82 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



fluctuations in forest land are less than in open ground. The 

 influence of the forest in preventing the cooling of the 

 ground by the radiation of its heat is most noticeable in Oc- 

 tober and November, and least in January and February. 



METEOROLOGY IN HAVANA. 



The recent establishment of a signal station at Havana, 

 Cuba, brings to notice a number of meteorological observa- 

 tions that have been made at the Jesuit College in that city 

 during tlie past twenty-five years. The regular publication 

 of these observations and the deductions that may be drawn 

 from them lead to the conclusion that science will receive 

 very valuable aid from this station in the West Indies. The 

 prevailing wind in this region never deviates more than a 

 few degrees from the east. The total number of rainy days 

 in the year is on the average one hundred. Numerous coin- 

 cidences have been observed between mascnetic disturbances 

 and local storms or hurricanes, also between the former and 

 auroras, visible perhaps in distant lands. On the other hand,- 

 very frequently tlie records at Havana show remarkable 

 magnetic pei>turbations that have not been recorded by the 

 photographic apparatus at Greenwich, England. The ampli- 

 tude of the daily barometric range is least in June and July, 

 and greatest in the winter months. Fourteen years of ob- 

 servations have been insufticient to determine any certain 

 law respecting the j-ears of hurricanes. They are, however, 

 as is well known, far more frequent from July to January 

 than during the other half of the year. A careful investiga- 

 tion of the terrible hurricanes of October, 18*70, leads the 

 Rev. R. P. B. Vines to the conclusion that the winds circulat- 

 ing around the centre of the cyclone describe a circle, and 

 the whole cyclone describes a curve on the earth's surface, 

 such as would be given by wrapping a spiral around a parab- 

 ola, the folds of the spiral being closest at the apex of the 

 curve. The rate at which the vortex of the cyclone of the 

 '7th of October crossed the island of Cuba was only four 

 miles an hour. The second storm, of the 19th of October, 

 began moving at the rate of nine and a half miles, and in- 

 creased to twenty miles an hour. The discharges of electric 

 fluid were very intense, and at Cardenas an appearance sim- 

 ilar to the aurora borealis was visible for ten minutes. The 



