374 ANNUAL OF SCIENTIFIC DISCOVERY. 



prevail at the earth's surface, while volumes of clouds, at a high eleva- 

 tion, might at the same time be moving rapidly on an opposite direc- 

 tion. These counter currents have sometimes {riven origin to a 



^j O 



phenomenon in the city of Cleveland, not well understood by all of its 

 good citizens. The vane of the lofty spire of one church, standing on 

 a high ridge of ground, may point steadily to the north, while that on 

 the low cupola of another church, which is situated on a less elevated 

 plateau, may be directed to an opposite point of compass with a stiff 

 southerly breeze at the same time. It has been surmised that water- 

 spouts are most common when there is great inequality of temperature 

 between the water and atmosphere. Their more frequent occurrence 

 at such times may have been dependent on other causes. Cool north 

 winds begin to prevail about the middle of October. The lake changes 

 its hue from green to slate color, varying as the temperature is warmer 

 or colder, and ultimately to a hue almost as dark as ink, at times when 

 the sky is obscured with heavy clouds. The emanations from the 

 lakes then begin to condense and pass off to the south, in the form of 

 thick clouds, without discharging, at first, much rain. About the 20th 

 of October, the cold from the north seems to gain the ascendency ; 

 squalls of rain, hail, and rounded snow appear alternately, with inter- 

 vals of clear and warm weather. These squalls always precede the 

 autumnal frosts. The gardners feel no apprehension for their tender 

 vegetables till these premonitions have appeared. Common observa- 

 tions, as well as the more sure test, the rain-guage, show that larger 

 amounts of evaporation from the lake are carried south, where they 

 condense in the form of rain and snow, than fall upon this vicinity. 

 During winter comparatively little snow falls, and still less accumulates 

 here, though it may be abundant on the higher grounds, thirty or forty 

 miles in the interior. 



The indigenous vegetation of this vicinity is of rather a southern 

 type - - shown by the absence, in a great measure, of evergreens, and 

 the occurrence of more Genera, as the Cercis, Ilex, ^Esculus, Nelum- 

 bium, Gleditschia, Magnolia, &c. Eliott's Botany of South Carolina 

 and Georgia has been found to be a convenient hand-book for inves- 

 tigating our flora. On the other hand, strange hyperborean plants 

 are frequently found, which have been washed down from the far 

 northwest, through the chain of great lakes. Many of the birds are 

 species whose most northern ranges of migration have been assigned 

 many degrees south of this by ornithologists. 



The insect tribes show still more strikingly southern affinities. The 



o ** 



Papilio Cresphontes has been repeatedly taken here, though it has 

 been considered as exclusively southern in its resorts. In the south 

 the larva feeds on the orange and lemon --here it lives on the 

 Ilerculcs-club. The Papilio Ajax and Marcellus have also been 

 described as southern insects; and the late Mr. Doubleday located the 

 former exclusively in Florida and fixed the most northern limit 

 of the latter in Virginia. Still they are common at this point, 

 and subsist, in the larva state, on the Pawpaw. An undescribed 

 species of Libythea has been taken in Northern Ohio ; it has been 



