Improved Means for Maintaining the Pitch in Organs under Varying Temperatures.
Year: 1897

page_text: Date of Application, 6th Aug., 1897-Accepted, 11th Sept., 1897
COMPLETE SPECIFICATION.
Improved Means for Maintaining the Pitch in Organs under
Varying Temperatures.
I, HENRY WILLIS Junior of 19 Belmont Drive, Newsham Park, Liverpool in the
County of Lancashire, Organ Builder, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
The object of this invention which applies to organs fitted with independent reed
work is to provide means for the facile adjustment of the pitch of the reed-work to
the pitch of the flue-work or vice versa when the true adjustment is disturbed by
change of temperature.
The pitch of organ pipes as is well known rises and falls with the temperature of
the surrounding atmosphere. If change of temperature affected the pipe-work of an
organ equally, fluctuations of pitch would not be of much importance, but the
sensitiveness of organ pipes is far from uniform, large pipes being more sensitive than
small ones, flue pipes made of metal more sensitive than reed-pipes or flue pipes made
of wood. The presence of a congregation, use of gas for lighting, heating apparatus
&c. cause thermal variations, which, affecting the pipe-work unequally disturb the
pitch adjustinents to an extent often unpleasant to cultivated ears.
These adverse conditions I seek to neutralise by the means I will now proceed to
describe.
In organs of the type to which my invention applies a difference of pitch between
the metal flue-pipes and the reed pipes can be removed by adjusting the wind pressure
on which the reed pipes speak to the thermometric conditions existing at the
moment.
If the temperature is above the average or that in which the organ was tuned or
adjusted, the reed-work not being as sensitive as the metal flue-work will be found to
be "flat" and require a slight increase of wind pressure to "sharpen" it and bring
it into accord with the flue-work.
If the temperature is below the average the reed-work will be sharp to the flue-work
and require a slight reduction of wind pressure to bring the pitches into accord.
For ordinary purposes adjusting the pressure of the wind supplied to the reed-pipes
will suffice, but where a more accurate result is desired the flue-work can be adjusted
for its own error, and the discrepancy between the large and small pipes may be
removed. A rise in temperature raises the pitch of or sharpens large pipes to a greater
extent than it disturbs small pipes, but an alteration in the wind pressure influences
small pipes to a greater extent than large pipes, and consequently a slight increase of
wind pressure corrects this discrepancy in pitch. A falling temperature has a contrary
effect and necessitates a reduction in the pressure of the wind supply to the pipes.
To derive the utmost benefit from my invention flue pipes made of wood should
generally be supplied from the same source as the reed-work their sensitiveness being
approximately similar. My invention may be carried out in many ways, the essential
feature being the adjustment of the wind pressures to the thermometric conditions
existing at any moment.
Weights corresponding to given variations of temperature being provided, the ther-

page_text: a
mometer will indicate when, in which direction, and the extent of alteration required.
cord
This adjustment of weights may be effected at the reservoirs or
communication may be established to some convenient position where the weights
11.
can be manipulated.
Thus supposing it to be desired to bring the means of adjustment within reach
of the player while sitting at the key-board, a cord in connection with each reservoir
may be led over and under guide pulleys to the organ front and a weighted rod
attached thereto to receive the adjusting weights, which will be slotted to provide for
their facile application and withdrawal as the temperature of the atmosphere varies.
The advantage of this arrangement will be readily appreciated by organists who will
be enabled to adjust the pitch of the various parts of their instruments with the
facility afforded to players on other wind instruments such as the cornet and flute.
I should point out that the permissible variation in wind pressure is not large and
is determined by the stability and condition of the pipe work.
I may further remark that when my invention is applied to organs in which the
trebles of the flue work are normally supplied with wind of a different pressure
to the bass (by dividing the sound board etc.) a still better result' will be obtained.
The same remark applies with respect to the reeds for if the trebles are
supplied with wind of a greater pressure than the bass, or from a separate source
greater accuracy of pitch is obtainable.
nature of
Having now particularly described and ascertained the
said
invention and in what manner the same is to be performed, I declare that what
I claim is
'my
1. The means above described for maintaining an uniform pitch throughout the
organ in varying atmospheric temperatures.
2
2. Providing the organist with means for regulating with facility the pressure of
the wind supplied to various parts of the organ as and for the purpose above set
forth.