A first report on the relations between climates and crops . takino^ these sums, which all relate to positive temperatures onthe centigrade thermometer only, Linsser begins with April 8 atPoulkova, because on that date the gradually rising daily tempera-tures pass through the freezing point. -It would have made nodifference if he had begun with January 1, or December 1, or withthe date of lowest mean temperature, which would be about themiddle of January. On the other hand, for Brussels his sums beginwith January 15, which is the date at which the lowest mean dailytemperature occurs, which tem
A first report on the relations between climates and crops . takino^ these sums, which all relate to positive temperatures onthe centigrade thermometer only, Linsser begins with April 8 atPoulkova, because on that date the gradually rising daily tempera-tures pass through the freezing point. -It would have made nodifference if he had begun with January 1, or December 1, or withthe date of lowest mean temperature, which would be about themiddle of January. On the other hand, for Brussels his sums beginwith January 15, which is the date at which the lowest mean dailytemperature occurs, which temperature is about -|-2->° C. so thatif he had begun with January 1 there would have been a constantslight addition to all the numbers in that column. The dates ofblossoming are given in days counting consecutively from the 1st ofJanuary, and may be converted into the days of the month or viceversa by the following table: Day of theyear. JanuaryFebruary 1March 1April 1 -Slay 1 Date. O-^*- Leapnary. ^**i- •1 - --- yl 1 I:{2 iii 60 61. If we take the dilference between the sums of the temperatui-es forthe first and seventh grou])s of plants in the preceding table we obtainfor Brussels 1,972° C, and for Poulkova 1,280° C, or a difference ofabout 700° C., which corresi)()nds to about forty days at Poulkova. sothat we must immediately conclude that the same stages of develop- 214 merit are attained by means of very ditJerent sum totals of tempera-tures at Poulkoya and Brussels. But possibly we should have taken the initial i^oint of vegetationat some other temperature than 0° C. In order to test this pointLinsser performs the computations of the sums of temperatures above1°, 2°, 3°, 4°, 5°, and 6° C, respectively. His result for 6° C. is asfollows: Group, i Brussels. Poulkova. Group. Brussels. Poulkova. 1 < I !, 6 412 9a5 1,154 368435 2 1 20 3 97 4 212 224 None of these successive hypotheses as to the initial temperaturefor vegetation
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