{a) The firH Figure in the upper part ó f the Plate is a
Man founding a Flute upon the Stairs*leading to the Hall
{b) T|edirftGate-houfe, "1
" Xc) A Mart Handing about gcrYa'rds from the firH Gate-
, houfe, where obferve that the Sound is not then difcernible
at the fir ft Letter (a)3 from whence the Man founds the In
Hrument, but at the Letter | j | which is another Gat?
houfe Handing as defcrib’d in the Cut. *
(^Lfs a Man nËoving about io Yards nearer to the Gate-
houfe (cj, and then the Sound is not difcernible from the
Gate-houfe (e), as it was before, but from the firH Letter
rW Bméi the Hall-Hairs, where’ thé Man is 'founding the
TnHrument.
Thefe Phaenomena clearly demonfira-te to us, that'the
Motion of Sound is undulating euwaving, and not in direét
Lines ; fo that thejsound being fepercuffed fromlM lthe-
firH Gate-hopfe, the, Undulation from thence pafies by the
Man Handin^at ip , but is repercuffed again from the Gate-
houfe^), from whence th e ‘Undulation o f the Air being
much greater, it -there terminates at and that is the
Centrum Thoiiocampticum, or Center o f Sound in that
place : Rupthe Man Handing at fc\ moving to-1 the Man
fiandmgift { d f then the Sound vanifhes from the Gate-
houfe 0 , but-is very difcernible from (a), where the Mari
isfounding the InHrument; and the reafbn is very obvij
oxvs, betaufe the\jndulation o f the Air paflesby him Handing
at (d), but i§ repercüfied Vgain from the Hall, from
whence it terminates at (d), which W the Centrum
fhonocdmpticum, or Center of Sound in that plape.
_ The lower pagt of the Plate fheivs the Flafoes-of'Lightning,
thelargenefs of the Hail-Hones that fell in that Storm
and Hares and Birds that were kill’d by them.
T h a t th e E x p lic a t io n e ft th is P la te r e fe r s to th e j a f l ‘P la te E n g ra ven by Mr J3urghws o f Oxford, fig u r e d TAB. i. a n d th e E x p lic ittd n 'o f M r lo^'nd.ey’s M i-
c io fn e tie , as lih ew tje Mr. Brotlierton j- E x p e r im e n ts d e fc riE d m th e B o o k, re la te to
M r. BuiM)ei j fe c o n d P la te , fig u r e d TAB. a. w h ere h is various E x p e r im e n ts concerning
th e C ircu la tio n o f th e S a p in T re e s, are fu lly 'd efcrtb 'd , being ta ken fro m th e ortgttialy d's
Hkewifte th e O b ferva tio h s m ade by th e M ic rom e tre ; ■ ƒ th o a g fifiA t hecefja ry n o t to ■ >‘
C u ts w ith th e re ft, becauje th e y w ere th e ft ■G en tlem en s, a n d n o t m in e .,