[ 44 $ ] 
and nail Points under the Heads of the Keys, it is 
manifeft, that if an Organift play a Minim upon c y 
that is, if he prefs down c for the Space of a Second, 
the Nail will make a Scratch upon the Cylinder of 
i Inch in Length, which is my Mark for a Minim . 
Again, if he reft a Crotchet ? that is, if he ceafe 
playing for the Space of half a Second, the Cylinder 
will have moved under the Nails half an Inch with' 
out any Scratch 5 but if the Organift next preffeth 
down d for the Space of half a Second, the Nail 
under d will make a Scratch upon the Cylinder half 
an Inch long, which is my Mark for a Crotchet . It 
will likewife be differently fituated from the Scratch 
that was made by c> and confequently diftinguifhed 
from it as much as the Notes now in Ufe are from 
one another by their different Situation in the Lines. 
{Vide Fig. 1.) ‘ 
Thefe three Inftances include all that can be per- 
formed upon an Organ, &c. (Maxim I.) 
Therefore it is already demonftrated, that whatever 
is play’d upon the Organ during one Revolution of 
the Cylinder a {Fig. 2.) will be infcribed upon it in 
intelligible Characters* 1 proceed to fnew how 
this Operation may be continued for a long time. 
In Fig . 3. aa, b, c , d y are the fame as in Fig . 2. Let 
^ be a long Scroll of Paper wound upon fuch a Cy- 
linder as Let eeee be the fame Scroll brought 
over the Cylinder a a, to be wound upon the Cylin- 
der yy , as faft as the Motion of aa (which is deter- 
mined by a Tendulum) will permit. 
It is manifeft, that whatever is play’d upon the 
Organ during the winding up of yy will be written on 
the Scroll by the Pencils b, c , d, &c. 
All 
