Of Light and Colours.

The several Sorts of Rays, after theyare refracted, appear in their own proper

Colours

the Thickness of the Glass O E, In Diamond, it wouldhe at the Depth of } of the Thickness, and soon for allthe other Bodies mentioned in the foregoing Table.

32. On the other Hand, as the Point C recedes fromthe Point O, the Angle CEO, which is etjual to theAngle of Incidence E C D, becomes greater, and there-fore also the Angle of Refraction HCK, or the re-fracted Ray H C, will have a greater Inclination to thehorizontal Line A B, and therefore also C F ; on whichAccount ’tis evident the Distance of the apparent Placeof the Object, viz. the Line O M, will decrease, andof course the Object will seem to rise in the Perpendi-cular. And when the Angle CEO is so great, thatthe Ray C H is refracted parallel to the Horizon or be-comes coincident which A C, then C M will becomeC O, and the Object at the Bottom at E will appear onthe Surface of the Medium at O.

33. In this Cafe, if the Medium be Water, we haveC E : C O :: 4 : 3, whence we shall find OE — 2,65nearly ; therefore in any Veflel, whose Width is 2 C O

6, and Depth OE — 2,65, when fill’d with Water,any Object placed at the Bottom, when viewed in thePerpendicular, will appear raised from E to M, \ of theDepth ; and as the Eye recedes from the Perpendicularto the horizontal Line A C, the Object will appear torife from M to the Surface of the Fluid at O; all whichMay be confirmed by pouring Water into a commonTea-Difh, or Bason, and viewing the Flower, isc.Painted at the Bottom.

34. Hence appears the Reason why a straight Stick, asN C E, when placed with one Part C E in Water, willalways appear crooked, viz. in the Form N C M, thePart C E being raised by Refraction into the apparentSituation C M ; and the Part under Water will alwaysAppear shorter, for E C will be contracted into C M.All which is known by common Experience.

X 4 35 - Also,