( 
4» Signor Dj^7«i*s account of the Satellites of Saturn ^revt' 
ry remarkable. We hear of no expedients to view the hack- 
fiinsof cur Moon i but poffibly by future improvements of 
Telefcopes we may make fome guefs of the back parts of feme 
of the Moons of Saturn or Jupiter^ as Monfieur huUialdtis hath 
found blind fides of the Starry Firmament, as we call it. 
%* Tis vvellforus, thacMr. is an indefatigable perfon. 
For, this his latter Task requires a mans age to perform itfo 
exaflly as he hath. done : Befides his othe-r great labours , and 
what we expeft from his help for the Hijlory of Animals. 
6. ,/tro'chaiinos was very neceffary after fo maay wonderful 
difcoveriesof jf/>in.genera!. Much rich Oar is already digg'd 
cut of the Heart and from the bottom of Rocks and Mountains; 
but we wanctrany hands to melt ic down, and to form it inio U- 
tenfils. Thefe fubtile Fluids do encompafs us in vaft proporti- 
ons, and do befiege us both with ftrong and ftormy violence, 
and with treacherous and irrefiftible Infinuations. May the hap- 
py Author perfevere, and profper in compleating the large 
branch of moft fubtile and no lefs ufeful philofopby. 
7. I do not remember, I ever faw any thing that might be 
compared with this laft philofophical Account of ^jMnfck ; nor 
indeed any thing before, that could fatisfie my own poor and 
dull fcruples. And many of thefe Obfervationsdo fcem tome 
to open a door for great depths , and great variety of Philofo- 
phical information. I was not a little delighted to read in Mr. 
Bcyle^s Traft of Mens ignorance of the Ufefulnefs $f Natural 
Things, in his Second Tomeof the Ufefulnefs of thatPhilofo- 
phy, p.14, ThdLi equal wire- firings y made of d/Jffring wettals, 
and having a due Tenfion^ mil yield founds differing as to (harfnefs^ 
by determinate Mujical Notes or the Divifions of them^ I do 
not know, whether this Author, Merfennus^ or any other , hath 
examined. How far the proportions of Metalline mixtures, or 
the nature of other fonorous bodies, may be indicated by this 
Mufical Expedient. Many fuch hints and overtures may be had 
in this acute, or rather harmonious difcourfe. 
'J 
