Certain nations, or rather races of men, have a disposition to increase in numbers and are continually throwing off swarms; while other nations or races, from some progressing deficiency of vital stamina similar to the gradual decline of old age in the individual, are sinking in population, and the countries they have occupied becoming open to the immigration of the prolific and more vigorous races. The causes which tend to produce the one or the other condition of human vitality, seem to lie beyond the bounds of philosophic inquiry, but the fact itself is sufficiently clear. Hitherto the swarming or emigration of the more prolific races has been left to little else than instinctive or brute feeling of necessity--has at least not been entered upon by any government or society with any thing like the vigour and compass of plan which would result from a rational estimation of its importance, under proper regulation, to the comfort and happiness of the community. When more than one-half of the earth is wilderness, and transport become so easy, it is treason to the human race to speak of preventive or destructive checks. As things are now situated, every adult in Great Britain has a right to demand of the Government to be put in a condition of marrying, should he incline, with the certainty by common industry of providing comfortably for a family. This condition of things is the great, the only test of a good Government. The Government that cannot or will not provide for this, is either grossly ignorant, impotent, or criminal, and unfit for its place. A sufficient emigration of the labouring and property classes, would improve the home field for labour and capital, and raise wages and the returns upon capital so high that every industrious man would be able to maintain a family in comfort as soon as he had reached maturity, say the age of 21, and had attained a fair proficiency in his calling or business. Marriage about 21 is desirable on several accounts. The head of the family is stronger and healthier to provide for his children, and more likely to survive and provide for them till they attain strength to provide for themselves. The children are also stronger and healthier and easier provided for:--And the earth is comparatively a desert. The British Navy ought to be employed during peace as transports, carrying out emigrants to our colonies--in laying the foundation of future empires. By this, two very desirable ends would at once be gained--a sufficient and safe means of transporting our surplus population to new lands, and the proper discipline and experience of the Navy itself.