occupied by the wagon. It is no exaggeration to say that the natives were much astounded to see a little iron boat weighing four tons pulled by two men from the bottom of the Passaic and left standing high and dry on the bank. The next day the accidental submergence was explained by the absence of two five-eighths inch screw plugs from the bottom of the central compartment in which the operator would be seated while the boat was in operation. By opening a stop valve while the boat was in operation under water a sufficient quantity of water would enter, surround the operator in his diving suit, and render the boat and its contents heavier than water, so that it would sink as it did after having been launched with the plug holes open. The reason that it did not sink, and that it was so easy a matter to pull it ashore, was because the total weight on board on that occasion was much more than it was designed to carry. The central space then carried water equal to the weight of the diver and his suit of armor, as well as the additional quantity that would fill the space around him, as well as that which would be due to the distention of the suit by air pressure while it was in action during diving. The actual practicability of being able to handle the boat under these conditions was the first important point proved by experiment on the day following the launch. "We proved conclusively, a few weeks after, that our estimate of the quantity of fresh compressed air required to support life comfortably in the operator was probably a little excessive. The quantity of compressed air, as well as the pressure required to force all water out of the boat and to cause her to float light on the surface, was ample. A few days after the launch, the engine having been given a slight test, the boat was towed up the river to a point opposite the old Pennington house. In the launch that towed her were Mr. Dunkerly, Captain John Lister, and three men prominent in the 'Fenian' movement."