Distributional pattern of the cities and towns in Kantô District, East-central Japan, has been changing in the past 100 years since the Meiji Restoration of 1868. However, there has been practically no geographical studies concerning this point primarily because of the lack of comparable statistical data. In Japan, administrative boundaries do not always coincide with the actual limits of built-up areas. In most cases, Japanese cities (shi) and towns (machi) have been over-bounded, but the case of metropolises like Tokyo has tended to show the inner-bounded type recently.
In this paper, the authors employ the terms “cities and towns” as defined by built-up areas constructed by delimiting areal expansion of urban built-up areas on large-scale topo-graphical maps irrespective of administrative units. Urban population was obtained by multi-plying the average urban (built-up area) population density of the respective periods to areal size of the built-up areas or urban settlements measured on the maps. Urban population utilized for calculating the average population density was obtained from administrative unit population of some urban administrative units with a rural population of less than 20% for the Meiji and Taisho Periods. For the Shôwa Period (present-day), the average population density of the densely inhabited districts for 1960 Census was utilized. The lowest limit of urban population was set at 1, 000 persons.
As Fig. 1 shows, both the number and the size of urban settlements or cities and towns have tended to increase chronologically, resulting in higher densities. In the Meiji (I) Period, the central-place type distribution was not very conspicuous as compared with the following Taish (II) Period, but still linear arrangement of towns was clear along major highways as post towns (shukuba-nachi) mostly for pedestrians. In the Taishô Period, central-place pattern became more complete, at least so represented on the map. This is primarily due to the evolution of towns with more than 1, 000 population as local economy grew. Although incipient, the formation of satellite towns and cities was also recognized around Tôkyô. In the Shôwa (III) Period, the distributional pattern is modified by the increase of many satellite towns and cities around Tôkyô to a considerable degree. In East Kantô, the central-place type pattern is still apparent, not making a sharp contrast to the preceding period. A further detailed survey of those towns and cities in East Kanto shows that the average dis-tance between all cities and towns is 8. 9km. This is somewhat lower than 10.5km which was theoretically obtained by some selected samples from various parts of Japan. Such a difference in density may imply some other causes for town emergence than the central place concept. The actual and theoretical average distances in West Kanto are 6.4km and 9.8km, manifes-ting relatively more advanced industrialization than in East Kanto.
Population density of the built-up areas for the three periods are 20, 000 persons per km² for the Meij i Period, 15, 000 persons for the Taishô Period, and 10, 000 persons for the Shôwa Period. This declining tendency seems to have a correlation . with the increase of per-capita income.

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In this paper the author analyzes the mechanism of natural recharge of unconfined ground water at Hakusan on the Hongô terrace in Tôkyô putting emphasis on water balance. Special attention is paid to variations in soil moisture, whose amount has not exactly been observed though the important role of it in the hydrologic cycle is widely accepted. As a result of this study some characteristics are found concerning the mechanism of unconfined ground water recharge in urban area and redistribution of soil moisture in the Kantô Loam formations.
The Hongô terrace, whose top is about 25m above sea level, is a Pleistocene upland (M 2), and is located in the eastern margin of the Musashino upland. This terrace consists of the volcanic ash called Kantô Loam (6 to 7m thick), Yamanote sand and gravel (4 to 5m thick, but its upper part of 1 to 2m in thickness is clay), and the sand stratum of Upper Tôkyô formation (more than 5m thick) in the descending order. The main uncon-fined aquifers of ground water studied are the Yamanote gravel bed and the sand stratum of Upper Tôkyô formation. Annual variation of ground water level in the aquifer is within the range of 6m to 12m below the surface. The studied area is located in an ordinary residen-tial area and the experimental garden (Tôkyô University Botanical Garden) is nearby. From April in 1962 to March in 1968 ground water level in the unconfined aquifer was measured daily in an observation well at Hakusan. At that place, the fluctuations of ground water level is affected by rainfall. Relation between rainfall and ground water level was in-vestigated, and the rise and fall of round water level in one period was found to be deter-mined by the total rainfall bserved in a 6-month period before that time. Contribution of the rainfall about 1 to 2 months before is the most prominent. However, the individual rises of ground water level correspond to individual rainfalls observed in the preceding 10 days.
At Hakusan, hydrologic elements such as rainfall, fluctuations of soil moisture, the outflow of ground water and artificial recharge to the main aquifer were observed for one year from April in 1967 to March in 1968. Water balance analysis was applied and the relationship between the annual march of these water balance factors and that of ground water level was investigated.
As for the annual total of water balance factors, about 1000mm of annual rainfall can be divided into following entries : the surface runoff is about 210mm, the amount of evapo-transpiration about 500mm, effective rainfall (amount of rainfall that is available for ground water recharge) for ground water recharge 290mm, of which 280mm is actually added to ground water storage. In addition to this, a 410mm of artificial recharge from leakage of waterworks pipelines is added and the total ground water recharge to the aquifer is 690 mm. The discharge from ground water reservoir is 670mm.
It is worthy of note that unconfined ground water in urban area is balanced by a large quantity of artificial recharge (leakage from pipelines).
The amount of evapotranspiration at Hakusan is about 50 to 60 percent of its average value in the Kanto Plain, which was calculated by the method of heat budget.
Soil moisture measurement from the surface to the depth of 15m was made by a neutron soil moisture meter. The seasonal variation of soil moisture is large in a layer from the surface to 8m (Kantô Loam formation and Yamanote Clay bed), and the difference between the maximum in summer and the minimum in spring is more than 100mm. It is recognized that soil moisture changes greatly and it moves upward in the lower part of Kanto Loam formation, in which little variation of soil moisture was believed to exist, though existence of slow downward movement of soil moisture was reported.

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Based upon the writers previous studies on the concentration of deaths/in winter in Japan and West European countries on the one hand, and on the other, the considerable moderation of seasonal variation in mortality or rather “deseasonalization” of deaths in the Scandinavian countries and the United States, the writers/attempt in this paper to analyze quantitatively the difference between these two types of seasonal variation in mortality and specifically the geographical difference in relationship between mortality (stroke and infant) and temperature in the three cities of London, Tôkyô and New York, and they sincerely want to build up one of the groundworks necessary for long-term biometeorological forecast. For such statistical analysis, covariance in two-way layout is used.
Covariance analysis indicates that there is no significant difference among the three cities between the regression of mortality (stroke and infant) on temperature in spring and that in autumn in the 1960's, so the changes per 10°C in the death rate are calculated by the average regression coeffcient. Mortality is inversely related to temperature, and the increase or decrease per 10°C in the death rate for stroke turns out to be larger than that for infant mortality in the three cities. In both Tôkyô and London, the rise of the death rate for stroke in fall is considerably large, or 28.5% and 39.3%, respectively, in contrast to only 8.7% in New York over three and four times larger, respectively.
As for infants, the mortality rate decreases or increases very slightly (not more than 1.5%) in New York along with the ups and downs of temperature. The corresponding rate of increase or decrease is about 8% in London. In Tôkyô, however, the infant death rate declines by about 14% with temperature up 10°C and goes up by as much as 20% with a similar drop of temperature.
The changes in the death rate with the variation of temperature turn out to be the smallest in New York among the three metropolises. All this clearly indicates that central heating, widely adopted in American cities, has brought about favorable bearings upon mortality, especially that of infants who can live entirely in the artificial climate. It is also to be noted that mortality from stroke undergoes much larger changes with the ups and downs of temperature in London than in Tôkyô, and vice versa in the case of infant mortality.

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