310 



SCIENCE 



[N. S. Vol. XXXVIII. No. 974 



investigation of 134 West India hurricanes 

 occurring in the 36 years 1876-1911. The area 

 visited by these storms includes the Gulf of 

 Mexico, the Caribbean Sea and the tropical 

 ocean for a few hundred miles east of the West 

 Indies and Florida, — thus the routes leading to 

 and from the Panama Canal on the Atlantic 

 side will lie for a great distance in the heart 

 of the hurricane zone. There are two main 

 hurricane paths, one following the inside Gulf 

 Stream route and the other the line of the 

 northward Atlantic drift off the north and 

 east coasts of the Greater Antilles and Florida. 

 The former is most frequented by the cyclones 

 in June and July and the latter in August, 

 September and October. In these last three 

 months 88 per cent, of the 134 cyclones oc- 

 curred. Their tracks are normally parabolic, 

 open to the east. The average rate of move- 

 ment on the first branch (northwestward) and 

 during the " recurve " (northward), is 11 miles 

 per hour. On the second branch (moving 

 northeast) the mean velocity increases to 16 

 miles per hour. The mean duration was 5.8 

 days (maximum 19, minimum 1 day). The 

 number of West India hurricanes in the 20 

 years 1880-1899 was 86, as against 418 ty- 

 phoons in the west Pacific and 184 cyclones in 

 the Bay of Bengal during the same period. 

 Professor Fassig considers West India hurri- 

 canes as mainly the result of general atmos- 

 pheric movements and not of local differences 

 in temperature. When in summer the equa- 

 torial belt of calms has moved some distance 

 north of the equator, the defiective action of 

 the earth's rotation is sufficient to produce a 

 cyclone when an adequate initial impulse 

 comes from the somewhat conflicting trade 

 winds north and south of the doldrums. 



HUMIDITY AND FROST DAMAGE 



Professor A. G. McAdie in the Monthly 

 Weather Review for April, 1913, in an article 

 entitled " Frost Studies — Determining Prob- 

 able Minimum Temperatures," points out that 

 in frost damage to plants the relative humidity 

 of the air is a very important factor. For in- 

 stance, in the frost of January 4-Y, 1913, in 



southern California the dryness of the air 

 favored rapid radiation and evaporation, caus- 

 ing damage to plants not only on account of 

 the low temperature but also through serious 

 interference with proper plant functions, espe- 

 cially in connection with transpiration, which 

 became injuriously rapid. 



On another page of this number, Mr. E. S 

 Nichols, local forecaster at Grand Junction, 

 Colo., in connection with a damaging frost on 

 April 23 also calls attention to the fact that 

 on dry frosty nights greater injury is done 

 than on moist ones with equal air temper- 

 atures. He has accordingly warned fruit- 

 growers in his district to begin smudging on 

 dry frosty nights at higher temperatures than 

 on damp ones.' 



CLOUDINESS AND SUNSHINE OF NORTH AMERICA 



An important contribution to the climatology 

 of North America entitled " Bewolkungsver- 

 haltnisse und Sonnenscheindauer von Norda- 

 merika," by Arthur Glaser, has recently ap- 

 peared.' The area covered is limited on the 

 north on account of lack of observations to 

 include only southern Canada. There are 

 three general regions where the mean annual 

 cloudiness is in excess of 60 per cent. — around 

 Puget Sound, the Great Lakes and the Cana- 

 dian Maritime Provinces. A minimum of less 

 than 20 per cent, occurs in the region about 

 the lower Colorado River in southwestern Ari- 

 zona and southeastern California. This rela- 

 tive distribution in general remains the same 

 throughout the year. Maximum cloudiness for 

 southern and eastern United States and the 

 Pacific coast including the Great Basin comes 

 in winter; for the Great Plains, in spring; for 

 New Mexico, Arizona, most of Mexico and 

 Florida, in summer; and for the country 

 roughly north of latitude 43 degrees and east 

 of the one hundredth meridian, in November. 

 Minimum cloudiness comes in winter over cen- 

 tral Canada; in spring over most of Mexico 



' See also E. A. Beals, ' ' Forecasting Frost in 

 the North Pacific States," Weather Bureau Bull. 

 No. 41, 1912. 



* Aus dem Archiv der Deutschen Seewarte, 

 XXXV., 1912, Nr. 1, quarto, 63 pp., 22 figs., 7 

 charts. 



