262 Professor Traill on the Cultivation of 
The average temperature at Gibraltar and its vicinity, 
throughout June, at 9 a.m. = 73°. 
at 9 p.m. — 70°, while the monthly average 
of Deluc’s hygrometer — 41°. During this period, the hy- 
grometer was twice observed to indicate only 35°, and it was 
once as high as 52°: the last was during a Levanter, or south- 
east breeze, with an obscure atmosphere and oppressive heat. 
In the month of July, while still to the south of the Sierra 
Morena, the average temperature from the Ist to the 24th of 
the month was at 9 a.m. 86°. 
at 9 p.m. 82°.5. 
At the hottest time of the day, the thermometer in the shade 
usually stood from 92° to 96°; and on one occasion I found it 
as high as 99°.5. An accident to my hygrometer rendered the 
observations with that instrument imperfect. 
For several months of the year, scarcely any rain, except an 
occasional thunder-shower, falls in Andalusia; but the dews 
are most copious. In severe winters, there are sometimes 
slight nocturnal frosts, which are very injurious to the sugar- 
canes. But the climate along the Mediterranean coasts of 
Andalusia is so mild, that tropical plants in general need 
scarcely any protection ; and the nightingale is said to remain 
there throughout the year. 
It is well known that the range of the barometer is ex- 
tremely limited in the south of Europe, and it is still less in 
equatorial regions. By consulting the register of this instru- 
ment, kept at the Garrison Library in Gibraltar, at a few feet 
above the level of the sea, I found that for eight years the 
barometer had generally stood from 30.01 to 30.10. During 
the whole period, it had been once so low as 29.70, and once 
so high as 30.20: the first happened during a thunder-storm in 
the winter of 1810 ; the latter in the summer of the same year. 
It might have been expected that a branch of agricul- 
ture so interesting, so little known in the rest of Europe, 
would have arrested the attention of British travellers in 
Spain ; but it has scarcely been noticed by any of our travel- 
lers. In the Antiquarian Travels of the Rev. Edward Clarke, 
published in 1763, we perhaps ought not to expect to find any 
notice of this subject. But neither in the valuable “ Journey 
