come very much into use, and attempts have even been made to introduce them into armies, though the expense of the chemical powder may be an objection.

PERENNIAL. In Botany, is applied to those plants whose roots will abide many years, whether they retain their leaves in winter or not those which retain their leaves are called evergreens; but such as cast their leaves, are called deciduous, Some of these have annual stalks, which die to the root every autumn, and shoot up again in the spring.

complicated to be here considered in detail. The unhealthy nature of certain occupations, the impetuosity of the passions, and the corruption of manners, prove no less fatal to life than the original weakness of the human frame. In general, the mean duration of human life is between 30 and 40 years; that is, out of 30 or 40 individuals, one dies every year.

This proportion varies in a singular manner, according to șex, localities, and climates, and even from one province to another. In 1774, there was, according to Sussmilch, one death for every 26 men and women in Prussian Silesia, and I for every 36 in the March of Brandenburg. In SwePERENNIAL PLANTS. In Gardening, are den, according to Wargentin, they reckon 1 in 33 such as are of long duration. Such plants as are for the men, and 1 in 35 for the women. In Denperpetuated by the roots, whether the leaves and mark, the proportion is, according to the statistics stocks decay annually in winter, or always remain, of Thaarup, 1 in 37 2-elevenths including Holstein. provided the roots are of many years duration, are In Norway, according to the same author, they perennial. All plants, therefore, with abiding roots, allow 1 in 48 4-ninths. The German and Russian both of the herbaceous, shrub, and tree kinds, are geographers affect to establish a proportion still perennials; though in the general acceptation of more favorable for Russia, viz. 1 in 58 or 59; but the word perennial, it is most commonly applied there is reason to believe that they proceed on erto herbaceous vegetables with durable roots, more roneous data. It is certain that in small districts, especially those of the flowering kind, which among the proportion which the number of deaths bears gardeners are commonly called simply perennials, to that of the living inhabitants is sometimes exparticularly the fibrous-rooted tribe; but it is equally tremely low. In the parish of Woerdal, in Norapplicable to fibrous, tuberous, and bulbous-rooted way, the mortality was only 1 in 74, during ten plants, whose roots are of several years duration; years. In the government of Woronetz in Ruslikewise all shrubs and trees of every denomina-sia, the mortality was that of 1 in 79 9-elevenths; tion, as having abiding roots, are perennial plants.

PERIGEE. In Astronomy, that point of the sun's or moon's orbit, wherein they are at their least distance from the earth, in which sense it stands opposed to apogee.

PERIHELIUM. In Astronomy, that point of a planet's or comet's orbit, wherein it is in its least distance from the sun; in which sense it stands in opposition to aphelium.

PERIOD. In Astronomy, the time taken up by a star or planet in making a revolution round the sun; or the duration of its course till it return to the same point of its orbit. There is a wonderful harmony between the distances of the planets from the sun, and their periods round him; the great law whereof is, that the squares of the periodical times of the primary planets, are to each other as the cubes of their distances from the sun; and likewise, the squares of the periodical times of the secondaries of any planet, are to each other as the cubes of their distances from that primary. This harmony among the planets is one of the greatest confirmations of the Copernican hypothesis.

PERIOD OF LIFE. The natural limit of human life seems to be from 80 to 90 years. Few men survive that period—the greater majority die long before they even approach it. Of all newborn infants, one out of four dies the first year. Two fifths only attain their sixth year; and, before the twenty-second year, one half of the generation is consigned to the grave. The order which death observes in cutting off his victims is one of the most wonderful phenomena in nature--the causes by which it is effected are too numerous and too

but it is physically impossible that proportions so favorable can obtain in a country of large extent. In France, it appears that the proportion is 1 death in 35; and that is perhaps the most unexceptionable basis that can be adopted for any country of the same extent.

It is said that the mortality is much greater in towns than in the country. Wargentin calculates that in Stockholm 1 in 17 men dies, and 1 woman in 21. According to Price, there dies in the large towns of England, every year, 1 out of from 19 to 23; in the small towns, 1 in 28, and in the country, only 1 in 40 or 50.

Aristotle long ago exhorted governments to prevent the accumulation of inhabitants in cities. Sussmilch compares cities to a continually raging pestilence. Such a sweeping assertion exaggerates the effects of an evil whose existence cannot be denied. The inhabitants of the country enjoy two great advantages over those of towns, a purer air, and a more sober and regular life. On the other hand, rural employments expose those who follow them to so many accidents, and subject them to so many hardships, and to such a miserable mode of living, that it may be doubted whether the real disadvantages in cities are as great as has been supposed. The apparent disproportion is probably owing, in a great measure, to the circumstance of the hospitals being almost always established in towns, and many of the sick being brought to them from the country. Out of from 20 to 21,000 deaths in Paris, it is generally found that from 6 to 7000 have taken place in the hospitals alone.

It appears that the air of open and elevated plains, and of mountains having a free approach, is conducive to longevity. The same thing may be said of an insular atmosphere, which is always renovated by the breezes from the sea, Russia,

Norway, Sweden, Denmark, Scotland, Ireland, and Switzerland, are the countries which furnish the most numerous and the most authentic examples of men and women having had their lives extended beyond the period of 100 years. In these countries we may reckon one centenarian for every three or four thousand individuals. But, we know that there are many countries in which longevity is common, although we do not exactly know to what extent. Pliny mentions that part of Italy which extends from the Apennines to the Po, and from Placentia to Bologna, as containing a great number of men, from 100 to 150 years of age, at the time of the census which was taken under the emperors Claudius and Vespasian.

trades, and the quality of food commonly used, are circumstances which exert a greater influence than climate upon the propagation of the human race. It has been observed, that people who live upon fish, multiply faster than those who subsist on nothing but flesh. The fecundity of the women of Sologne, a country by no means healthful, is perhaps to be ascribed to the buckwheat which constitutes the principal article of food to the inhabitants of that canton; for this kind of grain, as is observed in birds, appears to stimulate the organs of generation, whilst rye, on the contrary, is said to occasion infecundity in the fowls that feed upon it. Among tribes that lead a wandering life, and are not very numerous, there are fewer Rare examples, however, of extrenie longevity, children born than in those better peopled counof a life of 150 years and upwards, seem to be tries where the individuals of both sexes are brought common to all countries without distinction. If nearer together, and are more frequently in the England, the salubrity of which is so highly ex-presence of each other. In populous countries, tolled, has furnished three or four examples of men however, which have attained a high degree of arriving at the age of from 150 to 169 years, Hun- civilisation, the number of births diminishes, owing gary, which, generally speaking, is not a very to the dearness of provisions, which makes it more healthy country, has seen the celebrated Peter difficult to support a family, and consequently renCzartan prolong his life to the 185th year, and John | ders marriages less frequent. The period in which Rovin, at the age of 172 had a wife of 164, and a a people subsist principally by agriculture, and younger son of 117. It is in the Bannat of Teme- when the conveniences of life are easily procured, suar, a very marshy district, and subject to the appears to be that in which population most rapidputrid fever, that these examples of longevity, and ly advances. many others, have been observed. A mode of It is owing to the physical influence of the air, life, which is sober, and unruffled by tumultuous the food, and the mode of life, that certain seasons passions, singularly contributes to longevity. Ac- of the year are more favorable to fecundity than cording to the author of a very curious little work, others. Pliny calls the spring the genial season. called the Apology for Fasting, 152 hermits, taken Hippocrates had previously observed, that spring in all ages, and under every climate, produce a sum was the season most favorable for conception. total of 11,589 years of life, and consequently an Aristotle has justly remarked, that the sun and average of 76 years and a little more than three man labor together in the reproduction of man. months for each; whereas the same number of Observations made in several countries, concur in Academicians, the one half belonging to the Acad- determining the months of December and January emy of Sciences, and the other to that of Belles to be those in which the greatest number of chilLettres, give only 10,511 years of life, consequent-dren are born. Local circumstances, depending ly 69 years and a little more than two months for upon the manner of life peculiar to a nation, may the mortal career of each. It is therefore not im- modify or alter this general rule. In Sweden, acprobable, that in the ages of patriarchal innocence, cording to Wargentin, the month in which there the period of 150 or even 200 years, was much are most births is that of September, and the month more commonly attained than it is in our times. of January only ranks next to it. This fact is This is what the ancients affirm of the Seres, of easily explained, when we recollect that among all the Cyrni of India, of the Epians in Ætolia, and the nations of the north, particularly in the counof the inhabitants of Mount Athos and Tmolus. try, the season of Christmas and the new year is devoted to festivity and mirth.

In the ordinary course of nature, at least among civilized nations, the number of births exceeds the The number of births is directly and materially number of deaths. But the proportion varies with affected by causes of a moral and political nature. the situation. In the country, there is frequently The difficulty of finding subsistence is unfriendly 1 born yearly for every 22 of the population. In to the increase of marriages, and it is only from towns, the proportion is less favorable, being often marriages that a state can hope to see a numerous 1 to 40, more generally 1 to 35. In this respect, race of children arise. Libertinism, a community climate occasions a remarkable difference. The of wives, polygainy, and divorce, have never had most healthy climate is not always that in which a salutary influence on population. It has been there are most children born-for example in Den- shown by the most authentic calculations, that of mark, the proportion of births to the existing in- two bodies of individuals, equal in number, that habitants is as 1 to 31; in Norway as 1 to 34. In which lives in a marriage state produces more France, the proportion is as 1 to 29. There are children than that which promiscuously indulges reckoned in Sweden 4 children to a marriage-in in the commerce of the sexes. As to the celebraFrance 4 1-2; consequently the ancient opinion, ted institution proposed by Plato, we must refer to which considered the north as the officina gentium, that philosopher himself. The community of the cradle of nations, although supported by many wives that he thought of, was regulated by severe philosophers besides the antiquary Rudbeck, is al-laws, and had for its object to limit population, by together destitute of foundation. purifying it. The polygamy of the East, considThe manner of life, the nature of the different ering the numerical equality of the two sexes,

should also fix the period of puberty among the Negroes at seven or eight years. But so far is this from being the fact, that all the accounts which we have consulted, seem to prove that the age of puberty among the Negroes is not much earlier than among the southern nations of Europe. It appears, then, that even in the torrid zone, the physical phenomenon in question, depends rather upon the difference of the race, than upon that of the climate.

allows a plurality of wives to one man, only by condemning to celibacy a great proportion of the community. Montesquieu accordingly, has declared it to be very injurious to population; but this philosopher has at the same time defended the facility and frequency of divorce. He has ventured to attribute to this cause the immense number of inhabitants which he assigns to the ancient Roman empire; and he has gone so far as to insinuate that the Christian religion by inculcating continence, and the indissoluble nature of the marriage union, has diminished the number of the human race. This calumny is easily refuted by the testimonies of the ancients themselves, who all agree in representing the primitive sanctity of marriage as the direct source of the inexhaustible strength of the Roman republic, whilst under the emperors, in the age of corruption, Italy would have remained uncultivated for want of hands, had the soil not been labored by legions, or rather by whole nations of slaves, collected together from all parts of the world. All the evil which has actually arisen from the celibacy of the clergy-a celibacy no where enjoined in the Gospel-cannot countervail the services which Christianity has rendered, merely with regard to the increase and preserva-arrive as late at puberty as those who live near the tion of our species.

The immoderate use of strong liquors tends to enervate the frame, and to exhaust the powers of propagation. An active, sober people, equally moderate in their passions and their pleasures, will always be superior in fecundity to a people debauched by luxury, effeminacy, and voluptuous enjoyments. A proof of this may be obtained by comparing an agricultural country to one which is filled with vineyards. It appears to be proved that a square league laid out in fields, can furnish occupation and food only for 1390 individuals, whereas a space of equal extent, planted with vineyards, supports 2604 persons. Why then are districts abounding in vines, often more thinly peopled than agricultural provinces under the same climate? Why are the vine-dressers so often in miserable circumstances? For no other reason than that drunkenness is more prevalent in such a district, and because the annual produce of the vine is more uncertain than crops of grain.

There are other facts still more conclusive. All the Russian and Danish travellers who have given us written accounts of Lapland, and the other countries in the neighborhood of the Frozen Sea, agree in stating that the women of these regions are not only very lascivious, but that they become marriageable at an early period. A Frenchman who has seen much, and seen with observation, assures us that the Swedes become sensible to the passion for the sex at the age of 12 years. In Russia the peasants often marry at the same age. In the Vivarais, a mountainous and cold tract of country, the natives are as soon marriageable as in the other provinces of the south of France. The savages of America, who dwell under the line,

pole. With them the men do not marry before they are 30, nor the women before 20.

It appears then that we should consider this physical difference rather as inherent in the particular race than as dependent on climate. The cause is often to be found in the extreme corruption of manners. Be this as it may, the phenomenon of which we speak has probably but little influence on the number of births, and none whatever upon the increase of population. In the first place, it is observed, that in every country where women are marriageable at a very early period, they also sooner cease to bear children; in India they become old at 30. In the second place, the children in those countries are more feeble, and subject to greater mortality.

This last observation can even be extended indiscriminately to all nations; we should always beware of inferring an increase of population, solely from the number of the births appearing to be greatly superior to the number of the deaths. "The period of puberty arrives sooner,' it has When this excess is extremely disproportionate to been said, 'in warm and southern countries, than the number of deaths and marriages, there is reain cold climates, as those of the north, and of ele- son to suspect some want of exactness in making vated mountains.' This commonly received opin- out the lists, or some extraordinary physical cirion must be understood with some limitation. It cumstance. The proportion of births to marriages, is true, for example, that the Barbary women are on an average, and in a country of some extent, generally mothers at 11 years of age, and cease to can scarcely be more than 5, or less than 3 births bear children at 30. Buffon, quoting from Theve- to one marriage. The ordinary proportion, in the not, says, that in the kingdom of the Deccan, boys most civilized countries in the world, is four births are married when 10 years old, and girls when to one marriage. The proportion between births eight, and that there are some who bear children and deaths is, one year with another, from 101 to at that age; so that they may be grandmothers before they are 20. But if this were purely the effect of climate, as Buffon imagines, a very singular consequence would follow. The climate which the Negroes of Senegal inhabit, is certainly warmer than that of Barbary, and even than that of the peninsula of the Deccan. If then it is the influence of climate alone which accelerates the period of puberty among the nations of India, and which fixes it at 10 or 11 years of age, the same influence

150 for every 100. This last proportion indeed occurs only in some provinces of small extent, and singularly favored by nature. Every proportion higher than this, with regard to an extensive country, ought to be viewed with suspicion, unless verified by calculations and registers of undoubted correctness and authenticity. To mention only one example; the Russians may be permitted to assert that almost every year, (even in time of war,) there are more than one million of individuals born

in the Russian empire, whilst only from 500,000 | in consequence of which, about the 15th year, the to 600,000 die. But we also must be allowed to numbers of the two sexes are brought almost to an express our doubts as to these marvellous results, equality; there is, however, still a surplus in favor and to ascribe, in part, this disproportion between of the males. But this surplus in the number of the deaths and the births, to the carelessness of the men, even though were it three or four times those who keep the registers. greater, is carried off by wars, by dangerous voyages, and by emigration, to the casualties of which the female sex are less exposed. Thus, the final result of this is, that in our climates the women are always more numerous than the men. This difference is particularly observable at the conclusion of a long war. According to Wargentin, it amounted in France, after the seven years war, to 890,000 in 24 or 26 millions of souls; and in Sweden, after the Northern war, about 127,000 in a population of two million and a half.

Euler has constructed the following table, by means of which we may see, at a glance, in how many years the population of a country may be doubled under certain conditions.

In a Country of 100,000 inhabitants, the Mortality being 1 in 36.

The deaths being The surplus of to the births as, births will be

This surplus will make of the sum of the living

The doubling of the population will take place in 250 12 years.

10 to 11

277

1 361

125

180

The same mathematician, founding on data extremely favorable to the propagation of the species, has constructed a table, the general result of which is, that the human race might be tripled in 24 years, and that at the end of 300 years the posterity of one couple might amount to 3,993,954 individuals. Taking the total number of the human race at 700 millions, (which is rather high,) the ratio of the deaths to the living population as 1 to 33, and that of the births to the living as 1 to 29 1-2, we shall have for the whole globe,

At the same time the difference of numbers between the two sexes is not in Europe sufficiently great, nor indeed sufficiently steady to warrant any conclusion unfavorable to the system of monogamy, that is, of marriages between one man and one woman. Such marriages only are fitted to insure domestic happiness, and to maintain pure morals; they are besides sanctioned by the soundest maxims of political economy; and none can doubt that the prevalence of polygamy, or the marriage of one man to several wives, would prove fatal to the welfare of Europe.

Some travellers have imagined that in warm climates there are more girls born than boys; and as the male sex is liable to more rapid destruction in such climates than in ours, the surplus of women must become very great; hence Montesquieu concludes that polygamy among these people admits of a very plausible excuse; but the position from which he sets out is altogether unfounded. The researches of Father Parennin in China, the list of baptisms kept by the Danish missionaries of Tranquebar, the various censuses taken by the Dutch at Amboyna and Batavia, and the observations made at Bagdad and Bombay, by the judicious Niebuhr, have demonstrated that the number of children of both sexes is not more disproportionate in the East than in Europe.

It is alleged with more reason, that there are some nations who, being in the habit of selling a number of their women to foreigners, experience a deficiency of them at home, which has obliged them to establish polyandrism, or the marriage of one woman to several husbands. Such a practice, if it does exist, is evidently the least favorable to population.

It has been commonly computed that a district, in which there are 10,000 infants born yearly, must contain in all, 295,022 inhabitants of both sexes, of whom 93,003 should be children below 15 years, and 202,019 persons above that age.

Among these individuals, there will be at the most 23,250 monogamie marriages, (the mean duration of which may be estimated at 21 years) 5812 widows, and 4359 widowers, the rest single.

PERIOECI. In Geography, such inhabitants of the earth as have the same latitudes, but opposite longitudes; or live under the same parallel and the same meridian, but in different semicircles of that meridian, or in opposite points of the parallel. These have the same common seasons

The peroration consists of two parts; a rapid PERSIAN LILAC. A handsome shrub, hav recapitulation of what has been said before; and ing a broader leaf and a finer flower than the com a declamatory address to the passions. The qual-mon lilac. ities requisite in the peroration, are animation and brevity.