On the Connexion of the Physical Sciences

by Mary Somerville

The space run through in one second by these stars is therefore—

α Centauri	5 leagues	Henderson and Maclear.
61 Cygni	10 leagues	Bessel.
α Lyræ	2 leagues	Struve and Peters.
Sirius	6 leagues	Henderson and Maclear.
Arcturus	22 leagues	Peters.
Pole Star	½ league	Lindenau and Struve.
La Chevre	12 leagues	Peters.
ι Great Bear	7 leagues	Peters.

There are three great discrepancies in the parallax of the star Argelander or 1830 Groombridge. M. Otto Struve makes it 0ʺ·034, which gives it a velocity of 251 leagues per second, while M. Faye finds the parallax to be between 0ʺ·03 and 0ʺ·01, which makes its velocity from 30 to 85 leagues per second.

These are all minimum velocities, because we can only determine on the celestial vault a projection perhaps much foreshortened of the real motions of the stars.

Note 232, pp. [398], [401]. The following are the binary systems whose orbits have been accurately determined:—

Name of Star.	Period in Years.	Perihelion Passage.	By whom Computed.
ζ Herculis	30·216	1831·41	Madler.
η Coronæ	42·500	1807·21	Madler.
ζ Cancri	58·910	1853·37	Madler.
ξ Ursæ Majoris	58·262	1817·25	Savary.
ω Leonis	82·533	1849·76	Villarceaux.
ρ Ophiuchi	73·862	1806·83	Encke.
3062 in Dorpat Catalogue	94·765	1837·41	Madler.
ξ Bootis	117·140	1779·88	Sir J. Herschel.
δ Cygni	178·700	1862·87	Hind.
γ Virginis	182·120	1836·43	Sir J. Herschel.
Castor	252·660	1855·83	Sir J. Herschel.
ς Coronæ	736·880	1826·48	Hind.
γ Virginis	632·270	1699	Hind.
α Centauri	77·000	1851·50	Jacob.

Orbit of γ Virginis.

Perihelion passage	1836·40
Inclination	27° 36ʹ
Position of ascending Node	19 7
Angle between line of Nodes and Apsides	295° 13
Excentricity	0·8794
Period in years	184·53

Orbit of ζ Herculis.

Perihelion passage	1830·56
Inclination	140° 39ʹ
Position of ascending Node	217° 14ʹ
Angle between line of Nodes and Apsides	266·53
Eccentricity	0·4381
Period in years	37·21