Part IV. Natural Pbilofopby. 
359 
but alfo to keep the Flame of equal drength, for all fuch 
purpofes as require it. 
The MODEL of an EYE. In which the Humours are 
reprefented by Glades of an anfwerable Figure. 
A BURNING-GLASS, about half a foot in Diametre 
A HOLLOW BURNING-GLASS. That is to fay, two 
thin concave GlaiFes fet together, and fo to be fill’d up with 
water when it is us’d. About the fame bignefs as the 
former: but burneth not altogether fo ftrongly.Contrived 
and given by Dr. John Wilkins late Bifhop of Chejier. 
A Large MICROSCOPE, with three Glalfes, and feve- 
ral Screws to fit it for all manner of pofitions. It magni¬ 
fies the Area of the Object to above a hundred times the ex¬ 
tent thereof to the bare Eye. 
A Leiler MICROSCOPE, fomewhat more managable 
than the former. 
The advantage of one with more GlafFes, is that it takes 
in a bigger Object, or a greater part of it. Of one with 
a fingle Glafs, that it ihews the Object clearer. So that to 
have a didinct reprefentation of it, ’tis convenient to make 
ufe of both. Of the latter kind, I have feen feveral made 
by Air. John Mailing in this City, not only with melted, 
but with Ground-Glades fo very fmall, that one of thefe 
Ground-Glades being weighed in the AJfay-Scales in the 
Tower , was found not above the fourfeorth part of a 
Grain. The Diametre or Chord >V h part of an inch. 
Another, fo fmall, that thofe Scales were not nice enough 
to weigh it. The Chord hereof to that of the former, 
is as two to three. Thefe are the cleared and bed that ever 
Ifaw. 
An OTOCOUSTICK,or Indrument to help the hearing, 
made of Ivory. In fhape like a Funnel , faving that the Abfe 
is bended for the more convenient application to the Ear, 
and reception of the found. Given likewife by Bifhop 
Wilkins. 
Another of Copper, funnel’d at one end, as the former, 
and alfo belly’d in the middle. 
A Third of Tin, of a Conick. Figure, and with a Cochlea 
within it. The bed of all the three, is the fird. 
A Pair of HYDROSTATICK Scales. Ufed, amongd 
other purpofes,to examine the fpecifick Gravity of Bodies. 
A 
