and the maximum daily temperatures for the dates of flowering give the results in the following table:

Again the accord with the results of previous years is satisfactory. but the individual variations are so large as to show that there is no clear connection between the epochs of flowering and the mean temperatures. Next the sums of temperatures received by these plants since the last severe cold is computed, assuming 0° C. as the initial temperature, with the following results:

These sums agree well among themselves for the two years, but are notably higher than the sunis for the four previous years, the excess being so much larger than the uncertainty, as deduced from the agreement of the numbers among themselves, that we can scarcely consider that such sums as these represent the true influence of climate on these plants.

The dates of flowering and harvest of rye and winter wheat at 700 or 800 stations give the following results:

The mean temperatures at the date of flowering are, for rye, in 1884, 14° C., and 1885, 12.2° C.; for winter wheat, in 1884, 15.1° C., in 1885, 16.4° C. These figures agree well with the previous four years, but the individual discrepancies show that there is no simple relation between the flowering of these plants and the mean temperature.

Again, the sums of temperatures are computed from the 1st of December; 5° C. is subtracted from all the mean daily temperatures and the sums of the positive remainders are given. Since in previous years 6° C. has been adopted, whereas the evidence points toward a lower figure, therefore Angot now gives the results of a recomputa

tion of the five years, adopting 5° C. as the lower limit of useful temperatures, with the following results:

Sums of mean daily temperatures, less 5° C. and rejecting negative remainders, from December 1 up to the dates of flowering and of harvesting.

The differences between the numbers for flowering and harvesting show, as in previous years, that although winter wheat requires more heat (716° C.) to bring it up to the flowering point than does rye (515° C.), yet after having attained that point the wheat requires less heat (547° C.) than does the rye (581° C.) in order to ripen the grain to the harvest. This fact, which has shown itself in each of the six years, can be considered as well established.

The harvest of spring barley.—The dates of harvest are, as before, reduced to sea level by allowing for retardation at the rate of four days per 100 meters. The sums of mean daily temperatures, less 5° C., counting from the 21st of March, which is the mean date of sowing, and up to the date of harvest, are given for each year in the following table:

The general mean for these six years is (within the range of its probable error) the same as the corresponding figures for winter rye.

In a fourth memoir, Angot (1890) gives similar computations for the harvests of 1886 and 1887 in France, the number of stations being now appreciably larger than in the preceding years. A new computation of the retardation due to altitude gives him 3.7 days per 100 meters for the lilac, 4.0 for the chestnut, 3.7 for the elder,

and 3.5 for the oak. For all these he adopts 4 days, as in previous

years.

Leafing. The mean temperatures at the dates of leafing for 1886 and 1887 are given, as follows:

The sums of temperatures received by these plants from the last freezing period up to the time of leafing, and counting from 0° C. as the initial temperature, are as follows:

The flowering of the lilac, chestnut, elder, and linden.-A new determination of the rate of retardation of flowering for these plants gives 4.7, 4.2, 4.4, and 3.8 days per 100 meters, respectively, for which, as before, 4 days is adopted. The mean temperatures at the times of flowering for the years 1886 and 1887 are as follows:

The sums of temperatures above 6° C., counting from the last freezing period and up to the date of flowering, for the years 1886 and 1887 are as follows:

The probable errors of these sums, considered individually, are quite large, and their agreement from year to year is not sufficient to justify the belief that we have attained to a satisfactory expression for the connection between the temperature and the date of flowering. Flowering of rye and winter wheat-Harvest of rye, winter wheat, and spring barley.-A new investigation, based on an increased number of stations for the years 1886 and 1887, gives for the rate of retardation of these epochs the following figures: Flowering of rye, 4.2 days per 100 meters; flowering of winter wheat, 4; harvest of rye, 4.5; harvest of winter wheat, 4.3; harvest of spring barley, 4.2. We can, therefore, as before, take 4 days as an approximate value for all these phenomena.

The mean temperature at the time of flowering is determined, both for daily means and for daily maxima, as follows:

Again, the average numbers agree well from year to year, but the individuals from which they are derived have a wide range.

The sums of the mean daily temperatures, less 5° C., counting from December 1 for the winter rye and wheat, but from March 21, for the spring barley, are as follows:

From the flowering to the harvest, on the average of these two years, rye has received 1,048-364-684° C., and winter wheat 1,236682=554° C., but on the average of eight years, 1880-1887, the sums of temepratures, less 5° C., have been, for rye, from December 1 to the flowering, 477° C., and from flowering to harvest, 607° C.; for winter wheat the numbers are, respectively, 708° to 549° C. From the beginning of vegetation up to harvest the numbers are: For rye, 1,084° C.; winter wheat, 1,256° C.; spring barley, 1,103° C. These results can be considered as having definitely established the fact that

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in France rye requires less heat to bring it to the harvest and winter wheat more; but, on the other hand, from the flowering to the harvest rye requires more and winter wheat less.

The following table gives a résumé of Angot's general average dates and temperatures for sea level for the whole of France for the years 1880-1887:

As to the sums of the mean daily temperatures above 5° C., counting from December 1:

The harvest of spring barley occurs when the sum of the mean daily temperatures, less 5° C. and counting from March 21 or the average date of sowing, amounts to 1,102° C.

The large variations of the individual numbers whose means are given above are probably due to special meteorological conditions, and Angot states that he will report upon these if it is possible to take them into account when ten whole years of observations have accumulated.

REQUESTS FOR PHENOLOGICAL OBSERVATIONS.

The influence of a climate upon cultivated crops is parallel to its influence upon uncultivated plants, and the comparative study of climates in their relations to plants can be attained by careful observations of the general features of the natural life of special plants that are widely distributed over the earth. To this end several special invitations have been issued urging the observation of certain phenological stages.