As a typical case we may review the history of Nova Aurigæ. On February 1, 1892, an anonymous post-card was received by Dr. Copeland of the Royal Observatory, Edinburgh, that read as follows: “Nova in Aurigæ. In Milky Way, about 2° south of χ Aurigæ, preceding 26 Aurigæ. Fifth magnitude slightly brighter than χ.” The observatory staff at once looked for the nova and easily found it with an opera glass. They then examined it through a prism placed before their 24-inch reflector and found its spectrum. It proved to be that of a “blaze star.” Dr. Thomas D. Anderson turned out to be the writer of the anonymous post-card—his name modestly self-obliterated by the nova’s light. He had detected the star on January 24, but had only verified it as a new one on the 31st. Harvard College Observatory then looked up its archived plates. The plates showed that it had appeared sometime between December 1 and 10. Its maximum had been attained on December 20, after which it declined, to record apparently another maximum on February 3 of the 3.5 magnitude. From this time its light steadily waned till on April 1 it was only of the 16th magnitude or ¹/₁₀₀₀₀₀ of what it had been. In August it brightened again and then waned once more. Meanwhile its spectrum underwent equally strange fluctuations. At first it exhibited the bright lines characteristic of the flaming red solar prominences, the calcium, hydrogen, and helium lines flanked by their dark correlatives upon a continuous background, showing that both glowing and cooler gases were here concerned. The sodium lines, too, appeared, like those that come out in comets as they approach the furnace of the Sun. An outburst such as occurs in miniature in the solar chromosphere or outermost gaseous layer of the Sun was here going on upon a gigantic scale. A veritable spectral chaos next supervened, staying until the star had practically faded away. Then, on its reappearance, in August, Holden, Schaeberle, and Campbell discovered to their surprise not what had been at all, but something utterly new: the soberly bright lines only of a nebula. Finally, ten years later, January, 1902, Campbell found its spectrum had become continuous, the body having reverted to the condition of a star.