344 The Variable Star Algol. 
Art. XXXIV.—On the Variable Star Bae, or § Perset; by 
Fr. A 
RGELANDER.* 
Axcot, or ? Perset, is aad one of the most remark- 
able of all the variable stars, on account of the shortness of its 
period, in general, and capeetally the ‘Hort time during which 
it continues at its minimum,—on account of the comparative pre- 
cision with which this minimum may be determined,—and the 
regularity with which the star goes through its period. This . 
regularity is so great that Wurm, even in the year 1819, that is 
to say, thirty-six years after Goodricke had discovered the peri- 
odicity of the variation of light in Algol, was able to represent 
all the observations by a uniform period, and did not venture to 
decide whether this period had become longer or shorter.t Nev- 
ertheless, the values of the duration of a period computed by him- 
self at various epochs, indicate the former of these —— 
From the earlier observations, comprising a series of 16 months, 
he found the period to be 2¢ 20h 48m 59s; after sixtealt yas 
nution of the time indicated by these ance: ‘hat been put 
beyond all doubt by modern observations, which have also shown 
that the amount of this diminution is not ‘proportional to the time, 
but is continually growing larger and larger. A collation of the 
duration of the period, as obtained by combining the nearly con- 
eous observations and-discussing these series according 
to the method of least squares, will show this very distinctly. 
we assume as the a oad bee that of the minimum which 
_occure d 1800, January 2, ing, Paris civil time, the first col- 
“umn of the following table 0 of periods gives the number comple- 
ted since this principal epoch; the second, the time; the third, 
the duration of the period which holds for this time, accompanied 
by the probable uncertainty of this latter determination. 
Periods of Algol. 
No. of minimum. Date. (..  hength of period. 
oe Ce a ae 2 
—1987 1784, May 27 220 48 5942 —- £032 
— 1405 1788, Dec. 21 5874 +009 
— $25 | 1793, July 11 58:39 +018 
751 | 1805, Nov. 25 58-45 + 0-04 
42398 1818, Apr. 13 5819 +010 
+3885 | 1830, July 3 6797 
6441 | 1842, Sept.20 | 55°18 0°35 
im.) 1848, July 18 | 5337 +008 
me glance at this table shows immediate!y that the snverels obser- 
eo eee bei represented neither by a uniform nor by a 
from the Astronomical Journal, No, 80, January 1855. _—- 
8 tronic ura for 183, 120, = 
