The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1868-09-23
Distnce orthe sun.

1880
element still remains unsatisfactory de
termined. The discovery made, not many
years ago, that the accepted value Of the
suns distance was some 100000 miles
too great, was reluctantly admitted by as
tronomers, Ii was easy, indeed, to show
that they might justly be proud Of having
determined the suns distance even within
this apparently enormous range of error
But none the less, it was unpleasant tc
have to admit that they had largely over
valued the accurancy of their calculations
or rather Of the observations on Hhich
their estimates had been founded.
That astronomers should have been in
error on this point, and yet that astronomy
should be spoken Of as the most exact Of
the sciences. may seem perplexiug 10 those
who are not familiar with the true quality
Of that exactness which is sought after by
astronomers. 1t resembles in sort the
accuracy of the horologist's art. We
know this is in no way dependent on the
scale in which clocks or watches may be
constructed. The great hands which sweep
over the dial plate of cathedral clock, aud
the delicate hands of pocket chronome-
ter, are equally well adapted to indicate
the fight Of time. And. in like manner,
the scale of the solar system might have
been many times less or many times great
er than it actually is, and yet the planets
would have swept on their stately courses
preclsel y as at present.
1t may not be amiss to point out briefly
what is the nature Of the problem astrono-
mers have sought to solve:
Imagine prisoner confined in room
which has a single circular window. only
six inches in diameter. Suppose him to
be provided with accurate instruments,
and conceive that directly in front of the
window, and somewhat more than a mile
of, there is an object,-say steeple-
whose distance he wishes to determine.
Then a moments consideration will show
that whatever the accuracy of his instru-
ments, and whatever his skill in using them,
yet, vita his base line OF only six inches,
he could not expect an error of less than
at least half mile in his result.
The position Of such prisoner cores
ponds closely with that of the inhabitants
Of the earth, limited to their little globe,
less thaa 5000 miles in smeter, as a
base from which to estimate the distance
Of the sun, upwards of 100000 miles
away.
But in some respects our prisoner is
better situated than the inhabitants of the
earth. A single observer. using, in one
place, single set Of instruments, is not
troubled with the numerous important
considerations which affect the value of
the work done in two observations situated
on opposite sides of the earth. Different
observers-each with his peculiar, prehaps
variable, personal equation must be
or else single observer, hav-
ing completed a series of observations in
one hemisphere, must commence a new
series when. perhaps important changes
may have occurred in his observing quail
ties in another.
Now, 70 return for a moment to our
prisoner. If there were objects interven-
ing between him and the steeple, and if he
had by any means obtained certain knowl-
edge of the relative distances Of these OBJ
iects. it is clear his power over his problem
would be greatly increased. Let the read
er look from opposite sides Of the window
at objects unequally distant, but nearly in
the same direction, and he will Immediately
see the sort of use our prisoner might
make of the knowledge spoken Of He
may not indeed, know the exact mathe-
NAUTICAL principles involved in the problem,
nor would this be the place to explain
hem, but be will see that there is some
hing tangible and appreciable in the new
iOrm of observation.
Now, the observer on earth has, at long |
intervals an opportunity of grasping at
;ome such aids as We have conceived avail |
IDLE to our prisoner. Venus and Mercury |
pass between US and the sun,
M by observing their transits carefully |
rom different parts Of the earth, astrono- /
ners have been able to gain juster coneep- /
ions of the suns distance than they could
otherwise have obtained. All the difficult |
les, however, which we have mentioned
Ibove are involved in the solution of this
orm, also the solution of the problem.
Yet, with no other aid, and with the
inefficient instruments OF
ne last century. astronomers managed TO
determine the suns distance with what
pay fairly be termed wonderful accuracy
ertainly within one-tIirtieth part OF the
rue distance. This is as if our prisoner
hould determine the steeples distance
within 30 or 60 yards.
Bot astronomers Of the present day,
sing a variety Of delicate methods, into
those nature we need not here enter,
ave arrived at more trustworthy results.
t is hoped that during the transits Of
Tenus in 1874 and 1882 these results
ray be improved upon. Yet even now.
re may note as great achievement of
lodern science the following series of
alues, differing little lproportoDately)
mong themselves, though well separated
ON the old determination 95,274.00O
tiles: The German astronomer Hansen, I
laking use Of q peculiarity in the moons !
lotion as guide was led TO the value 81.
10000 miles; Stone of the Greenwich OBJ
srvatory. was led by the same means
)nly the peculiarity was estimated by
Their instrIments,l to the value 92400,
DO miles. Winuecke and Stone from OH /.
,rvatiOns Of Mars. obtained, respectively.
le values 81 100000 miles and 81 100000 ,
lies. Estimates founded on a compari- !
IN Of the velocity Of light as Determined
? the experiments Of Fizeau and Fou- ,,
IuIt with the astronomical determination. i
We value of 81 100000 miles A meth '
] employed by Leverrier, and founded on
peculiarly Of the .earth's motion, gives !
100000 miles. And, lastly. the new !
Itimate obtained by Simon Newcombe I
J. 81 founded on observations Of Mars 5
1862, make the suns distance 81, 400,
10 miles The mean Of these values is !
I'll 900 miles, or nearly 10000 miles +
IS than the greatest estimate, d
From the above results, it will be seen :
at astronomers over estimated the accur-
" of their calcltlafions uhen fheu er- | !