1. Asa Whitney's patent of April 25, 1848, for an "improvement
in the process of manufacturing cast iron railroad wheels," was for
a process, not for a combination.
2. Where only vague and uncertain directions could be given as
to the degree of foreign heat to be applied in any particular case,
there, when a patentee in his specification, establishes a
maximum and a
minimum, the ascertainment of the
proper intermediate degree may be left to the skill and judgment of
the operator practicing the process.
3. It is as true of a process, invented as an improvement in a
manufacture, as it is of an improvement in a machine that an
infringer is not liable to the extent of his entire profits in the
manufacture.
4. In such a case, the question to be determined is what
advantage did the infringer derive from using the invention over
what he had in using other processes then open to the public and
adequate to enable him to obtain an equally beneficial result? The
fruits of that advantage are his profits, and that advantage is the
measure of profits to be accounted for.
5. When a patent is for an entire process made up of several
constituent steps or stages, the patentee not pretending to be the
inventor of those constituents, his claim to the process as an
entirety does not secure to him the exclusive use of the
constituents singly. What is secured is their use when arranged in
the process.
6. The profits recoverable from an infringer are the measure of
the patentee's
Page 81 U. S. 621
damages, and though called
profits, are really damages,
and unliquidated until a final decree is made.
7. Interest upon unliquidated damages is not generally
allowable, and should not be alloyed before a final decree for
profits.
Appeal from the Circuit Court for the Southern District of Ohio;
the suit being a bill by Whitney for an alleged infringement by
Mowry, of a patent which Whitney had for an improvement in the
process of making wheels for railcars. The case was thus:
Wheels for rail cars require to be made in a special way. The
"tread" of the wheel, as it is commonly called -- that is to say,
the periphery -- the surface which runs over the rail -- must be
very hard, or else it will wear out. On the other hand, the
interior portions of the wheel, especially the hub, against which
there is no friction, but on which there is great strain, need not
be so hard, but must be very tough. Now here are requisites which
by a law of the metal do not coexist in the same casting. Iron can
be very hard only when it exists in a state of
laminated
crystallization, and then it is brittle. It can be very tough only
when it exists in a state of
granulated crystallization,
and then it is soft. Now how is the "tread" to be made very hard
and the interior very tough? This was the first problem in regard
to iron car wheels. And it was thus solved. It had been long
observed that where molten iron was cooled
suddenly, it
came out solid in the laminated or hard and brittle form, but when
cooled slowly it came out solid in the tough and softer form.
The problem, of course, then was to cool rapidly the part of the
melted mass of iron which was to make the "tread" of the wheel, and
to cool more slowly the rest which was to make the interior of the
wheel -- that is to say, the spokes and hub. To do this, the moulds
into which the molten iron was to be cast were made of sand,
surrounded by a circle of iron; this circle, called in the
manufacturer's language a "chill." Iron being a rapid conductor of
heat and sand a slow one, the part of the molten mass which came
against
Page 81 U. S. 622
the iron or chill -- the part, in other words, of the molten
mass which was to form the tread -- was cooled rapidly and came out
in the laminated and
hard (though brittle) form, while the
parts of the wheel nearer to the hub, and especially the hub itself
(which is a very thick part of the wheel, and where a very great
strain is put when the rail car is in motion), cooling slowly, the
requisite toughness was obtained, through
this part (and
particularly the hub, owing to the greater mass of it) coming out
in the granulated and tough (though soft) form. The cut below,
which represents a piece fractured from off that part of the wheel
including the flange, which runs over the rail, indicates the two
forms. The lower part or chilled "tread" (which in the ordinary car
wheel itself is about half an inch deep) being distinguished by its
laminated crystallizations and light gray color, and the upper part
which runs in the direction of the hub by its granular
crystallization, and a deeper gray line.
image:a
This problem, therefore -- the problem of obtaining a
hard tread, and a tough interior and hub -- was solved. The thing
desired was attained through the process of a sand mould with an
iron "chill."
But of this good result in one way, a very bad one in another
was the consequence. The wheels had no strength. And here was the
cause. A mass of iron in its molten state
Page 81 U. S. 623
is larger than the same mass of iron when cold. Now here the
molten iron was poured into the mould at the hub. Thence it flowed
out through the sand mould of the spokes to the tread. There it
came in contact with the chill, and as soon as it touched the
chill, it was cooled, crystallized, and reduced in volume almost
instantly. The metal immediately behind it, on the contrary, being
in contact with the sand, parted with its heat more slowly and
remained in a fluid or semi-fluid state much longer. Thus it
happened that the periphery of the tread cooling and shrinking
first, reduced its diameter, while the hub and spokes remaining in
a fluid or soft state, presented little or no resistance to the
contraction of the tread or rim. But as these spokes and
image:b
hub subsequently parted with their heat and passed into the
solid state, an inherent strain began to be exerted between the rim
and hub. The spokes were too short. Restoration of so much of their
length as had been diminished by the
Page 81 U. S. 624
prior cooling and shrinking of the rim was demanded. All parts
of the wheel having passed into the solid state and become
comparatively unelastic, the spokes were severed by mere tensile
strain before the temperature of the whole mass was reduced to that
of the atmosphere. And the same result followed when, instead of
spokes, disks or plates were used on the sides of the wheel, as
shown in Figure 3.
To obviate this effect, a rude practice was, on the one hand, to
uncover and expose to the air the thick parts of the wheel,
sometimes, in addition, pouring cold water on them, while on the
other the thin portions would be covered with burning fuel or hot
sand. Still, however, the wheel would always strain and usually
break.
The great matter now was to remove this difficulty. One plan was
to divide the
hub into sections, as shown in Figures 2 and
3, instead of casting it solid. This, of course, relieved the
spokes from the tensile strain they were subjected to when
connected with the solid hub, the spokes connected with each of the
sections being left comparatively free to contract in length (only,
however, it may be added) by carrying the section of hub to which
they were attached with them.
To restore the requisite
strength to the hub, the
spaces between these sections would be subsequently filled with
pieces of metal of the exact size of the spaces, and wrought iron
bands would be shrunk on to each end of the hub so as to hold
firmly together all the sections and the metal fillings or plates
between them. Figure 4 illustrates the metal fillings or plates and
bands that would be put into and on the hubs.
image:c
Wheels of this description were used till 1840. At that date,
our roads began to be made more substantial, and higher velocities
upon them being demanded, the cast
spoke-wheel, thus
filled out at the hub, began to show great defects. The expense of
filling the spaces between the sections was considerable. There was
difficulty in putting the
Page 81 U. S. 625
wrought iron bands on the ends of the hub and of boring out the
divided hub so as to make it fit well on the axle and to secure it
from becoming loose. Yet if these things were not effectually done,
the wheel broke or changed its position on the axle, and the cars
were thrown from the track.
image:d
To avoid these difficulties other means were employed to
compensate for the unequal cooling and shrinking of the parts.
These were nearly all confined to making the hub solid and
connecting the hub and rim by a disk or plate, which was generally
made double, two plates extending from hub to rim, in form convex,
as in Fig. 5, or otherwise curved, so as to be susceptible, as was
supposed, of contracting or expanding in diameter as much as would
be required by the unequal cooling and contraction before noticed.
In one of these forms, the hub was also divided, as shown in Fig.
5, it being expected that with the shrinking of the outer disks it
would about close up. These wheels, when skillfully made, were an
improvement on the spoke-wheel, with the hub divided into sections,
so far as safety was concerned, but they were still faulty.
What, in this obviously not yet perfect art of making cast iron
car wheels, was wanted was some way to make such wheels, having a
solid hub, and either
spokes, or any desired form of
plates, single or double, straight or curved, as
represented in Figs. 6 and 7 below, and possessing all the
requisites of durability and strength in the respective parts, and
yet free from the defects which had attended, up to this time, all
wheels yet made, and not requiring the expenditure of special labor
upon the mould or pattern before casting, nor upon the finishing of
the wheel for use, after it had been cast and cooled -- some new
and effective device which should eradicate and annihilate the
difficulties which have been already imperfectly described, and
which were still baffling manufacturers and inventors in this art.
A new process of
Page 81 U. S. 626
prolonging the time of cooling, in connection with
annealing wheels would, if rightly conceived, secure the desired
end.
image:e
It was in this state of the art and of its necessity that
Whitney made a claim for what he called "a new and useful
improvement in the process of manufacturing cast iron railroad
wheels," and on the 25th of April, 1848, obtained a patent for it
for fourteen years.
The specification in his patent was thus:
"My improvement consists in taking railroad wheels from the
moulds in which they are ordinarily cast as soon after being cast
as they are sufficiently cool to be strong enough to move with
safety, or before they have become so much cooled as to produce any
considerable inherent strain between the thin and thick parts, and
putting them in this state into a furnace or chamber that has been
previously heated to a temperature as high as that of the wheels
when taken from the moulds. As soon as they are deposited in this
furnace or chamber, the opening through which they have been passed
is closed and the temperature of the furnace or chamber, and its
contents, gradually raised to a point
a little below that at
which fusion commences,
Page 81 U. S. 627
when all the avenues to and from the interior are closed and the
whole mass left to cool no faster than the heat it contains
permeates through, and radiates from the exterior surface of the
materials of which it is composed. By this process, all parts of
each wheel are raised to the same temperature, and the heat they
contain can only pass off through the medium of the confined
atmosphere that intervenes between them and the walls of the
furnace or chamber; consequently the thinnest and thickest parts
cool and shrink simultaneously together, which relieves them from
all inherent strain whatever when cold."
"The figure below represents a vertical cross-section of the
FURNACE OF CHAMBER, wherein is shown a pile of wheels as they"
image:f
"are placed to be annealed. The cover of the furnace, being
movable, is raised when the wheels are put in, and then closed and
covered with earth to prevent the too rapid escape of the heat. The
damper in the flue leading to the chimney is also closed after the
wheels are put into the furnace and the opening in the lower wall
stopped by an iron plate banked with earth, which prevents the
escape of the heat in that direction. [
Footnote 1] "
Page 81 U. S. 628
"To heat this furnace, I have used anthracite coal, it requiring
less than one-fourth of a ton to anneal two tons of wheels. The
heat required to perform the process may, however, be obtained by
the use of any other fuel that may be less expensive at the place
where the process is to be performed, or the requisite heat may be
taken in a suitable conduit from the furnace in which the metal is
melted from which the wheels are made, after it has performed that
office, to the chamber in which the annealing process is to be
performed. In either case, however, the furnace or chamber must be
made of such form, and have such appendages connected with it, as
to enable the operator to control the quantity and intensity of the
heat used by admitting more or less of it into the chamber, and of
excluding it entirely."
"The advantages resulting from the process of prolonging the
cooling and annealing as above described are that the wheels may be
made much stronger, when made of the same weight, than they can be
when cast and cooled in the ordinary manner, and railroad wheels
having any form of spokes or disks connecting the rim and hub, if
subjected to this process, will not require their hubs to be cast
in sections and the spaces between the sections subsequently filled
with some suitable metal and wrought bands put on to the hub."
"Wheels subjected to this process of cooling and annealing will
be stronger without bands on their hubs than those of the same
weight cast and cooled in the ordinary way having the wrought iron
bands on. In this way, the original cost is diminished and the
wheels rendered more durable than they would be when made in any of
the ways heretofore employed."
"I do not claim to be the inventor of annealing castings made of
iron or other metal, when done in the ordinary way; nor do I claim
to be the inventor of any particular form or kind of furnace, in
which to perform the process. But what I
do claim as my
invention and desire to secure by letters patent is the process of
prolonging the time of cooling, in connection with annealing
railroad wheels in the manner above described -- that is to say the
taking them from the moulds in which they are cast, before they
have become so much cooled as to produce such inherent strain on
any part as to impair its ultimate strength, and immediately after
being thus taken from the moulds, depositing them in a previously
heated furnace or
Page 81 U. S. 629
chamber, so constructed, of such materials, and subject to such
control that the temperature of all parts of the wheels deposited
therein, may be raised to the same point
(say a little below
that at which fusion commences), when they are allowed to cool
so fast, and no faster, than is necessary for every part of each
wheel to cool and shrink simultaneously together, and no one part
before another. [
Footnote
2]"
Whitney being in possession of his patent as already described,
one Mowry, of Ohio, conceived that he too had made a valuable
improvement in the same branch as Whitney professed to have made
one, and on the 7th of May, 1864, also obtained a patent. His
specification, illustrated by a vertical cross-section of his
furnace, says:
"My invention consists in the use of charcoal or other
equivalent substance, interlaid with the wheels in the annealing
pits, in connection with the regulated admission of air, for the
purpose of heating the wheels up to a proper temperature,
prolonging the heat, and permitting them to cool in the course of a
given time, gradually, as will be more particularly explained
below."
"The operation of my invention is as follows:"
"A layer of charcoal having been laid on the perforated bottom
of the annealing pit, the wheels, as they are turned out of the
moulds red hot, are placed in the pits, with a layer of charcoal
between each wheel, a layer of charcoal being laid on the uppermost
wheel, and on this a perforated metal plate is laid."
"The charcoal becoming now ignited by the hot wheels, the cover
of pit is then laid on and the damper opened so as to admit just
sufficient air to effect the combustion of the contained charcoal
in the space of seventy-two hours, less or more, as may
Page 81 U. S. 630
be found necessary for the annealing operation. The draft of air
in the apparatus shown on drawings is from above downward, but it
may, without affecting my invention, be from below upwards by
conveying the air from the horizontal flue up through the pits and
through the aperture in cover, and from thence through flues into
the main shaft or chimney
C; the result will be the same
in both cases, and the adoption of one or the other plan will be
dictated by convenience."
image:g
Under his patent, Mowry employed a process of annealing such as
it described, and Whitney thereupon filed a bill to enjoin him as
an infringer. Mowry answered, denying infringement, alleging the
invalidity of Whitney's patent for want of novelty and for want of
utility,
"
Inasmuch as the said process would ruin and destroy the
hardness on the rim of the car wheels, known as the 'chill,' and
thus greatly detract from the usefulness and durability of the
wheels. "
Page 81 U. S. 631
A large amount of testimony being taken on both sides, the cause
was brought to a final hearing on the pleadings and proofs, and all
the issues being found for Whitney, the cause was referred to a
master to taken and state an account of the gains and profits which
the defendant had derived from the infringement of Whitney's
patent.
The master reported, on the 1st of August, 1868, that Mowry had
made use of Whitney's patent in the manufacture of 19,819 wheels,
and for the use of the process in making these wheels charged
him:
Profits on these wheels . . . . . . . . . . . $91,501.86
Interest on the said profits to
1st August, 1868. . . . . . . . . . . . . . 19,984.21
He further reported that Mowry, prior to the 1st of April, 1861,
and without the use of the process complained of in this cause, had
built up his business to its then condition. That the use of the
process did not diminish, but did increase the cost of making the
wheels manufactured by Mowry. That while Mowry used the said
process, he did not make any difference in the quality of iron used
for the manufacture of car wheels, nor in the weight or form of car
wheels, nor by reason of the use of such process, in their price.
That Mowry's business was apparently not increased by the use of
the process, and that he had sold the wheels he had since
manufactured without the process complained of as readily as those
manufactured by use of the process, and at the same
prices.
[The patentee himself, it should be here added, in 1862, when
applying for an extension of his patent, had stated under oath that
he believed there was no essential difference in the cost per pound
of making cast iron chilled car wheels of the various patterns, and
by the different modes in use, provided the same skill and system
controlled the manufacture; that by his process he was enabled to
make them lighter than those made in any other way for a similar
service, and therefore could afford to sell them at the same price
per wheel as other makers, and save the cost of the
Page 81 U. S. 632
difference in weight; that this saving of metal he deemed to
measure the essential advantage he had over his competitors, and
also the profits arising from his patent, and he estimated that
ten pounds per wheel would be a fair average of the metal saved
by his process. [
Footnote
3]]
Mowry excepted to the charge made, as above stated by the
master, of profit derived by the entire manufacture of the wheel,
and the case was recommitted to the master with instructions to
inquire:
1st. Whether the wheels made and sold by Mowry had or could have
any market value without being subjected to the process patented by
Whitney.
2d. If they had or could have been made to have such value by
any annealing or slow cooling process outside of the Whitney
patent, how much additional value, if any, they derived from being
subjected to that patented process?
To this the master returned that he was unable to report any
division of profits, and, being uninformed as to what was covered
by the patent, he reported that if the entire process of reheating
and prolonged cooling used by Mowry in the manufacture of the
wheels was an infringement of the complainant's patent, the total
profit realized by the defendant from the manufacture and sale of
the wheels was due to the use by him of the complainant's
invention.
He reported secondly that if there was no infringement of the
complainant's patent, unless the wheels were subjected to the
process of reheating -- that is to say if the process of slow
cooling used in connection with reheating was old, and not a part
of the complainant's invention, nor included in his patent -- no
part of the profits realized by the defendant from the manufacture
and sale of the wheels was due to the use by him of the
complainant's invention.
[This second finding of the master the court set aside,
sustaining an exception to it that not only the entire process
described in the patent, but each part of such entire process, was
the invention of Whitney, and the use of any material,
Page 81 U. S. 633
substantial and essential part of such entire process -- the
slow cooling being a substantial and material part, whereby only an
improved chilled cast iron railroad wheel could be made, and
beneficial effects the same in kind, if not in degree attained,
that were attained by Whitney's entire process -- was an
infringement of Whitney's patent, and that the profits derived from
the use of such material, substantial and essential part should be
accounted for in this case.]
But the master, in addition to the second finding thus, as just
mentioned, set aside, further found that had the wheels
manufactured by the defendant been left to cool in the open air,
they would have had no value as car wheels, and have been worth
only the value of the iron of which they were made; that reheating
in connection with slow cooling, or slow cooling without reheating,
was indispensable to make marketable cast iron wheels of the
configuration of those made by the defendant; that there was no
reheating process for the manufacture of cast iron car wheels
outside of the complainant's patent.
The master also found that the wheels could have been removed
from the moulds and finished without being subjected to the
reheating process or without any extraneous heat, and he specified
two modes in which it might be done. Wheels so manufactured, he
reported, have and did have, during all the time in which the
defendant used the complainant's process, a market value equal to
that of wheels manufactured by that process.
There were some other findings which may be briefly noticed:
1. That the 19,819 wheels were annealed wheels, and sold as
such.
2. That if the complainant's patent included prolonging the time
of cooling the wheels, as used by the defendant, the process
conferred upon them their entire market value, above their weight
in iron, but not so if the complainant's patent covered only the
application of extraneous heat to the wheels after they are taken
from the moulds.
3. That taking annealing to mean reheating in connection
Page 81 U. S. 634
with slow cooling, no other process of annealing in connection
with slow cooling than that patented to the complainant and that
described in the patent of the defendant appeared to have been
known.
4. That the wheels made by the defendant required no treatment
other than that described in the complainant's patent to complete
them as annealed wheels.
5. That still taking annealing to mean reheating in connection
with slow cooling, the annealed wheels could not have been made by
any process outside the complainant's patent.
Upon these findings, the court below decreed against Mowry the
entire profits made by him in the manufacture and sale of the
wheels from beginning to end; the profits resulting from the
reheating, and regulated slow cooling in connection, and those also
which might have resulted from mixing and melting the iron, casting
in moulds, making the chill, and from the possible advance on the
iron above its cost, with $10,980.22 additional interest on the
whole, from the 1st of August, 1868, when the original reports were
made, to August 1, 1870; at which time the subject was finally
heard.
The final decree thus stood:
Profits on 19,819 wheels . . . . . . . . . . $ 91,501.86
Interest to date of original report
(August 1, 1868) . . . . . . . . . . . . . 19,984.21
Interest on $91,501.86 (from August 1,
1868, to August 1, 1870) . . . . . . . . . 10,980.22
-----------
$122,465.29
From this decree Mowry, the defendant, appealed.
Page 81 U. S. 639
MR. JUSTICE STRONG delivered the opinion of the Court.
The defenses set up to the complainant's bill for an
infringement are that the patent is void for want of novelty in the
invention, and for want of utility, and also that it has not been
infringed by the defendant.
To determine how far these defenses are sustained, it is
important to have a clear apprehension of the state of the art when
the patent was granted and of the invention which it was intended
to secure to the patentee. Prior to the 2d of August, 1847, cast
iron railroad wheels had been cast, and cast in chills -- that is,
they had been cast in sand moulds with an outer circumference of
iron. The effect of this outer circumference was to produce a more
rapid chill on the periphery of the wheel, thereby crystallizing
and hardening it so that the wheel was made stronger and more
capable of resisting the friction of the rails. But the parts of
the wheel were of different thicknesses. The hub and the rim were
much thicker than the plate which connected them, and of course
they cooled after casting more slowly than the plate. The
consequence of this unequal cooling was to produce a strain between
the thick and thin parts that greatly impaired the strength of the
wheel. Various devices had
Page 81 U. S. 640
been made to guard against, or to remedy the mischief resulting
from, this inherent and inevitable strain caused by unequal
contraction in cooling. The most common of these perhaps was
casting the wheel with the hub in sections in order that the
sections might accommodate themselves to the contraction of the
plate. But this was expensive. It required the open space between
the sections to be filled up with other metal, and generally it
required the hub to be hooped. It is unnecessary, however, to
describe these devices. It does not appear that in any of them the
idea existed of making a car wheel with chilled tread, straight
plates, and solid hub,
annealed and cooled so as to leave
it uninjured by the strain attendant upon the unequal cooling of
the thick and thin parts. Annealing some kinds of castings was
known and practiced before 1847. This is abundantly proved by the
witnesses, and various modes of annealing plain castings had been
described by scientific writers both in this country and abroad,
before that time. But there is no evidence that we have been able
to discover that cast iron car wheels had ever been subjected to an
annealing process, in connection with slow cooling, before the
process was discovered or invented by Whitney. In all the
experiments made for annealing other castings, the object sought
was different, and in them all, as well as in the process described
in the publications given in evidence, the effect upon the annealed
metal or glass was not to leave them in the condition in which it
was sought to bring car wheels, with the crystallization or chill
of the periphery unimpaired, and the plate or thin part unaffected
by strain. Cast iron railroad wheels are castings of a peculiar
kind. The methods of slow cooling, or of annealing and slow
cooling, which were applied to other castings before 1847, were not
adapted to their peculiarities or to what they needed. They are not
homogeneous throughout. They are of different thickness in their
several parts, and hardened at the tread, while the plate and hub
are not crystallized, but are soft and tough. These different
qualities of the different parts it is necessary to preserve, and
what was needed when Whitney's invention
Page 81 U. S. 641
was made was to preserve them and at the same time relieve
against any strain caused by unequal cooling which might impair the
strength of the wheel.
If now we proceed to inquire what Whitney's alleged invention
was, as described in his specification and claim, it will be seen
that it was a process not to make a car wheel or to destroy any of
the advantages which had already been secured, but to add another.
Its avowed object was to obtain a new value, or rather exemption
from imperfection. It was to remedy the evil of strain resulting
from the more rapid cooling of one part of the wheel than the
cooling of the other parts. And this was sought to be accomplished
by a process that insured the cooling of all parts, both the thick
and the thin, with equal slowness. The process consists of several
parts. The first is taking the wheels from the moulds after the
melted iron has been run into the moulds, before they become so
much cooled as to produce strain on any part sufficient to impair
their ultimate strength. The second is placing the wheels
immediately after their removal in a furnace or chamber previously
heated to about the temperature of the wheels when taken from the
moulds, the heat in the furnace being subject to control. The third
is applying heat until the temperature of all parts of the wheels
shall again be raised to the same point (indefinitely said to be a
little below that at which fusion commences). The fourth and last
stage in the process is allowing the wheels, after they have been
thus reheated, to cool so fast as and no faster than is necessary
for every part of each wheel to cool and shrink simultaneously
together, and no one part before another. It is therefore a patent
for a process, not for a combination. Neither as a whole nor in
parts can it be considered without reference to the ultimate object
in view, which was to retard cooling by a second application of
heat supplied until all parts of the wheel are raised to the same
temperature, and then permit the heat to subside so gradually that
the cooling of the parts shall not only commence at the same point
of temperature, higher than that where hurtful strain begins, but
shall continue
Page 81 U. S. 642
equable till all artificial heat ceases. The removal from the
moulds to the furnace or chamber, the removal at the time
described, before the incipient strain has become permanently
hurtful, and to a place where more heat may be applied, and where
the heat can be under control, are parts of the process to secure
equable cooling during the time when cooling without such
appliances is likely to produce strain and consequent weakness. It
is apparent that this is more than a process for
annealing. That is included, it is true, but it is only a
small part. It is applying foreign heat to a hot chilled wheel at
the point of time when it has reached a particular stage of cooling
by means of such foreign heat bringing the whole casting up to a
higher and uniform temperature, and maintaining an equable
abatement of heat in a furnace or chamber under the control of the
operator. We have sought in vain through the proofs submitted in
this case, for any satisfactory evidence that this process was
known before 1847, when Whitney commenced it, or that anything
equivalent to the process was known. Certainly nothing of the kind
had ever been applied to cast iron railroad wheels, and, as we have
seen, they are castings of a peculiar character, not admitting of
the treatment that may be applied to other castings. What they
needed was (what was substantially described by one of the
witnesses) the discovery of the fact that the chilled cast iron,
constituting one part of the wheel, could be subjected to heat less
than that which would cause fusion without producing any material
effect upon its hardness, while the cooling of other parts of the
wheel could be so prolonged by applying that heat externally as to
enable all parts to cool without being subjected to the strain
attendant on unequal contraction and, in addition to the discovery,
they needed the invention of a process by which it could be
practically carried out. Such a discovery and such a process were
needed for no other castings. The novelty of the patentee's
invention is not therefore disproved by evidence that glass, or
speculum metal, or even other iron castings had been annealed and
slow-cooled, prior to the time when it was made. Of this
Page 81 U. S. 643
there is very considerable evidence both in the testimony of
witnesses and printed publications. The specification disclaims
invention of annealing iron castings done in the ordinary mode. It
claims annealing when applied to cast iron railroad wheels, in the
mode or by the process described. It is not, therefore, merely an
old contrivance or process applied to a new object, as case of
double use. A new and previously unknown result is obtained --
namely the relief of the plate of the wheels from inherent strain
without impairing the chilled tread, a result which, though
anxiously sought, had not been obtained before Whitney's invention.
We are therefore of opinion that the defense set up that the patent
was void for want of novelty of invention is unsustained.
The validity of the invention is next assailed for the reason
that the process described in it, and claimed, is denied to be
useful, because it would destroy the hardness of the rim, or tread
of the car wheel known as the chill, and thus greatly detract from
the durability and usefulness of the wheels.
It is undoubtedly true that a chilled periphery or tread is
essential to the usefulness of a car wheel. Indeed, the evidence is
that whenever car wheels are spoken of, wheels with chilled tread
are meant, and any process which destroys the chill must render
them valueless for the purposes for which they are needed.
It is also true that the fusing point of cast iron is in the
neighborhood of 2,786 degrees of Fahrenheit, twelve or fifteen
hundred degrees above the point at which, according to the
evidence, the chill of the tread of a car wheel would be destroyed.
If, therefore, the process patented to Whitney requires, after the
removal of the wheel to the heated furnace or chamber, the
application of a degree of heat closely approximating the point of
fusion, it must be conceded that instead of being beneficial, it is
positively hurtful. And this is what is contended by the appellant.
The objection seems to be aimed at the sufficiency of the
description of the
Page 81 U. S. 644
patentee's invention, which it is abundantly proved he practiced
successfully through many years, rather than at its utility.
Whitney conceived a process and practiced it. That process may have
been a highly useful invention, and therefore patentable, and yet
he may have failed so to describe it as to teach the public how to
practice it. The law requires every inventor, before he can receive
a patent, to furnish a specification or a written description of
his invention or discovery and of the manner and process of making,
constructing, using, and compounding the same, in such full, clear,
and exact terms, avoiding unnecessary prolixity, as to enable any
person skilled in the art or science to which it appertains, or
with which it is most nearly connected, to make, construct,
compound, and use the same. The specification, then, is to be
addressed to those skilled in the art and is to be comprehensible
by them. It may be sufficient though the unskilled may not be able
to gather from it how to use the invention. And it is evident that
the definiteness of a specification must vary with the nature of
its subject. Addressed as it is to those skilled in the art, it may
leave something to their skill in applying the invention, but it
should not mislead them. The objection here is that, in describing
the degree of heat to be applied after the wheels have been
deposited in the heated chamber, the patentee states it to be such
that the temperature of all parts of the wheels "may be raised to
the same point (say a little below that at which fusion
commences)," and the defendant insists that this amounts to a
direction to raise the heat to a degree that must destroy the chill
of the tread, and thus render the casting valueless as a railroad
car wheel. But it is obvious that only vague and uncertain
directions could have been given respecting the extent to which the
heat is necessary to be raised. It must differ with the difference
in the progress of cooling which has taken place before the wheels
are removed from the moulds. The process requires this removal
before they have become so much cooled as to produce such inherent
strain on any part as to impair its ultimate strength. Precisely
when such a strain begins cannot
Page 81 U. S. 645
be known. Cooling commences the instant the casting is made, and
with cooling commences contraction, and strain must soon follow.
Plainly it is impossible to describe the point of time when the
strain has proceeded so far as to impair the ultimate strength of
any part of the wheel. That, in the nature of things, must be left
to the judgment of the operator. But before that time, the strain
may be checked, and this is what is contemplated by raising the
temperature of all parts of the wheel to the same point or degree.
The moment that is done, the strain ceases and the primary object
of the patentee's process is accomplished. The state of things is
reproduced which existed before the contraction and attendant
strain began, when the slow cooling is allowed to follow in an
atmosphere so heated and regulated that each part of the wheel
loses its heat at an equal pace with all others.
Now anyone skilled in making cast iron railroad car wheels in
view of this specification must see that the object of the process
is to relieve from and guard against hurtful strain without
destroying the chill, and that heat is applied only for that
purpose. It requires no particular science or skill to enable an
operator to perceive that the moment all parts of the wheel are
raised from a point above where serious strain begins, and where
yet the thick and thin parts are in different stages of cooling, to
a stage where the degree of temperature of all parts is the same,
and above the degree where serious strain commenced, the thing
sought has been attained. Then the avowed purpose of the inventor
has been accomplished. It would be most unreasonable to read the
directions of the specification without reference to the object
which they profess to have in view. The evidence is that the chill
is formed while the casting is in the mould, and that the hurtful
strains commence after the formation of the chill. Indeed it is
manifest there can be no strain until the chill is complete. It
must be, therefore, that all the heat which is needed to relieve
from the strain is that which suffices to raise the temperature of
the thin part, or plate, to the degree at which the strain
commenced -- a lower
Page 81 U. S. 646
temperature than that which existed when the chill was formed.
Hence an operator, in following the directions of the
specification, would be taught by his practical knowledge that the
instant all parts of the wheel had been heated to that temperature
no more heat was needed.
And we do not think it a fair construction of the patentee's
language to hold that it requires the heat to be raised in all
cases to a degree only a little below the point of fusion. He does
not attempt to give any more definite direction than that all parts
of the wheel must be raised to the same temperature, suggesting in
a parenthesis ("say, a little below that at which fusion
commences"). He fixes a
maximum. The heat must not reach
the point of fusion, and the prescribed
minimum is that
degree where the heat of the different parts of the wheel is equal.
Within those limits, the degree is left to the judgment of the
operator, and within those limits it is clear from the evidence
that the process may be applied without injury to the chill. The
proof is that it has been successfully applied in the manufacture
of a vast number of wheels, and that failure has been very
rare.
There are some witnesses who have testified that the Whitney
process, as they understand it, would destroy the chill of the
wheel. But they explain their understanding to he that the wheels
are to be reheated to a degree far beyond what is required to
relieve from strain, and thus heated for no purpose. They keep in
sight the
maximum limit, and approach near to that,
overlooking entirely the
minimum, and disregarding the
single object of the process, namely, relief of the plate, or thin
part of the wheel, from the strain caused by unequal
contraction.
We are therefore of opinion that the patent is not void for want
of utility, and that the specification sufficiently describes the
process invented and claimed.
The remaining defense is a denial that the process conducted by
the defendant is an infringement of Whitney's patent.
What the process of the defendant was is clearly set out
Page 81 U. S. 647
in a patent which he obtained on the 7th of May, 1861. It
consists in placing in a pit the wheels as they are turned out of
the moulds red hot, with a layer of charcoal beneath the lowest
wheel, and a layer between each wheel as well as above the
uppermost, and covering the pit with a perforated metal plate. The
charcoal is ignited by the hot wheels, and just sufficient air is
admitted to effect combustion of the coal. Thus the wheels are
reheated and permitted gradually to cool. There are some minor
details which it is unnecessary to mention. So far as relates to
reheating the wheels and retarding the cooling by the application
of additional heat, it is obvious that the process is substantially
the same as that covered by the complainant's patent. The object is
the same, and the mode of attaining it is in substance the same.
The purpose of the charcoal interlaid with the wheels is avowed to
be to heat them in the pit to a proper temperature, prolonging the
heat and permitting them to cool gradually in a given time, said to
be severity-two hours, more or less, as may be found necessary for
the annealing operation. The rapidity of combustion of the charcoal
is regulated by a damper in the flue. And this process is followed,
as the specification explains, that the different parts of the
wheels may adjust themselves to each other, and accommodate the
unequal contraction which results from the process of chilling. It
is under this patent and in accordance with its directions that the
defendant has prepared his car wheels for market. As the object of
the patentees is the same, relief from the strain incident to
unequal contraction, the only inquiry is whether the object is
attained by substantially the same means. The idea of Whitney was
undoubtedly arresting contraction before any remediless strain had
commenced, and regulating the progress of cooling so that all parts
of the wheel may maintain an equal temperature at all stages of
cooling. Manifestly the process of the defendant embodied the same
idea and carried it out by means identical in principle. It reheats
the wheels when removed from the moulds to the chamber or pit. It
prolongs the cooling in connection with the reheating,
Page 81 U. S. 648
and it subjects the rapidity of cooling to control of the
operator. The form or structure of the furnace, chamber, or pit, is
not claimed by either patentee.
It hardly seems necessary to resort to the opinions of experts
in order to reach the conclusion that the process of the defendant
is only formally different from that of Whitney, while the
essential element of the two processes is the same. But the
testimony of the experts examined, taken as a whole, clearly
supports such a conclusion. It is true some of the witnesses
testify that in their opinion the processes are different, but when
they attempt to describe the difference they point out only matters
which are merely formal, only variances in the mode of using the
same process. On the other hand, several witnesses, entirely
competent to apprehend the principle of the invention, and the
devices for practically using it, have testified that the processes
of the defendant and of the complainant are substantially the same
in principle, mode of operation, and in the effect produced. We
must therefore conclude that the charge of infringement made in the
bill has been sustained and that the complainant was entitled to a
decree for an injunction and an account.
We come next to the consideration of the account stated by the
master and confirmed by the circuit court.
The master reported that Mowry, the defendant, used Whitney's
process in the manufacture of 19,819 wheels, and the account has
been stated on that basis. For the use of the process in making
these wheels the defendant has been charged with $91,501.86 as
profits made by him (more than four dollars and sixty cents on each
wheel), besides $19,984.21 interest upon such profits to the first
day of August, 1868, and the further sum of $10,980.22, being
interest from August 1, 1868, to August 1, 1870.
It is very obvious, in view of what the patentee himself stated,
under oath, in 1862, when applying for an extension of his patent,
[
Footnote 4] that the account
has been erroneously stated. If
Page 81 U. S. 649
he was correct in this statement, the profits arising from the
use of his patent in manufacturing 19,819 wheels (valuing iron at
the price proved to have been paid for it by the defendant) must
have been less than $5,500, instead of over $91,000, decreed in the
circuit court -- about thirty cents per wheel, instead of four
dollars and sixty cents. It is not an unfair presumption that if
the profit to the patentee was no greater than he claimed it was,
it could not have been more when the invention was used by an
infringer. Now it is clear that Whitney is not entitled to receive
more than the profits actually made in consequence of the use of
his process in the manufacture of the 19,819 wheels. It is the
additional advantage the defendant derived from the process --
advantage beyond what he had without it -- for which he must
account. But he has been held liable far above this. The master
reported, in the first instance, the difference between the cost of
the wheels and the price for which they were sold as the profits
realized by Mowry, thus charging him the profit obtained from the
entire wheel, instead of that resulting from the use of Whitney's
invention in a part of the manufacture; and this, though he found
at the same time and reported that Mowry had built up his business
before he commenced the use of Whitney's process; that the use of
the process did not diminish the cost of making wheels, but
increased it; that while he used the process, he used the same
quality of iron that he had used before, and made no difference in
the weight or form of the wheels, or in their price, and that the
wheels made by him before he commenced the use of Whitney's
invention, and since he has abandoned it, have sold as readily and
at the same prices as those manufactured by that process.
Exception was taken to the charge of the profit made by the
entire manufacture of the wheel, including not only the selection
and mixing of the iron, but its melting, pouring into moulds,
forming the chill, removing from the moulds, and cleaning, as well
as annealing and slow cooling; and the case was again sent to the
master with instructions to inquire:
Page 81 U. S. 650
First. Whether the wheels made and sold by the
defendant had, or could have been made to have any market value
without being subjected to the process patented to Whitney;
and,
Second. If they had, or could have been made to have
such value by any annealing or slow-cooling process, outside of the
Whitney patent, how much additional value, if any, they derived
from being subjected to that patented process.
Upon the findings (stated
supra 81 U. S. 632 --
REP.) made by the master on this order, the court decreed against
the defendant the entire profits made by him in the manufacture and
sale of the wheels from beginning to end, not only the profits
resulting from the reheating and regulated slow cooling in
connection, but also those which may have resulted from mixing and
melting the iron, casting in moulds, making the chill, and from the
possible advance on the iron above its cost, with interest on the
whole.
This we think was an error. The findings of the master justified
no such decree. It must be conceded that the findings are
incomplete, obscure, and in some particulars incongruous, but it is
not a legitimate construction of them taken together, that the
benefit which the defendant derived from the use of the
complainant's invention was equal to the aggregate of profits he
obtained from the manufacture and sale of the wheels as entireties,
after they had been completed. It is as true of a process invented
as an improvement in a manufacture, as it is of an improvement in a
machine, that an infringer is not liable to the extent of his
entire profits in the manufacture. [
Footnote 5] If the wheels made by the defendant would have
had no market value above that of cast iron if they had not been
annealed and slow cooled, the same may be said if they had been
cast without a chill. The same principle, therefore, which gives to
the complainants the aggregate profits of the entire manufacture
would give the same profits to a patentee of the process of
chilling,
Page 81 U. S. 651
if there were one, and as there are many processes in the
manufacture, for each of which it is conceivable there might be a
patent, and as everyone of the processes is necessary to make a
marketable wheel, an infringer might be mulcted in several times
the profits he had made from the whole manufacture. We cannot
assent to such a rule. The question to be determined in this case
is what advantage did the defendant derive from using the
complainant's invention over what he had in using other processes
then open to the public and adequate to enable him to obtain an
equally beneficial result. The fruits of that advantage are his
profits. They are all the benefits he derived from the existence of
the Whitney invention. It is found that there were other processes
by which the inherent strain caused by unequal cooling could be,
and was prevented, counteracting which strain was the sole object
of the complainant's invention, and a car wheel could be prepared
for similar service, valuable in the market and salable at a price
not less than was obtained for those which the defendant
manufactured. The inquiry then is what was the advantage in cost,
in skill required, in convenience of operation, or marketability,
in bringing car wheels by Whitney's process from the condition in
which they are when taken hot from the moulds, to a perfected
state, over bringing them to the same state by those other
processes, and thus rendering them equally fit for the same
service. That advantage is the measure of profits. It is quite
unimportant what name was given to the products of the processes,
whether one could be called annealed wheels and the other could
not, except so far as affected their marketability.
The record shows that the court overruled the alternative
finding of the master that if there is no infringement of the
complainant's patent unless the wheels are subjected to the process
of reheating -- that is to say if the process of slow cooling used
in connection with reheating is old, and not a part of the
complainant's invention, no part of the profit derived by the
defendant from the manufacture and sale of the wheels was due to
the use by him of that invention.
Page 81 U. S. 652
One exception taken to this finding was that not only the entire
process described in the patent, but each part of such entire
process, was the invention of the complainant, and the use of any
material, substantial, and essential part of such entire process,
the slow cooling being a substantial and material part, whereby
only an improved chilled cast iron railroad wheel could be made,
and beneficial effects the same in kind if not in degree attained,
that were attained by the complainant's entire process, is an
infringement of complainant's patent, and the profits derived from
the use of such material, substantial, and essential part, should
be accounted for in this case. This exception the court sustained,
and thereby held that the defendant is chargeable with the profits
he derived from slow cooling alone. We cannot assent to this. The
patent is for an entire process, made up of several constitutions.
The patentee does not claim to have been the inventor of the
constituents. The exclusive use of them singly is not secured to
him. What is secured is their use when arranged in the process.
Unless one of them is employed in making up the process and as an
element of it, the patentee cannot prevent others from using it. As
well might the patentee of a machine, every part of which is an old
and known device, appropriate the exclusive use of each device,
though employed singly and not combined with the others as a
machine. The defendant was not, therefore, responsible for slow
cooling alone, or for the profits he derived from it. He was liable
to account for such profits only when he used slow cooling in
connection with reheating in the manner described in Whitney's
claim substantially, or when extraneous heat was employed to retard
the progress of cooling. We have said that slow cooling, is not
claimed in the specification as the invention of the patentee. And
it is found by the master that there are other modes of slow
cooling, and even other modes of relieving against the inherent
strain caused by unretarded cooling, than that practiced by the
complainant and claimed by him. Though, therefore, slow cooling is
an essential part of the complainant's process, it is an equally
essential part of other processes which
Page 81 U. S. 653
the defendant was at liberty to use in preparing his car wheels
for market.
We add only that in our opinion the defendant should not have
been charged with interest before the final decree. The profits
which are recoverable against an infringer of a patent are in fact
a compensation for the injury the patentee has sustained from the
invasion of his right. They are the measure of his damages. Though
called profits, they are really damages, and unliquidated until the
decree is made. Interest is not generally allowable upon
unliquidated damages. We will not say that in no possible case can
interest be allowed. It is enough that the case in hand does not
justify such an allowance. The defendant manufactured the wheels of
which the complaint is made under a patent granted to him in 1861.
His infringement of the complainant's patent was not wanton. He had
before him the judgment of the Patent Office that his process was
not an invasion of the patent granted to the complainant, and
though this does not protect him against responsibility for
damages, it ought to relieve him from liability to interest on
profits.
Decree reversed and the cause remanded with instructions to
proceed in accordance with the rules laid down in this
opinion.
[
Footnote 1]
There were other drawings and descriptions not given by the
reporter.
[
Footnote 2]
It may here be stated that, on the 7th of August, 1849, there
was granted to one Murphy a patent (extended subsequently for seven
years from the 7th of August, 1863) for a mode of cooling car
wheels which consisted in encasing and protecting from the air all
parts of the wheels except the hubs, and causing a current of cold
air, by means of connection with the main chimney, to pass through
the hubs, thus retarding the cooling of the plates and speeding the
cooling of the hubs. This process, it will be observed, was the
antithesis of Whitney's, the essence of which consisted in heating
the wheels until all parts of them had attained the same degree of
heat.
[
Footnote 3]
See supra, 81 U. S. 435,
Mowry v. Whitney.
[
Footnote 4]
See this statement,
supra, in brackets,
beginning at foot of p.
81 U. S.
631.
[
Footnote 5]
Jones v.
Morehead, 1 Wall. 155;
Seymour v.
McCormick, 16 How. 480.
