xliv AUTHOR'S PREFACE. 



Mongolia, Kan-su, Koko-nor, and Northern Tibet, 

 we travelled i i,ioo versts (7,400 miles), 5,300 (3,530 

 miles) of which, i.e. the whole distance out, were 

 sketched by means of the compass. This map, 

 which is appended on the reduced scale of 40 versts 

 (or about 2б| miles) to the inch,^ has been based 

 on 18 astronomical observations for latitude, which 

 I determined by means of a small universal in- 

 strument.^ 



The magnetic declination was ascertained at nine 

 places, and at seven the horizontal influence of the 

 earth's maofnetism. Four times a week we took 

 meteorological observations, frequently noting the 

 temperature of the earth and water, and the mois- 

 ture of the atmosphere with the psychrometer. We 

 determined the altitudes with the aneroid and boil- 

 ing water. Our researches were chiefly directed to 

 physical geography and the special study of mam- 

 malia and birds ; Ave made ethnological observations 

 whenever circumstances would permit. We also 

 collected and brought home 1,000 specimens of 

 birds belonging to 238 different genera, 130 skins 

 of mammalia, large and small, comprising 42 kinds ; 

 about 70 specimens of reptiles ; 1 1 descriptions of 

 fish ; and more than 3,000 specimens of insects. 



Our botanical collection includes the flora of all 



^ Reduced again, in the English version accompanying this trans- 

 lation, to a scale of slightly more than one-half that amount per inch. 



^ The longitude of these points, \vhich unfortunately could not be 

 determined, was found approximately by projecting my route survey 

 between the latitudes fixed, and by taking into account the declination 

 of the needle. 



