The following details of the great new star of 1572--the "Pilgrim Star" of Tycho Brahé--are given by Delambre.[344] In November, 1572, it was brighter than Sirius, Vega, and Jupiter, and almost equal to Venus at its brightest. During December it resembled Jupiter in brightness. In January, 1573, it was fainter and only a little brighter than stars of the 1st magnitude. In February and March it was equal to 1st magnitude stars, and in April and May was reduced to the 2nd magnitude. In June and July it was 3rd magnitude; in September of the 4th, and at the end of 1573 it was reduced to the 5th magnitude. In February, 1574, it was 6th magnitude, and in March of the same year it became invisible to the naked eye. From this account it will be seen that the decrease in light of this curious object was much slower than that of Nova Persei (1901) ("the new star of the new century"). This would suggest that it was a much larger body. There were also changes in its colour. When it was of the brightness of Venus or Jupiter it shone with a white light. It then became golden, and afterwards reddish like Mars, Aldebaran, or Betelgeuse. It afterwards became of a livid white colour like Saturn, and this it retained as long as it was visible. Tycho Brahé thought that its apparent diameter might have been about 3½ minutes of arc, and that it was possibly 361 times smaller than the earth(!) But we now know that these estimates were probably quite erroneous. Temporary stars were called by the ancient Chinese "Ke-sing," or guest stars.[345] A temporary star recorded by Ma-tuan-lin (Chinese Annals) in February, 1578, is described as "a star as large as the sun." But its position is not given.[346] About the middle of September, 1878, Mr. Greely, of Boston (U.S.A.), reported to Mr. E. F. Sawyer (the eminent observer of variable stars) that, about the middle of August of that year, he had seen the famous variable star Mira Ceti of about the 2nd magnitude, although the star did not attain its usual maximum until early in October, 1878. Mr. Greely stated that several nights after he first saw Mira it had faded to the 4th or 5th magnitude. If there was no mistake in this observation (and Sawyer could find none) it was quite an unique phenomenon, as nothing of the sort has been observed before or since in the history of this famous star. It looks as if Mr. Greely had observed a new or "temporary" star near the place of Mira Ceti; but as the spot is far from the Milky Way, which is the usual seat of such phenomena, this hypothesis seems improbable. In the so-called Cepheid and Geminid variables of short period, the principal characteristics of the light variation are as follows:-- "1. The light varies without pause. "2. The amount of their light variation is usually about 1 magnitude. "3. Their periods are short--a few days only.