NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 233 



case could also be expected, going on the assumption that a higher 

 air pressure corresponds to a more cloudless sky. Any indica- 

 tion from this that the daily temperature amplitude in Batavia 

 increases with increasing sun spots and prominences we do not 

 find. 



The daily temperature amplitude curve of Wellington (fig. 71, 

 II, T-A) does not show anything definite. The curve appears to 

 be somewhat irregular and shows a remarkable rise during the 

 whole time from 1883 to 1905. This rise is, however, similar to a 

 rise of the temperature curve for Batavia. It corresponds to a 

 general decrease of the number of prominences from 1883, which 

 is plainly shown in figure 69. 



l?05 1910 



Figure 87. Difference between mean maxima and mean minima of tem- 

 perature in degrees F. at Arequipa in July (I), February (II), and for all 

 the year (III). IV: yearly mean of the difference between the temperatures 

 at two o'clock and eight o'clock afternoon. 



The curve for the daily temperature amplitude in Mauritius 

 (fig. 71, III, T-A) also shows similarity with the air pressure curve, 

 in so far as it has the same partial maxima that are found in the 

 latter, and this could be expected according to what we have said 

 above, in case a higher air pressure corresponds with a cloudless 

 sky. However, there is no great similarity between this curve 

 and the temperature curve for Mauritius and just as little with 

 the sun spot curve. 



At Port au Prince the curve of daily temperature amplitude 

 (fig. 71, V, T-A) also shows similarity with the air pressure curve, 

 in so far that they have at least partially the same maxima, but 

 any great similarity with the temperature curve is not to be found 

 and just as little with the sun spot curve, except that from 1900 to 

 1910 possibly the two go oppositely. 



It may be thought, however, that at an inland station of the 

 tropics the daily temperature amplitude would respond more directly 

 16 



