C ) 
or three times longer then broad, thefe fometimes tare 
themfelves round on their ^x^j and Diameters as they 
go, they confift of Tranfparent and Opacous Parts. 
The firft of thefe natural Microfcopes performs k$ 
effeds by the fame Laws, viz. by the Refradlioa 5" 
the Rays of Light, as do the Glafs ones, and differs 
from themin nothiogbut its material Water : But when 
I began to attempt to fatisfie my ftlf how Objeftsare 
diftinftly feen in a Spherule of Water I found it at 
firft fomewhat difficult to explain, for whereas (M?//. 
muxy S. S. Dioptrka Nova Prop. XXXIL) OhjQ&s 
being placed in the Focus of a Convex Glafs (and con« 
fequently of Water) are feen diftinftly to the Eye, on 
the other fide the Glafs, ^and fo theReafon of the for- 
mer is obvious enough ; but 'tis as certain QDkptrica isr<?« 
va, Pr(>p. XLl Confered with Prop. XXVIII.) that if 
an Objedt be placed fb much nigher to the Eye then 
the focus of a Spher, as to be within its Surface, the 
Rays of Light muft come too much Diverging to Ihew 
the Objeds they come from diftindly. 
But at length, that other known Property, if I may 
fo call it, of light falling on different Mediums coming 
into my thought, viz. Refiedion, I found there might 
be a very eafie and natural Reafon given of its Perfor- 
mance , wjbich I 0iall now endeavour to demooftrate, 
upon fuppofitipn that the inferior Surface of the Splier 
is Refled:ive. 
Let the Circle in Figure 8. reprefent a Spher of 
Water, ^ an Objeft placed in its Focus, (ending forth a 
Cone of Rays, two of ^ which are AE A B which Op- 
ticians know coming into the Water at B and will be 
Refra(9:ed from their dire(3: Courfe and become B D at 
Dy they will, at their paffing into the Air, be again 
Refradedinto £> jSDJS, and lo run Parallel to one ano- 
ther, and to the axis of theSphear AE C6 now 'tis 
