320 



DISCUSSION OF THE SECULAR VARIATION 



Marietta series. 











Differences from 











Differences from 





HJ-&F.) 



HJ.&A.) 



AQ.toD.) 



Mean. 





i(J.&F.) 



JQ.&A.) 



iVQ.toD.) 



Mean. 



Jan. 

 and 



July 



and 





Jan. 

 and 



July 

 and 



g 





4th order. 



4th order. 



4tli order. 



Year. 





4th order. 



4th order. 



4lh order. 



Year. 











Feb. 



Aug. 













Feb. 



Aug. 



















J, 



„ 



. jj 





Q 



;, 



J, 



^ 



^ 



Q 



iSig 





(7S.2) 



(53-7) 





+ 3-0 



+ 1.5 



1847 



33-6 



70.9 



52-5 



+0.9 



—1.3 



+0.3 



1S20 



(34.8) 



74. 5 



53 



I 



+2.1 



+2.3 



+0.9 



1848 



33 



3 



70.7 



52.1 



+0.6 



—1.5 





1821 



32.0 



74.1 



52 



8 



-0.7 



4-1.9 



+0.6 



1849 



33 



2 



71.3 



52-1 



+0.5 



—0.9 



— 0.1 



1822 



31.0 



73-5 



52 



8 



—1-7 



+ 1-3 



+0.6 



1S50 



33 



4 



72.0 



52. 1 



+0.7 



— 0.2 



—0.1 



1S23 



32.0 



72.9 



52 



8 



—0.7 



+ 0.7 



+0.6 



1851 



34 



I 



71.9 



52.2 



+ 1-4 



—0.3 



0.0 



1S24 



(34-3) 



(72.9) 



(53 



2) 



+ 1.6 



+0.7 



+ 1.0 



1852 



33 



2 



71.9 



52.4 



+0.5 



— 0-3 



+0.2 



1825 



i35-3) 



(73-2) 



(54 



I) 



+2.6 



+ 1.0 



+ 1.9 



1853 



32 



8 



72.6 



52.6 



+0.1 



+0.4 



+0.4 



1S26 



35-2 



73-3 



54 



4 



+2-5 



+ 1.1 



+2.2 



1854 



32 







73-7 



52.9 



—0,7 



+ 1-5 



+0.7 



1S27 



36.0 



73-2 



54 



3 



+3.3 



+ 1.0 



+2.1 



1S55 



29 



4 



74.0 



52.2 



—3-3 



+ 1.8 



0.0 



1S28 



36.0 



72.8 



54 



2 



+3-3 



+0.6 



+2.0 



1856 



27 



8 



73-5 



51.3 



—4.9 



+ 1.3 



— 0.9 



1829 



33-8 



72.6 



53 



6 



+ 1.1 



+0.4 



+ 1.4 



1857 



29 



6 



73-1 



51.4 



—3-1 



+0.9 



—0.8 



1830 



31.2 



72.3 



52 



9 



—1-5 



+0.1 



+0.7 



185S 



32 



6 



72.9 



52.2 



— 0.1 



+0.7 



0.0 



1S31 



30.8 



71.6 



52 



3 



—1.9 



-0.6 



+0.1 



1S59 



34 







72.5 



52.7 



+ 1-3 



+0.3 



+0.5 



1832 



32-4 



71. 1 



52 



4 



— 0-3 



—I.I -I-0.2 



i860 



34 



4 



71.7 



52.6 



+ 1-7 



—0.5 



+0.4 



1833 



33-9 



71.6 



52 



7 



+ 1.2 



-o.6;+o.5 



1861 



34 



6 



71. 1 



52.4 



+ 1.9 



— I.I 



+0.2 



1S34 



33-1 



71-7 



52 



3 



+0.4 



—0.5+0.1 



1862 



34 



5 



71.5 



52.1 



+ 1.8 



—0.7 



— 0.1 



1S35 



31.0 



71.0 



51 



4 



—1-7 



-I.2_0.8 



1863 



33 



3 



72,2 



51-7 



+0.6 



0.0 



— 0-5 



1836 



29.8 



70. S 



50 



8 



—2.9 



—1.4—1.4 



1S64 



31 



I 



72.0 



51.4 



—1.6 



— 0.2 



—0.8 



1837 



29.9 



71. 8 



50 



9 



—2.8—0.4—1.3 



1865 



29 



6 



71. 1 



SI. 2 



—3-1 



— I.I 



— 1.0 



1838 



30.8 



72.6 



51 



3 



—1.9+0.4—0.9 



1866 



29 



2 



70.8 



50.9 



-3-5 



—1.4 



-1-3 



1839 



32.2 



72.0 



51 



8 



— o.5j — 0.2 — 0.4 



1867 



29 



3 



71.5 



50.5 



-3-4 



—0.7 



-1-7 



1840 



33-0 



71.2 



52 



I 



-(-0.3' — I.O — O.I 



i858 



30 



4 



72,4 



50-5 



—2.3 



+0.2 



—1.7 



1841 



33-6 



70.6 



52 



I 



+0.9 — 1.6 — 0.1 



1869 



(32 



6) 



(72.8) 



(50.7) 



— 0.1 



+0.6 



—1-5 



1842 

 1S43 



34-8 

 35-2 



70.5 

 71.0 



51 

 51 



8 



8 



+2.1 

 -2.5 



-1.7—0.4 



1.2 — 0.4 































1844 



34-9 



71.8 



52 



I 





— 0.4 O.I 



Mean 















1845 



34-5 



72.1 



52 



6 



— i!s 



—0.1+0.4 



of 49 



32.67 



72.19 



52.24 









1846 



33-9 



71.7 



528 



+ 1.2 



^.5+0.6 



years. 





















M 



tn. — Values in parenthesis 



are imperfect. 







If we examine, by means of the successive signs of the tabular differences, 

 Avhether or not a cold winter is followed by a cold summer, and whether the average 

 temperature of the year is below or above the normal, we find, from the New Haven 

 series, by comparisons of the signs for the cold months with those for the year, 

 the following results : an accord, a -\- sign being followed by a -j- sign, or a — sign 

 by a — sign, in 64 cases; and a discord, a -f- sign being followed by a — sign, or 

 the reverse, in 18 cases; there are 3 indifferent cases, one of the differences being 

 zero ; in all, 85 cases. Comparing the signs of the warmest months with those of 

 the year, we find 61 accords. 19 discords, and 5 indifferent cases ; and comparing 

 directly the coldest and warmest months there are 50 accords, 31 discords, and 4 

 indifferent cases. Altogether strongly favoring the conclusion that the changes 

 which constitute the secular variation are generally exhibited in winter as well as 

 in summer; in other words, the causes of these variations are alike, active at all 

 seasons of the year. In the case of Marietta, we have likewise for Avinter and year 

 30 accords, 17 contradictions, and 3 neutral cases; for summer and year 32 accords, 

 15 contradictions, and 4 neutral cases, and for winter and summer 19 accords, 30 

 contradictions, and 1 neutral case. Here the evidence is somewhat weaker, pro- 

 bably owing to the greater number and shorter secular undulations, due to the more 

 Avestern position of the station. 



