388 S. Holden—Measures of the Rings of Saturn. 
ce is the middle of the principal divisio 
d is the po in ring B where the shading off begins; it is 
a definite poin 
e is the Satay edge of the dusky ring. 
The remaining letters, h....n, refer to the west half of the 
system. 
Part. W. Struve, Bessel, Encke, Galle, Main, 
1826. 1830-3: 1837-8. 1837-8. 1840, 
ab Loe oe eave 
ac 2°61 ate 2°76 3°36 
ae 671 See 739 727 6°55 
af moe ps 
an 40°095 39°311 40°93 40°90 38°33 
11°05 E13 11°63 11°50 List 
ce (width) pie ones oe che 
cd Loek we te 
ce 4°11 saitee 4°63 SOb oes 
of aes ono wie bus is 
ct sahees ao eax 
cl 34-882 hee 35°41 34°18 eae 
de Sti Sen Dee ae mie 
ef : een aera oo o 
eg Eee 4:24 4°2 82 
6 26°67 sphere 26°15 26°36 25°24 
tg <n ain a —e ec 
ji ‘pes Sick eee ooee coe 
gh 17991 17053 17°68 1791 15°60 
hi Ces er wae a 
hj 42 2 8 
hn 11°05 Vis 11°63 11°50 1°37 
y aa pee eps ee eae 
al wie pa eee Sao Pare sate 
in Pa cei an peta ee Cae 
gk NG Lael ane eat ee 
jl 4°11 seats 4°63 3°91 ae 
a 671 Rs 7°39 ToT 6°55 
1 (width) 0°41 iss TAs ae eee 
la 2°61 bilray 2°76 3°36 aN 
mn weal eye eal ae eee 
Polar diam. fees 15°381 16°49 peel pies 
It is unnecessary to remind anyone who has looked over the 
great number of papers on Saturn, that for the want of a simple 
system of referring to the planet’ s features we are often in 
doubt as to what points, measures, and especially descriptions, 
refer. far, we have only the nomenclature of Struve who 
called the outer ring A, the inner B, and the dusky ring C. 
The accompanying table contains about all the useful meas- 
ures which have been made on this system since 1826. 
