[ *« 3 
which compofc the fundamental Sound, by vibrating 
each its particular proper Fluid at the Fame time; juft 
as the Afiemblage ot all the different primitive co- 
loured Rays meeting together, makes the white Co- 
lour or Light : And fo the Ear of a good Mufician is 
a kind of c Prifm> which can feparate and diftinguifh 
the Sounds or Tones from each other in xhs funda- 
mental Sound . He gives an anatomical Defcription 
of the Organs of Hearing j and has added fome good 
Figures of the external and internal Parts of the Ear, 
with the Euflachian Tube, much after the manner 
of Du Verney . 
He has aifo the Figure of an Inftrument, Page 292. 
to help thofe that are hard of Hearing, which he 
claims the Invention of. The particular Form of this 
Inftrument may be new to the Author ; yet we have 
had of this Kind in Ufe many Years in England for 
the fame Purpofe. He finifhes this SeXion with fome 
Reflexions upon a young Man of a Town called 
Chartres , who was born deaf and dumb, and whofe 
Hearing fuddenly came to him, and who fpoke fome 
Months after. In this Place he has a very good 
Figure of the Bafts Cerebri , by a tranlverfe Section 
through th q Frontal Sinufes a little above the Eyes, 
and continued through the temporal Bones ; demon- 
ftrating the Originations and Exit of the Nerves, 
with the Conjunction of the vertebral and carotid 
Arteries , according to the DifleXion of the famous 
Willis ; and then proceeds to his laft SeXion, which 
treats of Seeing . 
This SeXion, in a word, is on the Structure of the 
Eye, and all the Phenomena of Vifion. He begins 
it with the DoXrine of Lights and Colours , making 
ufe 
