Probably few people, in looking at the charts portraying the climates of the world that are found in reference books, realize how many observers have contributed to the preparation of such charts or the number of separate instrumental observations upon which they are based. In the United States alone there are something like 6,000 meteorological stations, at which upward of two and a quarter million observations are made every year--and a climatic chart is, of course, the fruit of _many_ years of observations. At the beginning of the present century it was estimated that there were 31,000 meteorological stations in operation throughout the world. The present number is doubtless much greater. At some of these stations observations have been made regularly, once, twice or three times a day, for 100 or 150 years. In round numbers one may say that, during the last few decades, meteorological observations have been made, the world over, at the rate of ten million a year, and the total number, since the keeping of regular weather records began, runs far up in the hundred millions. Organized meteorological observations were not unknown to antiquity--we have mentioned elsewhere the early rainfall measurements in India and Palestine--but the present era of such undertakings dates back only to the middle of the seventeenth century. In the year 1654 the Grand Duke Ferdinand II of Tuscany, through his chaplain and secretary, Luigi Antinori, secured the cooperation of several observers in Italy and the adjacent countries, to whom were distributed instruments and forms for maintaining daily records of the principal meteorological elements. Antinori and most of the observers belonged to the Jesuits, an order which has displayed extraordinary zeal in the furtherance of meteorology down to the present day. The observations thus inaugurated appear to have been kept up until about 1667, but unfortunately few of the records have been preserved. Several undertakings of similar character were launched during the next hundred years in France, England, and Germany. The most notable of such enterprises, however, antedating the foundation of the present official weather services, was the international system of observations maintained by the Meteorological Society of the Palatinate, founded at Mannheim in 1780 under the auspices of the Elector Karl Theodor. The chief credit for the epoch-making work of this society is due to its secretary, J. J. Hemmer. The society distributed standard instruments to its observers, who were widely scattered over the world; viz., fourteen in Germany, two in Austria-Hungary, two in Switzerland, four in Italy, three in France, four in Belgium and Holland, three in Russia, four in Scandinavia, one in Greenland, and two in North America (at Bradford and Cambridge, Mass.). The very detailed observations of this network of stations down to the year 1792 were published in twelve large volumes.