While Upper Egypt is nowhere more than a fertile strip, bordered by two deserts, the comparatively large area of the Delta, its intersection by a multitude of canals, and the absence of a large system of metalled roads, have long rendered necessary an improvement of communications in the interest both of the fellaheen and of the European or Levantine landowners. Agricultural roads offer but a partial solution of the difficulties caused by these conditions; donkeys, mules, and camels are still highly useful, and will long be extensively used for the transport of commodities over a short distance, or in cases where time is no object to the transporter; but it is unnecessary to dilate on the defects of animal compared with mechanical transport. Branches of the Nile and the canals which in the maps cover the Delta with such a network of blue lines are also of great value, but the number of canals which are perennially navigable is limited, and the canal barge is nowhere renowned for speed, while sailing boats cannot use certain canals at all in the dry season, and their use of others is often attended by the risk of grounding. _En passant_, Mr Wallace mentions a singular fact in connection with the making of the trunk roads. In Europe we are accustomed to see them kept as level as is consistent with the cost of making, and raised above the level while provided with proper drains to carry off the too abundant water. Here it has been found that to give the road much rise above the surrounding levels is a mistake, in consequence of the large amount of salt the unredeemed districts contain. The salt rises to the surface, forming an efflorescence as in the American plains, and especially in the stiff lands it has a tendency to interfere with the ways of nature, where the particles adhere together, causing them to fall apart in the shape of dust, which is one of the objectionable features of an Egyptian road. Anyone who has read about Egypt will recall matters full of suggestion of likely difficulties regarding the keeping open of a road, while those who have travelled through the country have much to say about the prevalence of dust. How many discoveries in the past have been made of wondrous relics that have lain buried for ages covered in deeply--and preserved--by the drifting dust or sand! And, with regard to this drifting, attention has been drawn by Mr Wallace, in his agricultural address, to a singular physical fact in connection with the shifting of the sand. This might be expected to follow, on the whole, the course of the prevailing winds, and be carried mainly in their direction; but there are singular variations, probably due to local waves or currents of air near the surface of the earth.