AMONG the interesting papers which appear in the Annales du Bureau Central Météorologique de France for 1878 there is one by Prof. Hildebrandsson, of peculiar value, On the Freezing and Breaking-up of the Ice on the Lakes, the Epochs of Vegetation, and the Migration of Birds in Sweden, based on the observations made by a numerous staff of observers scattered over the country. The paper is illustrated by a diagram showing the seasonal distribution of temperature for ten of the more typical climates of Sweden, and by twelve maps indicating the geographical distribution of the physical and biological phenomena under discussion. Since the lakes of Sweden, which occupy a twelfth part of its entire superficies, exert powerful and diverse influences on plant and animal life, according as they are frozen or open, special attention has been directed to their examination. The results show that while the lakes in the extreme south are covered with ice on an average of ninety days in the year, those in the extreme north are 230 days bound with ice. The average date of the freezing of the lakes in the north is October 10, whereas in the south this does not take place till December 10. On the other hand, the ice breaks up in the southern lakes on April 1, but m the north not until the first week of June. The maps shows the decided manner in which the curves are deflected and modified by such extensive sheets of water as are presented by Lakes Wener, Wetter, and Maelar, by height above the sea, and by the Atlantic in different seasons. During the freezing of the lakes the south-west winds of the Atlantic attain a maximum force and frequency, and under this influence the high lakes to westward ofj the head of the Gulf of Bothnia do not freeze till November 30, or six weeks later than the lakes in the same latitude near Haparanda. On the contrary, at the time of the breaking-up of the ice in spring, easterly winds are prevalent, and the ice on the lakes near the head of the Gulf of Bothnia breaks up four weeks earlier than that of the more elevated lakes to westward. An interesting examination is made of the dates of the breaking-up of the ice on Lake Maelar at Westerns from 1712 to 1871, and from a comparison of the averages of each of the ten-year periods it is seen that the earliest was April 14 for the decade 1722.31, and the latest, May 5, for 1802-11. Whilst the results for these 160 years indicate considerable fluctuations, they give no countenance to the idea that any permanent change has taken place in the climate of Sweden. Three maps show the number of days in which the plants that flower in the extreme south in April, and those in May, come successively into bloom, and the leafing of trees occurs at different places on advancing northward. As regards the plants which come into bloom in the south in April, their time of flowering is forty-five days later at the head of the Gulf of Bothnia, and sixty days later in the elevated districts to westward, but as regards, the plants which bloom in the south in May, the times are only twenty-five and thirty-five days. The curves of the May flowers are closely coincident with the curves representing the breaking-up of the ice of the lakes. The time taken for the advance northward from the south to the head of the Gulf of Bothnia is twenty-three days for the leafing of trees and the flowers of May, whereas the time taken by the April flowers is forty-three days. The curves showing the times of arrival of four of the more marked of the migratory birds differ much from each other. The lark arrives in the south on March 1, and in the north on May 1, and the arrangement of the curves of arrival closely agrees with the curves showing the breaking-up of the ice of the lakes but a month earlier. As regards however the wild goose, the cuckoo, and the woodcock, the curves showing their arrival assume a different form, and point to an intimate connection subsisting between the arrivals and the temperature of the place at which they arrive.