Observaciones acerca de las Reflexiones, Refracciones y Colores de los Cuerpos transparentes delgados

tanto como los producidos por el aire enrarecido en la séptima Observación. Pues allí se dilataban tanto que, al ser observados del modo más oblicuo, llegaban a una parte de la lámina más de doce veces más gruesa que aquella en la que aparecían cuando se observaban perpendicularmente; mientras que en este caso el espesor del agua al que llegaban cuando se observaban del modo más oblicuo guardaba con aquel espesor que los mostraba mediante rayos perpendiculares una proporción algo menor que de 8 a 5. Según mis mejores observaciones, era de entre 15 y 15-1/2 a 10; un aumento unas 24 veces menor que en el otro caso.

Sometimes the Bubble would become of an uniform thickness all over, except at the top of it near the black Spot, as I knew, because it would exhibit the same appearance of Colours in all Positions of the Eye. And then the Colours which were seen at its apparent circumference by the obliquest Rays, would be different from those that were seen in other places, by Rays less oblique to it. And divers Spectators might see the same part of it of differing Colours, by viewing it at very differing Obliquities.

Now observing how much the Colours at the same places of the Bubble, or at divers places of equal thickness, were varied by the several Obliquities of the Rays; by the assistance of the 4th, 14th, 16th and 18th Observations, as they are hereafter explain'd, I collect the thickness of the Water requisite to exhibit any one and the same Colour, at several Obliquities, to be very nearly in the Proportion expressed in this Table.