WARD’S NATURAL SCIENCE BULLETIN. 
3 
Meteors and Meteorites. 
The term Meteoroid lias been given to those 
dark particles which are darting through space' 
in all directions, and which become visible only 
when they enter our atmosphere and are ignited 
by the friction, when they are called Meteors or 
Shooting Stars. The term Meteor, however, is 
often improperly restricted, in common use, to 
the largest of these bodies, which are also called 
Fireballs or Bolides. And those which pass en- 
tirely through the atmosphere, and complete their 
fall to the earth, are called Meteorites or Aerolites, 
with various other names descriptive of their 
structure and chemical composition. 
To appreciate the great heat which consumes 
the meteors so quickly, we have but to remember 
that heat is only a form of motion, and that our 
earth moves through space at the rate of 98,000 
feet per second, and should it meet a meteoroid 
at rest it would increase its temperature nearly 
600,000°, and in addition to this, many of the 
meteoroids are traveling in an opposite direction 
to that of the earth with a velocity varying from 
8 or 10 to 40 or 50 miles per second. The meteor- 
oids which produce the November showers, move 
at the rate of 26 miles per second in a direction 
nearly opposite to that of the earth, so that they 
meet our atmosphere with a relative velocity of 
44 miles per second, which corresponds to a tem- 
perature of between threeandfourmillion degrees, 
sufficient to consume the hardest known substance 
almost instantly, and only those of large size or 
slow motion are permitted to reach our earth be- 
fore being entirely consumed. And were it not 
for this protection afforded by the air, in arrest- 
ing and destroying the meteoroids we should be 
intolerably pelted with them. 
It has been estimated that not less than ten mil- 
lion meteors, visible to the naked eye, enter our 
atmosphere daily. And this number must be in- 
creased 20 to 40 times if we include those which 
the telescope would reveal. After midnight, 
when everything is favorable, an average of 
nearly one meteor a minute is visible to a group 
of observers, from a single station. The greatest 
number are to be seen just before daybreak, be- 
cause at that time we are on the front side of the 
earth, as it moves through space. The elevation 
at which most meteors are visible, has been 
found to be between 45 and 80 miles, very few 
being seen at a greater height than 100 miles; 
and they rarely come nearer than 30 miles 
without throwing down stones. 
It is generally believed (but there are strong 
reasons for doubting it), that some very large 
meteors that have entered our atmosphere, have 
passed out into space again, their great moment- 
um being sufficient to take them away from the 
earth's attraction. 
Whether or not all meteoroids move in ellip- 
tical orbits around the sun, like comets, it is a 
well-established fact that certain groups of them 
do, and occasionally our earth passes through 
one of these groups, giving us what are known 
as the meteoric showers. The more notable of 
these are the August showers, which occur annu- 
ally from the 9th to the 12th of the month, and 
the November showers, which have an interval 
of 33 years. The stream of the August meteors 
is estimated to be from five to ten million miles in 
thickness, as the earth, traveling with a velocity 
of two million miles per day, is immersed in it 
for several days, while the denser portion of the 
November stream is traversed by the earth in 
two or three hours, which implies a thickness of 
40,000 to 60,000 miles. It takes three or four 
years for this stream to pass the node, indicating 
a length of many hundred millions of miles, or 
about one-tenth of its orbit. 
The numbers seen per minute in the middle of 
the brightest of these star-showers, imply a mean 
distance from each other of from 25 to 50 miles, 
while on ordinary nights there is not more than 
one, on an average, visible in a million or two 
square miles. 
The November stream is much more concen- 
trated than the August stream, and the showers 
aie more reniarkable for the great number of 
meteors. History mentions their recurrence at 
intervals for more than a thousand years, and re- 
cords the great terror of the beholders, lest the 
end of all things was at hand. Many of our 
MINERALOGY. 
Our stock of Minerals at the present time is 
very choice and comprehensive. There is cer- 
tainly no other so large and good assortment for 
sale in detail on this continent. The specimens 
are fine, fresh and beautifully crystallized, and 
of sizes suitable for cabinet drawers as well as 
for the shelves of a museum. They represent, 
besides North American localities, those of Chili, 
Peru, the States of Colombia and Brazil, in 
South America; the mining districts of Corn- 
wall, Cumberland and Derbyshire, in England; 
the rich deposits of Saxony, Bohemia and Austro- 
Hungary; the Alpine region of France and 
Switzerland; the mines of Spain and Italy — with 
the islands off the coast (Sicily, Sardinia, etc.); 
Norway, Sweden and Russia. In Asia they 
include, besides Siberia, the tract of Asia Minor, 
India and Malacca. In Africa, Algeria, Egypt, 
the diamond fields in the South, and Australia, 
in which latter country Prof Ward is at the 
time of writing gathering further material. 
For full enumeration of the various mineral 
species consult our Catalogue of Minerals, 60 
pages; price 20 cts. 
Besides this large stock from which we sell 
individual specimens, we prepare Three System- 
atic Collections, with descriptive catalogues, as 
follows: The College Collection, for $250; 
the Academy and Normal School Collec- 
tion, for $100; and the Union School and 
Amateur’s Collection, for $50. In addition 
to these, our standard collections with catalogues, 
we prepare smaller and cheaper collections, as 
well as larger ones of any desired extent. 
The College Collection v contains every requisite — 
even to a series of 50 crystal models — for 
a thorough illustration of the science of min- 
eralogy. All the important species and their 
varieties are well represented in choice, hand- 
some specimens, neatly labeled and mounted, 
and accompanied by a special descriptive cata- 
logue of 39 pages. 
The Academy Collection, though numerically 
not so rich, has really nothing of import- 
ance omitted. Thus, in the classification 
adopted, the elements are represented by 8 speci- 
mens; the sulphides and allied compounds by 
14; chlorides, etc., 6; oxides, 42; silicates, 64 
phosphates, etc., 8; sulphates, 10; carbonates, 
18; hydrocarbons, 10; in all 180 specimens, well 
representing the relative importance of the differ- 
ent divisions. Each specimen in this, as in the 
other collections, is mounted on a separate black 
walnut block, to which is attached a printed 
label giving name, Dana’s species number, sys- 
tem of crystallization, chemical formula and 
locality. In the case of single detached crystals 
“oldest inhabitants” remember the shower of 
1833, in this country, and the consternation 
which it produced among the ignorant, particu- 
larly among the negroes at the South. The orbit 
of this stream extends beyond that of Uranus, 
and its period of revolution is 33J years. The 
orbit of the August meteors is about twice as 
great, and stretches far beyond Neptune, and 
their period of revolution is about 124 years. 
As the meteoroids of this group are distributed 
over its entire orbit, we meet them every year 
when we cross its path, but the November mete- 
ors are confined to a small portion of their orbit, 
and pass the point where they cross the earth’s 
orbit in about three years, and are not seen again 
until their next period of revolution. Doubtless 
those meteoroids will also, in time, become dis- 
tributed over their entire orbit, and we shall then 
have a shower of meteors every year about the 
10th of November. 
Many theories have been advanced in the past, 
to account for these strange bodies, but the evi- 
dence now accumulated proves beyond reason- 
able doubt, that they are near relatives, and 
probably the debris of comets. 
Tempel’s comet is now knowrn to be traveling 
in the same orbit as the November meteors, and is 
near the head of the train, and it appears, in like 
manner, that the second comet of 1862 (Swift’s 
comet), is traveling in the orbit of the August 
meteors. And the first comet of 1881 seems to 
be similarly connected with the April meteors. 
But the most striking case of the connection be- 
tween comets and meteors is afforded by the 
actual prediction of a meteoric shower on the 
night of November 27, 1872. In 1826 Biela dis- 
covered a comet which was found to have a 
periodic revolution of 6 years and 8 months, and 
to have been observed in 1772 and 1805. It was 
observed again in 1832, 1845, and 1852. In 1845, 
or January, 1846, it was observed to be in two 
parts, 150,000 or 200,000 miles from each other. 
In 1852 the two parts were separated nearly one 
and one-half millions of miles, since which time 
they have not been seen. In 1872 the conditions 
for observation were favorable, but no comet was 
seen ; by calculation it should have passed the 
point where it crosses the earth’s orbit early in 
September, while the earth reached the same 
point the 27th of November. Judging from an- 
alogy, there was every reason to believe that the 
earth would encounter a stream of meteoroids 
consisting of the remains of the lost comet, and 
that a small meteoric shower would be the result. 
Moreover, it was shown that the meteors would 
all diverge from a certain point in the constella- 
tion Andromeda, because that would be the di- 
rection from which a body moving in the orbit 
of the comet would seem to come. The predic- 
tion was fully verified in every respect, and the 
conclusion is irresistible that the shower of 
meteors in this case was originally a part of 
Biela’s comet. Although few scientific men now 
question a relationship between comets and the 
ordinary meteors, there are those, and among 
them some of our ablest men, who think that the 
large Meteors, or Bolides, and Aerolites, may be 
different astronomically, and perhaps physically, 
from the ordinary shooting stars, and in the past 
some contended that they originated in our 
atmosphere; others that they were ejected from 
terrestrial volcanoes. Another theory which re- 
ceived the endorsement of many of the best as- 
tronomers and mathematicians is, that they were 
projected from the moon; but the immense ve- 
locity, of some of them at least, seems to be an 
unanswerable objection to this theory. And at 
the present time the known facts, and all scien- 
tific thought, seems to point to the conclusion 
that the difference between them and ordinary 
shooting stars is analogous to that between rain 
and mist, and in addition to the reasons already 
given for connecting them with comets, may be 
mentioned the fact that meteorites bring with 
them carbonic acid, which is known to form so 
prominent a part of comets’ tails; and if frag- 
ments of meteoric iron or stone be heated mod- 
erately in a vacuum, they yield up gases consist- 
ing of oxygen, carbon, hydrogen, and nitrogen, 
and the spectrum of these gases corresponds to 
the spectrum of a comet’s coma and tail. 
By studying their microscopical structure, Mr. 
Sorby “ has been able to determine that the 
