that the conducting properties of bodies are augmented by cohesion, and
that heat is conveyed profusely and energetically through all solid and
ponderable substances. Thus gold, silver, and others of the most solid
metals are the best conductors. Next to the pure metals in conducting
powers are rocks, flints, porcelain, earthenware, and the denser liquids
as the solutions of the acids and alkalies. As a further evidence to
prove that the passage of heat through all substances is increased
by cohesion, even some of those which are known to be among the best
conductors are deprived of this property by a division or disintegration
of their particles. Pure silica in the state of hard, rock crystal is
a better conductor than bismuth or lead; but if the rock crystal be
pulverized, the diffusion of heat through its powder is very slow and
feeble. Heat is conducted swiftly and copiously through transparent
rock salt, but pulverization converts the solid mass into a good
non-conductor. Caloric has for the same reason a stronger affinity for
pure metals than for their oxides.
Again, wood is known to be a better non-conductor when reduced to
shavings or sawdust than when in the solid state. It is probably on this
account that trees are protected by bark, which is not nearly so dense
and hard a body as the wood. Wool, silk, and cotton are much diminished
in conducting qualities when spun and woven, for the reason that their
fibers are brought closer together.
Count Rumford discovered that hot water, at a given temperature, when
placed in a vessel jacketed with a clothing of twisted silk, and plunged
into a freezing mixture, cooled down to 185° Fah. in 917 seconds. But
when the same vessel was clothed with an equal thickness of raw silk,
water at the same heat and under the same process required 1,264 seconds
before it reached the same decrease of temperature. It was also found
by Sir Humphry Davy that even metals became non-conductors when their
cohesion was destroyed by reducing them to the gaseous state.
It is now generally admitted that, heat being motion, anything, which,
by the cohesion of particles, preserves the continuity of the molecular
chain along which the motion is conveyed, must augment calorific
transmission. On the other hand, when there is a division or
disintegration of atoms, such as exists in sawdust, powdered charcoal,
furs, and felt, the particles composing such bodies are separated from
each other by spaces of air, which the instructed among us well know are
good non-conductors of heat. The motion has, therefore, to pass from
each particle of matter to the air, and again from the air to the
particle adjacent to it. Hence, it will be readily seen, that in
substances composed of separate or divided particles, the thermal
bridge, so to speak, is broken, and the passage of heat is obstructed
by innumerable barriers of confined air. The correctness of
these assumptions has been so abundantly proved by experimental
demonstrations, that every mind that is tolerably informed on the
subject must be relieved of every shade of doubt respecting the greatly
superior non-conducting powers which bodies consisting of separate atoms
possess over those of a solid concrete nature.
The next matter of interest connected with the subject under notice is
its relation to the philosophy of radiation. It has long been known that
the emission of heat from a polished metallic surface is very slight,
but from a surface of porcelain, paper, or charcoal, heat is discharged
profusely. Even many of the best non-conductors are powerful radiators,
and throw off heat with a repellent energy difficult to conceive.
"If two equal balls of thin, bright silver," says Sir John Leslie, "one
of them entirely uncovered and the other sheathed in a case of cambric,
be filled with water slightly warmed and then suspended in a close room,
the former will lose only eleven parts in the same time that the latter
will dissipate twenty parts." The superior heat-retaining capacity which
a clean tin kettle possesses over one that has been allowed to
collect smoke and soot, lies within the compass of the most ordinary
observation.
The experiments of the eminent philosopher just mentioned furnish a
variety of suggestions on the radiation from heated surfaces. He found
that, while the radiating power of clean lead was only 19, it rose to 45
when tarnished by oxidation, that the radiating power of plumbago
was 75, and that of red lead 80. He also discovered that, while the
radiating power of gold, silver, and polished tin was only 12, that
of paper was 98, and lamp black no less than 100. He further says: "A
silver pot will emit scarcely half as much heat as one of porcelain. The
addition of a flannel, though indeed a slow conductor, far from checking
the dissipation of heat, has directly a contrary tendency, for it
presents to the atmosphere a surface of much greater propulsive
energy, which would require a thickness of no less than three folds to
counterbalance."
It is safe to infer from this analogy that the felt covering of boilers
should not only be of considerable thickness, but should be protected
by an external jacketing of some sort; for, though felt is a good
non-conductor, it is a powerful absorber and radiator, more especially
when it has been allowed to contract soot and dust.
Various experiments have lead to the general conclusion that the
power of absorption is always in the same proportion as the power of
radiation. It must be so. Were any substance a powerful radiator and at
the same time a bad absorber, it would necessarily radiate faster than
it would absorb, and its reduction of temperature would continue without
limit. It has, furthermore, been proved that the absorptive property of
substances increases as their reflecting qualities diminish. Hence, the
radiating power of a surface is inversely as its reflecting power. It is
for this reason that the polished metallic sheathing on the cylinders
of locomotive engines, and on the boilers of steam fire engines, is
not only ornamental but essentially useful. Decisive tests have also
established the fact that radiation is effected more or less by color.
"A black porcelain tea pot," observes Dr. Lardner, "is the worst
conceivable material for that vessel, for both its material and color
are good radiators of heat, and the liquid contained in it cools with
the greatest possible rapidity; a polished silver or brass tea urn is
much better adapted to retain the heat of the water than one of a dull
brown, such as is most commonly used."
A few facts like those above stated afford more decisive information
regarding the nature of heat than columns of theory or speculation. Yet
it is rather strange that when so many learned and reliable men have,
experimented so much and commented with such persuasiveness upon the
subtile agency of heat and the vast amount of waste that must accrue by
injudicious management, comparatively few have availed themselves of the
united labors of these indefatigable pyrologists; manufacturing owners
and corporations still persisting in having their steam boilers painted
black or dull red and leaving them exposed to the atmosphere. Some
persons, who pass themselves off very satisfactorily as clever
engineers, affect a contempt for the higher branches of science, and
assert, in a very positive and self-sufficient manner that experiments
made in a study or laboratory are on too trifling and small a scale to
be practically relied upon; that a tin kettle or a saucepan is a very
different thing to the boiler of a steam engine.
This may be so in one sense, but the same chemical forces which operate
upon the one will be just as active in a proportionate degree in their
action upon the other. It was said by Aristotle that the laws of the
universe are best observed in the most insignificant objects; for the
same physical causes which hold together the stupendous frame of the
universe may be recognized even in a drop of rain. The same observation
may be applied to the laws of heat in all their ramifications; for,
after all, our experiments are, in many instances but defective copies
of what is continually going on in the great workshop of nature.
It would be needless to insist on the wasteful and destructive effects
produced by the exposure of boiler surfaces to the open atmosphere.
Such a practice can be neither supported by experience nor justified by
analogy; and it is to be hoped that it may before long be consigned to
the limbo of antiquated absurdities and be satisfactorily forgotten.
Seeing that it cannot with any show of reason be affirmed that the
boiler covering materials in present use possess the requirements
necessary to recommend them; the question arises as to what is the best
means of achieving the object required. This is an inquiry which it is
the office of time alone to answer. As the problem is obviously one of
primary importance, and well worthy of the attention of inventors, it
is hazarding nothing to predict its satisfactory solution at no distant
date.
The plain truth is, boilers have of late become gigantic foes to
human life. Explosions have increased, are increasing, and should be
diminished; and they are, in many instances, caused by boilers being
strained and weakened by sudden contraction from having their surfaces
exposed when the fire has been withdrawn from them. Boilers are also
materially injured by the excessive furnace heat which it is necessary
to maintain to compensate for the large amount of caloric which
is dissipated from their surfaces, not only by radiation but from
absorption by the surrounding atmosphere.
As the views here laid down are drawn exclusively from the region of
fact and experiment, it is to be hoped that an enlightened sense of
self-interest may prompt those whom the subject may concern, to give it
that special attention which its importance demands.
* * * * *
Attachment of Saws to Swing-Frames.
To insure the efficiency of mill-saws, it is highly important to have
them firmly secured in the frames by which they are reciprocated.
Swing-frames for carrying saws are ordinarily of wrought iron or steel,
and made up of several pieces mortised and tenoned together in the form
of a rectangular frame or parallelogram, of which the longest sides are
termed verticals and the shortest crossheads or crossrails. In the case
of deal frames, the swing frame differs somewhat from that of a timber
frame, in having two extra verticals, which separate it into two equal
divisions. These are necessary in order that two deals may be operated
upon simultaneously, each division being devoted to a separate deal, and
likewise to enable the connecting-rod which works the frame to pass up
the center and oscillate on a pin near the top, thereby avoiding the
deep excavations and costly foundations required where the rod is
engaged with the pin at the bottom. The rack that advances the deals to
the saws passes through a "bow" in the connecting-rod and the middle
of the frame, the deals are placed on either side of it, on rollers
purposely provided. In sawing hard deals, the saws require to be
sharpened about every tenth run or journey, and every twentieth for
soft. Fifty runs, or one hundred deals, are reckoned an average day's
work; this is inclusive of the time required for changing the saws,
returning the rack for another run, and other exigencies. For attachment
to swing-frames the saws have buckles riveted to them; these are by
various modes connected to the crossheads. Each top buckle is passed
through the crosshead and is pierced with a mortise for the reception
of a thin steel wedge or key, by whose agency the blade is strained and
tightened. The edge of the crosshead upon which the keys bed is steeled
to lessen the wear invariably ensuing from frequently driving up the
keys. The distances between the blades are adjusted by interposing
strips of wood, or packing pieces, as they are termed, of equal
thickness with the required boards or leaves; the whole is then pressed
together and held in position by packing screws. The saws themselves are
subsequently tightened by forcing home the keys until a certain amount
of tension has been attained, this is ascertained only by the peculiar
sound which emanates from the blade on being drawn considerably tight
and tense. Great experience is required to accustom the ear to the
correct intonation, as in general the tensile strain on the saws
approximates so closely to the breaking point that one or two extra taps
on the keys are quite sufficient to rupture them.
Mr. Brunel, in the government saw-mills at Woolwich, adopted a method
of hanging saws by means of a weighted lever, like a Roman steelyard.
A cross-shaft affixed above the saws to the cornice of the main frame
carried a lever, weighted at one end and provided with a hook or shackle
at the other for engagement with the saw buckle. In using this apparatus
the blades were strained one at a time by linking the lever to the
buckle and then adjusting the movable weight until the desired tension
was acquired, after which the key was inserted into the mortise and the
lever released. This arrangement is not now in common use on account of
the trouble attending its employment, and at present the saws are merely
strained by hammering up the keys. The saw blades had usually a tensile
strain of upwards of one tun per inch of breadth of blade. It is to
be further observed that the cutting edges of the saws are not quite
perpendicular, but have a little lead, or their upper ends overhang the
lower about three eighths of an inch or one half of an inch, according
to the nature of the material to be sawn. The object of this is that the
saws may be withdrawn from the cuts in the ascending or back stroke, and
allow the sawdust free escape. The eccentric actuating the mechanism for
advancing the timber to the saws is generally set in such a manner that
the feed commences just at the moment when the frame has attained half
its ascending stroke, and continues until the entire stroke has been
completed. By this regulation the saws are not liable to be suddenly
choked, but come smoothly and softly into their work.--_Worssam's
Mechanical Saws_.
* * * * *
PATENT DECISION.
_In the matter of the application of William N. Bartholomew, assignor
to J. Reckendorfer, for letters patent for a design for Rubber
Eraser_--Letters patent for designs have increased in importance within
the past few years. Formerly but few were granted, now many are issued.
To this day they have made so little figure in litigation that but
three reported cases are known in which design patents have come into
controversy. With their increase, questions have arisen concerning their
scope and character, which have given rise to dispute and to inquiry as
to the correctness of the current practice of the office in this branch
of invention. While on the one hand, it is insisted that the practice
has always been uniform, and is therefore now fixed and definite; on the
other, it is asserted, that there has never been, and is not now, any
well-defined or uniform practice, either in the granting or refusal of
design patents.
The act of 1836 made no provision for the patenting of designs. The
earliest legislation upon this subject is found in the act of August 29,
1842, section 3; and the only legislation upon the subject is found
in this section and in section 11, of the act of March 2, 1861. The
definition of the subject matter, or, in other words, of a "design," is
the same in both acts. It is is follows:
"That any citizen, etc., who, by his, her, or their own industry,
genius, efforts, and expense, may have invented or produced any new and
original design for a manufacture, whether of metal or other material
or materials, any original design for a bust, statue, bas-relief, or
composition in alto or basso-relievo, or any new and original impression
being formed in marble or other material, or any new and useful pattern,
or print, or picture, to be either worked into or worked on, or printed,
or painted, or cast, or otherwise fixed on any article of manufacture,
or any new and original shape or configuration of any article of
manufacture not known or used by others, etc."
This definition embraces five particulars.
1. A new and original design for a manufacture.
2. An original design for a bust, statue, etc.
3. A new and original impression or ornament to be placed on any article
of manufacture.
4. A new and useful pattern, print, or picture to be worked into or
worked on, or printed, or painted, or cast, or otherwise fixed on any
article of manufacture.
5. A new and original shape or configuration of any article of
manufacture.
The first three of these classes would seem to refer to ornament only;
the fourth to ornament, combined with utility, as in the case of trade
marks; and the fifth to new shapes or forms of manufactured articles,
which, for some reason, were preferable to those previously adopted.
The disputed questions which have thus far arisen under these
definitions are:
1. What variations may be claimed or covered by the patent consistently
with unity of design.
2. Is a new shape of an article of manufacture, whereby utility is
secured, a subject of protection under this act; and
3. Is mechanical function of any kind covered by it.
As to the first of these questions, it seems to have been assumed that
the design spoken of in all parts of the sections referred to covered a
fixed, unchangeable figure, that the protection of letters patent did
not extend to any variation, however slight, but that such variation
constituted a new design, might be covered by a new patent, and might
safely be used without infringement of the first. This, it is said, is
the correct theory of the law, and has been the uniform adjudication of
the Office.
Neither of these statements is absolutely correct. The law by no means
defines a design with such strictness. The language is, "new and
original design for a manufacture," "new and original impression or
ornament," "new and original shape or configuration." It would seem to
be too plain for argument, that the new design, or impression, or shape,
might be so generic in its character as to admit of many variations,
which should embody the substantial characteristics and be entirely
consistent with a substantial identity of form. Thus, if the invention
were of a design for an ornamental button, the face of which was grooved
with radial rays, it would seem that the first designer of such a button
might properly describe a button of five rays, and, having stated that
a greater number of rays might be used, might claim a design consisting
generally of radial rays, or of "five or more" rays, and, that it could
not be necessary for him to take out a patent for each additional
ray that could be cut upon his button. So, if the design were the
ornamentation of long combs by a chain of pearls, it would seem that a
claim for such a design might be maintained against one who arranged
the pearls, either in curved or straight lines, or who used half pearls
only, and that such modifications if they had occurred to the designer,
might properly have been enumerated in his specification as possible and
equivalent variations. In short, I can see no reason, under the law, why
designs may not be generic, why what are called "broad claims," may
not be made to them, and why the doctrine of artistic or aesthetic
equivalents may not be applied to them.
This has been recognized to a greater or less extent in the
adjudications of the courts and in the practice of the Office.
One of the reported cases is that of Booth _vs_. Garelly 1, Blatch 247.
The design is described as consisting of "radially formed ornaments on
the face of the molds or blocks of which the button is formed, combined
with the mode of winding the covering on the same, substantially as
set forth, whether the covering be of one or more colors." The
specification, in "substantially" setting forth the design, contained
this language: "It will be obvious from the foregoing that the figures
can be changed at pleasure by giving the desired form to the face of the
mold by depressions and elevations which radiate from a point, whether
in the center of the mold or eccentric thereto."
In the consideration of the case by the Court no objection was made to
this statement or claim. In the case of Root _vs_. Ball, 4 McLean 180,
the learned judge instructed the jury that "if they should find that the
defendants had infringed the plaintiff's patent by using substantially
the same device as ornamental on the same part of the stove they would,
of course, find the defendant guilty. To infringe a patent right it
is not necessary that the thing patented should be adopted in every
particular; but if, as in the present case, the design and figures
were substantially adopted by the defendants, they have infringed the
plaintiff's right. If they adopt the same principle the defendants are
guilty. The principle of a machine is that combination of mechanical
powers which produce a certain result. And in a case like the present,
where ornaments are used for a stove, it is an infringement to adopt the
design so as to produce substantially the same appearance."
It has been the constant practice to grant patents for designs for fonts
of type, for sets of silver plate, for a series of printers' flourishes,
and the like. This class of cases has always passed without objection.
Two other cases which have arisen within the Office deserve notive.
The first was for a series of miniature shoulder straps, with emblems
denoting rank, provided with a pin, to be worn under an officer's coat,
upon his vest, or as a lady's breastpin. The drawing shows eight of
these pins with emblems of rank, varying from that of second lieutenant
to major-general, specification describing the brooch for a second
lieutenant goes on to say: "I propose to introduce, on some of them, the
different ornaments showing the respective ranks of the army, from a
major-generalship to a second lieutenancy. See Figs. 2, 3, 4, 5, 6, 7,
8."
The second case was that of an application for a monogram visiting
card, on which the name was to be inscribed or printed in the form of a
monogram. The applicant filed a drawing, showing a card upon which was
a monogram of his own name. In his specification he gives certain rules
for forming such monograms, and then says: "It is manifest that the
form of the letters as well as the letters themselves can be changed as
required by circumstances or the taste of the individual for whom the
monogram is designed; and that the general form and outline of the
monogram may be varied; and indeed, must vary to be adapted to the
particular name it is required to represent."
The claim was for "a monogram, visiting card, or visiting card upon
which the name is inscribed or printed in the form of a monogram,
substantially as herein specified."
This application was rejected by the Examiner and Board of
Examiners-in-Chief, but was allowed by the Commissioner upon appeal.
It is true that, before and since this patent was issued, many patents
have been refused for what I have called generic designs. One man having
designed a tack head, ornamented with radial lines, was compelled to
take out one patent for his tack with six radial lines, and another for
the same tack with eight. There are other instances of like character,
but they only serve to show that the practice of the Office has not been
uniform, and that the true practice is still to be adopted and followed.
I have no hesitation in saying, in view of the premises, that a valid
patent may be granted for a new genus or class of ornaments as well as
for specific ornaments, though I do not doubt that, under the statute,
every species, variety, and individual having distinct characteristics
under such a genus might also be patented, the patent being subordinate
and tributary to that which covered the class. From the nature of this
subject-matter there must always be more latitude in the issue of
patents for trifling changes, or form, or outline, since it is only
necessary that such changes should constitute a new "design" to entitle
them to a patent of this class.
The second question relates to the elements of utility in patents for
designs.
Upon this point, it is said by my predecessor, in Jason Crane _ex parte_
Commissioners, December-May, 1869, p. 1, that the construction which has
been given to the act of 1842, by the Office, ever since its passage, is
that it relates to designs for ornament merely; something of an artistic
character as contradistinguished to those of convenience or utility.