"[T]heir object is, by their rapid revolution, to displace the sand and mud on the bottom and, stirring them up, to mix them with the water so that they may be carried off by the current."

The boat has a series of watertight compartments into or out of which water is pumped so as to sink the vessel to the required depth for dredging.

He sued for patent infringement in the circuit court, seeking an injunction and "an account of all such gains and profits as they, the respondents, have received by their unlawful and wrongful acts and doings.

He began by analyzing 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.

The use of propeller screws "for the removal of sand and mud accumulated at the mouths of the Mississippi had frequently occurred years before" the patentee's alleged invention.

"Did he make a selection and combination of these elements that would not have occurred to any ordinary skilled engineer called upon, with all this previous knowledge and experience before him, to devise the construction of a strong dredge boat for use at the mouth of the Mississippi?

To grant a single party a monopoly of every slight advance made, except where the exercise of invention somewhat above ordinary mechanical or engineering skill is distinctly shown, is unjust in principle and injurious in its consequences.

It was never the object of those laws to grant a monopoly for every trifling device, every shadow of a shade of an idea, which would naturally and spontaneously occur to any skilled mechanic or operator in the ordinary progress of manufactures.

It embarrasses the honest pursuit of business with fears and apprehensions of concealed liens and unknown liabilities to law suits and vexatious accountings for profits made in good faith.

"[13] According to Justin Lee, the key policy guiding Atlantic Works "is the notion that a patent grant is a quid pro quo.

The patentee is granted a bundle of exclusionary rights and the public receives in return a disclosure of previously unknown technological know-how."