Joseph P. Bradley

“ The most important question, and first to be considered, is the validity of the patent.
It is obvious, from reading the specification, that the alleged invention consists mainly in attaching a screw (which the patentee calls a mud-fan) to the forward end of a propeller dredge-boat, provided with tanks for settling her in the water. It is operated by sinking the boat until the screw comes in contact with the mud or sand, which, by the revolution of the screw, is thrown up and mingled with the current. ”

“ But the Enoch Train did not exhibit all that was done in the matter of dredge-boats anterior to the alleged invention of Brady. If the application of dredging screws to the stem of a boat, driven by a propeller or otherwise, was not formerly exhibited in the Enoch Train, it was certainly exhibited in the invention of one Ephraim B. Bishop, which was patented in April, 1858, and was applied by Brady himself to a dredge-boat called the Wiggins Ferry, fitted up and operated by him at the mouth of the Mississippi in 1866. ”

“ Where the water was shallow we invariably went at the mud stern foremost. The stern was always loaded down to 18 feet when dredging, but the bows were not loaded down. In dredging, the stern was always several feet lower down than the bows, say three or four feet.' The boat built by the defendants, which was called the Essayon, was operated in precisely the same way. Being built expressly for dredging, her dredging screw was placed at her stem, it is true; but her mode of operation was the same as that of the Enoch Train. ”

“ When, after this, the government proceeded to build a boat expressly for dredging the mouths of the Mississippi, we should naturally expect to find it built as the Essayon was built, with her dredging screws at the stem instead of the stern. The making of them with longer blades than those of the propelling screw, and sharpened at the points, would be a matter of course. No invention would be requisite for any of these arrangements. ”

“ This boat was propelled by an ordinary center paddle-wheel, and to the bow was fixed two revolving conical-shaped screws, which, on being let down to the river bottom, cut and stirred up the mud and sand, and caused it to float away in the current. Each screw was driven by a separate steam-engine. Bishop was examined as a witness, and testified that the idea occurred to him from seeing a stern-wheel boat on the Arkansas river make a channel for herself by turning stern foremost and removing the sediment by the revolution of her propeller. ”

“ After going as far as we wish, we stop the dredging screw, lower the rake at the dredging end, and back out into deep water, using either or both of the screws to go back with, thus dragging the mud after us that the dredging screw has cut up from the bottom, and earrying at out into deep water ”

“ It creates a class of speculative schemers who make it their business to watch the advancing wave of improvement, and gather its foam in the form of patented monopolies, which enable them to lay a heavy tax upon the industry of the country, without contributing anything to the real advancement of the art. ”

“ This propeller is driven in the ordinary manner by steam-engines of ordinary construction. Near the bow of the boat I place another steam-engine, driving what I call the 'mud-fan,' which projects from and in front of the bow of the boat. This is formed by a set of revolving blades shown at A, turned, like the propellers, by a shaft passing through a stuffing-box, D. The blades are shaped somewhat like those of a propeller, but they are sharper on their fronts and less inclined on their faces. ”

“ That space was divided by a fore-and-aft bulk-head, making two water-tight compartments.
'The mode of filling the compartments was by stop-cocks in the sides of the vessel opening into the water-tight compartment; the draught of water could be increased from her natural draught of water, say to feet to 18 feet, according to the quantity of water let into the tanks. The more of operating was by running the vessel up and down over the bar, and thus stirring up the mud with the propeller screws. ”