Music Trade Review

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THE MUSIC TRADE REVIEW
THE PLAYING POWER IN PNEUMATIC MECHANISMS.
Analysis and Consideration of the Laws Governing Pneumatic Energy—Elightenment on a Sub-
ject That Will Be Welcomed by Those Who Have Not Given It Consideration—Of Interest
to All Having to Do with the Manufacture or Sale of Player-Pianos.
With all due respect to the player trade, one
cannot avoid the consideration that if the laws
which govern the production of playing power in
pneumatic mechanisms were better—or at all—
generally understood, there would be a great deal
less wild talk about methods and practice. It is
by no means the present purpose to attempt the
obviously impossible task of setting these things
right, but it is hoped that by suggesting some of
the more elementary considerations involved in the
production of pneumatic power we may be able to
clear up a few at least of the misapprehensions
current on the subject.
When one asks the ordinary plain man in the
trade what it is that makes the player "go" he
usually answers "vacuum." When pressed for in-
formation as to the meaning of this term and as to
what "vacuum" precisely does, he generally takes
refuge in saying that the thing is done by "suc-
tion." As to what "suction" is nobody seems to
have much information. There is a general agree-
ment that the bellows of a player-piano either
pumps air into the pneumatic action or else pumps
it out, and that the bellows is either filled, or
emptied to supply the necessary power, but apart
from this there appears to be very little extant
knowledge outside of the experimental rooms of
various factories.
Now all this is very painful. When you hear a
player man talking about the difficulty of "filling
the bellows" of a certain mechanism, and then im-
mediately after hear another one (or even the same
one) discuss high and low "vacuum," one feels
ready to lapse into a rather hopeless state.
It will therefore be well for everybody concerned if
we set forth here some physical facts which may
tend to clear up the prevailing fog.
What Is Power?
What is power? We do not know what in es-
sence it materially is, but we do know how it is
manifested. We know that energy of any kind is
never created out of nothing, but is ever being
transformed from one shape into another. We
know that we never get out of a machine in one
form of energy more than we have put into it in
another form. In other words, though the energy
that comes from a machine is manifested as a kind
of work quite different from that which is put into
it to make it go, the totalities of the two are equal.
We cannot conceive something arising from
nothing, and so we have no right to make the false
assumption that we can get power without expend-
ing equivalent energy to get it. This is the first
thing to remember. To have power you must ex-
pend power.
Now, we arc all agreed that the power which
actuates the piano action under control of the
music roll has something to do with air. In order
to learn what air has to do with the matter it will
be well for us first to learn something about air it-
self. We can neither see nor grasp air. We can
feel it when it is set in motion, and we know that
it is capable of conveying to us vibrations of
sound, light and heat, or at least that it does not
prevent the conveyance to us of such vibrations.
Yet any quantity of air is a quantity possessing
mass and density, subject to compression or ex-
pansion, and of definite composition under definite
conditions. In fact, the atmosphere is a great sea,
29 miles deep, at the bottom of which we stand.
This great sea of air naturally has weight, though
this be indeed very slight if compared with units
familiar to us. Having weight, it must exert pres-
sure. In point of fact it does exert pressure, so
that the weight of the whole sea of air, pressing
upon the portions of itself nearest to ourselves at
sea level, actually exerts a pressure in all direc-
tions of not less than 14.75 pounds to the square
inch! Why do we not feel this pressure? Because
it is exerted equally in all directions, within and
without our bodies, and so is ever in a state of
equilibrium until disturbed. When in this normal
State of equilibrium the air of the atmosphere is
imperceptible to us and incapable of
any work. Only when the conditions
exists are subjected to change can the
useful as a work performing agent.
second point to be remembered.
performing
in which it
air be made
This is the
Confusion as to Operation.
how, we have already remarked that a great deal
of confusion appears to exist as to the manner in
which air 'does its work in the pneumatic mech-
anism; the thing to be done is to operate the piano
aation. For this purpose small moving units in the
form of bellows must be caused to open and close,
performing these latter functions with enough
energy to overcome the inertia of the piano action.
It is perfectly plain that we cannot explain the
collapse of a pneumatic by attributing it to
"vacuum," for vacuum is nothing, and therefore
cannot do anything. What actually happens then
must be that if a state can be produced in refer-
ence to a pneumatic whereby the air can be thrown
out of equilibrium, the energy of the air's pressure
can be -used. This, of course, is what does hap-
pen.
Now, the bellows system of the pneumatic
mechanism is not designed to compress air; that is
to say, to cause a greater amount to flow into a
closed space than ordinarily would fill it. It is,
on the contrary, to expand air by withdrawing
from a closed space some of the air which in nor-
mal conditions would fill it. Any gas, like air, has
the property, among other properties, of completely
filling any closed space in which it may be placed.
When we speak of the amount of air that nor-
mally will fill a closed space, we mean that quan-
tity which will flow into the space without external
aid other than its natural pressure at the sea level
or elsewhere. Now, if we can withdraw from a
closed space any portion of the air that normally
fills it, the remainder will follow the before-men-
tioned property of gases and will expand to fill
the space again. But since the actual amount s
now less than before, it is obvious that in expand-
ing to fill the space it has become thinner. In
other words, in expanding it loses some of its pres-
sure. A given bulk of it will now exercise a
slighter pressure than before on a surface. And
since it has now sunk below its normal pressure, it
would seem clear that if a bulk of the normal air
can be brought into opposition with it, so that the
two states of pressure are kept separate, though
acting on one another, the normal pressure of the
atmospheric air will overcome the sub-normal pres-
sure, and will thus be able to perform work. In
other words, if we put normal atmospheric air
outside a closed box filled with a movable wall, and
inside that box we reduce the pressure of the con-
tained air, the normal air of the atmosphere will
act upon the movable wall because the air on the
other side of that wall is at lower pressure, and
hence the equilibrium between the two is disturbed.
The outside air will be more powerful and will
therefore cause the movable wall to be forced back-
ward upon the body of air contained inside the
closed box. As the wall moves backwards it will
gradually re-compress the contained sub-normal
pressure until the pressure of the latter is the same
as that of the atmosphere, when equilibrium will be
restored and the process will cease.
Here and here only we have the explanation of
the operation of a pneumatic. The external air is
enabled, through the pressure reduction brought
about in the closed box, to exert a push against
the movable wall of the box. This push consti-
tutes "work," and is what we mean by the "col-
lapse" of a pneumatic.
It is therefore quite plain that the vague pseudo-
idea of "vacuum" cannot be said to afford any ex-
planation of the operation of the pneumatic player
mechanism. In the article next month we shall
likewise show that the idea of "suction" also re-
quires to be greatly modified. We shall then ex-
plain the process of pressure reduction through the
bellows system.
(To be continued.)
BEHNING LINE WITH JINELLENBERG IN PHILADELPHIA.
Big Philadelphia House Gets Entire Behning Line, Including Grands, Uprights and Players—
Will Inaugurate Vigorous Policy in the Featuring of These Instruments.
It must be admitted by all who are in touch
with the player situation of this country that the
Behning player-piano has made a tremendous ad-
vance during the past twelve months.
Nearly ever week some new and desirable
connections are announced, and this week it is
learned that the great mercantile establishment of
N. Snellenberg & Co., Philadelphia, Pa., has se-
cured the representation of the Behning for that
city and the adjoining territory which it controls.
A large initial order has been placed which in-
cludes the entire Behning line, grands, uprights
and player-pianos.
It is the intention of the Snellenberg house to
exploit the Behning products effectively, and the
representatives of the house feel tfiat with the
Behning line they will be able to largely increase
their trade in their particular field.
SOMETHING OF JUE PISTONOLA
of devising a more compact action from the stand-
point of engineers. Hitherto the subject has been
dealt with by those branches of the music trades—
organ and harmonium makers—most in touch with
pneumatic actions, and naturally they adopted
the form, bellows, most familiar to them. Pneu-
matics are, however, used in several branches of
engineering, where bellows arc regarded as unsat-
isfactory, and consequently Messrs. Goldman and
Webb adopted instead pistons and cylinders of
metal, whereby much greater pressure of air is pos-
sible, notwithstanding that the exertion of pedaling
is much diminished.
The New Pneumatic Player Action Invented by
Two Englishmen—Its Especial Features.
The Pistonola is the name of a new pneumatic
p'ayer action which is being produced in London by
Messrs. Boyd, Ltd. It contains several departures
from the stereotyped action, and unlike the present
ones in use, which require the frame of the piano-
forte to be of larger size than normal in order to
accommodate them, says the London Music, the
Pjstonola can be placed in an instrument of the
usual dimensions. This has been achieved by dis-
carding the principle of the numerous bellows in
existing actions, and by substituting for them
small pistons. Compactness is, however, not the
only gain, for whereas bellows leak and are subject
to deterioration, the Pistonola is constructed of
metal throughout, and, besides being absolutely air-
tight, is virtually indestructible. It is claimed for
it, also, that it is extremely sensitive to the opera-
tor, and that it secures good attack and repetition.
We read further:
"American inventors have hitherto been so much
to the fore in the construction and improvement
of player actions that it is all the more gratifying
to note that the Pistonola is the outcome of five
years' work by two young Englishmen, H. C. Gold-,
man and C, F. Webb, who approached the problem.
"If all the advantages that are claimed for this
invention are even approximately realized, there
ought to be a future for the Pistonola, which is
certainly both interesting and ingenious. It is
another exemplification of the truth of the adage
that "outsiders see most of the game." Not often
de engineers succeed in solving musical problems."
BULLETINS OF ROLLS NEXT MONTH.
It will be noted that the usual bulletins of music
rolls do not appear in the Player Section this wee.k,
as none of the companies manufacturing music
rolls issue rolls in August.. The advance lists for
September will appear as usual in the August
Player Section of The Review,