Be ah oN TC 3b Say 
288 Mr. GoopricKe gi the Period of the 
‘Mean times of Algol’s 
leat Baer ' Nat: 
1783 h. altiy. 3S sg gow GL | ieee 
ee cae oe i an ipteryal of 99 revolutions, exch of 2 20 49. 14 

Q&, 25,6 4 
Jes. : oH Ditto 106. Ditto 2 20> ‘ay Bi hy 
Jon! 14 9 251 Dito 107 Dito 1) geod 
Li : a Ditte ‘gI Ditto 21) 20) 4puare 
<a ae ae aoe 
Nes a 5 ra Ditto 99 ‘Ditto 2 20 48 el 
ve - 2 eg Ditto 84 Ditto = 220 49 M4 
Fs $609. I se este oo 
i eH A nat Ditto —g2 Onttoet ae a 20 49° 9 
fee fF p oteabine of campog Dian 1 bale, iid 
a ee ee 
Hence the period of Algol’ variation is, on a mean, By 2 08 

t) 
T could have added feveral more comparifons: ef the ies 
kind; but thefe are, I] think, fufficient. It is to be remembered, 
that all the obfervations contained 1 in the above table are canny 
to mean time. Mf } 
It appears to me mow, that the’ duration ‘of the variation is 
about eight hours; ‘but, as it is difficult to hit exa€tly the be~ 
ginning and end of the variation, this may occafion different — 
obfervers to differ in this refpect. Before I conclude, I beg 
leave to mention a circumftance deferving of notice; which is, 
that 
