312 



DISCUSSION OF THE SECULAR VARIATION 



Table of consolidated mean annual temperatures at Brunswick, Salem, New Haven, and 



Philadelphia. 









I 



2 



3 



4 



5 



6 



7 



8 



9 



1780 



49°-3 



50-4 



48.7 



49-5 



46.9 



47-3 



48.2 



47-9 



48.5 



48.3 



1790 



48.5 



49.2 



47 



9 



50-3 



49.1 



48.7 



47-9 



47-5 



48 



9 



48 



I 



1800 



49.1 



49-7 



.SO 



.S 



49.6 



48.6 



49-7 



• 48.1 



47-7 



48 



7 



47 



S 



I8I0 



48.4 



49.2 



46 



I 



47-9 



48.0 



47.2 



46.4 



46.7 



47 



8 



49 







IS20 



47-9 



47 5 



49 



2 



47.6 



49.0 



50.4 



50.0 



48.6 



.SI 



2 



48 



4 



1830 



49-5 



48.9 



47 



s 



47-9 



48.4 



46.8 



45-2 



46.0 



47 



6 



48 



4 



IS40 



48.6 



48.5 



48 



9 



47-5 



48.4 



49-3 



49-7 



49.0 



49 



2 



48 



s 



1850 



49.0 



48.8 



48 



8 



49-5 



48.7 



48.8 



47-3 



47-9 



48 



4 



47 



8 



i860 



48.8 



48.9 



48 



S 



49.1 



49.2 



50.2 



49.0 



48. s 



47 



4 



49 



2 1 



1870 



51.0 





















1 General mean, 48.52. 



From the preceding table we form the successive means of the 4:th order, as 

 follows : — 









I 



2 



3 



4 



5 



6 



7 



8 



9 



1780 







(49.6) 



49.2 



48.5 



47.8 



47.6 



47-7 



48.0 



48.2 



48.4 



1790 



48.6 



48.7 



49 







49 



2 



49.1 



48 



6 



48.1 



48.1 



48 



3 



48.6 



1800 



49.1 



49-5 



49 



8 



49 



6 



49.2 



48 



9 



48.5 



48.2 



48 



I 



48.1 



I8I0 



48.1 



48.0 



47 



6 



47 



.s 



47-4 



47 



2 



46.8 



47-1 



47 



7 



48.1 



1820 



48.1 



48.2 



48 



3 



48 



S 



49.0 



49 



6 



49.8 



49-7 



49 



6 



49.4 



1830 



49.1 



48.6 



48 



I 



47 



8 



47-5 



46 



8 



46.2 



46.4 



47 



3 



48.1 



1840 



48.4 



48.5 



48 



4 



48 



3 



48.6 



49 







49-3 



49.2 



49 







48.9 



1850 



48.8 



48. 8 



48 



9 



49 







48.8 



48 



4 



48.1 



48.0 



48 



I 



48.3 



i860 



48.5 



48.7 



48 



9 



49 



I 



49-3 



49 



4 



49.1 



48.5 



48 



4 



(49-2) 



1870 



... 





















Also the following table of differences from the mean 48°. 5, a -\- sign indicatinj; 

 a warmer, a — sign a colder year than the normal one. 









I 



2 



3 



4 



5 



6 



7 



8 



""] 



1780 







+ 1.1 



+0.7 



0.0 



—0.7 



—0.9 



_o.8 



— o-S 



—0-3 



— 0. 1 



1790 



+0.1 



-\-o. 2 



+°-5 



+0.7 



+0.6 



+0.1 



—0.4 



—0.4 



—0.2 



+0.1 



1800 



-fo.6 



+ 1.0 



+ 1-3 



+ 1.1 



+0.7 



+0.4 



0.0 



—0-3 



—0.4 



— o.^ 1 



I8I0 



—0.4 



— 0-5 



—0.9 



I.O 



— 1. 1 



—1-3 



—1-7 



—1-4 



_o.8 



—0.4 



1820 



—0.4 



— °-3 



— 0. 2 



0.0 



+°-S 



+ 1.1 



+ 1-3 



+ 1.2 



+ 1.1 



+0.9 



1830 



+0.6 



+0.1 



—0.4 



—0.7 



— 1.0 



—1-7 



—2-3 



— 2.1 



— 1.2 



—0.4 



1840 



. — 0.1 



0.0 



. — 0.1 



■ — 0.2 



+0.1 



+°-5 



+0.8 



+0.7 



+0.5 



+0.4 



1850 



+°-3 



+0-3 



+0.4 



+°-S 



+°-3 



— 0. 1 



—0.4 



—0.5 



—0.4 



. 0.2 



i860 



0.0 



+0.2 



+0.4 



+0.6 



-I-0.8 



+0-9 



+0.6 



0.0 



— 0.1 



(+0.7) 



1870 



__ 





















The use of this table for obtaining the normal annual temperature from a single year or from a 

 few years of observation is obvious ; we have only to apply the tabular quantity with it.s sign reversed 

 as a correction to the mean (observed) temperature of each year 



