An inventor is in every case entitled to a claim commensurate with his invention, and the combinations invented by him may be generic, specific, peculiar, or particular according to the circumstances of each case.

§ 49. Generic Combination.

If the inventor be the first who combined devices of two or more distinct genera to produce a useful result, he is entitled to a claim that will secure to him the use of the combination of those genera, without restriction to any particular species of those genera, and without recital in his claim or restriction to the peculiarities of the combining mechanism by which he has combined the devices. The invention then consists of the generic combination of the two or more devices, and the claim is a generic claim with the legal effect that a subsequent new combination of particular species of the same genera of devices is included in the purview of the generic claim notwithstanding the fact that the subsequent new combination has an improved mode of operation, or accomplishes an additional function to that effected by the generic combination first made.

§ 50. Specific Combination.

If the generic combination be old, and a subsequent inventor be the first to combine two or more species of the same genera of devices in such manner that a new collective mode of operation is attained which is not attained by the old generic combination made by the first inventor (as was the case with the combination of the Crompton loom and with the harvester of Seymour), such subsequent inventor is entitled to a claim that will

secure to him the use of the combination of those species having the mode of operation described in the narrative part of the specification, without recital in the claim of, or restriction to the peculiarities of the combining mechanism by which he has combined his species of devices. The invention then consists of the combination of two or more specific devices, and the claim is a specific one, which while it does not include all the genera of devices of which the claimed devices are species, has the legal effect that a subsequent new combination of other species of the same genera, which new subsequent combination has the improved mode of operation incident to the patented specific combination, even though accomplishing an additional function thereto or attended with a new mode of operation as a whole, is included in the purview of the specific claim.

§ 51. Peculiar Combination.

If the generic combination be old and an inventor be the first to combine the same genera of the generic combination by means of combining mechanism differing from that previously used with the old generic combination, but attended with a new mode of operation, he is entitled to a claim that will secure to him the use of the combination of the genera by means of the peculiar combining mechanism used by him, and the combination is distinguished not only by the character of the generic devices but also by the peculiar mode of operation of the new combining mechanism by which the generic devices are combined. The claim should in such case recite not only the principal generic devices, but should also recite the combining mechanism either by name or by mention of the new mode of operation produced by it. In such

case the invention consists of the peculiar combination of two or more generic devices, and the claim is a peculiar one, which while it does not include the old generic combination of the principal devices nor new combinations of those generic devices by means of combining mechanism operating as the combining mechanism of the old generic combination did, has the legal effect of including within its purview subsequent new peculiar combinations having combining mechanism which produces substantially the same mode of operation as the combining mechanism of the claimed peculiar combination does, even though improved methods of operation be attained by the new subsequent combination.

§ 52. Particular Combination.

This last rule is sound with reference to new combinations of specific devices by means of particular combining mechanism not previously used in producing the combination of the same species of devices; and in such case the claimed combination is distinguished by the combined characteristics of the species of devices that are combined and of the combining mechanism. The claim in this case is a particularly restricted one, which should recite not only the principal specific devices, but should recite also the particular combining mechanism either by name or by mention of the particular mode of operation produced by it; and the claim is a particular one. Such a claim is generally very restricted in its purview; but if new and productive of a new collective mode of operation, is nevertheless entitled to include in its purview equivalents for the various devices required by its language.

§ 53. Four Classes of Combinations.

Combinations may therefore be classified as Generic, Specific, Peculiar, and Particular; and instances of these four classes are found in the history of every useful art.

§ 54. Instance of a Generic Combination.

In the history of the steam engine in the United States, the first cut-off valve which was used to cut off the supply of steam from the boiler to the cylinder before the stroke of the piston was completed, thereby permitting the steam between the cut-off valve and the piston to expand during the residue of the stroke, was a disc valve placed in the steam pipe and operated by a cam upon the engine shaft. This cut-off valve was supplementary to the ordinary steam valves of the cylinder, the cut-off valve being arranged between the boiler and the steam valves; and the cam was secured rigidly on the engine shaft, so that the cut-off of the steam was invariable, being generally effected at half the stroke of the piston. Here we have a combination of the steam cylinder, the cut-off valve, and means for operating the latter; and as this was the earliest combination of these three kinds or genera of members, it was a generic one, and the claim should have been broad enough in its purview to include every species and location of cut-off valve which was adapted to the work, and every species of operating means capable of operating the cut-off valve for the purpose required.

§ 55. Instance of a Specific Combination.

Subsequently, the mechanism for operating the cutoff valve was modified and was combined directly with the customary steam valves of the engine. This change

enabled each steam valve (which admitted steam to the steam cylinder) to do also the work of cutting off the supply of steam thereto at a fractional part of the stroke of the steam piston, and dispensed with the supplementary cut-off valve. The improvement was a valuable one, not only on account of the saving of the cost of the supplementary cut-off valve previously used, but also because the position of the cut-off valve, when it is also operated as the steam valve, is the closest possibleto the cylinder, so that there is the least possible quantity of steam additional to that in the steam cylinder to be expanded; and the economy is greater than with the previous supplementary cut-off valve. The cut-off mechanism in this case was invariable as with the first. of generic combination. The new combination consisted. of the steam cylinder, the steam valve, and the means. for so operating the latter as to cut off the supply of steam by its action; and the combination was a specific one. The claim in this case should have included in its purview every species of steam valve used as the cut-off valve, and every species of mechanism that could be combined with it so as to operate it as required to admit the steam and to cut off its supply from the boiler at a fractional part of the stroke of the piston.

§ 56. Instance of a Peculiar Combination.

Another step in the art was to make the device which operated the cut-off valve mechanism of such construction that its operation was variable, so that the cut-off could be adjusted to take place at any desired fractional part of the stroke of the piston. The combination then consisted of the steam cylinder, the cut-off valve, and the variable means for operating the latter with the