In August last I recieved a letter from mr Isaac McPherson of Baltimore, on the controversies subsisting between yourself and some persons in that quarter interested in mills. these related to your patent rights for the elevators, conveyors, and hopper boys; and he requested any information I could give him on that subject. having been formerly a member of the patent board, as long as it existed, and bestowed in the execution of that trust much consideration on the questions belonging to it, I thought it an act of justice, and indeed of duty to communicate such facts and principles as had occurred to me on the subject. I therefore wrote the letter of Aug. 13. which is the occasion of your favor to me of the 7th instant just now recieved, but without the report of the case tried in the circuit court of Maryland, or your Memorial to congress, mentioned in the letter as accompanying it. you request an answer to your letter, which my respect and esteem for you would of themselves have dictated: but I am not certain that I distinguish the particular points to which you wish a specific answer. you agree in the letter that the chain of buckets, and Archimedes’s screw are old inventions: that every one had, and still has, a right to use them, and the hopper boy if that also existed previously in the forms and constructions known before your patent: and that therefore you have neither a grant, nor claim, to the exclusive right of using elevators, conveyors, hopper boys, or drills, but only of the improved elevator, the improved hopper boy Etc. in this then we are entirely agreed, and your right to your own improvements in the construction of these machines is explicitly recognised in my letter. I think however that your letter claims something more: altho’ it is not so explicitly defined as to convey to my mind the precise idea which you perhaps meant to express. your letter says that your patent is for your improvement in the manufacture of flour by the application of certain principles, and of such machinery as will carry those principles into operation, whether of the improved elevator, improved hopper boy, or (without being confined to them) of any machinery1 known and free to the public. I can concieve how a machine may improve the manufacture of flour: but not how a principle abstracted from any machine, can do it. it must then be the machine, and the principle of that machine which is secured to you by your patent. recurring now to the words of your definition, do they mean that, while all are free to use the old string of buckets, and Archimedes’s screw for the purposes to which they had been formerly applied, you alone have the exclusive right to apply them to the manufacture of flour? that no one has a right to apply his old machines to all the purposes of which they are susceptible? that every one, for instance, who can apply the hoe, the spade, or the axe to any purpose to which they have not been before applied, may have a patent for the exclusive right to that application? and may exclude all others under penalties from so using their hoe, spade or axe? if this be the meaning, my opinion that the legislature never meant by the patent law to sweep away so extensively the rights of their constituents, to environ every thing they touch with snares, is expressed in the letter of Aug. 13. from which I have nothing to retract, nor ought to add but the observation that if a new application of our old machines be a ground of monopoly, the patent law will take from us much more good than it will give. —Perhaps it may mean another thing: that while every one has a right to the distinct & separate use of the buckets, the screw, the hopper boy, in their old forms, the patent gives you the exclusive right to combine their uses on the same object. but if we have a right to use three things separately, I see nothing in reason, or in the patent law which forbids our using them all together. a man has a right to use a saw, an axe, and a plane separately; may he not combine their uses in fashioning the same piece of wood? he has a right to use a knife to cut his meat, a fork to hold it;2 may a patentee take from him the right to combine their use on the same subject? such a law, instead of enlarging our conveniences as was intended, would most fearfully abridge them, and croud us by monopolies, out of the use of the things we have.

I have no particular interest however in these questions; nor any inclination to be made the advocate of either party; and I hope I shall be excused from it. I shall acquiesce chearfully in the decisions in your favor by those to whom the laws have confided them, without blaming the other party for being unwilling, when so new a branch of science has been recently engrafted on our jurisprudence, one with which it’s professors have till now had no call to make themselves acquainted, one bearing little analogy to their professional educations or pursuits, that they should be unwilling I say, to admit that one or two decisions, before inferior & local tribunals, before the questions shall have been repeatedly & maturely examined in all their bearings, before the cases shall have presented themselves in all their forms and attitudes, before a sanction by the greater part of the judges on the most solemn investigations, and before the industry and intelligence of many defendants may have been excited to efforts for the vindication of the general rights of the citizen; that one or two precedents should for ever foreclose the whole of a new subject.

To the publication of this answer with your letter, as you request, I have no objection. I wish right to be done to all parties, and to yourself particularly & personally the just rewards of genius, and I tender you the assurances of my great esteem & respect.

Th: Jefferson