2 ‘Sir H. C. Encierieiy’s Obfervation of the 
and thought the time of its greateft diminution was about 22 h. 
in the morning; calculating from thence by Mr. GooprickeE’s 
period of 2 d. 20h. 48’, the time of leaft brightnefs was to “8 
about one o'clock this morning. ‘ 
All the following obfervations were made with an excellent 
night-glafs, magnifying about eight times, witha field of 5°, 
in which therefore Algol and the p were diftinétly vifible at 
once. 
I firft looked out at midnight, and readily found the ftar, 
though hardly vifible to the naked eye from the vapours near 
the horizon. It appeared much bigger than the g, and full as 
big again as the z, alfo in the.field at the fame time. 
At 123 h. I looked again, and faw but little difference, as 
Algol was then alfo evidently much fe cs than g. I at that 
time faintly peagcven it with with the naked eye. 
At 1h. ro’ the ftar was but very little bigger than p, the 
diminution having gone on moft rapidly in the interval be- 
tween the two laft obfervations. ‘Though higher above the 
horizon it was much lefs (if at all) vifible to the naked eye. 
At 1h. 35’ it was, I think, diminifhed (though but little) 
fince the former obfervation. It was ftill, however, a very 
little larger than , but notat all vifible to the naked eye. 
At 2 h. it was fcarce at all altered from the laft obfervation ; 
but, if any thing, feemed recovering its light. 
F had meant to obferve its progrefs {till further; but return- 
ing to the glafs at half an hour after two, clouds had. fuddenly 
covered the whole fky. 
The fact of the diminution of Algol is, newer fully 
confirmed (if confirmation was wanting) by this obfervation,. 
and the cecuracy of the period fixed by Mr. Goopricke afcer- 
tained,,. 
DS! 
