And thus it is neccd^xy to fuppofe in the Pipes of an Organ ; 
which have each their determinate Sdund and not to be cor- 
re6led, in their little Inequalities, as the Voice may be by the 
guidance of the Ear. 
But Tythagoraiy^Vidi thofe who follow him found (by the Ear) 
that this Equality of Intervals would not exadly anfwer the 
Mufieal Appearances, in Concords and Difcords : juft as our 
Organifts and Organ-makers be now aware; that their Pipes at 
equal Intervals do not give the julfc defired Harmony, without 
fomewhat of Bearing-^ that is, of fome little variation from 
the juft Sound. 
The Tythagorims^ to help this, changed the notion of Equal 
Intervals into that of due Troportions. And this is followed by 
Zarline^ KeppJer^ Cartes^ and others who treat of Speculative 
Mufick in this and the laft Age. And tboiigh they fpeak of 
Notes and Half-notes ( in a more grofs way ) much as others do, 
yet declare themfelves to be underftood more nicely. 
And though our prefent Gam-ut take no notice of this little 
diveriity ; yet, in Vocal Mulick, the Ear diredls the Voice to 
a more juft proportion. And, in String Mufick, it may m like 
manner be helped by ftraining and flackening the Strings, or 
moving the Frets. But, in Wind Mufick, the Pipes are not 
capable of fuch correftion ; and therefore we muft be content 
with fome little irregularity therein ; that fo they may tolerably 
anfwer ( though not exa£Hy ) the difierent Compofitions ac- 
cording to the different placing of Mi in the Gam-ut. 
Now the Defign of Mr. Harris feems to be this ; either ( by 
multiplying intermediate Pipes ) to bring the Organ to a juft 
Perfeaion : Or elfe ( if that cannot be done ) to reft content 
with the little Imperfection that is ; which though, by more 
Pipes, it may be Ibmewhat abated, yet cannot be perfectly re- 
medied And in this I think we muft acquiefce. 
I am 
Tours to ferve you 
Oxford June 
2.7» i6p8. 
John Wallis. 
