Amédée Guillemin

“ Such hypotheses, far from being of injury to science, are indispensable for its progress: they stimulate the observer's mind, constantly suggest to him fresh observations, and become a hinderance only when they are held to be demonstrated truths, and when men refuse to give them up after they have been proved to be erroneous, or after they have served their purpose.—La Nature. ”

“ Among the weightiest of these, the one which compares temporary stars to variable periodic stars must be rejected at once—not on the ground that these two classes of stars are absolutely distinct, but because the periodicity being due, either to a movement of rotation or to occultation on the one hand, or to a phenomenon peculiar to the star itself on the other, the first hypothesis is clearly inadmissible for the explanation of new stars, and the second is precisely the question to be solved. ”

“ The spectrum of the other portion of the star's light probably showed that this terrible conflagration of gas had surcharged and rendered more vividly incandescent the solid matter of the photosphere. When the free hydrogen had been exhausted, the flame died away by degrees, the photosphere became less luminous, and the star returned to its former state. . . . We must not forget," adds Mr. Huggins, "that light, though it travels with such great velocity, nevertheless requires a certain time to come to us from the star. ”

“ Before we come to the two latest temporary stars, which have succeeded each other in an interval often and a half years, and which are worthy of a detailed description, let us briefly state the questions to which these apparitions have given rise among astronomers, and the hypotheses which have been offered for their solution.
To what causes must we refer the nearly always sudden apparitions of these strange bodies, their variations of lustre, their intermittence, as also their changes of color? ”

“ At Paris, too, the sky was almost constantly overcast for some days after the reception of Schmidt's letter. By taking advantage of infrequent and imperfect seasons of clear sky. Prosper Henry succeeded in observing the new star. Compared with the star 915 of Weisse's catalogue (hour 21) , it had this approximate position:
It was of the fifth magnitude, and appeared to be of a greenish color, almost blue, as compared with a neighboring star (42,304 of Lalande) .
The new star was also observed at Vienna by Littrow. ”

“ In Tycho Brahe's time it was not known that the light of the Milky-Way results from the aggregation of an indefinite number of stars, or stellar masses, and that it is within this immense agglomeration and in its vicinity that the nebulæ properly so called are rarest. ”

“ Though the temptation is strong to draw from this fact conclusions as to the physical condition of this new star, its temperature, the chemical reactions it must exhibit, I will make no comments, nor offer any hypotheses. We lack, I think, the data necessary for reaching a profitable conclusion, or at least a conclusion that can be verified. However attractive such hypotheses may be, we must not forget that they He outside of the domain of science, and that, instead of being of service to science, they are likely to hinder its progress. ”

“ So far the constitution of this star resembles that of the sun; but it offers an additional spectrum composed of bright lines. Here, then, is a second source of special light, and this source must be a luminous gas. Furthermore, the two principal bright lines of this spectrum show that this gas consisted mainly of hydrogen; and their great brightness proves that the temperature of the luminous gas was higher than that of the photosphere. These facts, taken in connection with the suddenness of the outburst of light in the star, its immediate
Fig. ”