Upon part of the site was erected a _horizontal mill_, by Captain Hooper, who also built a similar one at Margate. It consisted of a circular wheel, with large boards or vanes fixed parallel to its axis, and arranged at equal distances from each other. Upon these vanes the wind could act, so as to blow the wheel round. But if it were to act upon the vanes at both sides of the wheel at once, it could not, of course, turn it round; hence one side of the wheel must be sheltered, while the other was submitted to the full action of the wind. For this purpose it was enclosed in a large cylindrical framework, with doors or shutters on all sides, to open and admit the wind, or to shut and stop it. If all the shutters on one side were open, whilst all those on the opposite side were closed, the wind acting with undiminished force on the vanes at one side, whilst the opposite vanes are under shelter, turned the mill round; but whenever the wind changed, the disposition of the blinds must be altered, to admit the wind to strike upon the vanes of the wheel in the direction of a tangent to the circle in which they moved.--(Dr. Paris's _Philosophy in Sport_.) This mill resembled a gigantic packing-case, which gave rise to an odd story, that when the Emperor of Russia was in England, in 1814, he took a fancy to Battersea Church, and determined to carry it off to Russia, and had this large packing-case made for it; but as the inhabitants refused to let the church be carried away, the case remained on the spot where it was deposited.