22 



and so operate as to assist rather than to retard nature in her efforts, we 

 shall certainly be pursuing the wiser course. 



That this is not an idle suggestion may be shown by the experienoe of 

 other countries. The burying of several towns and villages in England and 

 Prance by blown sand is upon record ; near St. Pol de Leon, in Brittany, a 

 whole village was completely buried beneath drift sand, so that nothing was 

 seen but the spire of the church. A part of Downham, in Suffolk, England, 

 in 1688, was overwhelmed by sand which had traveled five miles in a cen- 

 tury and covered more than 1,000 acres of land. A considerable tract of 

 cultivated land, on the north coast of Cornwall, has been inundated by drift 

 sand forming hills several hundred feet above the level of the sea. 



The prevailing winds in Wisconsin, being from the westward, the villages 

 and cities towards the east will be endangered, by loosening and thus setting 

 this sand a-drift. 



Along nearly the whole eastern shore of Lake Michigan, sand hills are 

 found ; the sand probably thrown up by the waters from beneath the water. 

 These immense "dunes" are now confined to the 'mmediate shore of the 

 lake by the dense forest behind them. A struggle is going on between the 

 sand and trees, for the mas ery of the situation ; and already many large 

 trees are buried half their length while still maintaining their original posi- 

 tion. When the thoughtlessness of the people shall have removed these 

 trees and sent them to Illinois and Wisconsin in the form of lumber, or burnt 

 them in the log heap, they will very soon have cause to regret their folly. 



TREES AFFECT THE ELECTEIC CURRENTS. 

 According to the very careful, patient and exceedingly delicate observa- 

 tions of Dr. A. Wislizenus of St. Louis, continued through several years, it 

 appears that there is almost always more or less positive electricity in the 

 atmosphere ; most in winter, least in summer, corresponding inversely with 

 the temperature; with a regular daily fluctuation, the greatest amount being 

 at 9 a. u. and 6 f. m. ; the least at 3 p. m. and 9 f. m. It is when the amount 

 of positive electricity in the air is small or none, that we must look for 

 thunder-storms, bail, rain, or high winds; all of which are usually accom- 

 panied by negative electricity. Now, any thing that tends to keep up a due 

 equilibrium, to prevent the occurrence of negative electricity in the air, 

 will therefore, by just so much, diminish the liability to storms with thunder, 

 hail or dry winds. In some distr cts in Europe, where hail storms are so fre- 

 quent as to cause considerable damage to crops, the experiment has been 

 tried of preventing their occurence by very numerous lightning-rods (called 

 paragreles), and with great success. With the exception of the beech, our 

 trees may be considered as so many paragreles, carrying off the surplus elec- 

 tricity before it has time to accumulate in distructive quantity. Trees and 

 lightning-rods do not attract the electricity from the clouds, as many 

 suppose, but only afford a convenient conductor over which it can pass 



