46 KIHKKIA. 



iMiilinii of that f;f Viliiisk, and tin' sccijuil i:(»iisisLs of tlii- ilistricis of Vorkiioyari.sk, Kolyiii.sk 

 iiinl till' hasins of llio (Jli'iirk ami Loiia holow Zlii^'ansk in the Vihiisk and Yakutsk distiifts. 

 Till- liisl, sonlli-w'i'sloiii ZMMi', lias an an^a of 38 tliousarnl sr|nan' f/orj^rapliioal inilfs, \ho 

 .scconii, Murili-castcni znni', covi-r.^ .'52 tlniusand. Taken Ironi loin |Miints id' observation silnatfd 

 in till' lir>l part of tin- Yakutsk n•^'ioIl, tin- mean yearly teni|)i'ratiire is about — 8" Cel., the 

 mean winter tciniieraliiic is — 33", that id" the eoldest month — 36". tlie mean snmtner temjK'- 

 ratiiro +15", that of the hoitest month -}-\l": the ilillerenn.- between the temperatnres of 

 winter and siimima' is 48", the dilfereiiee bi;tween the e.oldi^st and hottest months is 53"; that 

 is to say, the climato is far moie enntinental than that of the nei^'iibonring forest zone of 

 Eastern Siberia. I'ndei- these eliniatic conditions, the soil wliifli the snn's rays do not i)eiietrato 

 to a j,neater ileplli than iliiee-joinths of an arsliine, is always frozen. Nevertheless the mean 

 temperature of the livi'-months period of vegetation is -j- 11", and even -|- 12" in Olekminsk 

 anil Yakutsk, whilst the high summer temperiiliire of -\-lb° during the powerful insolation of 

 the short summer period permits (d' sporadic agrieultnre in some parts of this portion of 

 the Yakutsk region. 



One of the cold poles of the northern hemisphere is situated in the north-eastern polar- 

 tuiulra pait of the Yakutsk frontier country. Thus, in Yerkhoyansk under 67" 34' north lati- 

 tude ilu^ iiieaii yearly temperature falls to — 17" Cel.; the mean winter temperature is — 47'*, 

 that of the coldest month — 49" Cel., whilst the mean summer temperature hardly exceeds 

 -|-13" and that of the hottest month +15"; the difference of temperature betw"een winter and 

 summer is 60'\ ami between the hottest ami coldest months G4"; this is a type of the most 

 continental climate in the Old A\'orld. Three and a half degrees farther north at Ustiansk, 

 nnder 70" 53' north latitude, the climate is already milder. The mean yearly temperature 

 exceeds —16" Cel.; the winter temperature is— 37" Cel.; that of the coldest month is — 41°; 

 the summer temperature is +9", and that of the hottest month -fl3: the difference between 

 the temperatures of winter and summer is only 47**, and that between the hottest and coldest 

 months 54", On the other hand the mean temperature of the five-months period of vegetation, 

 which in Yerkhoyansk hardly exceeds 8", does not amount to inore than 3" at Ustiansk, or 

 in other words, the mean temperature of 9" lasts about five months at Yerkhoyansk and only 

 three months at Ustiansk. 



At the mouth of the Lena, at Sagastyr, where there was for nearly two years a 

 meteorological station of the Russian Imperial Geographical Society, the climatic condi- 

 tions are still more unfavourable. The mean temperature (below — 17"), the winter temperature 

 (—36") and that of the coldest month (—42") at, Sagastyr are closely approximate to 

 those of Ustiansk, but the mean summer temperature of less than -{-3", and that of 

 the hottest month of lessUhan +5°, place all organic life under the most unfavourable condi- 

 tions of existence, especially as at a depth of 0.8 metre the soil never thaws and in winter 

 has a temperature below —20" Cel. Under these circumstances, cultured life in the polar 

 tundra zone of the Yakutsk frontier country is rjuite impossible. At Yakutsk in the forest 

 zone the Lena is clear of ice during 160 days in the year, whilst at Ustiansk the Yana is 

 only clear during 100 days. The climate of the south-western forest pai't of the Yakutsk region 

 is also less favourable than that of East Siberia, with reference to the amount of rainfall 



