METEOROLOGY. 



PLANTS to a great extent are dependent for their healthy- 

 existence upon cHmatic conditions. Each species has 

 a minimum temperature, 32° F. (0° C), below which 

 growth is arrested, and in some cases the plant actually dies 

 owing to the freezing of the cell contents and the subsequent 

 rupture of the cell walls. After periods of severe frost, it is 

 not unusual for numbers of the less hardy species— e.^., 

 laurel, gorse, &c., to be killed. 



On the other hand, plants have a maximum temperature, 

 about 122° F. (50° C), above which none will live. In 

 our latitude this temperature is never reached, although 

 indirectly a spell of very hot weather may so deprive the 

 more sandy tracts of moisture that vegetation gets parched 

 or scorched up. Between the minimum and maximum there 

 is an optimum, or best temperature, at which the plant 

 flourishes, and this is found to vary with the species. It 

 may be taken for granted that a forwaid season indicates 

 that the average temperature is high and therefore not far 

 from the optimum, and conversely if the readings of the 

 thermometer show a high average temperature, the season 

 will be forward. 



Owing to latitude, the East Riding climate is that charac- 

 teristic of the cold temperate zone of the Northern Hemisphere. 



The physical features, the two plains, divided by the Wolds 

 and the proximity of the North Sea, have an appreciable 

 effect on the climate. There is, for example, found to be 

 slightly more frost and rain on the east of the Wolds than 

 on the west. The configuration of the Wolds, half enclosing 

 Holderness as they do, may account for the fact that Southern 



