right hand is raised and thrown over her drooping head. The figure on the right hand is a man, and that on the left a woman, supporting themselves on their arms, and apparently thinking intensely. Their backs are to the dying figure, and their faces are turned to her, but without an attempt to assist her. On another compartment of the vase is a figure coming

both