Prof. Schouw on the Geographical Distribution of the Vine. 3 65 
Hungarian wines, (Tokay, for example), are distinguished for 
strength ; the cause of which Wahlenberg seeks to find in the 
prevailing dry easterly winds. Frequently, in a particular dis- 
trict, or even in a single vineyard, wine of a particular flavour is 
produced, such as Constantia, Hocheimer *, &c. 
It appears from a Table I have published, that the mean yearly 
temperature of any particular place affords no perfect rule for the 
distribution of the vine. Thus, the mean temperature of London 
is higher than that of Zurich, and very little lower than that of 
Geneva, and yet the former lies nearly 3° beyond the northern li- 
mit of the vine, while the two last are within it. Ofen, again, lies 
1J° south of it, while the mean temperature is very little more 
than that of London. In Sicily the vine ceases to grow, on ac- 
count of the elevation, where the mean temperature is greater than 
that of London ; and this, it appears, is still more strikingly 
the case in the Canary Islands. The mean temperature of 
summer has much greater influence. It is higher in Zurich, 
Geneva, Paris, and Ofen, than in London, or in Sicily, at a 
height where the mean yearly temperature is greater. It is, in- 
deed, easily comprehensible, that the temperature of that period 
at which the grapes ripen, must be the most important. Herein 
lies the cause why the northern limit in Europe does not recede 
from the pole in our progress eastward, but, on the contrary, is 
found in a lower latitude in the western than in the middle parts ; 
for, although the mean yearly temperature decreases considerably 
from west to east, the temperature of summer, on the contrary, 
encreases even on the same parallel, and much more on the same 
isothermal line. On that account, the upper limit in Italy, Sicily, 
and Teneriffe, is proportionally much lower ; for, towards the 
equator, the heat of summer does not increase nearly in an equal 
degree with the medium temperature. A high summer tempera- 
ture, combined with a low annual temperature, can, however, on- 
ly to a certain extent, make a country adapted to the culture of 
the vine. Thus, the isothermal summer heat of Moscow is 
1905, which is higher than in Paris, Zurich, or Geneva, and 
yet grapes at the former only ripen under glass. It may, in- 
deed, at once be affirmed, that a severe cold, especially a cold 
* There are numerous varieties of the grape-vine, differing in flavour and other 
qualities ; and the prevailing culture of particular varieties often gives a character 
to the wine of the district. — Edit. 
