22 



The Vegetation of the 



had only a sum of 40 degrees. So the elm must either be in bloom on the 

 4th of February, when the sum of heat was 280 degrees, or required, in 

 1878, a sum of 460 against 280 m 1886. Amelanchier was in bloom in 

 1878 on the 27th of March, with a sum 454 degrees, and in 1861, on the 

 11th of April, with 453 degrees. December, 1860, had only a sum of 27 

 degrees; accordingly, Amelanchier required 679 degrees in 1878, and only 

 480 in 1861, or the due time of blooming was in 1878, the 8th of March. 



BAKOMETER. 



The observations on the pressure of the atmosphere comprise twenty- 

 five years from December, 1860, to November, 1885. 



The mean reduced to freezing point was 29.628 inches; the mean, at 

 7 A. M., is 29.644; at 2 p. m., 29.606; at 9 p. m., 29.634. The highest stand 

 was observed in January, 1866, 30,671, and the minimum in April, 1880, 

 28,581, the range being 2.090. 



The greatest range in one month was observed in January, 1866, 

 1.676; the smallest in August, 1878, 0.283. The highest mean of a month 

 had, December, 29.698; the lowest May, 29.548. 



The greatest range in twenty-four hours was observed in January, 

 1.028. In July it is only 0.389. 



There are generally two oscillations in twenty-four hours, with two 

 minima at 11 a. m. and 10 p. m., and two maxima at 4 a. m. and 4 p. m. 

 The rise and falling is, in the tropic countries so regular, that it is pos- 

 sible to determine the daytime from the stand of the barometer; in our zone 

 it is more variable, so that often a continuous falling or rising for several 

 days is observed. 



Table 4. 



BAKOMETER REDUCED TO FREEZING POINT. 



December 1860 — 1885. 



7 A.M. 



2 P.M. 



9 p.m. 



Mean. 



Maxi- 

 mum. 



Mini- 

 mum. 



Kange. 



Greatest 

 change in 

 24 hours. 



December 29.714 29.680 29.717 29.704 30.389 28.771 



January ^29. 724129.685 29. 726129.712 30.67 r28. 795 



February 29.688 29.649 29.683 29.673 30. 453 28. 823 



March 29.632 29.600 29.632 29.621 30.364 28.612 



April 29.572 29.540 29.568 27.560 30. 252|28.. 581 



May 29. 57 129. 532 29. 554 29. 5.52 30. 041 128.670 



June 29.583 29.540 29.565 29.565 29.956 28.996 



July 29.607 29.572 29. .587 29.-589 29. 944|29. 134 



August 29.608 29.572 29.590 29..591 29.965 29.207 



September 29.670 29.626 29.651 29.648'.30.083l29.05l 



October 29.677 29.629 29.664 29.057 30.254 29.025 



November 29.679 29.637 20.678 29.664 30. .308 28.725 



Year 



29.644129.606 



29.634 29.628 



30.671 



28.581 



1.618 

 1.876 

 1.630 

 1.752 

 1.671 

 1.371 

 0.960 

 0.810 

 0.758 

 1.031 

 1.229 

 1..583 



2.090 



1.017 

 1.028 

 0.967 

 0.950 

 0.811 

 0.750 

 0.508 

 0.484 

 0.492 

 0.617 

 0.718 

 0.838 



1.028 



