DISCUSSION OF BAROMETRIC OBSERVATIONS. 



Table IV. 



Computed normal pressure for every day in the year. 

 [Tenth order of means from Table U.] 



469 



Day of the month. 



1 



2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 



10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 

 18, 

 19 

 20. 

 21 

 22. 

 23' 

 24 

 25 

 26 

 27. 

 28 ! 

 29. 

 30. 

 31. 



799+ 



795 



791 



791 



796 



805 



813 



816 



811 



799 



786 



776 



765 



751 



740 



742 



757 



770+ 



770 



762+ 



762 + 



775 



788+ 



788 



772 



748 



732+ 



732 



744 



758 



765 



760 



748+ 



745 



758 



778+ 



791 + 



785 



766 



753 



756+ 



772 



784 



777 



751 



716 



687+ 



673 



671 



675 



684+ 



694 



697 



693 



688 



689 



697 



708 



715 



711 



697 

 681 

 675 



685 



701 



711 



708 



696 + 



689 



691 



704 



720 + 



656 

 671 

 681 



682 



678 



684 



706 



731 



741 + 



732 



713 



695+ 



732+ 686+ 



731 + ' 683 



715 I 683 



693 I 684 



677+' 685 



674 4-! 682 



658 



653 



651 



647 



638 



624 



612 



608+ 



619 



642 



670+ 



692+ 



702 



719 



710 



695 



680+ 



671 



666 



662 + 



659+ 



658 



658 



658 



661 



667 



703 I 674 

 700 I 680 

 697+ 684 



674 



667 



654 



641 



633 



628 



624 



620 



619 + 



624 + 



632 



638 



645 



672 



656 



643 



638 + 



644 



656+ 



670 + 



683 



690 



689 



681 



669 



694 



686 



671 



655 



645 



644 



649 



651 



647 



641+ 



642 



652 



672 



696 



714 



684 



681 



678+ 



681 



689+ 



699 



706 



708+ 



705 



695 



682 



672 



668+ 



674 



750 

 762 

 773 



784 



796 



809 



820 



825 



820 



807+ 



795+ 



793 



803 + 



816 



818 + 



807 



787 



770 



766 



778+ 



803 



824+ 



829+: 



814 



790 



774 + 1 



774 



784 



790 



784 



765 



742+ 



728+ 



729 



741 



755 



764 



765 



760+ 



751+ 



741 



732 



725 



721 



720+ 



724 



727 



728+ 



730 



738 



752+ 



772+ 



794 



810 



810+ 



793 



769 



753 



748 



748 



747+ 



746 



745+ 



749 



754 



759 



757+ 



747 



732 



719 



714 



713 



716+ 



723 



731 



731 



72« 



703 



688+ 



684 



685 



689 



689 



687 



684+ 



682 



677+ 



667 



6.52 



645 



655 



679 



704 



718 



723 



723 



720 



716 



716 + 



723+ 



734 + 



747 



759 



770 



779+ 



786 



790 



793 



796+ 



797 



791 



780 



768 



761 



761 



763 



761 



759+ 



765 



778 



792 



800 



On applying the test of Mr. De Forest to this series the total number 

 of signs occuring in groups of three or more is found to be less than half 

 the whole number of terms by 18 — a difference much less than that of 

 Table I, though nearly double the probable difference of a iierfect 

 adjustment. 



In resiject to the treatment of the 29th of February, this table is less 

 accurate than the others ; for the pressure for that date, as derived from 

 Table II, should in strictness have been allowed only one-fourth of the 

 weight of the other values ; but as such a discrimination could not con- 

 veniently be made in the computation, the 29th was treated precisely 

 like the adjacent dates. In all the other tables due allowance is made 

 for the peculiarity of that date. 



The sign + appended to numbers in Table IV indicates a fraction be- 

 tween -^Q^- and ^0%. Smaller fractions are disregarded, and for larger ones 

 the third figure is increased by 1. 



MEAN DEPARTURE FROM NORMAL VALUE, AND PROBABLE ERROR. 



In describing the method of deriving the numbers which constitute 

 Table II it was shown that for each day of the year, along with the 

 mean pressure, another number was deduced, which was called " the 



