310 SCIENTIFIC RECORD FOR 1884. 



beat by Liiigley's, Forstei's, and Frolicli's iiictliods, be recog:ni;:es \]\;\{ 

 Forster's granite pillar bas a mncb more constant seusitivem ss and 

 certainly cbanges very slowly; be bas tberefore nndertaken a modifica- 

 tion of bis own apparatus looking to an independence of tbe variations 

 of tbe temperature of tbe air. {Z. 0. G. M., xix, p. 400.) 



184. Dr. W. Koppen pnblislies an interesting study of the effect of 

 bot, temperate, and cold weatber on tbe organic world, and proposes a 

 new distribution of tbe limits of temperate zones, namely, tbe tropical 

 zone, wbere every montb tbe temperature is above 20° C; tbe suhtropic 

 zone, wbere four to eleven montbs are bot, or above 2(P; tbe temper- 

 ate zone, wbere from four to twelve montbs are temperate, namely, 

 from 10° to 20°, and tbis be divides into tbree subzones, tbe v.niform 

 temperate, baving bot summers and cool winters or temperate summers 

 and cold winters ; the- cold zone, where from one to four montbs are 

 moderate and tbe remainder cold ; and tbe polar climates, wbere all 

 montbs are cold, namely, under 10° C. He sbows tbat tbis empirical 

 division (lower tban 10°, from 10° to 20°, and above 20° C.) accords rea- 

 sonably well witb pbenomena of animal and vegetable lU'e. Evei-y wbere 

 tbe progress of civilization bas been from tbe warmer into tbe cooler 

 countries. {D. M. S., i, p. 215.) 



185. Dr. A. Woeikof, on tbe dependence of tbe daily variations of 

 temperature upon local circumstances, especially topograpby, formu- 

 lates bis views about as follows: 



1. A convex surface, such as a bill or mountain, is a cause tbat dimin- 

 isbes tbe daily range ol temperature, and by so mucb tbe more in pro- 

 l)(»rtion to tbe ratio of the vertical to tbe borizontal dimensions. 



2. A concave surface, as a valley or bollow, increases tbe daily range 

 of temperature, but only up to certain limiting ratio of vertical and bori- 

 zontal dimensions. 



3. As a norujal condition in respect to tbe daily ami)litude be adopts 

 a perfect plane surface; be gives numerous examples of tbis, quoting tbe 

 data from Asia and Europe; be eliminates tbe effect of cloudiness and 

 winds, and leaves tbe outstanding daily an)plitude to be explained as 

 due to tbe influence of tbe topograpby. Quantitatively it would seem 

 tbat tbe daily amplitude in tbe bigb valleys of tbe Indus, 3,500 meters 

 above tbe sea, 'in January and February, is greater tban in some of 

 the driest places on tbe low^ 'plains of Northern India. {Z. 0. G. 31., 

 XVIII, p,21l.) 



186. G. J. Symons gives tbe first results of simultaneous tbermometric 

 and bygrometric observations at heights 4, 170, and 2G0 feet, wbich were 

 made on behalf of the Eoyal Meteorological Society on tbe cathedral 

 tower at Boston. During clear November weather tbe average temper- 

 ature at tbe highest point was greater tban at tbe earth's surface by 

 reason of tbe excess of cold due to radiation at night, buton cloudy, 

 windy weather, the average temperature was lower above tban below. 

 In foggy weather the temperature at the highest point was always higher 



