312 The American Geologist. November, 1904. 
the inflnence of the conjunction is the sought cause of the 
paralleHsm of the moons' orbits Avith those of the planets. 
But there are other forces at work upon different prin- 
ciples and leading to different results than that of attraction. 
One of these forces we shall point out presently. Let us 
first, however, notice that the peculiarity which we here 
come in contact with and which the cosmogonists have paid 
most attention to, is the analogy existing between the planet- 
ary orbits and the Sun's plane of rotation ; and also the cor- 
responding analogy between the moons' orbits and the 
planet's plane of rotation. 
Why, we may ask, does not the Sun rotate perpendicu- 
larly to the plane of the planets' orbits, as well as in a plane 
identical with them? And why do not the planets rotate 
perpendicularly to the plane of the orbits, of the moons as 
well as in a plane coinciding with them? 
It appears at the first glance as though the planets were 
subject in one way or another, to the force by which the 
Sun rotates, and that the moons likewise have something 
to do with the rotation of the planets. This is the point 
which science so- long, but unsuccessfully, has sought to ex- 
plain. 
In a following chapter we shall discuss the law of rotation 
and we shall then solve this problem, and show that these 
things are simple, and that they may be easily understood 
after we have founcl the key to the secret. This key we can- 
not find, however, until we have cleared away a number of 
misconceptions. It often happens, as we shall find, that what 
has been accepted as a result of one single cause only, is 
the result of several causes acting together, and it may even 
be the result of causes which so far have been unknown or 
misunderstood. In order, therefore to explain correctly 
any phenomenon which is a result of a combination of causes, 
we must distinguish each cause and every factor and explain 
them separately. 
§IO. THE CAUSE OF THE INCLINATION OF THE LUNAR 
ORBIT TO THE ECLIPTIC, AND OF THE PERIODICAL OSCILLATION 
OF THIS INCLINATION. 
The inclination of the lunar orlnt to the ecliptic varies, 
according to C. -\. Young. l)et\vccn 4' =^j' and 5° 19', the 
