Frost and snow are of course unheard of at Zanzibar, and hail, not uncommon in the interior, never (?) falls upon the island or the coast. During the wet season generally, especially when the heats are greatest, the hills of Terrafirma are veiled with clouds, and sheet-lightning plays over the horizon. The islanders assure the stranger that storms of thunder and lightning are rare, and that few accidents happen from the electric fluid. M. Alfred May, for instance, declares that thunder is heard only three or four times a year. The same is said in West African Yoruba, in parts of the Brazil, and even in Northern Syria—Damascus, for instance. It would be curious to inquire what produces this uniform immunity under climatic conditions so different. At Zanzibar, however, the phenomenon is irregular as the seasons. I was told of several deaths by the ‘thunderbolt,’ and in the year 1857 the S.W. monsoon was ushered in almost daily by a tempest. Lieutenant-Colonel Hamerton, when sailing about the island, lost by lightning his Baloch Sarhang (boatswain); he himself felt a blow upon the shoulder like that of a falling block. No blood appeared upon the side, but it was livid to the hip, and for some days the patient was decidedly ‘shaky.’ Some explained his escape by his wearing flannel; others by his standing near the davits of a longboat, which were twisted like wax by the electric fluid. The mainlands of Zanzibar and of Mozambique are subject, as might be expected, to tornados, which much resemble those of the West African coast. Accompanying the formation and the dispersion of the nimbus, they are often violent enough to wreck small craft. Caught in a fine specimen, I was able to observe all the normal phenomena,—the building up of the warning arch, the white eye or gleam under the soffit, the wind blowing off shore, the apparent periodicity of throbs, and the frantic rage of the short-lived squall. The cyclones and hurricanes of the East Indian Islands rarely extend to Zanzibar. During 14 years there was but one tourbillon strong enough to uproot a cocoa-tree. It passed over the city about midnight, overthrowing the Mábandani or roof-sheds, and it was followed by a burst of rain. Colonel Sykes (loco cit.) remarks, philosophically explaining the why, ‘Another peculiar feature in the climatology of Zanzibar is that there is seldom any dew experienced.’ The reverse is the case, as might be known by the strength of the nightly radiation. Captain Guillain (i. 2, 72) declares that the rosées which accompany the rains are sufficient for watering the ground, and observes (p. 94), I presume concerning those who remain in the open air, ‘Rester à terre entre huit heurs du soir et le lever du soleil c’est s’exposer à une mort très probable, sinon certaine.’ The sunset, never followed by twilight, is accompanied by a sudden coolness which, as in equatorial, and even sub-tropical regions generally, causes a rapid precipitation of vapour.