SIMOOM. A wind or haze was ob served by Mr. Bruce, in the course of his travels to discover the sources of the Nile, which is supposed to be in some re spects analogous to the sirocco. It is called by him the simoom, and from its effects upon the lungs, we can entertain but little doubt, that it cpnsists chiefly of carbonic acid gas in a very dense state, and perhaps mixed with some other noxious exhalations.
Mr. Bruce, who, in his journey through the desert, felt the effects of the simoom, gives of it the following graphical de scription " At eleven o'clock, while we contemplated with great pleasure the rugged top of Chiggre, to which we were fast approaching, and where we were to solace ourselves with plenty of good water, Idris, our guide, cried out, with a loud voice, fall upon your faces, for here is the simoom. 1 saw from the south-east a haze coming, in colour like the purple part of the rainbow, but not so compressed or thick. It did not oc cupy twenty yards in breadth, and was about twelve feet high from the ground.
It was a kind of blush upon the air, and it mooed very rapidly ; for I scarce could turn to fall upon the ground with my head to the northward, when I felt the heat a its current plainly upon my face. We all lay flat on the ground as if dead, till Idris told us it was blown over. The meteor or purple haze which 1 saw was indeed passed ; but the light air that still blew was of heat to threaten suffocation. For my part, I found distinctly in my breast that Iliad imbibed a part of it, nor was I free from an asthmatic sensation till I had been some months in Italy, at the baths of Poretta, near two years after wards." Though the severity of this blast seems to have passed over them almost instsneously, it continued to bloiv so as to exhaust them till twenty minutes before five in the afternoon, lasting through all its stages very nearly six hours, and leaving them in a state of the utmost despondency.