Mr. Rothman (' Mem. Astron. Soc.,' vol. xu. pp. 409.415) has shown strong reasons for supposing that the mass given by Laplace has beeu too much diminished by his successors, and that the second fraction above named should be increased by about its tenth part at least, and probably by more. The most uncertain of all the results of the theory of gravitation Is the mass of A planet which has no satellite.
This planet revolves on its axis in about ; though this, owing to the absence of definite spots on its disci, can hardly be con. eidcri711 as a ery accurate. Its light and heat are to that of the earth as 1911 to 1000.
The elements of the orbit of Venus, which are usually taken from Lindenates Tables (1810), have lately undergone a searching exami nation by comparison with seven years' observations made at Green wich. Means. Main and Glaialutr, who made this examination have their own resulting elements, compared with those dedu:3d for their own epoch, from the above-mentioned tables. In the following list we have adopted the new elements, placing the old ones after them in parentheses; but taking the Enid:1r variations entirely from those given as the result of the investigation just quoted (' Metn..Aetron.
Soc.,' vol. xii.). The eemiaxie major alone remains untouched; for though the examiners found reason to Inspect that it was somewhat in error, they did not feel able to decide with certainty as to the amount of the alteration.
Elements of the Orbit of renus.
Epoch 1336, January 1, 0s mean metronomic:al time at Seeberg (42". 56* east of Greenwich).
ScmAa.:1a major '7233316, that of the Earth being assumed as the unit.
Eccentricity '00684568 (.00682206); its secular diminution (or dimi nution in 100 years), .00009200.
Inclination of the orbit to the ecliptic, 3' 23' 34".34 (3' 23' its secular increase, 10".035.
Longitudes from the mean equinox of the epoch (1) of the ascending node, 75" 12' (75' 12' its secular decrease (combined with the precession), 3095".23 : (2) of the perihelion, 129' 15' 8" ( l29' 11' 18") ; its secular increase (combined with the precession), 49" 62; of the planet (meau), 332' 1' 35"13 (332' 1' 33'1).
Mean sidereal motion in 365i days, 2106041".49 ; sidereal revolution, menu solar days.
When Venus is to the went of the nun she rises and seta before hint, and was then called Phosphorus and Lucifer by the ancients ; but when she is to the e.st of the elm she data and sets after him, and was then called Hesperus. The old terms of our almanacs," Motningatar " and " Evening.Mar," have reference to these positions.