W811.) Answer to the Queries relative to Secondary Planets. 423 
copy, (tle booksellers’ edition, 1803, 10 
vols. with Johnson’s and Steevens’s notes, ) 
in the place referred to by your correspondent. 
April 18th. 
a 
To the Editor of the Monthly Magazine. 
SIR, 
REMARKED in your extensive and 
] useful Miscellany. of March 1, an 
observation of Copernicus, jun. with 
respect to the earth and moon, as well 
as other primaries, with their seconda- 
ries—that “Our earth’s different he- 
mispheres successively receive the benefit 
of the moon's reflected light; whereas one 
of the moon’s hemispheres receives no 
reciprocal adyantage from the reflected 
light from the earth. We may be confi- 
dent (says he) that the wisdom and good- 
ness of the Creator, had some important 
end in view, whereby these globes are, 
upon the whole, greatly benefited by the 
manner in which they are arranged. 
Not having met with any opinion or con- 
jecture formed upon this subject, I 
therefore beg to propose as a query: 
What benefit of consequence is attained, 
or (which is the same) what important 
inconvenience is avoided hy the secon- 
dary planets, from their having always the 
same hemisphere turned toward their 
priniaries ?” 
Tn answer to this query, I beg leave to 
observe, that the moon’s hemisphere, 
’ which is turned constantly to the earth, 
2ppears to consist nostly ef solid matter, 
and to be mountainous. By this moun- 
tainous condition of the moon’s surface, 
the reflected light becomes more equably 
distributed than it would be were the 
surface asmoothone. This equal distri- 
bution of light is one great benefit which 
the inhabitants of the earth receive from 
that nature of the moon’s surface, which 
is turned toward it. The solid part of the 
moon being always turved toward the 
earth, may perhaps act more powerfully 
upon it in point of gravitation, than if it 
were aqueous, and thus our tides are 
kept in stronger agitation; by these tides 
agitating the water to an hundred ta- 
thoms depth, the nauseous particles occa- 
sioned by the excrements of its numerous 
inhabitants, and putrid matter arising 
from other causes, are diffused from its 
surface to that depth, which otherwise 
would glat-as a thick crust upon that sur- 
face; this agitation, with other circum- 
8tances, such as the fresh air received by 
the water, from its incursions into the 
land; its communication with the atmo- 
sphere by the aérial tides; the electric 
effluvia passing through it in different di- 
rections, as well as from the regions 
above, together with the fresh water con. 
stantly flowing into it, tend to preserve 
the aqueous parts of our globe from the 
putrefaction which would otherwise take 
place, and render the surface of our 
earth not habitable: thus we enjoy an in- 
calculable advantage in this action of the 
moon. The advantage we receive from 
the tides in other respects, are numerous. 
The tides we should receive from the 
action of the sun alone, would not pro- 
duce this effect; but when conjoined with 
the moon, or when she is in quadrature 
im part opposed by those of the sun, do, 
upon the whole, produce the most bene- 
ficial effects. 
With respect to the moon, without en« 
tering upon a dispute whether she is in- 
habited or not, it may be remarked that 
the observations made by Dr. Herschel, 
prove that she has an atmosphere, and is 
mountainous similar to our ea-th, and 
therefore may be inhabited. The ad- 
vantages received from this mountainous 
structure, as furmerly stated, render it 
unnecessary to be adduced as an argu- 
ment in proof of her being inhabited. 
From the similarity of the moon to our 
globe, we may suppose that she is, like it, 
composed of land and water. Ourglobe, 
so far as is known of its surface, is in four 
parts of five covered with water, and only 
one part is solid land. If we may, from 
her similarity in other respects, suppose, 
the greatest part of the moon’s heini= 
sphere, which is not exposed to our view, 
to be covered with water: we know that 
our tides, which are exposed to the moon, 
are greater than our opposite tides, there- 
fore the earth being a body so much 
greater in magnitude than the moon, 
must make greater tides in the moon than 
she can make upon the earth, but the 
tides upon her opposite hemisphere, must 
be less than they would be upon her 
direct hemisphere. Again suppose that 
the moon revolved about her axis once iA 
twenty-four hours, her tides‘in that case 
would be forty times greater than ours; 
bodies acting upon one another, recipro- 
cally as their quantities of matter: but 
her revolutionary motion is near thirty 
times less than that of the earth, and her 
tides are considered to be upon her oppo- 
site hemisphere, aud not direct tides as 
those she gives to the earth; thus circuine 
stanced, her tides will not exceed ours in 
point of elevation, but the agitation 
would he too slow to preserve the salu- 
brity of the waters; bat when we bring 
her 
