scope (prop. 1 
sition, the reflecti 
142, Remarks on Dr. Enfield’s Institutes 
consistent with the supposition that the distance of the plane 
surface, either from the object, or the lens, remains unalter- 
ed. Those who will consult Rutherforth’s Optics, Ch. 
VIL. will see that this inconsistency has arisen from an at- 
tempt to blend into one, two propositions of which the con- 
ditions were different. We will add, although the remark 
has no relation to the last edition, that the mistake in the 
statement of the magnifying power of the double micro- 
a} se from prec 
at the limit of distinct vision. In uniting these two propo- 
sitions into one, Enfield. inadvertently retained the condi- 
tion of the former. Siete RR 
Prop. 44.. “ Reflection is caused by the powers of at- 
traction and repulsion in the reflecting bodies.” ‘This pro- 
position is altered and abridged from the following in Ru- 
therforth: ‘ Bodies refract and reflect light by one and the 
ame pi rently exercised in different circumstan- 
es.” ‘The illustration of this proposition by the original 
Z ion - 
(ia regard to which so much pains had. been taken 
in the previous: scholium to exclude other hypotheses,) is 
entirely omitted. The student is left to wonder why * at- 
racti is mentioned in the proposition as having any 
cern with reflection; and the identity of action in the - 
iam ich refraction and reflection are produced, is 
t out of his sight) if ES 
Prise: 46. Schol. Although perhaps nothing positively 
erroneous is advanced in this scholium concerning Sir Isaac 
Newton’s theory of fits of easy transmission and reflection, 
we cannot but object toa naked statement of a theory, 
tripped of all the facts which it was formed to explain, and 
k 
4VCrLilit 
‘made at the same time in so obscure a. manner as must im- 
