Our patent laws are too free in allowing the granting of patents on modifications of design while fundamental patents are still in force. This works great hardship on original inventors, forcing them to take out a great many patents on features of design rather than on invention. I have taken out nearly one hundred United States patents with over one thousand one hundred claims covering a few fundamental inventions, some of which cover details of construction for which I should not have been forced to seek protection. All original inventors complain of this system. I know of several instances where patents on modifications of design have been granted, which modifications have been in common use for several years by others, but were only considered as a design and not as an invention. Then some designer hits on the same arrangement and considers he has made an invention, and applies for and takes out a patent which has already been in common use but has been looked upon purely as a design by its originator rather than an invention. Then the original designer may be hauled up before the courts and put to great expense to prove that it was in prior use as a design. While Captain Lauboeuf and the Krupps have taken out several patents on detail mechanisms for use on submarine boats, they have never--so far as I am aware or the patent records show--attempted to claim to be the original inventors of the type of submarine with buoyant ship-shaped form of hull consisting of a pressure-resisting body surmounted by a watertight, non-pressure-resisting body which gives suitable form for surface speed and seaworthiness, which is the principal characteristic of vessels built by them. I feel, therefore, that certain misinformed authors should, in the interests of the truth, correct their statements if they issue new editions of their work or write further on the development of the submarine. During the years of practical experimental work with the _Argonaut_, Mr. Holland continued in his efforts to get the _Plunger_--building under the 1893 appropriation--in shape for submerged trials, but without success. The large steam installation, sixteen hundred horsepower, was largely responsible for this. As I remember, there was only about eighteen inches between the main engines, with large steam supply and exhaust pipes overhead and under foot. These engines were designed to run at over four hundred revolutions per minute. The boiler was located nearly in the centre of the vessel and so nearly filled the ship that there was barely room between the top of the boiler and ship to creep from "forward to aft." [Illustration: THE "HOLLAND"