The New York herald., 1876-03-25


The letter sN'' in each figure shows the north point
of tho disk The figures placed that the top OF
the figure corresponds the highest part of the disk
as seen by the naked eye through telescope which
does not nvert
There many ways to the eclipse. An easy
and well known method is by the aid Of piece OF
smoked glass. A portion OF the glass should be so
deeply smoked that the be with difficulty
through it, and protect the eye, the should DO
first seen through this portion. Then moving the
glass gradually TO sde where tho smoke is thin
ner place readily be found should there DO
light clouds, where the DO well In re-
moving the glass fail first shut tho eye to
admitting the full glare of the SUMS rays
for an instant II you wish demonstrate your
friends your scientific proclivitics OF you will
hold the smoked side of the glass next to the
Stained glass has the disadvantage Of not being
adjustable and either the eye will be dazzed In the
bright sunlight the will be nearly invisible
undor light clouds. Either the smoked glass a dark
glass may be used with an opera glass; spyglass
telescope But still greater will be required to
avoid njuring the eye, and it will be well to place over
the object glass a cap reducing the aperture TO two
inches less Large telescopes sometimes
provided with eyepeccs specially designed for
ing the sum- which the full aperture may be used
advantage.
safer and better way to observe an ecipse of tho
is by throwing the image OF the sun upon
In this several persons may tue image at
The simplest way TO do this Is by making pinholc IN
the middle Of large card and letting the sun shine
through II upon sheet OF white paper at distance OF
a loot moro. II hore several small openings in
the card, not too each other-t matters not Of
what shape-thcre will be corresponding NUMBER Of
images OF the A tin cullender Tor instance held
at distance Of eight or ten feet, Will give regular
series Of images So the summer season, the
in the foliage OF rec will produce irregular
Of images ol the sun which will be seen To show
the phases OF an eclipse
II magnfying giass-the less IL magnifcs the bet
ter-is placed over tho opening the screen must DO
held exactly at the distance OF which the edge OF the
disk distinctly defined This forms obscura,
and any form Of camera obscura will show the phases
OF the eclipse we'll In this the opening may be
made large the Ions, unless the image should be
found too bright burning glass Is unsuitable for
this purpose not only because II is 100 large conccn.
trating TOO much light and heat probably setting tho
screen irc, but because It's focus Is t that
the SUMS image viii be too small weak spectacle
forming image at n distance OF two feet
best.
the shadow the extent Of the eclipse and tho solar
spots aud motted surface Of the sun all be
by several persons at the same time, by simply draw
ing the eycp'ecc slightly 80 that the SUMS rays
shall form a magnned image upon screen, which
should be protected from the direct OF tho sun;
and this regard as the most satisfactory mode OF view
ing solar eclipse.
The present is not favorable year for sun spots II
their periodicy, which seems TO be well established,
be relied upon, they should be this year least
spicuous numbers and IN extent But IL happens
that at present there several spots large enough to
be easily seen IN the telescope on the side OF the
turned toward uq which will probably continue until
after the eclipse l counted yesterday morning less
than twenty three OF which prominent stretch
In line across the middle Of the disk, about twenty
hve degrees north solar latitude The western spot
consists OF large nucleus OF irregular outline to-
gether with confused OF smaller nuclei, the
whole surrounded by an umbra three times the dame
ter Of the earth Passing eastward by series OF small
spots, we TO the central spot, the nucleus OF
which, without its umbra, is nearly as large
earth After interval we come 10 tho eastern spot
which Is about the size OF moon. THESE spots
are represented in hgurcs ] and ,, and partially
In ngure 2, tho umbra being omitted because IL
could not well be represented IN It's proper proportion
without a much larger diagram. The distance Of these
spots, 10 east, great that II earth
were 10 dropped the Of the umbra OF the
western spot, moon at us present distance from
us, might a dropped at the same time into the east
ern spot lily measurements not sufficiently
exact 10 enable 70 predict with certainty whether
the principal spots will fall for few minutes be-
hind tho edge OF the moOn or Will bc close TO tho
moon at tho time OF the middle OF the eclipse. To
ascertain this u would DO necessary, not merely 20
mako careful determination OF the position OF the
spots al the time Of observation aud 10 compute tho
rotation Of tho sun Tor period OF about thirty two