New-York tribune., 1878-03-02
NEW PUBLiCA HONS.
NEwCoNB,s POPULAR ASTRONOMY.

volume Professor New comb has endaavorcd to Wr%
hook that would be OF interest 10 an intelligent icaEt
not specially vcrsed in Astronomical science, Nhe u
treatise mIg D 10 some extent, tue uses
sccutla. men as well FOR general purposes Oi Tfci
encc. II is not popular astronomy i'll the sense
being written at the popular level; II - certainly nol
meant Tor children schOOlbOys. On tAc 6thcr hand
there is no attempt a: hchtS of language or ilnagra
ton The great facts Oi astronomy which al the lle-e
lay are somewattritc fully presented. as they ou
fobe, i'm complete treatise that science NcNeFbccs'
the book it. interesting the conventional stHe 81 ''i
word aad has the great merit Oi simplicity tha never
wegres the readers attention. II presents the he"es'
a. well as the old discoveries and free from tue ci10i~
which mar most OF tc treatses On astronomy that an
dcsl,,ed FOR noIproiessiCna Ordinary readers
viii appreciate the circumstance that no mathematc'H
formulas employed.
Tire met nod OF the book in respects peculiar
In cacn division Of the work he history Of discovery
made 20 su4erve the purpose OF explanation Ihus y
giving the views the anciCnts opportunity Is found
for describing the rnOus of the heavenly bodies as they
appear. exposition of the Ptolemac system serves
further sketch the paths OF the planets among inc
stars step hy step Tcderis led toward TIE theories
OF COpernous Kcpler, ana Newton, and is shown why
and how their hypotheses best explained The facts OF
observation which have b.cn already detailed. great
advantage Is thereby gained ordinary rcotises OF
astronomy which present the recent knowledge IrSt
and either give tie facts unsupported, or press theI
acceptance by means Of the stern logic OF geometry In
ana be measured they grow Fun Justice is done
10 the ancient astronomers, and docs not seem so sur
png after reading the account OF II That the system o.
Poemy held back The progress Of science for fourteen
eenturier, it served llly to explain majority
OF the celestial movements. But whether or not Pro
fessor Newc0mb has weakness in favor OF the great
Ecvprian sagc he certainly has for the prics;y
astronomers who constructed the Grceorian cai' ndar
o doubts whether there is any practical object gained
by uniformity between the years Of the calendar and
those of ASTRONOMY thinks that it may hereafter be
conceded at the common o. the people, VINO long
opposed the change OF calen nlar more nearly night
than the wisdom of the learned IAN additional com
IlcatlOn was Introduced into the reckoning of time
without any other real object than that OF making Easter
como al the right time" The Professor regards IL
as possible that in the year 1900 concerted action
may be by leading nations with view TO return
TO the Old mode of reckoning
Tho tleorv of the tides is a mystery to many people
who are not lacking in information on other scientific
subjects carrie conviction TO the average human
IIlnd this explained by means OF geolne
try is the great fact that the tide rises on the
side Of the earth opposite the moon as wei as on tat
which is turned toward her Not few people have ne
ceped the notion that the moon pulls the earth toward
her. laves the water tie furhest side little be-
hind in the process Popular Astronomy explains the
matter with perfect clcarness. 1t is shown that the
earth and moon rCyOyc around common centre OF
gravity which within the earth about Of
the way from its centre TO its circumference, and on
hne from the of the earth to the moon. cen
rfueal developed il this revolution The direc-
that force is Of COURSE outward from tue centre
Of rotation, and hence the on the opposite side
from that the further side OF tie earth
from the noOn-buges outward On the side nearest
the attraction the chief cause OF he oceans
rise but there is also small centrifugal force there,
since al that point the Of rotation is about tLou-
sand miles below the sea.
The comparisons used for explanation are admirable.
Ono of no astronomical
science is the vasness with wbch II deals. The dis
of the nearest planets are quite lnconceVG-
bic but 10 provide the reader with vague notion OF
the relnOtrness OF the fixed stars almost useless at
tempt Ii is however, interesting 10 know that II we
conceive traveller jOurneyng from the sun TO the out
ernosf planet of our ~ stem, rate OF speed that
would carry him that plauc in tweutyour hours, he
would acgward have Keep the same rate OF travel
for eighteen twenty years before reaching the near
est fixed star ana mus, continue his journey as much
LONGER before coming TO another. Yet such speed
wc,lld carry voyager across the Atlantic from New
YORK Liverpool less than 0ncteuth of second of
TIME An equally appropriate comparison gives an IDEA
OF spectrum analysis. Let us suppose that from an IN
heap Of gold. consisting of pieces OF various
weights, each nation should Plck out the pieces
that came nearest 10 ills own coins. Then, from the
remainder OF tic heap, let undertake to ascertain
what are tCns tat have cued out the pieces. We
know the weights OF the coins which each nation uses
We should proceed to put the remaining heap
Ill rows ACCORDING tHdt al i4cOon WI
the weight Of soyeregns and half soveres were miss
Ing those we should conclude, taken by England
The absence Of pieces OF fycfranc weight we should
attribute 10 their selection by France. America would
be held BILE for the departure o. go so, a. SO
and S2e weights and through the pile. Colnpr
ing the heap of gold with tie solar spectrum the missing
coins will stand Tor the dark, spectral uc5 the absiac
lion Of gt as shown by these lnes VIII enable US to
detec; what one chemical clements incrposed as
glowing gas has absorbed its special coinage from the
Golden rays of noon. For the rays which element,
when heated glowing .its, are the Same WHICH
that sas il used as a screen for light, will absorb.
In the EOTeties OF the science, u DOCK Is
n mine of information The theories OF the constitution
Of the sum- both ancient and modern are very fairly pre-
septcd Father Secchi, NJ. Faye and Professors Young
and langley are allowed the benefit Of their state
ments OF views this subject. Professor Newcomb
thinks that weight has not been given TO an ONCE
tion TO the theor the photosphere is composed OF
c,ouds fo,tinc on a gaseous phere. The objection
that the phoosphere presents erutions Ike Tie
crOmOspherc although exhibits AT times Tue ehoI
nous al,ysses which termed sin Spots Ihe tefehlty
Of the surface ef the pho0sphtre gives occasion Tor Dc
lief that Il is solid or a dense fluid. Such condition OF
the exterior would be III conflict with The tne0ry
tetroney sus stained Us mathematical and physical con
sideratons) that the interior Of tie sun is gaseous
though pressure brnS the gaseous matter nearly
10 the loud condition. that great iuinary may
be merely large bubble. Tic question a. to the exs
tcnce Of an intyMTcurial planet is discussed ana con
cusicns are reached contrary 10 the Opinions ol lie Nc
rer The theory that the Irregularities OF bercuiys o.
BIT may be caused by group Of innunegabIe snaN
planets OF "planetods," Involved in difficulties
on which even The zOdaic0 light throws little uumha
tion very full exposition OF what is called
the lbIation OF the moon, will probably bring
news to people who suppose that it because the moon
swings al times that she shows occasionally strip OF
the eide that turned away nom the Garth The
oscillation pronounced apparent ht not real; yet The