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The present paper is a study on the evolution of the relationship man–woman in the Mexican Republic, as a whole and by states, during 70 years; the main reasons that affect variation in this relationships and the corresponding conclusions. The paper is well illustrated with 6 general maps and 33 graphs, which allow to consider at firts sight the evolution, matter of the study, and to establish pertinent comparisons.

In this brief paper we try to find some modern analogs of the past climates in order to explain the conditions which could have been the dominant ones during the great development of Teotihuacan. Similarly, we try to find in the climate a reason for the collapse of such a flowering culture. Several attempts have been made to know the circumstances for Teotihuacan´s decline and fall; some authors agree that both: environmental and social facts were involved. Without trying to rest importance to the other factors, we will analyze only the climatic aspect, particularly from the point of view of precipitation correlating it with that from other regions of Europe and Africa, goberned by the Bermuda–Azores high pressure cell. With base on these correlations and on phenomenological and historical evidence to describe climatic situations during Teotihuacan´s time in other parts of the world: northwestern Europe, Egypt and Yucatan, we deduce climatic fluctuations on the Teotihuacan area. The hypothesis that we formulate using all these data is that the climate during the great development of the culture in the Teotihuacan area was as humid as it can be during the most humid years at the present. We also assume that the decay and fall of Teotihuacan was due, in part, to the intense drought that started at about AD 700–750, as the relationship between climatic data and climatic proxies from Europe and north Africa suggest.

The paper presents the analysis of the various investigations made on urban climate in Germany, mostly since 1930. The author gives the values of climatic alterations and pollution levels in several German cities and he compares them with the values found for Mexico City.

This paper presents in an objetive way the changes in geographic–economic and social–geographic structures in Chile. It analizes the growth of the populatión and some of its reprecussions: Educational Reform; unemployment: Chilean Agrarian Reform; the nationalization of minning lands; the state industrial consolidation; regional planning tending to promete economic and adminitrative decentralization and secure a better development of the country.

The purpose of this work is to present in a global way the bathing resorts in Mexico. It allows the inmediat analysis of many aspects, as for example their distribution, their degree of explotation, their accesibility and their relation with the physical mediun. This paper indicates also the importance that the bathing resorts have as touristic recourses, whose explotation constitutes an economic activity that suplies high incomes to the country.

This paper is a detailed climatic study of the Sierra Tarasca, Michoacan, Mexico area, following the original Köppen climatic classification and the Köppen´s classification modified by Garcia. Comparatively the latter is better suited to make an accurate description of the climatic conditions of the area.

This paper presents in an objective way the changes in geographic–economic and social–geographic structures in Chile. It analyzes the growth of the population and some of its reprecussions: Educational Reform; unemployment: Chilean Agrarian Reform; the nationalization of minning lands; the state industrial consolidation; regional planning tending to promete economic and administrative decentralization and secure a better development of the country.