An example of the climate of the Sahara has already been furnished in the notice of Algeria, and in the northern part of the continent the only other at all well-known climate (apart from Egypt) is the _Soudan_. Practically rainless in parts, the climate is intensely hot and dry, the relative humidity showing one of the lowest records in our collection; but as the equatorial zone is approached a moderate rainfall develops, and throughout the region the large daily range of temperature results in the nights being comparatively cool, and therefore less trying than many parts of India. The northern portion is too dry to be very unhealthy, apart from the danger of abdominal chills, but as we ascend the Nile it expands into the immense marshes described by Baker and others, which are necessarily intensely malarious, while round the great lakes the sleeping sickness, previously rare or unknown there, is spreading rapidly. Commencing with the dry Soudanese region, climatic tables of three stations will be found below, the first and most northern of which, it will be seen, is practically rainless. The figures of the first table are averages of ten years’ observations. WADI HALFA. LAT. 21° 55′ N.; LONG. 31° 19′ E. E.F., 590; E.M., 128. =========+===========+============+===========+===========+=========== Month | Mean | Mean | Mean | Relative | Rainfall |Temperature| Maximum | Minimum | Humidity | | | Temperature|Temperature| | +----+------+-----+------+----+------+-----+-----+ | F. | ~C.~ | F. | ~C.~ | F. | ~C.~ | At | At | | | | | | | | 9 h.|21 h.| ---------+----+------+-----+------+----+------+-----+-----+----------- January |59·4|~15·2~|73.7 |~23·2~|47·5| ~8·6~| 42 | 44 | February |62·6|~17·0~| 77·2|~25·1~|48·4| ~9·1~| 39 | 36 | March |71·5|~21·9~| 87·5|~30·8~|56·5|~13·6~| 30 | 30 | April |80·5|~26·9~| 95·8|~35·5~|63·7|~17·6~| 23 | 24 | May |87·8|~31·0~|104·3|~40·2~|70·5|~21·4~| 17 | 19 |Practically June |90·7|~32·6~|106·7|~41·6~|74·4|~23·5~| 20 | 22 |_nil_. July |90·5|~32·5~|105·7|~40·9~|74·5|~23·6~| 23 | 30 |Drops August |90·0|~32·2~|103·5|~39·7~|75·0|~23·9~| 31 | 34 |recorded September|88·7|~31·4~| 99·6|~37·6~|73·5|~23·1~| 35 | 38 |15 times October |82·5|~28·1~| 97·2|~36·2~|69·0|~20·6~| 37 | 10 |in 10 years November |70·7|~21·8~| 85·0|~29·4~|58·7|~14·8~| 41 | 43 | December |63·0|~17·2~| 76·6|~24·7~|51·0|~10·6~| 45 | 45 | ---------+----+------+-----+------+----+------+-----+-----+ Year |78·0|~25·6~| 92·9|~33·8~|63·5|~17·8~| -- | -- | =========+====+======+=====+======+====+======+=====+=====+=========== The two remaining tables are for the year 1901, and are not even complete in places. Kassala is, of course, much nearer the sea than Omdurman, and hence its better rainfall.