VOL. Lll.] PHILOSOPHICAL TRANSACTIONS (5l3 



sel, it was nearly as low as the .paper. Pouring water into the vessel, and viewing 

 the shilling through the medium of water, with one eye, while he beheld witVi 

 the other eye, where the edges of the shilling were projected on the paper, and its 

 parallels, he found the shilling appear larger, at every additional inch depth of the 

 water; and this was the case if either eye was used; and the same when the eye 

 was removed far from the surface, or near to it, or in any position to it. 



He took large vessels, filled them with water, and placed different bodies at the 

 bottom of those vessels. It always followed that the greater depth of the water 

 he looked through, in the direction from his eye, to the objects in the water, the 

 nearer those objects appeared to him. Thus light bodies appeared more mellow 

 and faint, and dark bodies rather better defined, than out of the water, when 

 they were not deeply immersed. And thus they appeared, under whatever direc- 

 tions or positions he viewed the bodies. 



He placed different bodies in proper vessels of fair water, and immersed his face 

 in the water ; viewing the bodies in and through tue water, they all appeared 

 plain, when not too far from the eye, and though a little hazy at the edges. 

 they appeared much enlarged, and always larger through a greater depth of water. 

 Thus a shilling appeared nearly as large as a half crown, within a red glowing arch 

 on that side opposite to the sun, when the sun shone on the water. From this 

 experiment he concluded, that divers see light objects not only larger, but very 

 distinctly in the water. 



These and several other circumstances being considered, they left him with 

 but little doubt, whether the atmosphere refracts horizontally or not, as some 

 protuberances observed in the sun's limb must have been wholly owing to such a 

 cause, and the nearly allied strata in the atmosphere. That the apparently formed 

 mountains of trees and bushme«its at sun-rising, so easily comparable with other 

 trees and bushments of equal magnitude at other times, but in their affected state 

 as much larger, must also be owing to the same cause. He therefore concluded 

 that these were proofs that objects seen through a medium of greater depth or 

 density, do appear more large ; and that therefore not only the sun and moon, 

 but that all other objects seen at great distances under a horizontal direction, d(> 

 appear larger to the naked eye, than objects of equal magnitude and distance ap- 

 pear when seen under a vertical direction. 



Though the quantity pf medium, with its density, be here mentioned, as if it 

 was the efficient cause of this effect, possibly it may be some other cause in the 

 horizontal vapours, water, and other mediums which produce effects nearly pro- 

 portionate to the difference arising from a comparison of the quantity of medium 

 or density. Whether this effect arises from density or rarity, reflection, refrac- 

 tion, or inflection, acceleration, retardation, or absorbency of the rays, seems to 

 deserve a proper inquiry. What others may find to be the cause of this phe 



