Rurasey's machinery, the greatest part, must consist of copper, or Brass such as cylinders, tubes, cocks and valves, together with curious wrought iron ; now 800 pounds (were it all made of Iron) could not cost less than double the sum. As this evidence is not brought to prove anything about M*". Rumsey's iniorily it is of no importance, and the absurdity it contains might have been spared. Whether his machine or my machine are best, is nothing to the purpose ; I have been daily altering, and never watched kis motions and blunders, as it is evident he did mine. He it seems made a secret of his doings, whilst mine were open to all the world.

It is proper I should not pass over this part of my work, without acknowledging, that I have been greatly indebted to the assistance of my ingenious friend M^". Henry Voight of this city : who has uniformly, from my hrst undertaking to build a boat, allbrded me valuable hints ; and has united with me in perfecting my plans. To his inventive genius alone, I am indebted for the improvement in our mode oi creating steam; a thought which struck him above two years ago, the drawing having been shewn to several persons ; for we nen)er made a secret of any part of our works ; but a fear of departing from old established plans, made me fearful of adopting it, until I had found by his invention of creating steam, that a condenser might be constructed on the same principles (viz a spiral pipe or worm) only by reversing the agent, for the best way of applying fire to evaporate water into steam, must also be the best way of applying cold water to condense steam, that is the bringing the greatest quantity of fire into action upon the greatest surface of water -- or the contrary -- And we had an additional inducement to study this subject bacause the common way of fixing boilers, required so great a load of brick work, that it over-loaded our boat.