this species of property may be ascertained, and secured; and the persons to whom such titles may be granted. The words, "any manner of new manufactures" in the statute of Jac. I. as understood and explained in British Courts of Justice, are co-extensive in signification with the words "new and useful art, machine, manufacture, or composition of matter, or any new and useful improvement on any art, machine, manufacture, or composition of matter," made use of in our statute. British authorities, therefore, so far as circumstances are similar, and the reason of the cases remains the same, will be pertinent for determining what kinds of new invented things may be the legal subjects of patent monopolies.

The famous cases of Boulton and Watt vs. Bull, and Hornblower and Maberly vs. Boulton and Watt, are the most prominent, interesting and important, as respects the kinds of invention, discovery or improvement, which may be secured by patent to the inventor; and afford many rules and observations, which ought not to be omitted in the present essay. The patent on which the action of Boulton and Watt vs. Bull was commenced, was for a new invented method of using an old engine in a more beneficial manner than heretofore, by

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the mechanical employment of certain principles. The case is reported in 2 Hen. Black. 463, as follows:

This was an action on the case for infringing a patent, by which the plaintiff was secured in "the sole benefit and advantage of making, using, and exercising, and vending, a certain invention of him, the said plaintiff; being a method by him invented, of lessening the consumption of steam and fuel in fire engines:" which patent was, by a private act of Parliament, (15 Geo. 3. c. 61.) continued to the plaintiff for twenty-five years. The gen

eral issue being pleaded, the cause came on to be tried after the sitting of Trinity Term, 1793; when a case was reserved for the opinion of the court; which stated, that by letters patent of 5th January, 1769, the king granted to the plaintiff Watt, who had duly assigned two thirds of the patent right to the plaintiff Boulton, that he might for fourteen years, make, use, exercise and vend, his new invented method of lessening the consumption of steam and fuel in fire-engines, under the usual condition of enrolling a specification:That Watt, by his specification, declared, that his new invented method of lessening the consumption of steam, and consequently fuel, in

Boulton

and

Watt,

vs. Bull.

fire-engines, consisted of certain principles: setting them forth particularly; by which it appeared that the object of the patentee, was to condense the steam, without cooling the cylinder or steam vessel; and that the means adopted to effectuate this, were in substance, to enclose the cylinder or steam vessel, in a case of wood, or any other material, which will confine the heat, or transmit it slowly: to surround it with steam, or other heated bodies, and to suffer neither water, nor any other substance colder than steam, to enter or touch it during that time.* The case

*The specification was as follows. "My method of lessening the consumption of steam, and consequently of fuel, in fireengines, consists in the following principles.

"First. That vessel in which the powers of steam are to be employed to work the engine, which is called the cylinder in common fire engines, and which I call the steam vessel, must, during the whole time the engine is at work, be kept as hot as the steam that enters it; first, by enclosing it in a case of wood, or any other materials that transmit heat slowly: secondly, by surrounding it with steam or other heated bodies ; and thirdly, by suffering neither water, or any other substance colder than steam, to enter or touch it during that time.

"Secondly, In engines that are to be worked wholly or partially by the condensation of steam, the steam is to be condensed in vessels distinct from the steam vessels or cylinders, although occasionally communicating with them: those vessels I call condensers; and while the engines are working, these condensers ought at least to be kept as cold as the air in the neighbourhood of the engines, by the application of water or other cold bodies.

then, described the old engine; and stated that the plaintiff's was a new and an useful invention; and that the specification was of itself sufficient to enable a mechanic, acquainted with the fire engines previously in use, to construct fire engines producing the effect of lessening the consumption of fire and steam. in fire engines. And the questions for the opinion of the court were, 1st. whether the

16 Thirdly, Whatever air, or other elastic vapor, is not condensed by the cold of the condenser, and may impede the working of the engine, is to be drawn out of the steam vessels or condensers, by means of pumps, wrought by the engines themselves, or otherwise.

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Fourthly, I intend in many cases, to employ the expansive force of steam to press on the pistons, or whatever may be used instead of them, in the same manner as the pressure of the atmosphere is now employed in common fire engines. In cases where cold water cannot be had in plenty, the engine may be wrought by the force of steam only, by discharging the steam into the open air, when it has done its office.

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Fifthly, When motions round an axis are required, I make the steam vessels in form of hollow rings, or circular channels, with proper inlets, and outlets for the steam, mounted on horizontal axles, like the wheels of a water mill; within them are placed a number of valves, that suffer any body to go round the channel in one direction only: in these steam vessels are placed weights, so fitted to them as entirely to fill up a part or portion of their channels; yet rendered capable of moving freely in them, by means hereafter specified. When the steam is admitted in these engines, between these weights and the valves, it acts equally on both; so as to raise the weight to one side of the wheel, and by the reaction of the valves, successively to give circular motion to the wheel; the valves opening in the direction in which the weights are pressed, but not in the contrary; as the steam vessel moves round, it is supplied with

said patent was good in law, and continued by the act of Parliament above mentioned? 2dly, whether the specification was sufficient to support the above patent? On the part of the defendant, it was argued on three grounds: 1st. on the patent itself. 2ndly, upon the act of Parliament. 3dly, upon the act and patent taken together. 1st. upon the patent itself, it was objected, that it was for a formed instrument, or machine, and as such void; because it was admitted that there was no specification descriptive of any formed instrument whatever; nor any drawing or model; but that supposing it to be a patent for mere principles, (as the specification stated the invention to consist of principles,) it was neither originally good in law, nor continued

steam from the boiler, and that which has performed its office, may be discharged by means of condensers, or into the open air.

"Sixthly, I intend in some cases, to apply a degree, of cold, not capable of reducing the steam to water, but of contracting it considerably; so that the engines shall be worked by the alternate expansion and contraction of the steam.

"Lastly, Instead of using water to render the piston, or other parts of the engine air and steam tight; I employ oils, wax, resinous bodies, fat of animals, quicksilver, and other metals in their fluid state.

To the above specification, this memorandum was added by Watt; that he did not intend that any thing in the fourth article, should be understood to extend to any engine where the water to be raised enters the steam vessel itself, or any vessel having an open communication with it.