In the present state of the law in this country it appears to be
necessary for a scientific man whose investigations may have any
practical bearing to refrain from communicating his work to any
scientific society, or publishing it in any journal until he has
registered it and paid a fee to the Government under the so-called
Patent Law. This unfortunate system is well calculated to prevent
scientific men in general from giving any attention to practical
applications, and to deter them from an attempt to make their
researches useful to the community. If a scientific worker publishes
in the natural way, no one has any rights in the thing published; it
is given away and lies useless, for no one will care to expend capital
upon a thing over which he has no effective control. In this case
practical developments generally wait until some outsider steps in
and either patents some slight addition or modification, or else, as
sometimes happens, patents the whole thing, with some slight addition.
If a scientific worker refrains from publishing and himself takes out
a patent, there are innumerable troubles and possible litigation ahead
of him, at least if the thing turns out at all remunerative; but the
probability is that, in his otherwise occupied hands, it will not so
turn out until the period of his patent right has expired.
Pending a much-to-be-desired emendation of the law, whereby the
courts can take cognisance of discoveries or fundamental steps in
an invention communicated to and officially dated by a responsible
scientific society, and can thereafter award to the discoverer such
due and moderate recompense as shall seem appropriate when a great
industry has risen on the basis of that same discovery or fundamental
invention--pending this much-to-be-desired modification of the law, it
appears to be necessary to go through the inappropriate and repulsive
form of registering a claim to an attempt at a monopoly. The instinct
of the scientific worker is to publish everything, to hope that any
useful aspect of it may be as quickly as possible utilised, and to
trust to the instinct for fair play that he shall not be the loser when
the thing becomes commercially profitable. To grant him a monopoly is
to grant him a more than doubtful boon; to grant him the privilege of
fighting for his monopoly is to grant him a pernicious privilege, which
will sap his energy, waste his time, and destroy his power of future
production.
[Illustration: FIG. 24 (Fig. 5 of Specification 11,575/97).--Syntonic
Radiator, adapted for sending and for receiving.]
However, the author, in consultation with friends, decided that
registration was, under present conditions, necessary, and,
accordingly, for his attempt at syntony and other improvements in the
Hertz wave method of signalling, he can refer here to certain patents
taken out, in conjunction chiefly with Dr. Alexander Muirhead, his
co-worker, which are numbered respectively as follows:--
[Illustration: FIG. 25 (Fig. 13 of Specification 11,575/97).--Diagram
of connections for Syntonic Receiver; _e_ being coherer and _w_
a non-inductive conducting or capacity shunt, to eliminate the
self-induction of the receiving instrument.]
(1) 11,575 of 1897, wherein is described the general syntonic principle
and the mode of prolonging the duration of the vibrations emitted by a
radiator or by a receiver. This is done by adding to it electromagnetic
inertia (that is, a self-induction coil) in such a way as to lessen
its radiating power, converting its type of emission from something
like a whip-crack into something more like that of a struck string.
(Not pushing it so far as to make it like a _fork_, though that could
be done if desired: see _Journal_ Inst.E.E., December, 1898.) But too
prolonged a duration of vibration is not desirable, for it can only
be obtained at the expense of radiating power. For the most distant
signalling the single pulse or whip-crack is the best, and this is
what in practice has hitherto always been employed; but, with it,
tuning is of course impossible. A radiator with several swings is
less violent at its first impulse than is a momentary emitter; but
then the lessened emitting power of a radiator is to be compensated
by a correspondingly prolonged duration of vibration on the part of
the receiver or absorber, thus rendering the radiator susceptible
of tuning to a special similarly-tuned receiver or resonator. The
tuned resonator is then to respond, not to the first impulse of the
radiator, but to a rapidly worked up succession of properly timed
impulses; so that at length, after an accumulation of two or three,
or perhaps four, swings, the electrostatic charges in its terminal
plates become sufficient to overflow and spit off into the coherer,
thereby effecting its stimulation and giving the signal. A resonator
not properly tuned--_i.e._, one tuned to some different frequency of
vibration--would not be able to accumulate impulses, and hence would
not respond, unless of course it were so much too near the radiator
that the very first swing stimulated it sufficiently to disturb the
coherer; in which case, again, there is no room for tuning. The two
points to attend to for syntonic discrimination are: (_a_) that the
receiver shall not be so near the emitter as to feel its impulses too
easily, _i.e._, without accumulation; (_b_) that the properly tuned
receiver shall be so arranged that it can work up and accumulate the
impulses of the radiator, and before attaining its maximum swing can
overflow into the coherer associated with it and thus give the signal.
[Illustration: FIG. 26 (Fig. 10 of Specification
11,575/97).--Interchangeable Self-Induction Coils for signalling to
different stations.]
[Illustration: FIG. 27 (Fig. 3 of Specification
11,575/97).--Diagrammatic representation of Syntonic Radiator and
Receiver. The middle spark gap _h_₂ _h_₃ is unnecessary, though
sometimes helpful. The main charging is done by impulsive rush at the
outside knobs.]
[Illustration: FIG. 28 (Fig. 7 of Specification 11,575/97).--Syntonic
Radiator with earth connection arranged for sending.]
The general appearance of a pair of signalling stations on this plan
is shown in Fig. 24, where the huts contain the sending and receiving
instruments. The self-induction coil joining the two capacity-areas is
better depicted in Fig. 25, which also shows one mode of joining up the
coherer to a syntonic receiver. (The galvanometer and shunt are, of
course, merely typical of any kind of telegraphic instrument whatever.)
Fig. 26 indicates one form of sender with three alternative syntonising
coils for speaking to three distant attuned stations. Fig. 27 shows
a radiator arranged for receiving, but illustrates another method of
charging, and one frequently employed by the author, viz., the method
by impulsive rush (compare Figs. 11, 12 and 19, on pp. 14 and 25 of
this book). The terminals of the Ruhmkorff coil are here connected, not
to the capacity-areas direct, but to a pair of knobs near the centre
of gravity of each area, so that when the discharge occurs each area
is suddenly charged oppositely, and the two opposite charges are left
to surge into one another and set up the oscillations. This impulsive
method of charging is essentially that adopted in the spherical
whip-crack emitter depicted in Fig. 19 (p. 25, _ante_), the two poles
of the sphere having but small capacity and being joined by as thick
a conductor as the equator of the sphere. But for such a radiator as
is indicated in Fig. 24 or Fig. 27 the author commonly found that a
third short spark gap in the middle was an improvement, and so, as is
well known, did Prof. Righi find it, and embodied it in his well-known
double-sphere double-knob emitter.
[Illustration: FIG. 29 (Fig. 12 of Specification
11,575/97).--Single-point Coherer, with clockwork Tapper-back operating
on the projecting end of the spring clamped at P and lightly touching a
needle point _n_.]
The specification also contains figures of earth-connected forms of
radiators, with or without self-induction coils, of which Fig. 28 may
be here reproduced; and likewise a modification of the point coherer
depicted in Fig. 17, on page 22 (_see_ Fig. 29, and also fig. on page
27), where the spiral wire spring is replaced by a piece of straight
watch-spring, clamped at one end, adjusted by a screw at the other, and
lightly touched by a needle point at its middle; a very gentle tapping
back stimulus being provided in the form of a clockwork or other
mechanically-driven motor grazing lightly against one end of the spring
protruding beyond the clamp for the purpose.
[Illustration: FIG. 30 (Fig. 14 of Specification 11,575/97).--Another
diagram of connections for Syntonic Receiver, with Coherer in a
secondary or transformer circuit; a conducting or a capacity shunt for
the telegraphic instrument being applicable as before.]
[Illustration: FIGS. 31 and 32 (Figs. 5 and 6 of Specification
18,644/97).--Modes of connecting a Coherer to one or to a pair
of Syntonic Radiators so that it may feel their _electrostatic_
disturbance.]
[Illustration: FIG. 33 (Fig. 11 of Specification 18,644/97).--Actual
connections for a Sending and Receiving Station on the plan shown in
Fig. 37. Left-hand side shows spark sending, right-hand side shows
Coherer receiving.]
Fig. 30 shows a coherer inserted in a secondary or transformer circuit,
and operated inductively by the oscillations of the receiver, which are
thus transformed up and raised in potential.
(2) No. 16,405, 1897, wherein are described chiefly various practical
methods of decohering, by means of cams and otherwise, which are
appropriate when working rapidly with automatic transmitter and siphon
recorder.
(3) No. 18,644, 1897, represents different ways of connecting up a
coherer to a syntonic resonator, so as to get the benefit of its
overflow without interfering with the working up of the electric
oscillations, _e.g._, Figs. 31, 32 and 33. It also shows a plan for
constantly decohering by a rapidly revolving cam a number of coherers
in parallel, so that one at least is always ready to receive an impulse
(Fig. 34). Further, it arranges to utilise the earth or a cable
sheath, or other uninsulated conductor, for the purpose of conveying
electric impulses to a distance (Figs. 35, 36, 37 and 38). And next
it is arranged to assist the coherer to feel the full effect of any
electric jerk by shunting out the battery and galvanometer, which are
necessarily in series with it, by means of a condenser of moderate
capacity (Fig. 35), which also shows a self-induction mode of sending
a stimulus along an uninsulated line. This condenser obstructs all
steady currents, such as give the signal, but it transmits freely any
momentary electric impulses, such as stimulate a coherer.
[Illustration: FIG. 34 (Fig. 1 of Specification
18,644/97).--Single-point Coherers in parallel, with successive
decoherence.]
[Illustration: FIG. 35 (Fig. 3 of Specification 18,644/97).--A
self-induction method of sending jerks into a badly insulated line, and
arrangement for detecting such jerks by a single-point Coherer.]
[Illustration: FIG. 36 (Fig. 4 of Specification 18,644/97).--Another
arrangement for sending jerks into a bare or badly insulated line, and
connections for Coherer detection.]
[Illustration: FIG. 37 (Fig. 10 of Specification 18,644/97).--Another
mode of sending a jerk from a spark gap at _j_ into a badly insulated
cable or other conductor, which is connected at the other end to a
Coherer, the circuit being completed inductively through the air by
means of the areas _p_, _p_₁. The dotted lines s represent the switch
connection of Fig. 33.]
[Illustration: FIG. 38 (Fig. 13 of Specification 18,644/97).--Another
method of signalling through a pair of imperfect conductors, such
as gas and water pipes _i_, without the above elevated inductive
connection.]
[Illustration: FIG. 39 (Fig. 3 of Specification 29,069/97).--Diagram
of Coherer connection to Syntonic Collector, with capacity shunt for
telegraphic instrument.]
(4) No. 29,069, 1897. In this patent various methods of connecting
up the shunting condenser, whose object it is to transmit all jerks
undiluted to the coherer, are shown, all adapted to work with a
syntonic resonator (Fig. 39). There is also shown a complete switch
(Fig. 40) for effecting the transition from “sending” to “receiving,”
exposing the coherer to the full effect of the distant radiator, and
completely protecting and isolating it from its home radiator; the
switch being so arranged that signalling is impossible unless the
home coherer is protected. A rotating commutator is also shown, whose
object is to expose the coherer to the full influence of a receiver,
especially of a non-syntonic receiver or simple collector, without
its being shunted or otherwise interfered with by the telegraphic
apparatus; to which, however, immediately afterwards the rotating
commutator connects it, and then effects the tapping back.
Connections are shown (Fig. 41) for a complete sending and receiving
station on this plan with a syntonic radiator and resonator indicated
(though not to scale). But with syntonic resonators the revolving
commutator method is not found to be necessary; the sending and
receiving switch, together with the closed box for protecting the
coherer in an instantly accessible manner is therefore the chief
feature of this diagram.
[Illustration: FIG. 40 (Fig. 6 of Specification 29,069/97).--Switch at
a Sending and Receiving Station, to change all the connections with a
protected Coherer from receiving to sending by depressing the knob _l_.]
[Illustration: FIG. 41 (Fig. 7 of Specification 29,069/97).--Diagram of
connections at a protected Coherer Station with Syntonic Radiator and
Collector.]