New-York tribune., 1874-07-07
THE COMET AND THE EAR1H.
WE SHALL NARROWLY ESCAPE CONTACT WITH THE
TAM-REsULr OF THE LATEST OBSERVATIONS
r~tffI IrToH

WE SHALL NARROWLY ESCAPE CONTACT WITH ihh
rAII-REsULr OF THE LATEST OBSERVATIONS
AND CALCULATIONS.
TO the Bditor OF Tho Tr'oune.
SIR: Since writing my communication IN
THE TRIBUNE OF July have satished mYsef tina, 'no
delay Of the comets tail from curvature VIII DC hoou
four days. during which time the earth VIII nave move"
80 far that probable errors OF computation OF Vi %
nation would bring rs within It, Having settled thal
pont shall Introduce an Illustration which otherwise
might have been TOO suggestive Of danger tall man,
having an inda-rubber club two feet long, and three
inches diameter at the end, sees SPIDER runnht
very rapidly table He raises his ciup aol' a
arms length, and brings 1t down Win errlho pio"
He aims for point feet in advance OF the spider'
so as allow for its notion and strikes very nearly tue
point which the spider would have reached when tne
Iuh st uc the table hut in consequence OF tho club
bending little more than he anticipated the spider es-
capes By one inch This approximate representa-
ton on small SCALE OF what will take place wthh 'ne
next three weeks with two exceptions. In the h's'
place the club instead Of being OF rubber Is OF such
atenuated material that IL the spider hit he would
not know 1t; and secondly an ordinary SPIDER "ou 10
many thousand too large to represent the ear
Perhaps shoud add third that the size OF the cuo Is
only known from estimates, since 1t may increase IN
thickness during the blow
on July 1 estimated the length OF the tail
OF the comet TO be 1so, but the END oi
it was 80 faint that many persons saw IL
not much more than half that distance. On July l
estimated the length to 100, and company OF per-
sons with me varied in their estimates from 100 to li by
comparison with stars TO me, and one, by the
aid of little Imagination" could see it for length OF
I6o Taking my estimates the tail had Increased IN
length co per cent within these two days. although Par
OF this may be TO unnoced haze III the atmosphere
on the 81.
The brightness Of the the Sd and 5h indicates
that it Will have On equality July IA with the star
Affair the brightest with three exceptions visible
turus in brightness am by no means confident that
the present will be equally bright.
The motion OF the earth is 150OO0 miles per day. that
of the comet about 100000 miles per day, and VIII con-
time about the same long it remains visible The
motion OF that part of the tail nearest us is nearly
100000 miles per day. that 70 miles per second which
is 5000 times faster than the motion Of express train
The thickness Of the tail assume at about 5OOOcO
miles at the distance OF 26OOO0OO miles from the head,
when it Shall have reached that length. III the earth
were to pass centrally through it, the passage would
edge as at first thought possible would not occupy
more than four hours Ny computations indicate
that the nearest approach the center of the tail will be
less than 1000 900 miles, which would be distance
from the edge Of the tail OF 100000 miles which is SIX
times the distance Of the moon. But this VIII be suli-
cently near TO 1t 10 appear enormously large II II
can be seen at all OF which hope to he able to speak
more definitely within few days. Onc thing is certain,
IL Will be there whether we see IL or not.
Neg York July G. 1874 HENRY VI. PARKuURsr