98 Observations on the Climate of Italy 



we know good wine to have been made, viz. the Oasis. Now 

 the mean temperature of Cairo is 22'5 C.* The Oasis lies 

 from 4 to 6 south. Let us take as a mean 5. The in- 

 crease of mean temperature corresponding to 5 of latitude is, 

 as I shall presently show, for these countries, not less than 

 1 ^ C. This makes the mean temperature of the Oasis 24 ; 

 and unless we believe the climate of ancient Egypt to have 

 been cooler than at present, we must admit that good wine 

 may be made under that temperature. 



The vine, in fact, is less impatient of heat than might be 

 supposed from the circumstances said to attend its cultivation 

 at Bushire. Superb grapes are grown at Cawnpore in British 

 India in about 26^ latitude, at an elevation of not more than 

 1000 or 1200 feet above the seaf. Humboldt informs us 

 that excellent grapes are found at Cumana in 10^ latitude 

 with a mean temperature of 27'7 CJ. It must be recol- 

 lected that the heat of the Persian Gulf is excessive. The 

 mean temperature of the month of July is 34 C., and the 

 thermometer at noon rises even to 44 C. , a degree of heat 

 surpassed at few spots on the surface of our globe. To find 

 higher temperatures than this we must go to Nubia, where 

 Caillaud frequently observed 48 ||, and the Oasis of Mour- 

 zbuk, where Ritchie and Lyon experienced even the extraor- 

 dinary heat of 53 0< 8 C. ; the thermometer rising daily for 

 whole months to from 4-6 to 52 ^f. 



To find the increment of mean temperature from Cairo 

 to the Oasis, I have calculated two years' observations made 

 by Browne in the Oasis of Darfur. We know so little of the 

 interior of Africa, that these observations possess a good deal 

 of interest. They were made partly at Cobbe in latitude 

 14 11', and partly at a place called El Fasher, which seems to 

 have been in the neighbourhood, but which I do not find on 

 Browne's map. The hours of observation were 7 a.m. and 

 3 p.m., a few days only are wanting to complete two years. 

 I find the following monthly means : 



o 



January ... 18-5 C. July 30'6 C. 



February... 19'9 August 32'0 



March 27-2 September 33'1 



April 30'1 October ... 28-9 



May 29'7 November.. 25'6 



June 29*4 December.. 23*4 



* Humboldt, Lignes Isothermes. Mem. d'Arcueil, vol. iii. Tableau. 



t Nouvellcs Annales des Voyages, vol. xxx. p. 317- 



j Quoted by Schouw, Pflanzen-Geographie, p. 209. 



Voyage aux Regions Equinoxiales, vol. xii. p. 208. 8vo edit. 



|| Voyage a Meroe et au Fleuve Blanc. 



*t Lyon's Travels, Meteorological Register. 



