If we take Greater London we embrace a far wider and yet still a homogeneous community, for it cannot be denied that the adjoining boroughs just outside the pale of the administrative county are policed from the same centre, are London to the Post Office, and commonly regard themselves, what they must soon be officially, as an integral part of the Great Wen. Greater London--within the fifteen-mile radius--is far more homogeneous and compact than Greater Chicago, for example, or even than Greater New York or Greater Boston. We have here an aggregation of 6,580,000 inhabitants and, as we have already seen, 443,420 acres. But perhaps the fairest estimate of London is the natural one of a single mass of buildings, without any unoccupied or unimproved areas. This gives us a solid, compact city of 85,000 acres and 6,000,000 inhabitants; extending from Edmonton on the north to Croydon on the south, and east and west from Woolwich to Ealing. Nor can one doubt, at the present rate of expansion, that even more distant areas than Croydon will eventually be included, although the Scotsman may have been a little "previous" who addressed a letter to a friend at "Bournemouth, S.W." [Illustration: A MAP OF PARIS PRINTED UPON A MAP OF LONDON, SHOWING THE RELATIVE SHAPES AND SIZES.] In the following article we propose to compare with London the sizes of the chief cities of the world and, by printing a black map of each city upon a map of London, to display their relative magnitude at a glance. Let us see, to begin with, how Paris compares with London as represented in the above diagram. At a _coup d'oeil_ we perceive that the French capital is for its population remarkably small in area, a fact clearly owing to its fixed military barriers, which make growth upward rather than outward. Consequently, dwellers in Paris often have six or eight pairs of stairs to climb where the dweller in London has but two. There have been repeated agitations for municipal expansion, but so far nothing has been done to annex the surrounding communes. Paris has a population of 2,700,000, living in 75,000 houses, and an area of over thirty-one square miles. If, however, the agglomeration of houses be taken--including the suburbs--the area is forty-five square miles and the population 3,600,000, although, as yet, this is not actually and geographically Paris. [Illustration: BERLIN COMPARED WITH LONDON.]