The remarks made in this paper are due to the action of the United States Patent Laws, as interpreted by one of the examiners, whose duty it was to adjudicate upon the practicability of an invention submitted to him, and whose decision was adverse to the granting of a patent. Protection was solicited for an improvement upon a previously patented mechanical aërial machine, the success of which had been proved by the inventor through the action of a model. The patent was refused on account of the alleged impracticability of the invention owing to the absence of gas as a supporting, or partly supporting, medium. Total misapprehension of the principles of flight is displayed whenever the balloon is recommended to take off part of the weight of any mechanical arrangement. However successfully the pure mechanical action may have proved itself in the conveyance of weights in the air whilst in the model form, the principle seems to be distrusted by some when proposed for extreme weight. But it fortunately happens that the resistance of the air to a body in motion, upon which we depend for success, bears a greatly increasing ratio to the extent of surface which that body assumes.