to the water wheel, he need not surely have been solicitous to engross every possible mode of protecting them by guards and covers, which no person could have wished to appropriate, who did not possess the undoubted right to use the wheels themselves. But from the careful and minute description, which he gives in his specification of these particular improvements, and from the complacency, Sir, with which you have dwelt upon their merits, wheel guards and wheel covers seem indeed to be regarded as the most important of his discoveries. Perhaps, they are so; but to my view, I must confess, Sir, they appear no more proper subjects for a Patent, than the "fenders of wood or iron of 66 any kind;"-the invention of " placing the steering "wheel and steersman further forward in a Steam "boat than is usual in other vessels ;"* or the improve

The great anxiety manifested to secure, by a forestalling specification, the exclusive right to wheel guards, covers, and fenders, of all sorts and descriptions, certainly betrays some lurking doubt or apprehension as to the water wheels themselves. For if Mr. Fulton had felt secure in his title to the latter, why should he have taken so much pains about those things which are mere accessories to their use? Apprehensive that the circumstance of his "having been the first to demonstrate the superior advantages of "the water wheel," might not be altogether sufficient to its exclusive use, he seems to have determined to prevent any other person from adopting the same propeller, except at a disadvantage; and notwithstanding he had placed guards round the outside of his wheels only, and had simply covered them with boards, he is not content with patenting these as his invention, but claims the exclusive right "to project from the side or sides of a Steam boat, "beams, or timber, or spars, or fender, or fenders of wood or iron "of any kind, to guard or protect the water wheels, whether by "boards, netting or grating, canvass or leather, or in whatever "other manner it may be, to prevent their throwing water on deck, ❝or entangling in ropes." Vide Appendix D.

ment of "giving breakfasts, dinners, tea, ant suppers to passengers, either in the cabins, or under an awning upon deck."*

Had the Committee, therefore, "possessed that "accurate knowledge," in regard to the first project of Mr. Ogden, which you consider so important; had they even "seen the marks of an abortive "birth," which, you say, are " still visible upon his "boat," I doubt, Sir, they would nevertheless have persisted in believing that she had been constructed upon" principles invented by Fitch, and improv"ed by Dod." The importance ofMr. Dod'simprovements you seem to admit, but you deny their originality; and suppose me to have given up the cranks for which he obtained a patent, because every body "must have told me that cranks were the very first " means applied to convert the libratory motion of "an engine beam into a rotary motion."†

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Strange as it may appear, Sir, nobody ever had the condescension to "tell" me so but yourself; for really, it is not "every body" that can pretend to that intimate acquaintance with the history of mechanical inventions, which you, doubtless, claim by the same sort of title, if not from the same source of power, to which you owe your military skill-in virtue of an honorary degree from the "Philosophical Society;" or, from having been brevetted a CIVIL ENGINEER, by your Commander in Chief. Taking it, therefore, for granted you speak knowingly, as well as authoritatively, permit me to ask, whether there was but one mode in which these vul

* Vide Appendix C. + Colden's Vind. p. 80.

gar cranks could be made to effect the purposes of their creation? Was there no room for improvement-no scope or latitude for invention? Had human ingenuity exhausted itself upon the subject, before Mr. Dod existed, or had its exercise been already claimed as one of the exclusive privileges of Mr. Fulton?

In the first two boats which were built by Messrs. Livingston and Fulton, it will be recollected that instead of the lever beam above the cylinder, as in Watt and Bolton's engine, there was substituted a triangle of cast iron on each side of its lower extremity. The two triangles were fixed on the same shaft, so that they worked together; and they were connected at one of the angles of their respective bases, to shackle bars or pitmen, descending on each side of the cylinder, from the cross beam in which was fitted the head of the piston rod. The angles at the respective bases of the triangular beam to which the pitmen were attached, moved therefore through a curve in a perpendicular direction, whilst their vertical angles, from which other shackle bars were connected with cranks, fixed at the sides of the propelling wheels, moved through a curve, in a horizontal direction; and in this manner a rotary motion was communicated to the wheels.

Now, instead of adopting these triangular beams and horizontal shackle bars, Dod retained the lever beam upon the top of the cylinder; attached the upper end of the piston rod to one end of the beam: and to obtain his rotary motion, he connected the other end of the beam with the head of a shackle bar or pitman, the lower extremity of which he fixed to a crank in the middle of the axis or shaft,

athwart the boat, upon which the wheels were hung, whilst a perfect rectilineal motion was given to the piston rod by means of the parallel link.* To per ceive that this was a different, a simpler, and, in all respects, a better mode of converting the libratory into a rotary motion, than the cumbrous apparatus introduced for that purpose by Mr. Fulton, requires nothing but the exertion of that common sense which no brevet or diploma ever yet bestowed: for besides the evident saving in the friction, weight and expense of the machinery, the method used by Mr. Dod, induced the more material saving of room in the boat. Indeed it must have been from actual experience of the disadvantages of the old plan, that an alteration, similar in principle to that of Dod's, but by no means so simple in its contrivance, was adopted by Messrs. Livingston and Fulton, when they built the Paragon.

* It has since appeared that the same method of communicating the rotary motion to two wheels upon the sides of the boat, and connected by one axis athwart ships, had been adopted many years previous, by Mr. Morey, but it was not patented by him; nor does it appear that Dod had any knowledge of the fact. The most ingenious invention, however, for which this self-taught engineer has obtained a Patent, is an original method of driving a double set of wheels with a Steam engine, by means of parallel lever beams, suspended upon a pivot at their respective centres, and connected at their extremities by links, which Mr. Colden seems to have confounded with the common parallel link; a pitman then descends from opposite ends of each lever beam alternately, and drives both sets of wheels together. Thus, without a cog-wheel or toothed sector of any kind; he employs one Steam engine in a boat to drive four propelling wheels, and is enabled to avail himself of a larger proportion of propellers without making his wheels so wide as to project an inconvenient distance beyond the sides of the boat. Vide infra Append. I.

As to the parallel link, it will be found that Dod's Patent was not for its invention, but for a new and beneficial appropriation of that well known piece of mechanism. And although what you state, Sir, be true," that a parallel link had been affixed by Bol"ton and Watt to different parts of their engines, "many years before Mr. Dod could have thought of "it;"* you do not pretend it had ever before been applied in the same combination in which the latter had used it :-and if Dod did see it, as you suppose, applied in many instances on board of Mr. Fulton's "boat," he could not possibly have seen it used there as" a simple and easy mode of giving a perfect "rectilineal motion to the piston rod, although it be "attached to the end of the beam which moves in a "curve," because Mr. Fulton had dispensed with the lever beam above the cylinder, so that the piston rod of his engine was not, of course, by any means attached to it.

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Yet, Sir, you renew your former censures upon the Committee, for omitting to state, whether Mr. Dod had or had not seen the boats of Mr. Fulton, when they reported that the former had invented improvements upon the Steam engine," without "having seen Mr. Fulton's Patent or Specification." I informed you in my Letter, that the Committee "deemed it proper to notice that Dod had never "seen that specification, in order to guard against "the influence of his having availed himself of the "calculations contained in it concerning the requisite power of the engine in relation to the size and structure "of the boat." But you still affect to consider it ́“a singular idea; that he might have been suspected

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* Colden's Vind. p. 81.

+Letter to Colden, p. 55, 56.