Thermal constants for the blossoming and ripening of 889 plants, etc.-Continued. 57. The fruit ripens during the following season. 168 and 175. Did not bloom during the ten years. 179 and 189. Tree too young to blossom. 203. The concealed blossoms can not be accurately observed. 270 and 271. The dates of blossoming are too variable to allow of determining a thermal constant. 304. These figures obtain for moist years, but for dry years we have September 9 and 2237, respectively. 308. Blossomed only once during these ten years. 518. The blossoming of the tree is not easy to observe. 577. The tree died in 1855. 580 and 581. Too young to blossom. 702 and 775. Did not blossom. 716. Blossomed only once and died in 1857. 756. Did not blossom and died in 1856. 800. Dates are too variable to allow determining a thermal constant. 834 and 880. The dates when the hull hardens and colors and when it springs open, allowing the fruit to fall, are both given. LINSSER. The most elaborate and, I believe, the most important investigation into the relation between plant life and climate is that published by Karl Linsser in a first memoir (St. Petersburg, 1867) and in a second memoir of 1869. My personal association with him during 1865 and 1866 greatly stimulated my own early interest in the subject. The conclusions arrived at by Linsser are based upon the study of all available European observations. His knowledge of physics and skill in numerical computations as the chief of the computing division of the Imperial Astronomical Observatory at Poulkova has given his results a precision based on the well-established principles of probabilities and a clearness of interpretation that specially commend them to the physiological botanist. Linsser states that the principal hypotheses that had up to his time been framed as to the form of the connection between the phenomena of temperature and of phenology are the following three: (1) That for the same plant the same stage of vegetation occurs from year to year on the attainment of the same mean daily temper ature. |