The Processionary : Meteorology 



sally forth on the pine-trees while these are 

 battered by such a gale. 



The remarkable part of the business is that 

 the greenhouse caterpillars do not venture 

 out of their nests either. And yet for them 

 there are no boughs dangerously shaken, no 

 cold piercing beyond endurance, for it is not 

 freezing under the glass. What keeps them 

 in can be only the passage of that wave of 

 depression. On the 15th the storm ceases; 

 and the barometer remains between 29.6 and 

 30 in. for the rest of the month and a good 

 part of February. During this long period 

 there are magnificent sorties every evening, 

 especially in the greenhouse. 



On the 23rd and 24th of February, sud- 

 denly the Processionaries stop at home again, 

 for no apparent reason. Of the six nests 

 under cover, only two have a few rare cater- 

 pillars out on the pine-branches, while previ- 

 ously, in the case of all six, I used every night 

 to see the leaves bending under the weight of 

 an innumerable multitude. Warned by this 

 forecast, I enter in my notes: 



"Some deep depression is about to reach 



us." 



And I have guessed right. Two days later, 



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