How far existing conditions may be disturbed by new means of transit or by new works of life in New York City, no one can now tell. At present, the broad fact is, that the whole area of Brooklyn (excepting only the more remote parts of the Twenty-sixth Ward, the former town of New Lots) is nearer in distance to the New York City Hall than that part of New York City lying above One Hundred and Tenth street. Furthermore, the residence area lying between Fifty-ninth and One Hundred and Tenth streets in New York is not one-seventh of that lying between lines of like distance in Kings County. To attempt a close estimate of the future population of New York and Brooklyn might be neither wise nor profitable. Some conception of the general course or character of that development is the most that is practicable. All nineteenth century progress discloses a tendency to concentration of population. In our own country the inhabitants of cities formed one-thirtieth of the population in 1790; one-eighth in 1850; and nine-fortieths or half way between one-fifth and one-fourth in 1880. In this State a full one-half of the population dwelt in cities in 1880. The proportion now is not less than three-fifths, and is rapidly approaching, if it has not already reached, five-eighths. The population of the Union since 1820 has increased at a rate varying by decades from over 35 per cent. to 22.65 per cent. The lowest rate was that of the war decade. The rate per decade since 1870 has been more than 30 per cent. The population of the cities of New York and Brooklyn has at all times increased more rapidly than that of the nation. This was true even during the war decade, although the marked falling off of their rate of growth in that decade disclosed a decided sensitiveness to whatever influences accelerated or retarded national growth. New York and Brooklyn, indeed, have at all times shown by their rate and character of progress and growth that they are reflections of the development of the nation rather than of that of any State or locality. We may, therefore, safely say that the growth of the united population of New York and Brooklyn hereafter, as in the past, will depend chiefly upon the general progress of the whole nation. How rapid this progress will continue, how great proportions it may finally attain can only be vaguely conjectured. Lincoln's forecast of two hundred and fifty millions of souls during the life time of people who were in existence in 1861, would seem to have been over-sanguine, although it was not without parallel or precedent. The decade between 1850 and 1860, at the close of which he was speaking, had witnessed a most rapid national growth, that is, a rate of more than thirty-five per cent. for the whole Union. Percentages decline as aggregates increase. The rate of thirty per cent. which has prevailed since 1870, would not produce two hundred and fifty millions (250,000,000) of people until after 1940. It is too much to assume