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E.. §. Holden—Note on the satellite Tethys. 49 
Art. [V.—Note on the Brightness and the Stellar Magnitude of the 
third Saturnian satellite—Tethys; by EDwarp S. Houpen. 
[Communicated by permission of Rear Admiral Jonn Ropgers, U. S. N., Super- 
intendent U. S. Naval Observatory. ] 
ON November 20, 1878, I was observing Saturn's satellites 
with the 26-inch refractor, using an eye-piece magnifying 400 
_ diameters. Four satellites were nearly in the plane of the ring 
(position angle 94°-2). They were 
Tethys ; p=265°, s=35” ; (estimated.) 
Dione; p= 94, s=60" ; as 
Titan ; p= 944, s=over 150” (estimated.) 
Enceladus ; p=92 (est), s=81’’13 (measured.) 
At about 84 30™ as I had just completed the measure of the 
distance of Hnceladus, the sky became covered with flying 
As a cloud gradually (and as nearly as could be judged uni- 
j formly) darkened Satwrn as seen in the telescope, the appear- 
At this instant I endeavored to note the visibility of the 
* Annals Harv. Coll. Obs., vol. v, p. 164, etc. 
Aw. Jour, Scr.—Turrp Series, Vou. XVII, No. 97.—Jan,, 1879, 
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