E. 8. Holden— Measures of the Rings of Saturn. 391 
to the middle of the black division and not to some other 
1] the distances were measured parallel to the ie axis of 
the ring. In the Washington series they were single distances, 
each set usually containing four; at t Madison all are double 
distances, four in each 
I may add that it is my experience that the dusky ring is an 
object which requires to be measured under a high magnifying 
power, although it often seems to be better seen with a low one. 
S$ soon as measures commence, however, the advantages of 
the high power become apparent. 
Observations of Saturn’s Dusky Ring made with the ioral 
equatorial at Washington in 1879, and reduced to A=9°538 
Ro.| Taye v ui ci of axe.) We- oi 
1 |Sept. 10 uk 6°88 ote 7-02 0) 4 | +014 
2 ] gece 736 wenn 783 || 400} 1 | +0°47 
3 ¢ Bin 6°83 Boe 4 400} 2 | +0°62 
4 coky 7-05 ripe 724 || 400] 2 | +019 
5 goes T31 peraes 769 || 400 4 | +0°38 
6 seve 6-99 shies 772 || 400] 2 | +0-73 
7 sa 7-07 pon 758 || 600| 4 | +0°51 
8 : vee 6°82 pein 740 || 600] 4 | +058 
9 Oct. is 6°73 siuc 757 || 600] 3 | +0°84 
10 | , Oe 712 eee 765 || 600! 4 | +0°53 
ny wu ae 1-27 ae 749 || 600] 5 | +0-22 
12/ 14 Ae 6°86 oo 7°63 || 600| 3 | +0-77 
1x 20 suis T1 yey 721 || T*| 3 | +010 
Means, ue 7034004, .... | 75040-04 +0°47 
Washington Observutions of 1880 reduced to J=9°5389. 
acs | , 
Ro, | Bee yu u ci of piece Wt. A 
14 |Aug. 27 27°35 aye 27°45 ae Tl. 4 | +0°10 
15 27 27°62 eee 27-58 ---- ||400| 4 | —00 
16 28 ore 6°56 cee ds Oe 400) 4 | +026 
17 |Oct. 9 28-02 eee 27-74 sets 800) 4 | —0-2 
18 10} 27-44 ius 21-74 aor 800| 4 | +030 
19 11 27°26 ead 2751 wens 600 | 5 | +0°25 
Means, 27°5440-:09 656 | 27604005 692 | | | 4020 
* Terrestrial eyepiece magnifying 400 diameters. 
