Benjamin Robbins Curtis

“ As in the case under discussion; the moment a practical, scientific man is furnished with the idea of giving to the car a shape which will, by dispensing with the framing ordinarily used, enable him to make it lighter in proportion to its load, than it has ever been made before, he can multiply without end the forms in which this principle can be made to operate. He can make the car a polygon of an hundred sides, of twenty sides, or of eight sides. He can vary the angle of the cone, or pyramid, through which the coal is discharged, ad infinitum. ”

“ Where the invention consists of a principle embodied in a single form, the form is the principle and the principle the form, and there can be no violation of the principle without the use of the form. ”

“ Where form and substance are inseparable, it is enough to look at the form only. Where they are separable; where the whole substance of the invention may be copied in a different form, it is the duty of courts and juries to look through the form for the substance of the invention-for that which entitled the inventor to his patent, and which the patent was designed to secure; where that is found, there is an infringement ”

“ Still the question must always be, whether, whatever the shape he adopts, he is not availing himself of the principle first suggested by the partentee; a question which, in a court of law, is at all times a question not for the court, but the jury; after the former shall have given to the specification that construction which is to govern the latter in determining whether the infringement complained of falls, substantially, in principle and mode of operation, within the plaintiff's patent. ”

“ To understand the mode of operation introduced and employed by means of this form of the car body, it is only necessary to state, what appears on the face of the specification, and was testified to by experts at the trial as correct, that, by reason of the circular form of the car body, the pressure of the load outwards was equal in every direction, and thus the load supported itself in a great degree; that, by making the lower part conical, this principle of action operated throughout the car, with the exception of the small space to which the movable bottom was attached ”

“ The specification states:
'The transportation of coal, and all other heavy articles in lumps, has been attended with great injury to the cars, requiring the bodies to be constructed with great strength to resist the outward pressure on the sides, as well as the vertical pressure on the bottom, due not only to the weight of the mass, but the mobility of the lumps among each other tending to 'pack,' as it is technically termed. Experience has shown that cars, on the old mode of construction, cannot be made to carry a load greater than its own weight ”

“ The substance of this ruling was, that the claim was limited to the particular geometrical form mentioned in the specification; and as the defendants had not made cars in that particular form, there could be no infringement, even if the cars made by the defendants attained the same result by employing, what was in fact, the same mode of operation as that described by the patentee. We think this ruling was erroneous.
Under our law a patent cannot be granted merely for a change of form. ”

“ There being evidence in the case tending to show that other forms do in fact embody the plaintiff's mode of operation, and, by means of it, produce the same new and useful result, the question is, whether the patentee has limited his claim to one out of the several forms which thus embody his invention. ”

“ Because specifications are to be construed liberally, in accordance with the design of the Constitution and the patent laws of the United States, to promote the progress of the useful arts, and allow inventors to retain to their own use, not any thing which is matter of common right, but what they themselves have created. ”

“ It may be admitted, without hesitation, that the substitution of mechanical or chemical equivalents, as they are called, will not affect the rights of a patentee, but the cases in which this principle holds are where the modus operandi embraces more than a single way to reach the desired end. ”

“ Brown, 1 Wood. & Minot, 53, 57; Parker v. Haworth, 4 McLean's R. 372; Le Roy v. Tatham, 14 How. 181, and opinion of Parke, Baron, there quoted; Neilson v. Harford, Web. P. C. 341; Russell v. Cowley, Id. 470 ”