March *3, 1895.] 



SCIENCE. 



319 



production ; and southward by the mean 

 temperature of the hottest part of the year. 

 The ' total (luantity of heat ' is measured 

 by the sum of the excesses of mean daily 

 temperature over 43°; tliis temperature be- 

 ing taken as marking ' the inception of 

 physiological activity in plants and repro- 

 ductive activity in animals.' The ' hottest 

 part of the year ' was arbitrarily limited to 

 the six hottest consecutive weeks of sum- 

 mer. Tlie life zones, the northward con- 

 trol, and the southward control are showni 

 on three maps ; and the accordances between 

 the controls and the zones are ti-ulj' sur- 

 prising. The peculiar over-lapping of boreal 

 and austral types along the Pacific coast, 

 hitherto not cleai-l}- underetood, is thus 

 shown to obey the same controls as those 

 which elsewhere keeps these tj'pes apart ; 

 the western coast being exceptional in hav- 

 ing a great total quantity of heat, but a very 

 mild summer. The dependence of these 

 temperature controls on general geographi- 

 cal features offers a beautiful illustration of 

 the general principles of climatology. 



HARRIXOTOX's RAINFALL CHARTS OF THE 

 UNITED STATES. 



A QUARTO paper of text and tables and a 

 large atlas of charts, entitled ' Rainfall and 

 Snow of the United States, Compiled to the 

 end of 1891,' by Mark W. Harrington, 

 chief of the AVeather Bureau, has lately 

 been issued as Bulletin C, of that office. It 

 is based on all available records, of very 

 dirterent periods and values, but constitu- 

 ting the best body of material now in liand 

 for the study of precipitation in this coun- 

 try. The charts exhibit the monthly, sea- 

 sonal and annual rainfall, monthly maxima 

 and minima, and many other details. The 

 text calls attention to the chief features in 

 the distribution of precipitation, both in 

 plaeeand season. The unusually heavy rain- 

 fall in the southern Appalachians, averag- 

 ing over sixty inclies, and exceeding ninety 

 inches in 1892 at one station, is a new fea- 



ture. It may be doubted whether the rain- 

 fall of the more mountainous belts is in 

 general sufficiently represented. For ex- 

 ample. Pike's peak is the only mountain 

 meteorological station in Colorado, and its 

 rainfall (30") is greater than that of any 

 other station. It might therefore be tiiken 

 as indicating the rainfall on the mountains 

 of Colorado in general ; but, although there 

 are many other lofty peaks, the isohyetal 

 line of 30 inches does not include them. 

 One might, to be sure, in the absence of di- 

 rect observations, feel some hesitancy in as- 

 serting that these other summits actually 

 have a 30-inch i-ainfall ; yet one might feel 

 equal hesitancy in asserting, as the charts 

 do so emphatically, that the high peaks in 

 general have not a 30-inch rainfall. It is 

 stated that " in general the rainfall de- 

 creases also with the elevation above sea 

 level ;" and the decreased precipitation in 

 passing westward across the Great Plains 

 is taken as an illustration of this generali- 

 zation. It is questionable whether the il- 

 lustration is pertinent ; for other controls, 

 such as distance inland and relation to 

 mountain ranges, are here presumably of 

 much gi-eater importance than increasing 

 elevation. It is to be regretted that, in the 

 interests of a consistent terminology, Flor- 

 ida should be cited as a region of ' subtrop- 

 ical ' rainfall. Florida is a region of sum- 

 mer rains ; while regions of subtropical 

 rainfall always have their maximum in 

 winter, as in the region originallj' so named 

 1)V Dove, around the Mediterranean, and 

 again with equal distinctness in California, 

 Chili, South Africa and South Australia. 

 The southeastern coast of Asia has a sum- 

 mer rainy season, like Florida ; and Flor- 

 ida might therefore with some justice be 

 likened to the regions of monsoon rainfall, 

 but this would hardly do justice to its other 

 relations. As a matter of fact, no techni- 

 cal name has yet been suggested for sea- 

 sonal rainfall of the Florida kind. 



