^P4 Statural Hijlory 
and formation of pores^ as was fuppofed 24. of ihc^x^ Cha- 
pter of this Bcok.* Whence alfo 'tis equally eafie to make thefe 
three following IUations» 
!• That firings agreeing in either lengthy ^ig^^ft-> or tenfion^ can 
be made unifons but four ways. i . If they be of the fame 
lengthy bignefs^ and tenfion Q^r Caf,u Hyp.i.J 2. Of the fame 
lengthy and one a cize and tenfwn equally greater than the o- 
ther (per Caf,^^. Hyp.i.J 3. Of the fame ci^e^ and one a length 
tnd tenfion equzWy greater (per Caf. 2. Hyp.i.J 4. Of the 
fame tenfion., and one as much longer as 'tis lefs ( per C^f. 5 . 
Hyp, 2.) and after the fame manner when they difagree in 
all three^ as will be obvious to the confidering : Wherefore 
unifons are always (Irings of the fame, or a proportionable 
lengtk^bignefs^znd tenfion. 
2. That unifons may be moved by the fame force^ in the fame 
time ; or being moved by the fame or an equal/orce, will 
vihrate'm the hmttime ; as is manifeft in the fore-mention- « 
ed CafeSj to which all others bear Analogy. 
3. That Graves being moved by the fame or an equal /orce, the 
upper will vibrate in half the time, that the under does, or 
twice to its once (T'er Caf. lis'^- ^yp^i* is>' Cafi i, 6, 7, isf 
9. Hyp. I.J wherefore they can by no force be made to z/i- 
Irate together ; for as much as the fame firing (being of the 
fame length and tenfion J always vibrates in the fame time ; a 
greater /orce only making it fly out to a greater difiance^ or 
fetch a greater compafs in its vibrations^ and thereby move 
(but not vibrate ) fafter, per Concluf, poft Prdemiffa6, And 
P the fame is verified concerning all other Notes, 
205. Having done with his firfi Principle^ with the Hypothefes, 
and feveral Ofis attending it, the fame Reverend and Learned 
Dr. N, M, proceeds to his fecond Principle^ viz^ Tbat all tuned 
firings either are or confifi of unifons., which will plainly appear from 
the divifion of the Monocbord; where, 
1. Vnifons are as AB to BC, Pig- 6* i to i party or vibration., per 
lllationemu isr 2. 
2 . A Diapafon or OEiaves^ as EC to CD-> Fig. 7. 1 to 2 Vnifons, or 
2 to I Vibrat.per Illat. 3. 
3. A Diapente, or perfeft fifths^ as CD to Fi^. 8. 2 to 3 
Vnifonsy or 3 to 2 vibrat, 4. A 
