The iocIioatioQ of thefe two Drums is to taove in a proper 
tioD to the double'^; bucthe exiger cy of 
the ioftrumeoc makes them move difiTe- l^-^.f 
reotly from their iDClmation : bo that this 
is the jeofitiveOfgaa^^i which the Soul is to take notice of 
what is there afted. 
Betweeo ihe two drums there is no ^ Though the Author 
Mr properly fo called,"^ but on!y_ an ^^^^.Z^l 
which fcCOnding the ioclioations of^. tweenthe Drums? yet 
the drums to motion, and the motions admits of fuch Air in 
, - f. %% \ ' J- tne Cavern , and wjthin 
themlelveSjprelcrves all the inttrmediat theo^ Pttrcfum , the in- 
inclinations and m3tiQns.Aod the reafc- ^^rd part of theEar5be- 
, , o i • • 1 caule the Drums would 
DablcSoulpermanent lo its Dature,plac- j^ay^ no motionatalj; if 
cd in the flittiogBody as theForm there* there were nothi.ng bu-c 
of.bath this natural proper y,to make f;':;rugri;t 
what is temporal permanent, that is to mov'd by any other 
fay, to ftay Time in her fe!f, and to col- tiding, yet it cannot be a 
\ „ , - / , . J- ' means ^o convey motion 
led: all the times or the lotermediate in- from one body to ano- 
clinations and motions^ which are ia the ther.ic is ^l£b/J^,theia- 
, . . c I- • L fu L tcrnal inftrument or the 
Aura 5 m the doing gI wnicn , ine aD- Mover, tharJodges there 
ftra£ls from matter two things that are wuhin.hut not of ar,y Mo- 
dcmonftrated to be proporticnaMs the See 
logarithmcs,ofthe two Ration % ^ one of 
the drums IncliosiioDS to motioDj and the other of the drums 
motions themfelves- Whencethe Soul in hearing h^th al- 
wayes ready the two Ration double in ad, and haif cf the 
double in ^ inclination ^ of which Ihe 
makes ufe for meafures to apprehend ali atadeiu doppu,) 
th^ rations of Sounds. . , ' r 
If the Ear be within a Sonorous Sphere ,, the particles oi 
the Air affiled by the found do enter at the external pare 
of theEar, one after the other, and all pafsin order, through 
the fpiral wayes that are there, to the bottom of the Ear, 
where every one ftrikes the drum, and after that , by other 
fpiral wayes, iffue out of the Ear again, and (o give place to 
other particles of air, that fucceed to do the iame. 
The external drum being ftruck once, QiaKes frequently^ 
and, by means of the ihree little bones, the internal drum an- 
fwers to it ia a double frequency i and the anr,,m the cavern 
Eeceeee 2 ok 
