Chap, 4.] Qbjffts in Water magnified. 205 



ed, for the ray AC, (fig 7.) on coming in contact 

 with the furface of the refracting medium E F, does 

 not continue its courfe in the {trait line C b, but being 

 refracted at the point of contact C, it approaches the 

 perpendicular P p, and comes out at a. 



After coming out of the refracting medium, if we 

 fuppofe the furface G H parallel to E F, it ought to 

 proceed to B, having deviated from the perpendicular 

 in the fame degree in which it approached it on its firft 

 refraction, and thus it continues parallel to the line C B, 

 which is that in which it would have proceeded, if ic 

 had not been intercepted by the medium. 



This parallelifm cannot fubfift if the two furfaces 

 KL, HI, (fig. 8.) are inclined, as in the figure, be- 

 caufe the ray entering at a y and emerging at b, the ob- 

 ject A will be feen from the point B at e, which is out 

 of its true place. 



Converging rays become lefs convergent in pafling 

 from a rare to a denfer medium, as from air into wa- 

 ter ; and on the contrary, their convergence is -aug- 

 mented by paffing from a denfe to a rarer medium, as 

 from water into air, (See fig. 5.) In the fame man- 

 ner, diverging rays become lefs divergent in paffing 

 put of a rare medium into one which is denfer, and 

 their divergence h increafed by paffing out of a denfe 

 into a rarer medium. (See fig. 6.) This fact is A 

 necefiary confequence of the general law of refraction ; 

 but it will fatisfactorily explain why an object under 

 water appears larger to an eye above the furface than 

 it really is; and why all objects appear magnified feen. 

 through a mift ; for in all thefe cafes, the converging 

 rays, by which we fee the extreme points of the object, 

 and which during their pailage through the water, &c, 

 were refracted towards the perpendicular, on their 

 emergence into the air are made more fuddenly to 



converge, 



