C S39 ) 
PHILOSOPHICAL 
TRANSACTIONS. 
23. 1677. 
The CONTENTS. 
'^Letter of Dr. ^z\\\s^4:onc€mwg a neyv^!MulicalDi[c6verj* 
Jn Imfrovement of the Bononian Stone ^ Jbwingm the dark. 
Extraif jof a Letter out Scotland, concernifig a man of d 
grange Imitating nAture\as alfo of jeverd human calculus's, of 
anunufual hignejs. Mr.Lce^'eDhotcksLetter^givingfimeae^ 
count of the manner of his ohferving fo vaft a number of live In- 
feCis in fever al forts of vpater^ as was fxid in the next foregoing 
tract. A Continuation of the Hortulan and Rural Jdvertife- 
ments^ formerly fromifed. A Letter of ^JVlonJieur Hcvelius^ 
delivering his Obfervations , made for fever al years together^ 
concernifdg ^hree New Stars. An Account of tm Books : 
I. Traite de la PERCUSSION ou CHO^ des CORPS; par 
Monfieur Mariotte, t Academic Roy ale des Sciences ^ a Paris* 
II. JohanniTrithemii StEGANOGRAPHU, vindicata^ 
referata, ilJuflrata : Auth, Wolfgango Ernefto Heide! ^ 
Wormatienfi. 
Dr^NdWxss Letter to the Publi^er^ concerning a new Mujical 
Difcover/\ mitten fromOKfordyMarch 14. 1677. 
SIR, 
IHave thought fit to give you noiice of a difcovery thac 
hath been made here, (about three years fmce, or more) 
which I fuppofe may not beunacceptable to chofe of the Royal 
Society^who are Mufical and Matheaiatica!/Tis this ; whereas ic 
hath been long fince obfervedj that, if a Viol ftring, or Lute 
firing, be touched with the Bow or Hand, another ftring on the 
fanje or another Inftruojent not far from ir, ( if an Unifon to itj 
