METEOROLOGY. 



545 



standing the less differences at that season in the 

 temperature and humidity of wooded and open 

 regions. Mr. Woeikof attributes this apparent 

 anomaly to the resistance offered by woods to 

 the movements of moist currents, which gen- 

 erally circulate at a less height in winter than 

 in summer. A forest is thus a reservoir of 

 moisture. Water escapes from it only when 

 it rains heavily. Hence vegetation in forests 

 is usually indifferent to the droughts which 

 affect plants in open regions. 



Mr. Woeikof s observations in 50 stations in 

 Eastern Europe and Western Asia, between 

 the 38th and 52d degrees of north latitude, 

 indicate that the presence of forests has the 

 effect of considerably diminishing the tempera- 

 ture of the neighboring region, even to the 

 effect of neutralizing the difference in two 

 places in the same latitude, as between an in- 

 land and an insular climate. 



Dr. H. E. Hamberg has found that in the 

 districts of Sweden which are open and culti- 

 vated a forest lowers the temperature of air 

 and soil during evenings and clear nights, re- 

 stricting the period of daily insolation, and 

 thereby checks vegetation. The other influ- 

 ences of forests on temperature are either slight 

 or elude the ordinary mode of observation by 

 thermometers. Among the effects of this na- 

 ture is the shelter afforded by forests against 

 cold and violent winds. In certain cases they 

 may also yield protection against the cold air 

 or fog coming from districts in the vicinity 

 which are visited by frost. On the one hand, 

 a forest, where it is close at hand, offers me- 

 chanical protection against cold and violent 

 winds. On the other hand, it does injury, 

 either by retaining the solar heat required by 

 crops, or by lowering the temperature of the 

 soil during clear nights, and thus favoring the 

 development of hoar-frosts. The influence of 

 forests at a distance is not sensible. 



Electricity. According to Dr. Weinstein, ob- 

 servations of electric earth-currents, made in 

 Berlin by the aid of the telegraph-wires, show 

 a direction from northeast to southwest, while 

 in England the direction is more from north 

 to south, with a slight deviation toward the 

 east, and in France from north to south, with 

 an inclination toward the west. A regular 

 daily variation exists. In the night the current 

 was slight ; from eight o'clock in the morning 

 it regularly increased till it attained its maxi- 

 mum at noon ; thence it sank rapidly till 4 

 P. M., whence it continued uniformly weak, not 

 to return till the following morning. A course 

 precisely analogous to that of the earth-current 

 was manifested by the earth's magnetism. 



To demonstrate the coincidence of the two 

 phenomena, it was necessary to take for the 

 purpose of comparison, not a single earth- 

 magnetic element, but the earth's total mag- 

 netism. The earth's electricity and the earth's 

 magnetism showed, moreover, in their regular 

 daily course, their affinity, by the simultaneity 

 with which their disturbances occurred. It 

 VOL. xxvi. 35 A 



was so precise that, in one case, the distance 

 between Berlin and Wilhelmshaven could be 

 determined from the time when the earth's 

 current made itself felt in Berlin, and the time 

 when the magnetic disturbance occurred in 

 Wilhelmshaveu. The manifestation of it at 

 distant places on the earth points to a cosmi- 

 cal cause. Thus, in August, 1885, when the 

 emergence of an altogether unusual solar pro- 

 tuberance was observed in Paris a magnetic 

 disturbance was registered in Petersburg, and 

 a disturbance of the earth's current in Berlin. 

 The earth's current and the earth's magnetism 

 show further in common the periods of eleven 

 years, coinciding with those of the solar spots. 

 Collating the results of the observations which 

 have been made regularly at the Meteorologi- 

 cal Observatory in Odessa since the end of 

 1883, Mr. Klossofsky shows that there is an 

 intimate relation between the variations of 

 atmospheric pressure and those of electric po- 

 tential. 



Meteorology in New England The New Eng- 

 land Meteorological Society is seeking to col- 

 lect accurate records 'of earthquake-shocks, 

 especially of the time at which the tremors are 

 felt, to be handed over to the United States 

 Geological Survey for its use. The chief ques- 

 tions which it is desired to have answered 

 are : At what hour, minute, and second of 

 standard time was the shock felt? How long 

 did its perceptible motion continue ? Was it 

 accompanied by any unusual noise? Was more 

 than one shock felt ? Was it very light, light, 

 moderate, strong, or severe ? 



The reports of the third annual meeting 

 of the society, held October 19, showed that 

 the number of members was 110, against 95 in 

 1885, and that reports were now received from 

 between 140 and 150 observers, against 123 in 

 the previous year. More attention had been 

 devoted to improving the character of the ob- 

 servations than to increasing the number of 

 stations. Special investigations had been un- 

 dertaken, with the aid of grants from scientific 

 funds. A report on thunder-storms in New 

 England had been distributed to members, and 

 a report on the distribution of rain in cyclonic 

 storms was in press. In a paper on " Rainfall 

 Statistics in the United States," Prof. J. D. 

 Whitney gave reasons for considering the state- 

 ments which had been made concerning the 

 increase of rainfall on the Western plains as a 

 result of the cultivation of the ground, not 

 trustworthy. Mr. S. A. Eliot, in an essay on 

 the " Relations of Forests to Rainfall and 

 Water-Supply," showed that the opinion that 

 forests increase and clearings decrease the 

 rainfall was based chiefly on the diminution 

 of stream-flow in cleared districts ; but this 

 might be due to increased evaporation rath- 

 er than to increased rainfall ; and the effect 

 of forests in retarding evaporation was not 

 doubted. 



The Appalachian Mountain Club has decided 

 to establish a limited number of tueteorologi- 



