( 3^43 ) 
7. Demonftrates, that the long TelefcopeSj which ferve to 
fee remote objedts^may alfo ferve to fee near objedls that arc 
fmalU 
g, Demonftrates theConftruftion of Microfcopes, to fee 
the fmalleft Objeds. 
9. Shews the Conftrudion of a kind of Mixt or Ca- 
tadioptrique Telefcope, compofed of Refradion and Re- 
flexion. 
10. Shews, that one may fee at one and the fame time^with 
both Eyesjone and the fame Objed.by a Telefcope 5 and how 
to make fuch an one* 
1 1* Treateth of the Proportion of the refpeftive Convexi- 
ties and Concavities of Glaffes^to ferve for the conftru(9:ion of 
a Telefcope* 
The Third part of this Volume is fubdivided into two^which 
the Author calls the Po/itive,2ind MechamcaLThe Pofitwe teach* 
eth the aftual Conftrudion of Telefcopes^and their Ufcs^ and 
thatin 12 Sedions^ 
!♦ Delivers the manner of proportioning pofitively the 
Power of Glafles for Telefcopes ; together with the choice 
of their figure, though fpherical, and the tryal and gradua- 
tion of their goodnefs. 
3^ Teaches how to work adually all forts of Telefcopes, 
and how to ufe them. 
3 Teaches the manner, aftually to put into ufe the Cata- 
dioptrique Telefcope^which redrefs the objed by Reflcdion, 
that before had been inverted by Refraftion. 
4. Shews the way of making a double Telefcope in all 
Its kinds, to make Objefts to be (een by both Eyes at the 
fame time, much greater and much clearer, than with one 
Eye alone, 
5* Teaches in general,how to make aftually all forts of Mi* 
crofcopesjto fee diflinftly and to magnifievcry confiderably 
the fmalleft objeds. 
6. Treats of the Ufe of the Telefcope generally in all its 
kinds. 
7. Teaches a New and peculiar ufe of Telefcopes , for 
drawing 
