42 



SCIENCE. 



[N. S. Vol. YIII. No. 184. 



ing mid-summer the surface waters reach 

 a temperature of 23° C, the bottom waters 

 being 14° or 15°. The lake is at this time 

 in stable equilibrium and the stagnant bot- 

 tom waters are unfit for most forms of life. 

 But by the end of September the surface 

 has cooled so that a uniform temperature 

 prevails from top to bottom ; then gales 

 easily overturn the water body and it 

 slowly cools as a ' homothermous ' mass to 

 the winter minimum. 



W. M. Davis. 



CURRENT NOTES ON METEOROLOGY. 



CLIMATIC CONTROL OF TKANSPOETATION IN 



NORTHERN RUSSIA. 



From a recent book, entitled ' A Northern 

 Highway of the Tzar,' by Trevor-Batty e 

 (London, Constable, 1898), there is much 

 of interest to be learned concerning the 

 marked control which the climatic condi- 

 tion of northern Russia in October exert over 

 transportation and over the occupations of 

 the inhabitants. October is known in that 

 region as the Rasputnya season, Rasputnya 

 meaning literally ' the separation of the 

 roads. ' At this season ' the first frosts have 

 thawed and the first snows melted,' streams 

 of broken ice block the rivers, the morasses 

 are like quagmires ; ' the tracks, where any 

 advance has been attempted upon old forest 

 bog, a mixture of treacle and glue.' There 

 is an almost complete interruption of travel, 

 owing to the condition of the roads and 

 streams, until the settled frost of winter has 

 united the land and the water into one solid 

 frozen surface. " During the whole of Octo- 

 ber the government postal service is 

 stopped, labor contracts are off, and the 

 keepers of the stages are entirely freed from 

 their usual obligation to supply the trav- 

 eller with horses and sleighs." The con- 

 trol over transportation, here brought out 

 in one of its aspects, is an important re- 

 lation of climate and man which has not 

 yet received the careful study it deserves. 



KITE METEOROLOGY IN THE ANTARCTIC. 



In Das Wetter for May, Sprung advocates 

 the use of kites on the proposed Antarctic 

 expeditions, for the purpose of securing 

 accurate data as to the vertical temperature 

 gradient in high southern latitudes. At 

 present the calculation of the pressures at 

 altitudes of 2,000-4,000 meters in these 

 latitudes leads to rather unsatisfactory re- 

 sults, owing to the uncertainty which exists 

 concerning the actual temperatures prevail- 

 ing there above the earth's surface. By the 

 use of thermographs elevated on kite lines, 

 as has been so successfully done at Blue 

 Hill, it would be possible to obtain accurate 

 temperature data from the free air at con- 

 siderable altitudes, and these observations 

 could be used in calculating the pressures 

 aloft with a considerable degree of accuracy. 



AURORAS IN LONDON FROM 1707 TO 1895. 



A RECENT paper by Mossman, on 'The Au- 

 rora Borealis in London from 1707 to 1895,' 

 (^Journal Scottish Meteorological Society, Nos. 13 

 and 14, 1897), shows that the maximum 

 numbers were observed in 1848, 1787, 1789 

 and 1872. Auroras are most frequent in 

 October and April, and least frequent in 

 December and June. 



R. DeC. Ward. 



Harvard University. 



CURRENT NOTES ON ANTHROPOLOGY. 

 THE ARCHEOLOGY OF GUERRERO. 



The state of Guerrero lies on the Pacific, 

 directly south of the City of Mexico. Be- 

 fore the Conquest it was peopled by the 

 Mixtecs, who had a picture writing of their 

 own ; by the Nahuas, who were in the ma- 

 jority ; and by lesser tribes. The Mexican 

 antiquary, Orozco y Berra, writing thirty- 

 five years ago, asserted his belief that 

 within its area would be found one of the 

 oldest sites of the American race ( Geografia 

 de las Lenguas, p. 239). 



Especial interest, therefore, attaches to 



