DISCUSSION OF BAROMETRIC OBSERVATIONS. 



4G5 



of tliis atmospheric disturbance in every part of the year, as well as a 

 more accurate account of the annual fluctuation of pressure, the daily 

 means of the barometer for the twenty -five years were next arranged 

 under each day of the year in two columns, one column containing 

 those means which exceed the normal value for the particular day in 

 question, derived from Table I, the other column containing the means 

 for like-named days in the remaining years, all falling below the com- 

 puted normal value. Each column having been added, the difference 

 between its sum and the product of the normal value by the number of 

 means in that column was found. Then if d and d' represent these differ- 

 ences, jS" the normal value, and n the number of means in both columns 



taken together, (twenty -five, except when an omission occurred,) '"*" 

 is the mean of ths departures of the daily means from tJie normal value for 



that day of the year, and N-f -^iL. equal to th of the sum of the two 



n n 



columns, is the mean pressure for the same day. The mean pressures for 



every day of the year, thus deduced, are as follows : 



Table II. 



Atmospheric presfiure for every day in the year — directly from ohsei-raiions. 



Day of the month. 



707 

 640 

 670 

 609 

 769; 

 7361 

 725 

 677 

 676 

 651 

 727 

 712 

 739 

 776 

 757 

 659 

 608 

 684 

 724 

 690 

 597 

 674 

 611 

 618 

 655 

 612 

 582 

 628 

 651 

 649 

 613 



Sums 24. 018 J;J; ^32 |20. 836 



Meaus .7748 ".7280! .6718 



655 

 657 

 719 

 729 

 638 

 623 

 692 

 771 

 812 

 738 

 680 

 679 

 690 

 683 

 672 

 701 

 655 

 719 

 696 

 648 

 606 

 635 

 635 

 650 

 086 

 674 

 706 

 707 

 694 

 654 



651 

 638 



657 

 605 

 6501 

 616 

 599, 

 603 

 576 

 618 

 71l| 

 713i 



715; 



700: 

 703; 

 681 

 704 



7151 



623 



674 

 676; 

 639 

 631 

 635 

 617 

 677 

 692 

 748 



743 

 720 

 695 

 651 

 600 

 684 

 658 

 645 

 662 

 663 

 003 

 629 

 677 

 095 

 664 

 675 

 725 

 675 

 649 

 673 

 702 

 696 

 709 

 724 

 712 

 700 

 089 

 644 

 673 

 635 



20. 504 20. 459 20. 396 

 .6835 .6600 .6799 



704 

 720 

 684 

 676 

 723 

 742 

 702 

 692 

 698 

 702 

 689 

 688 

 712 

 730 

 705 

 688 

 677 

 685 

 672 

 641 

 619 

 678 

 718 

 740 

 735 

 683 

 693 

 714 

 669 

 693 

 731 



720 

 711 

 717 

 705 

 690 

 704 

 715 

 700 

 673 

 666 

 704 

 733 

 727 

 741 

 713 

 750 

 750 

 700 

 728 

 752 

 757 



7:.3 



751 

 751 

 738 

 773 

 771 

 753 

 681 

 700 

 766 



750 

 744 

 793 

 779 

 784 

 807 

 845 

 821 

 849 

 817 

 776 

 748 

 781 

 872 

 845 

 808 

 789 

 748 

 741 

 740 

 796 

 875 

 881 

 829 

 759 

 735 

 75' 

 790 

 820 

 804 



784 

 712 

 708 

 693 

 748: 

 773, 

 786 

 751 

 775 

 764 

 729 

 7201 

 731 

 724! 

 704' 

 706 

 766, 

 729 

 709 

 707 

 773 

 .772 

 763 

 840 

 871 

 827 

 711 

 708 

 771 

 773 

 720 



753 

 749| 

 733j 

 758 

 754^ 

 7891 

 770 

 717 

 679 

 723 

 729 

 703 

 686 

 768 

 755! 

 733 

 702 

 651 

 675 

 685 

 699 

 715 

 660 

 669 

 736 

 621 

 718 

 080 

 576 

 574 



742 

 729 

 732 

 700 

 731 

 763 

 674 

 790 

 726 

 750 

 728 

 758 

 799 

 743 

 830 

 773 

 782 

 802 

 830 

 755 

 842 

 739 

 708 

 776 

 807 

 747 

 7.32 

 761 

 701 

 813 

 827 



21. 603 22. 528 23. 889 2.3. 248 21. 160 2.3. 560 

 .697o' .7267! .7963 .7499 .7053, .7600 



As might be expected in so short a series as twenty-five years, the 

 values embraced in this table are far from escaping the effect of acci- 

 S. Mis. 31 30 



