═══════╤═════════╤═════════╤════════╤════════╤════════╤═══════════ Day │ Hour │Formation│Station │Altitude│Exposure│ Community ───────┼─────────┼─────────┼────────┼────────┼────────┼─────────── „ │ „ │ „ │ „ │ „ │ „ │ „ ───────┼─────────┼─────────┼────────┼────────┼────────┼─────────── 17/8/04│6:30 A.M.│ Spruce │ Jack │2550 m. │N.E. 5° │Mertensiare │ │ │ Brook │ │ │ „ │ „ │ Half │Hiawatha│2550 m. │N.E. 7° │ Asterare │ │ gravel │ │ │ │ „ │6:30 P.M.│ Spruce │ Jack │2550 m. │N.E. 5° │Mertensiare │ │ │ Brook │ │ │ „ │ „ │ Half │Hiawatha│2550 m. │N.E. 7° │ Asterare │ │ gravel │ │ │ │ ───────┴─────────┴─────────┴────────┴────────┴────────┴─────────── ═══════╤═════════╤═══════════════════╤═══════════╤══════╤════ Day │ Hour │POSITION OF READING│Thermograph│ Sky │Wind ───────┼─────────┼──────┬─────┬──────┼───────────┼──────┼──── „ │ „ │3 feet│Surf.│12 in.│ „ │ „ │ „ ───────┼─────────┼──────┼─────┼──────┼───────────┼──────┼──── 17/8/04│6:30 A.M.│ 9° │ 9° │ 9.8° │ 10° │Clear │ 0 │ │ │ │ │ │ │ „ │ „ │11.2° │11.2°│14.8° │ 10° │Clear │ 0 │ │ │ │ │ │ │ „ │6:30 P.M.│11.4° │11.4°│ 9.8° │ 11° │Cloudy│ 0 │ │ │ │ │ │ │ „ │ „ │ 12° │13.8°│16.4° │ 11° │Cloudy│ 0 │ │ │ │ │ │ │ ───────┴─────────┴──────┴─────┴──────┴───────────┴──────┴──── =102. Temperature sums and means.= The amount of heat, i. e., the number of calories received within a given time by a definite area of plant surface, can be determined by means of a calorimeter. From this the temperature sum of a particular period may be obtained by simple addition. In the present condition of our knowledge, it is impossible to establish any exact connection between such results and the functional or growth effect that can be traced directly to heat. As a consequence, temperature sums do not at present contribute anything of value to an understanding of the relation between cause and effect. The mean daily temperature is readily obtained by averaging twenty-four hour-temperatures recorded by the thermograph. The method employed by Meyen[6], of deriving the mean directly from the maximum and minimum for the day, is not accurate; from a large number of computations, the error is always more than two degrees. On the other hand, the mean obtained by averaging the maximum and minimum for the day and night has been found to deviate less than 1 degree from the mean proper. This fact greatly increases the value of maximum-minimum instruments if they are read daily at 6:00 A.M. and 6:00 P.M.