It is one of God's greatest gifts to mankind, for who is happy who does not serve? Hence it follows that service requires sacrifice. It is the foundation stone of every enterprise. Whatever it may be, its success or failure depends upon whole-hearted co-operation.

And may service and sacrifice continue to be the keynote of our progressive Association.—The Author.

As previously stated in this series, it is very essential that the control ports of the tracker bar be memorized. These ports were described in THE JOURNAL for July, 1928, and it is not necessary to repeat them but only to call attention to the fact that all numbers of the ports start at the outer ends of the bar and are counted inward.

Before starting the test, pump out the tracker bar ports.

Be sure that the automatic switch is at the "On" position before starting the test.

Have the blank portion of the music roll cover the tracker bar, with no perforations showing. Test for quietness of the electric motor ; pump and listen for any undue leaks. Throw the automatic switch on and off and note the reaction of the expression mechanism.

As port No. 5 bass end cancels the first, second and third intensity valves, test each valve to see if it is working properly. Likewise as port No. 4 treble end cancels the first, second and third treble intensities and port No. 9 treble end cancels pianissimo, test these valves also for correct action.

Ports No. 6 bass end and No. 5 treble end are the diminuendo ports. Port No. 9 treble end cancels pianissimo and the bass and treble hammer rails on a short perforation and also controls the re-roll at the end of the music roll, but only when there is a long perforation in the roll. Both treble and bass hammer rails should be at rest and normal intensities should prevail when starting the test.

On the treble normal test the pressure should be not less than 5-1/2 inches gauge pressure. With port No. 7 treble end open, which is the pianissimo, the pressure should be about 3-3/4 inches but not more than 4-1/2 inches. Port No. 8 treble end is the treble section of the hammer rail. It should rise when the port is opened on the bar and the chord should be softer than the preceding one.

Port No. 9 treble end now cancels the treble pianissimo and the hammer rail on a short perforation. The pressure should again become normal, or 5-1/2 inches. Port No. 1, either bass or treble, is the first intensity, and the gauge reading should be 6-1/2 inches. Run a finger over the chord to see if all the notes speak with the same degree of force. Port No. 4 treble end now cancels first intensity and the following chord should be struck at normal force, or 5-1/2 inches.

Ports No. 2 bass or treble ends are the second intensities and the pressure should be 8 inches. Test the chord as in the last instance. Port No. 4 treble end again cancels the second treble intensity and the next chord is again normal, or 5-1/2 inches. Ports Nos. 3 bass or treble ends are the third intensities. The pressure should be 12-1/2 inches, and the chord should now speak with more intensity than the preceding one.

Port No. 4 treble end again cancels the third intensity and the normal chord is now struck, or at a pressure of 5-1/2 inches. The first, second and third intensities, treble end, now come on together and the pressure should be 14 to 16 inches. Port No. 6 treble end is the crescendo, and in building up to maximum the chord should show a reading of 27 to 30 inches. The chord should be solid and distinct ; it is immediately followed by ports Nos. 6 bass and 5 treble, which are diminuendo, and ends with cancel ports Nos. 5 bass and 4 treble.

The same procedure is followed in the test for the bass end of the bar, and the pressures must agree in all cases. The crescendo and the diminuendo devices are operated by control ports, as heretofore explained, and the speed at which they operate is determined by the length of the perforations on the music roll, the spacing of the perforations and the speed at which the roll travels over the tracker bar.

The diminuendo effect is secured when the metering pin is at the lowest extreme of travel, twenty pulsations, or twenty single perforations on the music roll should move the pin from one extreme to the other. If the metering pin is operating correctly the passage on the test roll will gradually increase in volume until the maximum point is reached at twenty. Likewise with the bass and treble diminuendo perforations ; the test should show a gradual decrease until normal is reached.

Next on the test roll is a short number played at a tempo of 70. Adjustment may be made on the bass or treble regulators, if necessary, in order to secure uniform bass and treble effects, but if these adjustments are made care should be taken not to upset previous pressure settings. If all conditions are equal in the piano action, it should not be necessary to make any adjustments on the bass or treble regulators.

For the method of adjustments see THE JOURNAL for July, 1928.

The December installment will cover the Duo-Art mechanism.