Morrison Waite

“ What, therefore, is left for this patentee but the idea that if a pencil is inserted into a cavity in a piece of rubber smaller than itself the rubber will attach itself to the pencil, and when so attached become convenient for use as an eraser?
An idea of itself is not patentable, but a new device by which it may be made practically useful is. The idea of this patentee was a good one, but his device to give it effect, though useful, was not new. Consequently he took nothing by his patent. ”

“ A patent may be obtained for a new or useful art, machine, manufacture, or composition of matter, or any new and useful improvement thereof. In this case, as has been seen, Blair's patent was for 'a new manufacture,' being a new and useful rubber head for lead-pencils. It was not for the combination of the head with the pencil, but for a head to be attached to a pencil or something else of like character. ”

“ It is to be of any convenient external form. It may have a flat-top surface, or its top may be of a semicircular or conical shape, or any other that may be desirable. This would seem to indicate clearly that the external form was not a part of the invention. It was, however, urged upon the argument, that the invention did consist in the projecting surfaces extending out from the head, and which appear, as is claimed, in the drawings attached to the specifications. ”