The balls are rolled from one end of the alley, describe a curved line, and then strike the pins placed at the opposite end of the alley. No return track for the balls is required, and all that is necessary is to roll the balls from one end of the alley to the other. A recording slate, the tables for the guests, etc., are arranged between the two shanks or legs of the alley. It is evident that a person cannot play as accurately on an alley of this kind as on a straight alley; but if a ball is thrown with more or less force, it will roll along the inner or outer edge of the alley and strike the group of pins a greater or less distance from the middle. A room 36 ft. in length is of sufficient size for one of these alleys. * * * * * PATENT OFFICE EXAMINATION OF INVENTIONS. _To the Editor of the Scientific American:_ It is with considerable surprise that the writer has just perused the editorial article in your issue of March the 28th--"Patent Office Examinations of Novelty of Inventions" It seems to me that the ground taken therein is diametrically opposed to the views heretofore promulgated in your journal on this subject, and no less so to the interests of American inventors; and it appears difficult to understand why the abolition of examinations for novelty by the Patent Office should be recommended in face of the fact that the acknowledged small fees now exacted from inventors are sufficient to provide a much greater force of examiners than are now employed on that work. If inventors were asking the government to appropriate money for this purpose, the case would be quite different; although it may be shown, I think, that Congress would be fully justified in disposing of no inconsiderable portion of the public money in this way, should it ever become necessary. Recognizing the fact that the patent records of all countries, as well as cognate publications, are rapidly on the increase--and particularly in this country--making an examination for novelty a continuously increasing task, and that the time must come when such an examination cannot be made at all conclusively without a vastly increased amount of labor, from the very magnitude of the operation, it is nevertheless true that this difficulty menaces the inventor to a much greater extent, if imposed upon him to make, than it can ever possibly do an institution like the Patent Office.