1. Claim 1 of the Smith Patent, No. 1,262,860, for a method for
the incubation of eggs, held valid, and infringed. P.
294 U. S. 7.
2. Claim 1 covers broadly the essential elements of the Smith
invention,
viz., (a) the arrangement of the eggs at
different levels in staged incubation in a closed chamber, having
restricted openings of sufficient capacity for the escape of foul
air without undue loss of moisture; (b) the application to the eggs
of heated air in a current created by means other than variation of
temperature, and (c), as marking the boundaries of the claim, a
sufficient velocity in the current to circulate and diffuse the air
and maintain it throughout the chamber at substantially the same
temperature, whereby the air will be vitalized, moisture conserved,
and the units of heat carried from the eggs in the more advanced
stage of incubation to those in a less advanced stage.
Held:
(1) The claim is not limited by the particular mode of use
described in the specifications, since the claims of the patent,
not its specifications, measure the invention. P.
294 U. S. 11.
(2) Examination of the claim in the light both of scientific
fact and of the particular form in which the inventor reduced it to
practice as described in the specifications makes it plain that the
claim does not require any particular order or arrangement of the
eggs in staged incubation in the incubator, or that the propelled
air current
Page 294 U. S. 2
should reach them in any particular order, or that it should be
guided, controlled, or directed by any particular means, or in any
particular manner other than that it should be of sufficient
velocity to produce the results prescribed by the claim. Pp.
294 U. S. 9,
294 U. S. 13.
(3) There is nothing in the file wrapper to suggest that any
addition was made to Claim 1 to restrict the patent to any
particular order of arrangement of the eggs or any particular
direction or means of control of the current of air, other than its
velocity, and nothing to estop the patentee from asserting that the
claim is not restricted by such features. P.
294 U. S. 14.
(4) The claim is not limited by the prior art. P.
294 U. S. 16.
(5) The invention as claimed was infringed by respondents'
apparatus in this case. P.
294 U. S. 18.
3. The fact that a claim broadly covering the essentials of an
invention omits particular means of application which are called
for by other claims is evidence that the broader claim was not
intended to be so restricted. P.
294 U. S. 13.
4. The inventor of a novel method of artificial incubation of
eggs, which solved the major problems of that art in a highly
efficient manner and was attended by great practical and commercial
success, is entitled to broad claims in his patent, and to a
liberal construction of them tending to secure to the patentee the
benefit of his invention, rather than to defeat the grant. P.
294 U. S. 14.
5. A broad claim is not to be given a restricted construction
because its allowance in the Patent Office followed the rejection
of narrow claims. P.
294 U. S. 16.
6. The invention of a combination is not anticipated by earlier
and impracticable experiments for the same end with isolated
elements of the combination. P.
294 U. S. 17.
70 F.2d 564 reversed.
Certiorari to review a decree reversing a decree of the District
Court and holding valid, but not infringed, a claim of a patent for
an improved apparatus and method for the incubation of eggs.
Page 294 U. S. 3
MR. JUSTICE STONE delivered the opinion of the Court.
Certiorari was granted to review a decree of the Circuit Court
of Appeals for the Eighth Circuit, 70 F.2d 564, which reversed the
decree of the District Court and held valid, but not infringed, the
first claim of the Smith patent, No. 1,262,860, of April 16, 1918,
for an improved apparatus and method for the incubation of eggs.
[
Footnote 1] The Court of
Appeals for the Ninth Circuit held the same claim valid and
infringed in
Waxham v. Smith, 70 F.2d 457, in which case
certiorari was also granted. The question thus presented is one of
the scope of the claim.
Only so much of the patent as relates to a method for incubation
is now involved. Correct appreciation of the contentions made
requires a brief exposition of the well known phenomena which
attend the incubation of eggs under natural conditions.
The period for hatching eggs of the domestic hen is twenty-one
days. The eggs are cold at the beginning of the period of
incubation, although at that time generation has already progressed
slightly. Continuation of this process and successful incubation
depend upon the
Page 294 U. S. 4
application of heat to the eggs, and the maintenance of their
temperature at not less than body heat, about 100� F. and not more
than 105� F. Any substantial divergence from this range of
temperature results in deterioration or death of the embryo, and
consequent failure of the hatching process. If the temperature is
maintained within this range, the eggs, during the first ten days
of the period, absorb heat required to generate and maintain the
life of the embryo. The eggs are then said to be endothermic, or
heat absorbing. From the eleventh day until the end of the period,
the embryo has developed to a point at which the egg generates more
heat than is needed to keep the embryo alive. They are then said to
be exothermic. From that time on, the excess heat is given off to
the surrounding air or to objects in contact with the eggs, if at a
lower temperature than the eggs.
The development of heat accompanies the oxidation of food
elements within the egg, in consequence of which it gives off
carbon dioxide during the period of incubation and absorbs oxygen
from the external air, both of which pass through the shell of the
egg and its lining membrane. During the period of incubation, there
is also gradual evaporation of moisture from the egg, which tends
to reduce its temperature slightly. The best results are obtained
if the total evaporation during incubation does not exceed about
15%. Evaporation in excess of that amount affects the embryo
adversely; the chick when hatched being undeveloped and lacking
normal strength.
Successful artificial incubation therefore involves conformity
to three principal requisites: the maintenance of proper
temperature during the period of incubation, the prevention of
excessive evaporation of moisture, and the supply of an adequate
amount of oxygen, which involves also the removal from the
incubator of the carbon dioxide which results from oxidation of the
contents of the egg.
Page 294 U. S. 5
The artificial incubation of eggs is an ancient art. It appears
to have been known to the Egyptians two thousand years ago, and for
a comparable period to the Chinese. Until Smith, the patentee,
carried on his experiments, the effort had been generally to
reproduce as nearly as practicable the natural conditions of
incubation. In practice, eggs, in relatively small numbers, seldom
more than 300, and usually less, were placed on the same level in a
cabinet with heating means above the eggs, so that the temperature
above the eggs was maintained at a higher point -- about 103� F. --
than that below. To secure the requisite exposure of the eggs to
the higher temperature, it was necessary in the course of
incubation to turn the eggs frequently, as is done by the hen in
nature. Provision was made for supplying fresh air to the cabinet
and for humidifying the air within the cabinet. All incubators were
of the still air type -- that is to say, the only movement of air
within the incubator was that caused by variations of temperature
at different points within the cabinet, resulting in some
transmission of heat by radiation or convection. The opinion seems
to have prevailed that the presence of currents of air either
within or surrounding the cabinet was harmful. Successful operation
of this method required nice adjustments of the heating means so as
to avoid overheating as the eggs passed into the more advanced
stages of incubation, reaching their highest temperature about the
seventeenth day.
Smith, conceived the idea, embodied in his patent, of setting
the eggs in staged incubation within the cabinet and applying to
them, in convenient arrangement for that purpose, a current of
heated air, propelled by means other than convection. Staged
incubation is the successive setting of eggs in the same cabinet at
brief intervals of about three days. At the twenty-first day. there
would thus be several settings of eggs in the incubator, each at a
different stage of incubation, part in the endothermic
Page 294 U. S. 6
stage and part in the exothermic. Smith arranged the egg trays
or racks in tiers so that air could be freely circulated among the
eggs. He subjected them to a continuous current of air of the
requisite constant temperature of about 100� F. propelled by a fan
so that it would circulate freely and repeatedly throughout the
cabinet. The heat of the eggs in the later stages of incubation was
thus carried by the circulating air of lower temperature to the
cooler eggs in the earlier stages, so that there was a continuous
tendency to equalize the temperature throughout the cabinet at
approximately the temperature of the introduced current of air.
Before Smith, there had been efforts to set eggs in staged
incubation, but without practical success because of the
difficulties of securing adequate heat distribution within the
incubator. He was the first to apply mechanically circulated
currents of air to eggs so arranged. He followed this procedure in
conjunction with the use of a restricted opening for the
elimination of foul air. By this combination, the difference in
temperature of the eggs was equalized within the desired range
throughout the incubator during the period of incubation, the air
within the incubator was gradually replaced by fresh air, and the
moisture of the eggs was conserved. His method thus solved the
major problems of artificial incubation in a highly efficient
manner. It was novel, and involved invention.
See The Barbed
Wire Patent Case, 143 U. S. 275,
143 U. S. 283;
Krementz v. S. Cottle Co., 148 U.
S. 556,
148 U. S.
559-560.
That it was invention is not seriously disputed here, and, of
the many courts which have passed on the patent, none has denied
its validity. The new method had certain marked advantages over
earlier ones. It was possible to carry on the process of incubation
continuously by placing fresh eggs in the incubator at intervals as
those of the most advanced stage hatched and the new-born chicks
were removed. It was possible to apply
Page 294 U. S. 7
heated air to the eggs at a constant temperature, thus avoiding
the necessity of varying by nice adjustments the temperature of the
applied air, so as to conform to the varying temperatures of the
eggs as they passed through successive stages of incubation. As the
egg racks or trays could be placed in tiers, instead of on a single
level, it was possible to arrange them more compactly, and greatly
increase the number of eggs in a single incubator. Before staged
incubation as developed by Smith, it had not been practicable to
operate incubators of a capacity of more than about 300 eggs. By
use of the new method, it is possible to operate successfully an
incubator containing as many as 52,000 eggs, and the%age of eggs
successfully hatched by artificial incubation has been materially
raised.
The commercial success of the new method was immediate and
striking. At first, the inventor devoted himself to developing his
own hatchery for the use of the new method; it was the largest in
existence, with a capacity of over 1,000,000 eggs. In 1922, he
began the manufacture and sale of the new incubator.
In ten years he, and a corporation which he had organized for
the purpose, had made sales of incubators aggregating about
$24,000,000, having a total egg capacity of over 188,000,000. The
old type of incubation, with eggs arranged at a single level, all
in a single stage of incubation, has thus become obsolete.
That the method employed in the Smith type of incubator was
novel and revolutionary in the industry is not challenged. The
question presented here is what scope may rightly be given to Claim
1 of the patent; whether the petitioner has drafted it in such form
as to secure the fruits of his invention? Claim 1 reads as
follows:
"1. The method of hatching a plurality of eggs by arranging them
at different levels in a closed chamber having restricted openings
of sufficient capacity for the escape
Page 294 U. S. 8
of foul air without undue loss of moisture and applying a
current of heated air, said current being created by means other
than variations of temperature and of sufficient velocity to
circulate, diffuse, and maintain the air throughout the chamber at
substantially the same temperature, whereby the air will be
vitalized, the moisture conserved, and the units of heat will be
carried from the eggs in the more advanced stage of incubation to
those in a less advanced stage for the purpose specified."
It will be observed that the claim, standing by itself, asserts
the essential elements of the method of incubation to be: (a) the
arrangement of the eggs at different levels in staged incubation in
a closed chamber, having restricted openings of sufficient capacity
for the escape of foul air without undue loss of moisture; (b) the
application to the eggs of heated air in a current created by means
other than variation of temperature, and (c) as marking the
boundaries of the claim, the current of air is to be of sufficient
velocity to circulate, diffuse, and maintain the air throughout the
chamber at substantially the same temperature whereby the air will
be vitalized, moisture conserved, and the units of heat carried
from the eggs in the more advanced stage to those in the less
advanced.
To avoid petitioner's charge of infringement, two main
contentions are pressed by respondents: first, that Claim 1 is
restricted to an arrangement of the eggs in such order with respect
to the direction of the propelled current of heated air that it
will first come in contact with the more advanced eggs. Thus,
construed, respondents do not infringe, as concededly the movement
of air within their incubator does not pass to the eggs in staged
incubation in any particular order. Second, that the movement of
air in respondents' incubator, produced by the agitating action of
fans or propellers, does not result in "a current of air" traveling
in a constant predestined path within the meaning of Claim 1. In
passing upon these contentions,
Page 294 U. S. 9
it is necessary to ascertain the proper scope of Claim 1 and to
determine whether the characteristic features of respondents'
incubator come within its scope. Respondents maintain that the
claim is restricted in its scope in the manner indicated above (a)
by the disclosures of the patent itself, (b) by the prior art,
including the patentee Smith's own prior public usage, and (c) by
estoppels arising from the file wrapper record of the patent.
1. The court below rested its decision on its interpretation of
Claim 1, read in the light of the disclosures of the patent, as
restricting the patented method to a particular arrangement of the
eggs whereby the current of heated air, after being introduced into
the cabinet, first comes in contact with the eggs in the most
advanced stage of incubation. It reached this conclusion by
comparison of that part of the claim, which speaks of the units of
heat as being "carried from the eggs in the more advanced stage of
incubation to those in a less advanced stage," with the
specifications, which disclose an arrangement of the eggs such that
the introduced current of heated air first passes to the more
advanced eggs. As respondents' incubators have no such arrangement
of the eggs, and as, in consequence, the forced draft of heated air
does not reach the eggs in any particular order, the court held
that the respondents do not infringe Claim 1.
The patentee, obedient to the command of the statute (R.S. §
4888), gave such description of the manner of using his discovery
as would enable others skilled in the art to use it. The
specifications first describe generally the method by which the
eggs in staged incubation are arranged in tiers and subjected to
forced circulation of heated air through the incubating chamber.
The patent states:
"The temperature of circulating air should be such as will
prevent the eggs in the early stage of incubation from falling
below 100�, and the speed or velocity of the circulating air should
be such as to carry the heat
Page 294 U. S. 10
away from the eggs in the later stage of incubation, and thereby
hold the temperature of those eggs at 105� or slightly below that.
It is manifest that the temperature will remain practically the
same throughout the column of eggs, but the air is impelled with
sufficient velocity to carry the heat away from the eggs which
happen to be in the advanced stage of incubation."
The drawings and specifications show the eggs arranged in tiers
on either side of the chamber, with an open space or corridor
between at the top of which a revolving fan forces the air downward
in the open space of the corridor. Above the fan is a valve
controlled air intake for the introduction of fresh air, and above
the trays of eggs on either side are shown "outlets for the release
of foul air . . . of such restricted capacity as to prevent the
undue escape of moisture."
It is true that drawings and specifications indicate a
particular arrangement of the eggs from the top to the bottom of
the tiers of trays, according to the stage of the incubating
process, the eggs being arranged progressively from the least
advanced, placed at the top, to the most advanced, placed at the
bottom of the tiers. They indicate also that, as the eggs most
advanced are hatched, they are to be replaced by moving downward
the trays containing the several successive settings of eggs which
are in earlier stages of incubation. They also speak of a "column"
of air of such speed as to keep the temperature substantially
uniform, and show curtains hanging from the top of the chamber
covering the ends of the trays on either side of the corridor and
extending to a point a short distance above the floor.
With this arrangement, the air would be propelled downward to
the floor of the chamber, gaining access to the eggs by passing
beneath the ends of the curtains to the trays of eggs at the bottom
of the tiers. So much of the air as was introduced through the
intake would thus reach
Page 294 U. S. 11
the more advanced eggs first. It would then be deflected upward
through the egg trays to the top of the chamber, and so much of it
as did not pass out through the restricted capacity outlets located
at the top of the tiers of trays would be returned to the fan to be
propelled again through the described circuit.
We may take it that, as the statute requires, the specifications
just detailed show a way of using the inventor's method, and that
he conceived that particular way described was the best one. But he
is not confined to that particular mode of use, since the claims of
the patent, not its specifications, measure the invention.
Paper Bag Patent Case, 210 U. S. 405,
210 U. S. 419;
McCarty v. Lehigh Valley R. Co., 160 U.
S. 110,
160 U. S. 116;
Winans v.
Denmead, 15 How. 330,
56 U. S. 343.
While the claims of a patent may incorporate the specifications or
drawings by reference,
see Snow v. Lake Shore R. Co.,
121 U. S. 617,
121 U. S. 630,
and thus limit the patent to the form described in the
specifications, it is not necessary to embrace in the claims or
describe in the specifications all possible forms in which the
claimed principle may be reduced to practice. It is enough that the
principle claimed is exemplified by a written description of it and
of the manner of using it "in such full, clear, concise, and exact
terms" as will enable one "skilled in the art to make, construct,
compound and use the same."
Here, the specifications showed an arrangement of the eggs and a
means of guiding the current of air so that it would reach the most
advanced eggs first. But neither the arrangement nor the means of
guiding the current of air are requisite to the application of the
principle which Smith discovered and claimed. Without either, the
heated air may be given, as Claim 1 prescribes,
"sufficient velocity to circulate, diffuse, and maintain the air
throughout the chamber at substantially the same temperature
whereby . . . the units of heat will be carried
Page 294 U. S. 12
from the eggs in the more advanced stage of incubation to those
in a less advanced stage."
Claim 1 made no mention of curtains or any column of air or
means of guiding the current of air, and the inventor made no claim
for any particular arrangement of the eggs, except that they should
be at different levels. Moreover, while the specifications and
drawings show a particular arrangement of the eggs and a particular
direction of the current, nowhere, in specifications or claim, is
it stated either that the direction of the current is material or,
what is the equivalent, that the order in which it reaches the eggs
is material.
Only by resort to the assumption that heat units could not be
carried from the more advanced to the cooler and less advanced eggs
unless the initially introduced air first came in contact with the
more advanced is it possible to support the conclusion of the court
below, and read the claim as calling for a particular arrangement
which would enable the air current to reach the advanced eggs
first. Such, of course, would be the case only if the current of
air were to make a single circuit, and either remain at its end in
contact with the cooler eggs or pass out of the incubator
altogether. Neither occurs in petitioner's machine, and there is no
reason to suppose that either would produce the desired
equalization of temperature. The specifications and claim both
contemplate a continuous circulation of the current of heated air
through the chamber, which, regardless of its direction, would
continuously operate, by repeated contacts with the eggs in all
stages, to equalize the temperature throughout the chamber by
carrying heat units from the warmer to the cooler eggs.
The claim conforms to the specifications in prescribing
"restricted openings of sufficient capacity for the escape of foul
air without undue loss of moisture." The amount of foul air allowed
to escape through the outlet of restricted capacity necessarily
controls the amount of
Page 294 U. S. 13
air taken in. In petitioner's commercial machines, regulated to
produce the prescribed result in air vitalization and conservation
of moisture, the interchange of foul air for fresh is from 1/2 to
1% to 3% of the air content for each complete circuit of the
chamber. This means that the air content of the chamber must make
the circuit many times, theoretically from 33 to 200, before an
equal volume of fresh air would be drawn in through the intake.
Such continuous circulation of the air at constant temperature,
lower than that of the more advanced eggs and higher than that of
the less advanced, tends to produce the equalization of the
temperature of the eggs by flow of heat units from the warmer eggs
to the cooler, regardless of the direction of the current in the
circuit and regardless of the particular stage of the eggs which it
reaches first. With other factors constant, the efficiency of this
equalization process would depend upon the velocity of the current.
The statement of Claim 1 is that the current of air is to be "of
sufficient velocity to circulate, diffuse and maintain the air
throughout the chamber at substantially the same temperature." The
specifications state:
"It is obvious that the fans can be so arranged and can be
operated at such speed as to cause the hot air to circulate fast
enough to keep the temperature throughout the chamber between the
limits of 100� and 105�."
It is evident that Claim 1 does not prescribe that the current
of air shall be propelled by any particular means, except that it
shall be by means other than variation of temperature, nor does it
prescribe that the means of propulsion shall be given any
particular location, or that the current of air shall be guided by
any particular means or given any particular direction. The
omission of these requirements from Claim 1 is the more pointed as
the other claims of the patent speak in particular of a
power-driven fan, of the location of the fan, of curtains and a
partition obviously intended to give direction to the current
Page 294 U. S. 14
of air, of a vertically directed current of air, and of air
circulating from the bottom of the chamber into the parts of it
occupied by the tiers of egg trays. Thus, by striking and obviously
intended contrast with other claims, Claim 1 covers broadly the
essential elements of the Smith invention as we have already
described it.
Symington Co. v. National Malleable Castings
Co., 250 U. S. 383,
250 U. S. 385;
Lamson Consolidated Store Service Co. v. Hillman, 123 F.
416, 419;
Wm. B. Scaife & Sons Co. v. Falls City Woolen
Mills, 209 F. 210, 214.
Examination of the claim in the light both of scientific fact
and of the particular form in which the petitioner reduced the
claim to practice as described in the specifications makes it plain
that the claim does not call for a particular order or arrangement
of the eggs in staged incubation in the incubator, or that the
propelled current should reach them in any particular order, or
that it should be guided, controlled, or directed by any particular
means or in any particular manner other than that it should be of
sufficient velocity to produce the results prescribed by the claim.
If the matter were doubtful, it is plain from what has been said
that the character of the patent and its commercial and practical
success are such as to entitle the inventor to broad claims and to
a liberal construction of those which he has made.
Morley
Sewing Machine Co. v. Lancaster, 129 U.
S. 263,
129 U. S.
273-277;
Eibel Process Co. v. Minnesota & O.
Paper Co., 261 U. S. 45,
261 U. S. 63;
Winans v. Denmead, supra, 56 U. S. 341.
In such circumstances, if the claim were fairly susceptible of two
constructions, that should be adopted which will secure to the
patentee his actual invention, rather than to adopt a construction
fatal to the grant,
Keystone Manufacturing Co. v. Adams,
151 U. S. 139,
151 U. S.
144-145;
McClain v. Ortmayer, 141 U.
S. 419,
141 U. S.
425.
2. We find nothing in the file wrapper defense to disturb our
conclusion as to the correct interpretation of Claim 1. It is a
familiar rule that a patentee cannot
Page 294 U. S. 15
broaden his claim by dropping from it an element which he was
compelled to add in order to secure his patent.
I.T.S. Rubber
Co. v. Essex Rubber Co., 272 U. S. 429,
272 U. S. 443;
Smith v. Magic City Kennel Club, 282 U.
S. 784,
282 U. S.
789-790. But the file wrapper lends no support for the
application of this rule to petitioner's Claim 1.
The history of Smith's application in the Patent Office is a
long one. Four groups of method claims were successively presented
to the Patent Office, and three were successively rejected. The
fourth group ultimately matured into Claims 1, 2 and 3 of the
patent. It suffices to say that Claims 1 and 25 of the first group
claimed broadly,
"The method of hatching eggs by arranging the eggs in a column
and applying heated air forced about the eggs, the heated air being
adapted to the eggs in various stages of incubation,"
and "The method of hatching eggs by arranging the eggs in a
column one above the other and forcing heated air through said
column." In due course, the broad claims thus asserted were
modified and narrowed by the inclusion of new elements, until they
appeared in the form of Claim 1 of the patent. But, as we have
seen, none of these additions involves any particular order of
arrangement of the eggs or any particular direction or control of
the air current, except that the current is to be "of sufficient
velocity to circulate, diffuse and maintain the air throughout the
chamber at substantially the same temperature."
It is an illuminating fact that the entire written argument
filed in support of Claim 1, as it was finally presented to the
Patent Office and allowed, makes no reference to any order or
arrangement of the eggs, or to shifting the location of the eggs in
the incubator, no reference to the location of the fan, the
direction of the air current, or to curtains or partitions. The
features emphasized were the superiority, over drafts caused by
variations of temperature, of "current produced by mechanical
Page 294 U. S. 16
means" applied to eggs in staged incubation arranged at
different levels, the conservation of moisture, and the elimination
of foul air by the restricted air outlets, all features of Claim 1
which are characteristic of both petitioner's and respondents'
incubators. We find nothing in the file wrapper to suggest that any
addition was made to Claim 1 to restrict the patent to any
particular order of arrangement of the eggs or any particular
direction or means of control of the current of air, other than its
velocity, and nothing to estop the patentee from asserting that the
claim is not restricted by such features.
See Baltzley v.
Spengler Loomis Mfg. Co., 262 F. 423, 426;
National Hollow
B.-B. Co. v. Interchangeable B.-B. Co., 106 F. 693, 714. It is
of no moment that, in the course of the proceedings in the Patent
Office, the rejection of narrow claims was followed by the
allowance of the broader Claim 1.
Westinghouse Electric &
Mfg. Co. v. Condit Electrical Mfg. Co., 194 F. 427, 430.
3. Claim 1 is not limited by the prior art. It is urged that
there was disclosure by Smith by public use more than two years
before his application for the patent. At the time indicated, he
used commercially an incubator arranged in three completely
separated compartments, in each of which there was circulation of
the air by a fan. But there was no staged incubation in any single
compartment.
The German patent, Stulik, No. 155,917, issued in 1901,
disclosed the arrangement of trays of eggs in staged incubation in
an enclosed column or stack, with the endothermic eggs at the
bottom. The eggs were subjected to a rising column of heated air,
which was allowed to escape at the top of the chimney. There was no
forced draft of air, no circulation or recirculation of air, and,
in consequence, no carrying of heat units from the more advanced
eggs at the top to the less advanced eggs at the bottom.
Page 294 U. S. 17
Other patents named, as Winkler, No. 286,756, of 1883, and
Zimmer, No. 1,075,747, of 1913, show types of staged incubation,
but made no use of a current of air propelled by means other than
variations of temperature, and in other respects were so plainly
impractical as to call for no extended discussion. This is true
also of the description in the 1867 edition of Ure's Dictionary,
652, 653, said to represent a method of incubation devised in 1777
by Bonnemain, a Frenchman, and not used since the French
Revolution, by which eggs in staged incubation were placed in a
closed room heated by hot-water pipes, but without other means of
producing currents of air. Such rudimentary experiments with
isolated elements of Smith's combination did not anticipate his
invention.
See Smith & Griggs Mfg. Co. v. Sprague,
123 U. S. 249,
123 U. S.
255.
Other patents are cited showing varying types of incubators in
which the eggs were placed at different levels, but in which the
circulation of air through the incubating chamber by means other
than variations in temperature is wanting. [
Footnote 2]
The Proctor & Knowles patent, No. 426,321 of 1890, and the
Schwartz patent, No. 535, 175 of 1895, for methods and apparatus
for conditioning tobacco and other materials, as well as other
procedures for ventilation, are so remote from the problems and
procedure for hatching eggs as to call for no comment.
This history of the prior art serves to emphasize, rather than
to discredit, the striking advance made by Smith in effecting the
combination defined in Claim 1. More than the skill of the art was
involved in combining and adjusting its elements in such fashion as
to solve the major problems
Page 294 U. S. 18
of artificial incubation. The prior art discloses no application
of a continuously circulating current of air to eggs in staged
incubation which would restrict Claim 1 with respect either to the
arrangement of the eggs or the direction or control of the current
of air.
4. There remains the question of infringement. The respondents'
machine exhibits a closed chamber, with restricted outlet for the
escape of foul air and an intake for fresh air, with eggs arranged
at different levels in staged incubation, with a fan-impelled
movement of air which circulates and recirculates throughout the
chamber. The air moves over and about the eggs, carrying the units
of heat from the warmer to the cooler eggs, maintains a
substantially uniform temperature throughout the chamber, vitalizes
the air, and conserves moisture.
As Claim 1 of petitioner's patent is not restricted to any
particular order in which the current of air reaches the eggs,
respondents do not avoid infringement by interspersing
indiscriminately, as they do, the trays of eggs in different stages
of incubation. Respondents' claim of noninfringement is thus
reduced to the contention that their incubators do not employ
circulating currents of air called for by Claim 1. Their emphasis
is on the agitation of air in respondents' machine in such a manner
that its movement does not follow defined paths through the
chamber, so as to answer to the description "current of air."
In respondent's machine, fans or air propellers are located at
either side of the chamber, about midway of its height, near the
wall and between the wall and tiers of egg trays. They are
constructed and operated in such fashion that the air is "drawn" by
their action from the central corridor through the tiers of eggs
toward the center of the propellers. There, by the centrifugal
action of the propellers, it is thrown off the ends of the
propeller blades toward the top, bottom, and adjacent ends of the
chamber. There, it is deflected by ceiling, floor, and ends
Page 294 U. S. 19
of the chamber into the corridor, from whence it is, in due
course, again drawn through the tiers of eggs to the propellers.
The propellers are operated, and the air moves, continuously. Since
the main movement of the air at the top and bottom of the tiers is
toward the center corridor, and since the fans draw in air through
the middle of the tiers, there are points in the space occupied by
the tiers where the movement of the air is toward the corridor
until it joins and is turned back by the current moving toward the
propellers.
Claim 1, as already stated, does not call for a current of air
moving in any particular direction. Assuming, without deciding,
that it calls for a current of air so constant in its movement and
direction as not to depart substantially from a well defined path,
one would expect that a fan operating, as in respondents' machine,
within a closed chamber under substantially constant conditions
would produce currents of air without substantial variations of
path. No valid scientific reason or explanation is advanced for any
different result. Extensive testimony and elaborate arguments are
presented to support the contention that, notwithstanding the
application of force to the air within the closed chamber by the
action of respondents' propellers, under practically constant
conditions, the results produced are so variable that "the air goes
where it
listeth;'" they are not convincing. The conclusion is
abundantly supported by evidence that there is a continuous
movement of air from the blades of respondents' propellers toward
the top and bottom and sides of the chamber, thence to the
corridor, and thence through the tiers of egg trays back to the
propellers, and that this movement achieves the purpose declared in
Claim 1, "to circulate, diffuse and maintain the air throughout the
chamber at substantially the same temperature." The trial judge so
found.
That there is a mixture of the air and some confusion of its
movement in the corridor, and that, at different
Page 294 U. S. 20
levels within the space occupied by the tiers of trays, the
movement is not in the same direction is immaterial. It is enough
that there is a movement of air in current form following
substantially defined paths through the tiers of egg trays
sufficient to effect the desired transfer of heat units. Claim 1
does not prescribe that a current of air is to be maintained
throughout the chamber. It calls for the application to the eggs of
a current of air "of sufficient velocity to circulate, diffuse, and
maintain the air throughout the chamber at substantially the same
temperature." This respondents accomplish by the currents of air
set in motion either directly or indirectly by the movement of the
blades of the propellers. The method is that of Smith. Respondents
do not avoid infringement of the method by varying the details of
the apparatus by which they make use of it.
Cochrane v.
Deener, 94 U. S. 780,
94 U. S. 788;
Tilghman v. Proctor, 102 U. S. 707,
102 U. S.
730-731.
Reversed.
[
Footnote 1]
The patent has been extensively litigated. Claim 1 has been held
valid and infringed in
Buckeye Incubator Co. v. Wolf, 291
F. 253,
aff'd, 296 F. 680;
Buckeye Incubator Co. v.
Cooley, 17 F.2d 453;
Miller Hatcheries, Inc. v. Buckeye
Incubator Co., 41 F.2d 619;
Smith v. Jensma, 1 F.
Supp. 999;
Waxham v. Smith, 70 F.2d 457. It has been held
valid, but not infringed, in
Buckeye Incubator Co. v.
Blum, 17 F.2d
456,
aff'd, 27 F.2d 333;
Buckeye Incubator Co. v.
Petersime, 19 F.2d 721;
Buckeye Incubator Co. v.
Hillpot, 22 F.2d 855,
aff'd, 24 F.2d 341;
Boling
v. Buckeye Incubator Co., 33 F.2d 347,
reversed on other
grounds, 46 F.2d 965;
Snow v. Smith, 70 F.2d 564.
[
Footnote 2]
Guerin, United States patent, No. 3,019, March 30, 1843; Bassini
& Heyden, United States patent, No. 330,457, November 17, 1885;
Van Keuren, United States patent, No. 1, 160,793, November 16,
1915; Bell, United States patent, No. 691,837, January 28, 1902;
Koons, United States patent, No. 916, 454, March 30, 1909.