...the blue colour of the sky, and the bright azure which tinges the mountains of the distant landscape. As we ascend in the atmosphere, the deepness of the blue tinge dies away ; and to the aeronaut who has soared above the denser strata, or to the traveller who has...

...ascribe the colour of the sky, and the bright azure which tinges the mountains of the distant landscape. As we ascend in the atmosphere, the deepness of the...passage through the attenuated strata of the atmosphere. It is owing to the same cause that the diver at the bottom of the sea is surrounded with the red light...

...the blue colour of the sky and the bright azure which tinges the mountains of the distant landscape." He adds : " As we ascend in the atmosphere the deepness...denser strata, or to the traveller who has ascended the AJps or the Andes, the sky appears of a deep black, while the blue rays find a ready passage through...