WINDMILLS AND METEOROLOGY. 523 



Modern meteorology was still in an embryological stage when 

 the millers had attributed their true signification to the cirro- 

 stratus clouds which stretched out in long, narrow bands, some- 

 times from the horizon to the zenith. They called them " wind 

 trees." They were as well acquainted with the cirro-cumulus, the 

 alto-stratus, and the cumulus. Proof of this is found in the enig- 

 matical and obscure language of an old miller who declared he 

 had seen in the sky " a shepherd under the shadow of a tree while 

 the sheep were pasturing in the field." 



Besides looking into the nature and meaning of the cirrus 

 and the cirro-cumulus, the miller tried to calculate the force 

 of the wind in distant storms; he observed the direction and 

 velocity of the lower clouds; he estimated at sight the volume 

 and density of the storm clouds ; and if the wind fell off before 

 the rain came, he recollected the old saying, "A calm comes 

 before a storm." 



He especially displays extraordinary vigilance in times of 

 heavy showers. He observes, among other things, if the mills 

 farthest away in the direction of the rain have kept their sails 

 unfolded ; if they have, it is a good sign. He scrutinizes the 

 sky at every moment, from the zenith to the horizon ; he meas- 

 ures the curvature of the forward part of the precipitation or 

 of the storm. The lines of rain or hail that escape from it show 

 him by their length and their approach to the perpendicular how 

 intense the precipitations are. If the lines run obliquely, he is 

 shown the direction of the dominant wind in the squall in 

 short, no sign indicatiug the force and direction of the wind 

 passes unperceived by him. He knows likewise that these show- 

 ers are often accompanied by tempestuous, plunging gusts which 

 seem to come out of the clouds; and frequently, before the most 

 advanced flecks of the storm cloud have reached the zenith, the 

 sails of the mill are rolled up around the arms so as to give the 

 squall free passage. 



Except by meteorologists, it is still not generally known that 

 the air is urged on more violently on the right of the squall than 

 on the left ; but the old miller knew it long ago by experience. 

 The storms that passed by on his left, from west-by-southwest to 

 south, never gave him any fear, and he confidently left his sails 

 all unfurled in the wind ; but whenever he was directly threat- 

 ened with a storm which would pass over his zenith, or which 

 was coming from the right that is, from north-by-northeast to 

 east, at a distance of less than five kilometres he foresaw the 

 possibility of a strong blow, and took his measures accordingly. I 

 never knew of a miller who could account for the squalls from his 

 left being less formidable than those from his right. The expla- 

 nation of the phenomenon was reserved for modern meteorology. 



