The following diagram will, we think, demonstrate clearly the method employed: 

Upper row——­ o o o o o o o o o o Tim-

Middle row—–­ o o o o o o o o o o ing

Lower row——­    o   o   o   o   o   o   o   o   o   o  Pins.
------------------------------------------ Bridge.

* 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * &c
/// /// /// /// /// /// /// /// /// ///    Treble stringing. 
B   C  C[#] D  D[#] E   F  F[#] G  G[#] &c

The upper row of O’s represents the upper row of tuning pins.  To these are attached the first string of each unison.  To the middle row are attached the second or middle strings, and to the lower row are attached the third strings.  The diagonal lines represent the three strings of the unison (trio).  The asterisk on the middle one indicates that it has been tuned.

But one mute is used in tuning these unisons.  It is inserted between the trios in the order indicated by the figures 1, 2, 3, etc.  When inserted in place 1, between unisons B and C, it will mute the first string of C; so the first string of the trio to tune is always the third.  Then place your mute in place 2 and tune the first string of C. Then, without moving your mute, bring up third string of C[#], then third string of D and so on.  By this method, you tune two strings every time you reset your mute.

When through with the temperament, the next step is usually that of tuning the bass; but while we are in the treble we will proceed to give the method of setting the mutes in the upper treble beyond the temperament.  All three strings have yet to be tuned here, and we have to use two mutes.  The unisons are tuned in regular succession upward the same as in the example above.  The mute that is kept farthest to the left, is indicated by the letter A, and the one kept to the right, by the letter B, as in diagram below.

(T e m p e r a m e n t ) 1 2 3 4 5 6 7 &c. *** *** *** *** *** *** A B
/// /// /// /// /// /// /// /// /// /// /// /// /// ///
                           C[#] D D[#] E F [F#] G &c.

The mutes are first placed in the places indicated by the figures 1 and 2, thereby muting first and third strings of the first unison beyond the temperament, which is 3C[#].  The middle string of this unison is now tuned by its octave below. (If you have left imperfect unisons in your temperament, rendering it difficult to tune octaves by them, it will be well to replace your continuous mute so as to tune from a single string.) Having tuned the middle string of C[#], move mute B to place 3 and tune third string of C[#].  Then, move mute A to place 2 and tune first string of C[#].  Your mutes are now already set for tuning the middle string of D. After this is done, proceed to move mute B first, then mute A; tuning middle string, then third, then first, moving step by step as indicated in example above until the last unison is reached.  By this system you tune three strings every time the mutes are set twice.