During April 1755, while Ben Franklin was in Maryland to confer with General Braddock, he made a visit to the house, Belair, of Colonel Benjamin Tasker near Collington. While there, he observed the dust devil that evolved into a small tornado about which he wrote to Peter Collinson in August. Philadelphia, August 25, 1755

Dear Sir:

As you have my former papers on whirlwinds, etc., I now send you an account of one which I had lately an opportunity of seeing and examining myself. Being in Maryland, riding with Colonel Tasker and some other gentlemen to his country-seat, where I and my son were entertained by that amiable and worthy man with great hospitality and kindness, we saw, in the vale below us, a small whirlwind beginning in the road and showing itself by the dust it raised and contained. It appeared in the form of a sugar-loaf, spinning on its point, moving up the hill towards us, and enlarging as it came forward. When it passed by us, its smaller part near the ground appeared no bigger than a common barrel; but widening upwards, it seemed, at forty or fifty feet high to be twenty or thirty feet in diameter. The rest of the company stood looking after it; but my curiosity being stronger, I followed it, riding close by its side, and observed its licking up in its progress all the dust that was under its smaller part. As it is a common opinion that a shot, fired through a water-spout will break it, I tried to break this little whirlwind by striking my whip frequently through it, but without any effect. Soon after, it quitted the road and took into the woods, growing every moment larger and stronger, raising instead of dust the old dry leaves with which the ground was thick covered, and making a great noise with them and the branches of the trees, bending some tall trees round in a circle swiftly and very surprisingly, though the progressive motion of the whirl was not so swift but that a man on foot might have kept pace with it; but the circular motion was amazingly rapid. By the leaves it was now filled with I could plainly perceive that the current of air they were driven by moved upwards in a spiral line; and when I saw the trunks and bodies of large trees enveloped in the passing whirl, which continued entire after it had left them, I no longer wondered that my whip had no effect on it in its smaller state. I accompanied it about three-quarters of a mile, till some limbs of dead trees, broken off by the whirl, flying about and falling near me made me more apprehensive of danger; and then I stopped, looking at the top of it as it went on, which was visible, by means of the leaves contained in it, for a very great height above the trees. Many of the leaves, as they got loose from the upper and widest part, were scattered in the wind; but so great was their height in the air that they appeared no bigger than flies. My son, who was by this time come up with me, followed the whirlwind till it left the woods, and crossed an old tobacco-field, where, finding neither dust nor leaves to take up, it gradually became invisible below, as it went away over the field. The course of the general wind then blowing was along with us as we travelled, and the progressive motion of the whirlwind was in a direction nearly opposite, though it did not keep a straight line, nor was its progressive motion uniform, it making little sallies on either hand as it went, proceeding sometimes faster and sometimes slower, and seeming sometimes for a few seconds almost stationary, then starting forward pretty fast again. When we rejoined the company, they were admiring the vast height of the leaves now brought by the common wind over our heads. These leaves accompanied us as we travelled, some falling now and then round about us, and some not reaching the ground till we had gone near three miles from the place where we first saw the whirlwind begin. Upon my asking Colonel Tasker if such whirlwinds were common in Maryland, he answered pleasantly: "No, not at all common; but we got this on purpose to treat Mr. Franklin." And a very high treat it was too, dear Sir,

Your affectionate friend and humble Servant.

Ben Franklin