1876.] Variations of the Barometer in India. 41 



stations. 



Madras 



St. Helena 



Singapore 



Cape of G. Hope 



Makerstoun 



Hobarton 



Pekin 



Simla 



Oatherinenburg. . 

 Bogoslowsk 



Max. 

 local time. 



Mar, 



Apr. 



d h 



30 20 



31 4J 

 31 8 

 31 9 

 31 11 

 31 15 

 31 16 

 31 23 



1 3 

 1 9 



Stations. 



Hobarton 



Cape 



Simla 



Cather. .. 

 Pekin 



Min. 

 local time. 



Apr, 



Pi' 



ingapore . } 

 Madras ... 

 Bogos. . . . 

 St. Helena. 

 Makers. ... 



d h 

 2 10 

 2 12 

 2 12 

 12 

 14 

 19 

 19 

 19 

 1 



Stations. 



Hobarton . 



Pekin 



Cape 



Makers. ... 

 Madras ... 

 Singapore . 

 Bogos. ... 



Simla 



Cather. ... 

 St. Helena. 



Max. 

 local time. 



Apr, 



d b 

 4 7 

 4 8? 

 4 11 

 4 IP) 

 4 18h 

 4 19 



4 23 



5 

 5 3 

 5 12? 



At Madras a secondary maximum appears at 31*^ 19^, agreeing nearly 

 with the mean of the epochs for Pekin and Simla. At Pekin a marked 

 maximum occurs at 5^ 18^ ; the time given above refers to the inflection 

 corresponding with the secondary maximum at Hobarton : the principal 

 maximum at the latter station occurs nearly 24. hours later. 



It will be seen that the succession is different for the different turn- 

 ing-points, so that no general law of precedence can be deduced relatively 

 either to latitude or longitude. 



The movements for the two most easterly stations, Hobarton and 

 Pekin, have been projected first ; and as the difference of latitudes is 

 nearly 83°, the agreement of the two curves will appear very remark- 

 able. The first maximum and the following minimum occur nearly 

 simultaneously at the two places ; while even the secondary maximum 

 and minimum which follow at Hobarton are seen at Pekin in a distinct 

 inflection, the mercury rising thereafter to a maximum at both stations. 



At the Cape of Good Hope the curve is very regular with two equal 

 branches, having the maxima and the minimum within a few hours of 

 those for Hobarton and Pekin. 



The curves for St. Helena and Makerstoun, the two most westerly 

 stations, have been projected together ; at both the minimum occurs later 

 than at the other stations *. 



* Differences were expected to be the rule and not the exception in this investiga- 

 tion, and it has not been thought necessary to give curves for some stations merely to 

 show that such differences exist ; as, however, the movements have been examined by 

 me, I shall note that at St. Petersburg the first maximum occurs at the same time as 

 at Bogoslowsk, which is nearly in the same latitude, but the second maximum occurs 12 

 hours and the minimum 24 hours later at the former than the latter station. Also at 

 Nertchinsk, 11° north of Pekin, the first maximum occurs 4 hours later than at Madras, 

 and the second maximum (at 5*^ 5^^) 8 hours later than at Catherinenburg (7 

 hours earlier than the last maximum at Pekin) ; but the principal minimum occurs 24 

 hours before that at Pekin, and is followed by a secondary maximum and minimum not 

 shown at the other stations. In general at European stations the minimum appears to 

 be retarded as at Makerstoun. At Toronto there are three maxima and three minima 

 during the week. The object of this note has been to show the general action of 

 the same cause over the earth ; the deviations from the same types must be the subject 

 of other researches. 



