126 Notes on Central Asia. [No. 3, 
might be used for such an amplification are as yet but little digested. 
The travels of Fédorof, Kardin, Schrenk, my own, the observations 
of Golubef, the data collected and elaborated by Fakharof, have not 
yet appeared in print, and only short notices of them have been 
presented. I am consequently necessarily obliged to withhold the 
supplementary matter to the 2nd volume, at all events until the 
publication of my travels which is now delayed by all my time and 
attention being engaged on questions of pressing and vital importance 
to Russia. 
With regard to the 3rd volume of the Russian edition of Ritter’s 
Asia, containing a description of the Russian Altai, the not unim- 
portant materials relating to these mountains, which were collected 
by me on my journey, have been partly digested since my return, and 
I am therefore in a position to proceed at once with the publication 
of this volume with its supplementary portion. I think it necessary 
to allude briefly in this place to some of the general results of my 
visits to the Celestial mountains. They embrace three questions of 
the utmost importance to the geography of Asia, namely the height 
of the snow-line in the Celestial range, the existence of alpine glaciers, 
and the existence of volcanic phenomena in this region. 
On the first of these points I consider it incumbent on myself to 
dwell at length in reply to the doubts expressed by Humboldt as to 
the correctness of the elevation of the snow-line in the Celestial range, 
as determined by me. The height I fixed it at, namely 11,000 to 
11,500 feet, was ascertained by Humboldt from a letter I wrote to 
Ritter, which attracted his particular notice. This letter was pub- 
lished in the “ Zeitschrift fix Hrdkunde” with some explanatory 
remarks hy Humboldt. The method I adopted for ascertaining the 
height of the snow-line was not known to Humboldt, who grounded 
his supposition of an over-estimation of the elevation of the snow-line 
on certain theoretical and analogical considerations. 
Tnaccuracies in the determination of the height of the snow- 
line may arise from two sources first from what is taken to be the 
snow-line, and secondly from an imperfect method of measuring 
heights. 
In the first instance the observer may be deceived either by taking 
dissolvable for eternal snows, or by fixing their limit of height in 

