LECTURE VII.

THE PLANET VENUS.

“ The star that bids the shepherd fold,

Now the top of heaven doth hold ;

And the gilded car of day

His glowing axle doth allay

In the steep Atlantic stream.”— Milton.

We must now wing our flight to a planet much larger, muchmore brilliant than Mercury; one that from time to timeapproaches nearer to the Earth than any other ; hut one whosevery beauty is so dazzling that, bold as our eyes may be, weare forced to turn from its contemplation with baffled gaze.

We refer to Venus , admired, we may feel sure, ever since theEarth has been inhabited, when seen as the morning or eveningstar; but, in these days, wdien the habit of late rising is, wefear, becoming increasingly common, more often as the latterthan as the former.

The size of Venus is nearly the same as that of the Earth ;its diameter only falling short of the Earth ’s by about 15 Vthpart; its surface by about T l ff th part; its volume by betweeny^th and y T th part. But its orbit and the speed of its move-ment round the Sun differ much more considerably from thoseof the Earth . We will .therefore repeat, in a somewhat variedform, so much of the table, which we gave in Lecture V., asmay enable us to contrast its orbital motion with those bothof Mercury and of the Earth .

Days. Miles.

I has a ) (a mean dis- ^

Mercury < year of >88-! tance from the( nearly ) ( sun of about )

Venus r , 225 „ 67,000,000 „ of between 21 & 22 ,,

The Earth „ 365 „ 93,000,000 „ „ 18&19 „

The only point which calls for special remark in the abovefigures is, that the greater each planet’s distance is from the

3,000,0001 y e “ji t y [of nearly 30 miles per sec.