follows that the increase from generation to generation is 55 per cent, or that every 1,000 women are succeeded, at the interval of 33 years, by 1,553 women; every two couples, male and female, by three. If the interval is contracted, and the increase from 1,000 to 1,553 takes place in 30 years, the annual rate of population increases from 1.329 to 1.477 per cent; and as we assume by hypothesis that the births and the lifetime remain the same, the population would be ultimately one-ninth part more numerous than it was under the former conditions. Early marriages have the effect of shortening the interval between generations, and tend in this way to increase the population. 3. An increase in the fertility of marriages will evidently cause an increase in the population. 4. In ordinary times, a large proportion of the marriageable women of every country are unmarried, and the most direct action on the population is produced by their entering the married state. Thus, in the Southeastern division, comprising Surrey, Kent, Sussex, Hants, and Berks, the number of women of the age of 20 and under the age of 45, amounted at the last census to 290,209, of whom 169,806 were wives, and 120,403 were widows or spinsters. 49,997 births were registered in the same counties during the year 1850, or 10 children were born in 1850 to every 58 women living in 1851. Of the children, 46,705 were born in wedlock, 3,292 were born out of wedlock; consequently, 36 wives bore in the year ten children, and of 366 unmarried women of the same age, (20-45,) ten also gave birth to children. A change in the matrimonial condition of a large proportion of the 120,403 unmarried women, out of the 290,209 women at the child-bearing age, would have an immediate effect on the numbers of the population; and, if continued, by increasing the rate of birth to the living through successive generations, would operate on population like a rise in the rate of interest on the increase of capital. 5. The effect of migration on the numbers of the population is evident. It is probable that the emigration of Irish has contributed to the increase of the population in England, and it is certain that the emigration from the United Kingdom contributes largely to the increase of the population of the United States. The emigrants are a self perpetuating body in healthy climates, and they increase faster abroad than the general population at home, as they contain an excess of the population at the reproductive age; so that if their numbers are added together it is certain that we get, in the aggregate, a number much below the actual number of survivors. The population of Great Britain and Ireland, including the army, navy, and merchant seamen, was 21,272,187 in 1821, and about 27,724,849 in 1851; but in the interval, 2,685,747 persons emigrated, who, if simply added to the population of the United Kingdom, make the survivors and descendants of the races within the British isles in 1821, now (in 1851) 30,410,595. 6. The numbers of the population are increased by the abundance of the necessaries of life, and reduced by the famines, epidemics, and public calamities affecting the food, industry, and life of the nation. The pestilences of the middle ages-the famine, the influenza, and the cholera of modern times-are examples of one class of these agencies; the security and freedom which England has latterly enjoyed, are examples of the beneficent effect of another class of influences, not only on the happiness of the people, but also on the numbers which the country can sustain at home and can send abroad to cultivate, possess, and inherit other lands. The extent to which all these causes affect the increase of the population of Great Britain, will ultimately be known by means of a continuous series of such observations as have been commenced at the present census. DECLINE OF THE POPULATION OF SPAIN. The Clamor Publico, a Spanish journal published at Madrid, presents in the following statement a deplorable picture of the decline of Spain : Under the Moors, the population of Spain was 30,000,000; it is now 15,000,000. When Granada was conquered, in 1787, it was defended by walls flanked by 1,030 towers. The kingdom, of which it was the capital, was 70 leagues long by 50 broad, and possessed 32 cities of the first rank and 97 of the second. Granada, before its fall in 1487, contained 400,000 inhabitants, of whom 60,000 bore arms; it now contains about 60,000 souls, all counted. The population of the whole kingdom of Granada was 3,000,000. Malaga, in the seventeenth century, contained 80,000 in habitants; it now possesses only 50,000. Madina del Campo, in the seventeenth century, contained 60,000 inhabitants; it now contains 6,000. Merida, at the same epoch, possessed 40,000 inhabitants; it now possesses only 5,000. In the sixteenth century, the diocese of Salamanca had 127 cities and villages; it now has 13 only. Segovia, in 1725, had 5,000 families; now 2.000. Seville, in the seventeenth century, had a population of 300,000, of which 130,000 were employed in manufactures; it now contains 96,000, all told. Toledo, in the fifteenth century, had 200,000 inhabitants; it now has 15,000. Valence, which in the year 1600 counted a population of 600.000, now hardly numbers 60,000. In 1778, there were counted 1,511 abandoned villages in Spain, and the number has been increasing from that time to this. CENSUS OF THE SANDWICH ISLANDS, The Polynesian of March 18, 1854, furnishes the following summary of the census returus, taken December, 1853: In 1778, Cook estimated the population of the group at 400,000; but probably the real number was not over 300,000. In 1850, the number of inhabitants was 84,165. The rapid diminution of population since 1849 is partly explained by the existence of measles and smallpox, which were very fatal; but, aside from these extraordinary causes, there is a gradual and regular falling off, which by many is supposed to amount to as much as 8 per cent yearly. The district in which Honolulu is situated contains not far from 9,000 inhabitants, of whom 1,180 are foreigners. STATISTICS OF AGRICULTURE, &c. AGRICULTURE IN GERMANY. The Berlin correspondent of the London Times, writing to that journal, says:Among the earliest subjects that will engage the attention of the Zollverein conferences will be the reduction of the duty on iron-which the South German States, particularly Wurtemberg, are preparing to oppose' energetically-and, even more urgently than this, the facilitation of the internal traffic in grain, so as, if possible, to obtain an internal free trade in corn. The excessive emigration that is now taking place from the South of Germany--we may with propriety call it a Teutonic Exodus is mainly attributable to the dearness of provisions, though there are of course other troubles, of a political and social nature, which contribute to fill up their cup of bitterness to overflowing. From Bohemia and Moravia we hear of hundreds of families constrained to live on grass and roots. In the Palatinate and Rheinhessen, formerly remarkable for cheap living, the complaints of dear provisions have become general. Potatoes cost six times, hay five times as much as they did thirty years ago. Even in Prussia the price of corn (rye) in some parts has risen to sixty thalers (£9) the wispel (24 bushels) Representations were lately made to the President of the Ministry and Minister of Finance, stating that in Berlin, with the population over 400,000, there are at present only about 1,200 wispels of rye on hand, of which 200 are alrea ly sold, and that prices have been rising steadily for many years past, and the supply not increasing. The local statistics of Berlin show that while house rent has increased from certain local causes, the octroi levied at the gates on meat and all cereals, whether converted into food or not, had not increased in proportion to the increase of the population. By some authorities on this subject, this diminution or want of extension in the supply is attributed to the increased cultivation of tobacco; in some parts of the South of Germany two-thirds of the land that formerly produced wheat and potatoes now bears tobacco. Many years ago the annual consumption of tobacco in Germany amounted to 3 lbs. per head of the whole population, while in England it only amounted to lb. The difference now is doubtless still greater than it was then. In Silesia alone there are more than 4.000 acres devoted to the growth of this plant, which offers this great attraction, that its conversion into cigars supplies labor for a number of hands during the winter. Another cause for the insufficient production of corn may be found in the enor mously increased cultivation of beetroot for sugar purposes-a subject of so much importance to England and Ireland that I shall return to it specially on another occasion. Agriculture in general seems to be thriving in Prussia. The aggregate value of the annual produce of grain has increased by 50,000,000 thalers since the year 1820; that of cattle breeding by 60,000,000; taking both together as the produce of the land in general, the present annual value amounts to 500,000,000 thalers, against 300,000,000 in 1820. The great increase is doubtless due to the number of railways, which admit of the produce being brought to market; where there is no railway, the land has so little value, that it does not pay the proprietor to manure or drain it. If he wants to increase his produce for any purpose, it pays him better to purchase a few hundred acres more than to spend money on those he has. AGRICULTURAL PRODUCTIONS IN CALIFORNIA. We learn from the Pacific, that Mr. William Wolfskill, of Los Angeles, has fifty acres of land, which affords the following quantity and variety of products: Thirty-five acres of grape-vines, with about 1,000 plants to the acre, produce each about 1,100 bbls., or 34,650 gallons of wine. Three acres of peach-trees, with 100 trees to the acre, average 40 lbs. to the tree, 12,000 lbs. Seventy pear-trees average 1,000 lbs. to the tree, 70,000 lbs. Forty apple-trees, 240 lbs. each, 76,000 lbs. Twenty orange trees, bearing about 2,000 each. Twenty-five fig-trees, about 300 lbs, to the tree. Ten apricots, about 100 lbs. each. Ten citron bushes, with about 20 each. Sixty English walnut-trees, just beginning to bear. An olive-tree, and a few quinces. The value of these products on the ground is as follows: 750 bbls. of wine distilled make 4,725 gallons of brandy, at $1 80 per gallon... 11,025 gallons wine, at $1 per gallon. 12,000 lbs. of peaches at 5 cents per lb.. 70,000 lbs. of pears at 4 cents per lb.... 1.000 lbs. of apricots at 4 cents per lb.. 9,600 lbs. of apples at 10 cents per lb.... $8,505 11,025 600 2,800 400 960 2,000 100 Figs, walnuts, and quinces, no sale. Total..... $26,380 Mr. Wolfskill's ranch is about 700 miles by land from his garden or vineyard, on Punta Creek, in the valley of the Sacramento. There, about 3,000 head of cattle, and a hundred or two of horses range. And to amuse himself while herding his stock, he has planted a fine vineyard which will begin to bear soon, and set out near 1,000 trees of various kinds of fruit. Among them he has some fine olive-trees. He is now delivering a thousand head of cattle to the butchers at $40 a head. Mr. John Wolfskill has on the Punta some orange-trees that have lived through the cold weather of this winter, and he is not without hope of getting them to bear. JOURNAL OF MINING AND MANUFACTURES. IRON MANUFACTURES OF THE WORLD. The following statistics, so far as they relate to great Britain, are compiled from the returns of 1850, and from the recent trade and navigation returns: In 1850 there were 459 furnaces in the United Kingdom, nnd the annual yield of iron was 2,380,000 tons. The following figures are said to represent the produce of the respective countries named :— In 1850, therefore, while Great Britain produced 2,380,000 tons, and imported 28,000 tons, her total export of iron and hardware amounted to 809,100 tons. She, therefore, had left for home markets, over 1,500,000 tons. In 1796, the quantity of British iron made was 125,000 tons. The quantity of foreign iron retained for home consumption was 45,600 tons. The total exports of iron and hardware amounted to 408 tons; the total home consumption 170,000 tons. The contrast in 1850 is striking indeed, as calculated to show the progress of this manufacture. the figures stand thus: British iron made.......tons. 2,380,000 | Iron & hardw're exported. tons. Foreign iron retained ..... 28,000 Iron consumed at home ..... 809,100 1,598,900 In connection with the foregoing, the following table will show not only the rate of increase in the exports of iron, steel, and machinery, but also the gradually increasing proportion which, in the periods given below, the value of these exports bore to the total exports of the country. In 1814 they amounted only to 4.08 per cent of the whole; whereas in the present year they will probably exceed 20 per cent, amounting as they do to 18.85 per cent in the first ten months of the year: The increase since that period may be inferred from the following figures, which allude to the ten months ending Nov. 5, 1853:— Of countries which received the largest portions of this enormous mass of exports, the United States took not only by far the largest quantity of iron and steel, wrought and unwrought, but also the largest quantity of pig-iron-the quantity exported in 1850 being 57,000 tons. Next to the United States stands Holland, 13,100; France, 11.710; Prussia, 10,950; Canada, 10,890; Denmark, 7,570; Italy, 7,400; and the Hanseatic towns, 7,370 tons. Russia takes only 812, and Turkey 930 tons of pig iron. Of bar, bolt, and rod iron, the United States is also the largest customer-taking, in 1850, 263.530 tons. Next in order stands Canada, 46,340; East Indies, 36,200; Italy, 26,770; Turkey, 14,890; Hanseatic towns, 10,440; Holland, 9,350; and Portugal, 6,890 tons; Russia taking only 706 tons. The following table gives the total values of these three branches of iron manufactures exported to each country: Mr. Miller, in his discourse before the Historical Society, mingles geological and historical information in it very agreeably and profitably. The war of the Revolution had made terrible ravages in the State, yet her means for defence had not been exhausted; her mines and minerals were safe in the depths of the earth, beyond British power. At the call of liberty, these were poured forth from her mountain caverns to arm the soldier for battle. The Andover Works were held by the government till the close of the war; the mines of New Jersey for five years furnished iron and steel for the continental army. Peace came, and with it the ill fortune of these mines began. They were forsaken by the government, and heaps of ruins mark the places where a thriving business once flourished. At length, in the course of events, but owing to no favor or wisdom of the government, these sterile mineral regions are occupied again. The revolutionary mine, for fifty years a neglected waste, has been transformed by the magic power of modern art into a deposit of mineral wealth more valuable than gold, and has sent during the last five years, upon railroad and canal, 150,000 tons of its rich ores to the banks of the Delaware. Within the mineral region of New Jersey there were raised during the last year about 175,000 tons of ore, which will probably be augmented the next year to 250,000 tons. In the year 1851, one of the largest iron manufacturing establishments in the County of Morris was compelled, by the ruinous state of the iron trade in this country, to undergo the mortal process of a sheriff's sale. In the hands of its new owners, and under a more auspicious state of the market, its fires were re-kindled in 1852, and during the last year" Boonton Iron Works" used 11,600 tons of Jersey magnetic ore, consumed 23,000 tons of anthracite coal, 3,000 tons of limestone, 6,000 tons of pig-iron, employed in its operation 600 men, paid out for wages $22,000 per month, and manufactured 6,500 tons of nails and railroad spikes. Other establishments in the State consume a still larger quantity of ore, while the demand from abroad is daily increasing. To these mineral productions are about to be added extensive veins of Franklinite, which are to be opened and worked. In 1852, about one hundred years from the time when the first cargo of colonial bar-iron made its appearance in England, there |