432 Proceedings of the Royal Physical Society. 
districts are Mitidja, Bona, the Plain of Eghris, Gigelle, the 
plains of Zig, Habra, Zeybouse, and of Shotts, also the 
district through which the Macta Canal passes, and the 
borders of the Fezara Lake. 
3. Tunis and TripoliitThese regions are for the most 
part deserts, having a mean annual temperature of about 
70° F., and a mean annual variation of about 30° F. Diph- 
theria, dysentery, and diarrhcea are very prevalent, the two 
latter diseases being especially met with between July and 
October. Syphilis and acute and chronic rheumatism are 
also very common, but diseases of the lungs and liver 
exceedingly rare. Almost the whole of the district is 
malarious, with the exception perhaps of the area in which 
is situated the Lake of Bizerta, and also Porto Farina. 
Summarising the information we possess with regard to 
Northern Africa, we find that malaria, dysentery, diarrhea, 
leprosy, syphilis, and rheumatism are exceedingly frequent ; 
but it seems only probable that, were extensive sanitary 
measures adopted in the various countries referred to, and 
especially drainage and a good water-supply provided, the 
district would be far from inimical to emigrants from the 
south of Europe, and the climate is decidedly favourable to 
persons suffering from incipient phthisis. Such individuals 
should, however, spend at least two winters and the inter- 
vening summer in North Africa, if they would gain any 
decided benefit from a sojourn there. It is not altogether 
easy to estimate the progress made by France in the 
colonisation of Northern Africa, but on the whole I believe 
that gradual acclimatisation is taking place, and that in 
time the country may be completely and_ successfully 
colonised by that nation; and doubtless Italians and Spanish 
would fare equally well. 
II. NorTH-EASTERN AFRICA. 
In this division of my subject there are various climato- 
' logical areas to be considered—(1) The Delta; (2) the Valley 
of the Nile; (3) the Eastern Desert, including the coast of 
the Red Sea; and finally Abyssinia. Part of the country 
