Sirocco
2 of the 6 encyclopedias on this shelf carry an entry for Sirocco. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a hot wind storm. Most of the hot winds of the Old World are modified forms of the simoom. The sirocco originates in the Sahara and travels N. to the Mediterranean and southern Europe, but it is not so deadly as the prototype. It brings with it great quantities of the desert sand, and the air becomes so dense at times that the sun is obscured as if by fog. While it remains on the African mainland it is characterized by a very marked dryness, as there are no extensive water surfaces to supply it with moisture. As soon, however, as it is launched over the Mediterranean it begins to take up copious draughts, so that when it reaches Malta, Sicily, and the S. shores of Europe as a wind from between S. E. and S. W., it has undergone a change from a hot, dry wind to a hot, damp wind. The result of this alteration is that it becomes most enervating to the human constitution. During its prevalence iron rusts, clothes spoil with mildew, grapes and green leaves wither, wine will not fine, and paint will not dry. Sicily experiences the sirocco about a dozen times a year, but it is not so frequently met with in other parts of Europe.
Aiton's Encyclopedia (1910)
si-rok'ko, a hot, oppressive wind of Sicily and southern Italy. At certain seasons, particularly April and September, the sirocco blows from the south. It is no doubt a continuation of the African simoon. The sky grows hazy with reddish dust, and the wind is so depressing that people stay indoors to escape prostration. Three days is the extreme duration of a sirocco. It is a serious scourge to the husbandman. In Egypt this wind is called a Khamsin, meaning fifty, because it blows for fifty days. See Wind ; Simoon; Chinook
What Has Changed in the Last Century
The descriptions still hold: a sirocco does blow up from the Sahara ahead of low-pressure systems, picks up moisture over the Mediterranean, and dumps reddish dust on Sicily, Malta and southern Italy. What has changed is the explanation. Collier's 1921 idea that these are "modified forms of the simoom" and Aiton's 1910 claim that the sirocco is "no doubt a continuation of the African simoon" have given way to the modern account, in which the wind is warm air drawn northward on the leading edge of depressions tracking east across the Mediterranean. Satellites and dust-monitoring networks now follow individual Saharan dust plumes day by day, sometimes as far as the Alps and Britain, where they fall as "blood rain"; Aiton's note that Egypt's khamsin means "fifty" is better understood as naming a roughly fifty-day spring season rather than a wind that blows for fifty days on end.
Written for this edition, 2026.