But this argument is not conclusive, for though the total number of hydrogen molecules is fixed when the gas is enclosed, yet the number of luminous molecules may vary with the condition.
But during the first nineteen months of my life I had caught glimpses of broad, green fields, a luminous sky, trees and flowers which the darkness that followed could not wholly blot out.
When the interval is very small the discrepancy, though mathematically existent, produces no practical effect, and the illumination at B due to P is as important as that due to A, the intensities of the two luminous sources being supposed equal.
Combinations of rays sometimes resemble a luminous fan, or a series of fans, or part of a hollow luminous cylinder.
In these three volumes, which appeared at long intervals, the author's theories are not always in complete harmony, nor are they always presented in a very luminous or coherent manner, but they are marked by originality and vigour.
The distribution of illumination in the image of a luminous line is shown by the curve ABC (fig.
Helium stars are generally considered to be the hottest and most luminous (in proportion to size) of all the stars.
In another respect the observations of Fraunhofer appear at first sight to be in disaccord with theory; for his measures of the diameters of the red rings, visible when white light was employed, correspond with the law applicable to dark rings, and not to the different law applicable to the luminous maxima.
Mysterious doctrines are ascribed by Protestants to scripture; so half of revelation is regarded as matter for blind assent, if another half is luminous in experience.
It spontaneously inflames in air or oxygen; and when the gas is issuing from a jet into air the flame is greyish green, with a faintly luminous and yellow tip; the flame is probably one of the coldest known.