Money was now subscribed more freely, and the work on the boat continued uninterruptedly until May, 1787, when a trial was made, which revealed many defects in the machinery. The cylinder-heads were of wood, and leaked badly; the piston leaked; the condenser was imperfect; the valves were not tight. All these defects were remedied, and a condenser invented by Voight--the "pipe-condenser"--was substituted for that defective detail as previously made. The steamboat was finally placed in working order, and was found capable, on trial, of making three or four miles an hour. But now the boiler proved to be too small to furnish steam steadily in sufficient quantity to sustain the higher speed. After some delay, and much distress on the part of the sanguine inventor, who feared that he might be at last defeated when on the very verge of success, the necessary changes were finally made, and a trial took place at Philadelphia, in presence of the members of the Convention--then in session at Philadelphia framing the Federal Constitution--August 22, 1787. Many of the distinguished spectators gave letters to Fitch certifying his success. Fitch now went to Virginia, where he succeeded in obtaining a patent, November 7, 1787, and then returned to ask a patent of the General Government. A controversy with Rumsey now followed, in which Fitch asserted his claims to the invention of the steamboat, and denied that Rumsey had done more than to revive the scheme which Bernouilli, Franklin, Henry, Paine, and others, had previously proposed, and that Rumsey's _steamboat_ was not made until 1786. The boiler adopted in Fitch's boat of 1787 was a "pipe-boiler," which he had described in a communication to the Philosophical Society, in September, 1785. It consisted (Fig. 68) of a small water-pipe, winding backward and forward in the furnace, and terminating at one end at the point at which the feed-water was introduced, and at the other uniting with the steam-pipe leading to the engine. Voight's condenser was similarly constructed. Rumsey claimed that this boiler was copied from his designs. Fitch brought evidence to prove that Rumsey had not built such a boiler until after his own. [Illustration: FIG. 68.--Fitch and Voight's Boiler, 1787.] [Illustration: FIG. 69.--Fitch's First Boat, 1787.]