Apkil 3, 1885.] 



SCIENCE 



269 



tude of more than six thousand feet on single 

 parallels, it is evident that there must be 

 great diversity of climate, a full discussion of 

 which would occupy too much space for a 

 reasonable article. But that portion of the 

 Eg3'ptian Sudan which at this time attracts 

 the attention of the world by reason of the 

 presence there of European troops, and the 

 apparently intended operations of those troops, 

 can be here concisely considered. 



British troops now occupy two positions in 

 the Egyptian Sudan; viz., the province of 

 Dongola on the Nile, and the cit} r and port 

 of Suakin on the coast of the Red Sea. 



Italian troops occupy the port and vicinity 

 of Massowah, on the Red-Sea coast ; and the 

 Bay of Assab and its vicinity, on the same 

 coast, near the strait of Bab-el-Mandeb. 



Whatever may be the object of the Italian 

 government in thus occupying positions on the 

 Red-Sea coast, the object of the present British 

 occupation is declared to be war against El 

 Mahdi, and it will be necessary to consider 

 the climate of the territories occupied by his 

 forces. 



El Mahdi now occupies and rules over the 

 following : the province of Khartum, the prov- 

 ince of Darfur, the province of Kordofan, the 

 province of Senaar, the province of Berber, 

 the district of Gallabat, the province of Taka 

 (excepting the capital, Kassala), and the great 

 desert region between the Nile near Berber, 

 and the Red-Sea coast near Suakin and Agig. 



Thus we have to consider the climate in the 

 provinces and districts above named ; and first 

 the province of Dongola, now occupied by the 

 expeditionary corps under Gen. Lord Wolse- 

 ley, of probably about nine thousand British 

 troops. 



This is one of the rich and productive prov- 

 inces of the Egyptian Sudan, extending from 

 near Wady Haifa on the north, to the borders 

 of the province of Berber along the course 

 of the Nile. The correspondence from Lord 

 Wolseley's corps has, during the past few 

 months, made almost every hamlet and village 

 throughout its length known to all parts of the 

 world where newspapers are read. The cli- 

 mate of the region now occupied by the British 

 force is not only good, but very agreeable, 

 during four months of the year, — November, 

 December, Januaiy, and February, — though 

 Februan- sometimes gives specimen days of 

 the Khamseen wind which are ver} T tr}ing, even 

 to natives of the country. During the months 

 of March, April, May, and the first half of 

 June, however, the climate, though not very 

 unhealthy, is exceeding trying to all excepting 



natives of the country. The ordinary tem- 

 perature is very high during the day ; the ther- 

 mometer in the shade often indicating from 

 95° to 110° F., while during the night the 

 temperature falls to 65° or 70°. This great 

 difference makes it necessary to take great care 

 to preserve health ; and, with the best of care, 

 intermittent fevers are exceedingly prevalent. 

 These, if neglected, are liable to take typhoid 

 forms. During these months, the dust-storms 

 coming from the southward are of most dis- 

 tressing frequency and violence. While these 

 storms are hard to endure, and cause great 

 suffering, I believe they to a certain extent 

 destroy fever-germs, and prevent the climate 

 from being so fatal to Europeans as it would 

 otherwise be. From June to September the 

 southerly and south-westerly winds come 

 charged with moisture, though rarely yielding 

 rain ; and, while relieved from the dust-storms, 

 the European is more subject to fever influences. 



Such is the climate in which the British 

 troops are apparently to wait during the next 

 five months, before advancing against their hu- 

 man enemy. Should they wait there, under 

 the best possible care and with the best pos- 

 sible medical surveillance, the commander will 

 be fortunate should the ' unseen enenry ' not 

 reduce his force by more than ten per cent 

 before October next, while another ten per 

 cent would be so debilitated by repeated 

 fever-attacks as to require a month of cool 

 weather to restore their strength, and make 

 them fit for a vigorous campaign. 



The climate of Suakin can hardly be con- 

 sidered unhealthy, but for the excessive heat 

 which reigns there, except during the three 

 months of December, January, and February. 

 There the desert comes down to the very sea- 

 beach ; and the air of the desert, though burn- 

 ing hot, is not unwholesome. But the heat in 

 that region, where sometimes during two or 

 three successive years rain does not fall, while 

 the tropical sunbeams constantly bathe the 

 rocks and sands, is of an intensity not to be 

 conceived by those who have never experienced 

 the like ; and exposure to it b}* Europeans, 

 without extraordinar}' precautions, is certain 

 to produce sunstroke and congestions. The 

 thermometer in April, in the shade, will often 

 indicate a temperature of 100° to 105° F. ; but 

 even this does not indicate the effect upon a 

 foot-soldier, who, marching in the sun, receives 

 the direct rays, and, in addition, suffers from 

 the heat radiated and reflected from the light- 

 colored soil. It is, however, quite different 

 with the mounted soldier, whether on horse- 

 back or on camel-back ; as, if well covered, he 



