92. ESSAYS ano OBSERVATIONS 
mitted through its fabftance to the greateft 
ditances, viz.if the rays are always put 
into a new fit of moft eafy tranfmiilion at 
entering every new pore or particle. But 
is nat that fuppofition contrary to what 
Sir Ifaac teaches elfwhere, that the fits 
of reflection and tranfmiffion continue to 
return at equal intervals, after a ray has 
entered a tranfparent body, and are thus 
regularly propagated to the greateft dif- 
tances *? And, if this be true, how can 
the rays be tranfmitted to any fenfible 
diftance, fince they muft often arrive in 
fits of eafy refieCtion at the common fur- 
faces of pores and particles? But, al- 
though it could be underftood by the 
doétiine of the fits in light, why there ig 
no refiection from the interior’ parts of 
water and other pellucid mediums T, does 
not the rectilinear tranfmifficn of hehe 
through thefe bodies in all direGtions, and 
confequently in all degrees of obliquity, 
to their internal parts, prove, that thefe 
| pitta 
* Newt opt. book 2. part 2, prop. 12. - 
T ibid. book 2. part 3. prop, 4. 
