126 The Climate of Great Britain. 



may happen, therefore, that the observations of the next thirty 

 or forty years will afford a curve of different figure ; and that 

 by comparing the observations of the eighty or ninety years, 

 which would then be available, many, or all of the irregularities 

 exhibited in Fig. 3 might be removed. In this case we might 

 expect our climate-curve to assume the form indicated by the 

 light line taken through the irregularities of Fig. 3. It will be 

 observed that this modified curve exhibits but one maximum 

 and one minimum. It is not wholly free, however, from varia- 

 tions of flexure. It presents, indeed, six well- marked con- 

 vexities, and as many concavities ; in other words, no less than 

 twelve points of inflexion. The most remarkable irregularity 

 of this sort, is that exhibited near the end of November; and 

 it is noteworthy that this irregularity is presented by conti- 

 nental climate-curves also. It has been ascribed by Ertel to 

 the effect of the meteor-zone, which, causes the November 

 shower. But as it is exhibited by the curves of horary as 

 well as of diurnal means, while the meteor-zone cannot by any 

 possibility affect the temperature of the earth's following hemi- 

 sphere, and as, further, it does not correspond to the true date 

 of the shower, this view may be looked upon as doubtful. 

 The August curve occurring near the maximum elevation — 

 where slow change was to be expected, is also well worthy of 

 notice ; as are the January and May flexures. 



It will be noticed that nothing has been said of extreme 

 heat or cold occasionally experienced in England. As such 

 visits generally last but for a short time, their effects are not 

 very injurious, save on the very weak, the aged, or the invalid. 

 Corresponding to the passage of an intense heat-wave or cold- 

 wave, there invariably occurs a sudden rise in the mortality- 

 returns ; but almost as invariably the rise is followed by a 

 nearly equivalent, but less sudden, fall ; showing, conclusively, 

 that many of the deaths which marked the epoch of severest 

 weather occurred a few weeks only before their natural time. 



The weather during a part of the late winter was somewhat 

 severer than Our average English winter-weather. The ther- 

 mometer, however, at no time descended below zero, as it did 

 on January 3, 1854; and the diurnal mean did not descend at 

 any time so low as 10° 7', as it did on January 20, 1838. 

 There is no foundation for the opinion, sometimes expressed, 

 that our winter- weather is changing. An examination of ^ the 

 columns in the Greenwich meteorological tables, show that the 

 successive recurrence of several mild winters is not peculiar to 

 the last decade or two. The observations of Gilbert White, 

 imperfect as they are compared with modern observations, 

 point the same way. 



Among severe, but short intervals of cold weather, may be 



