REPORT ON METEOROLOGY. 
247 
St. Petersburg . . . . S. 41° W. 
Moscow.S. 35 W. 
Kasan. S. 52 W. 
Tobolsk. S. 47 W. 
Baron Humboldt thinks that the western winds diminish in 
frequency from St. Petersburg towards Central Asia, though 
they increase towards the North of Siberia* * * § . 
The direction of winds is greatly affected by the configura¬ 
tion of a country, their general direction being modified, so as 
to coincide with its natural lines of elevation and depression. It 
is probably on this account that in Egypt the winds are generally 
either north or south, the former prevailing nine months in the 
yearf. Where the climate is tolerably regular, as in the South 
of Europe, the direction of the wind makes all possible differ¬ 
ence in its character. The transition from a sirocco to a tra- 
montana at Rome or Naples is as great as the effect of ten de¬ 
grees of latitude. It is surprising therefore, that, powerful ele¬ 
ments as these aerial currents are, they have been so imperfectly 
studied. 
I have now before me the results of a register of the force of 
the wind by Lind’s anemometer for the year 1826, kept with great 
assiduity by my friend Mr. Snow Harris of Plymouth. I have 
already alluded to the connexion which he has pointed out be¬ 
tween the force of the wind and the horary oscillations of the 
barometer, which has not before been remarked : indeed the 
observation of the anemometer is so rare, that there are few 
meteorologists who have persevered in the use of it. This ren¬ 
ders the register of Mr. Harris the more valuable. The mean 
force of the wind for the whole year at 9 a.m. was 0*855; at 3 p.m. 
1*107 ; and at 9 p.m. 0*605. Mr. Harris informs me that he has 
found the anemometer of Lind a more satisfactory instrument 
than it is usually considered. The improvement of anemome¬ 
ters has been almost abandoned for some time ; indeed it may be 
doubted whether, with an element so momentarily variable, insu¬ 
lated observations can be of very great value. M. Leroy has 
proposed what he calls an Eolian clock, which by means of ma¬ 
chinery is intended to measure the direction and force of the 
windj. I think that if the anemometer is ever to become an avail¬ 
able meteorological instrument, it must be on some principle of 
self-registration such as I proposed about two years ago§. Either 
by a piece of clock-work or some simple movement put in action 
* Fragments Asiatiques, ii. 353, note. 
f Belzoui, Researches and Operations hi Egypt and Nubia, vol. i. 
X Bulletin des Sciences Mathematiques, ix. 32. 
§ Edinb. Journal of Science, January 1830. 
