The New York herald., 1878-03-25
LIT EEATU r E.
PROFESSOR nocKYrn ON srAncAzrsc.

Norman I.ockyer +. X. s. tMacmillan l. Co. states
in the that his work is based notes OF eight
lectures on ''Instrumental Astronomy" delivered at
the Royal Institution. These has expanded to EN-
brace points of interest not touched on in the
lectures The work is finely printed, and splcndidly
illustrated with 2l7 appropriate engravlngs and fine
autotype OF Newall's telescope. 1t is divided into
i've books. which treat respectively of 'srhe Pre-
telescope Age" sThe Telescope" "Time ana Space
Measuros.'' "Moderu Meridonal Observations, ,, 'The
Equatorial" ana 'Astronomical Physics" In the
opening chapter. on "The Dawn of stargazng," the
author says:-"Some sciences are Of yesterday; {;
others stretch far back into the youth OF time.
Among these there ono OF the beginnings OF which
We have lost all trace, coeva was It with the CON-
mepcement OF mans history and that science is the
one OF which have to trace tho instrument tai
developments Although our chief task is to enlarge
upon the modern II will not be WE'LL indeed II is i'm
possible, to neglect the old, because If for other
reason, the welding OF the old and new has been
perfect, the conquest OF the unknown so gradual"
Pursuing this plan the author begins at tho
beginning OF astronomical science and intro
duces the reader to the systems accepted by
tho ancients, which find their best illustration
in that propoundsd by Ptoemy. who made
the earth the centre the universe and the sun
planets revolve around her. Beyond the region
of the ultimate stellar regions Ptoiemy placed the
crystalline heavens or the abode OF the blessed.
Viewed IN the light OF modern knowledge this con-
ception OF the ancient astronomers Is inversion Of
fact; but be readily accounted for when
slider how difficult It was to determine truths of the
universe in ago properly termed preteescopic and
wanting in the most ordinary facties for correct OBJ
se.vations OF the movements Of the planetary bodies
AS the earliest instrument according TO the author,
the horizon, SO the first observations made
OF .he rsinss aud settings OF tho stars and rcl
tive apparent distances of the heavenly bodies from
zach other"
The second chapter Is dev oted to Tne First lnstru
mcn,s," OF which the best known the Gnomon,
for measuring the length OF the SUMS shadow, and
thus dete rmning the differences OF altitude in tho Pc
RODS between the sostices aud tho equinoxes, tho
former representing the highest and lowest and the
lattor the intermediate positions OF the SUM- The
third and fourth chapters devoted to description
of tho labors and discoveries OF tho great astrono
mors-Hipparchus, Ptolemy and Tycho Brahe. Pro-
fessor Lockyer calls Hipparchus the father Of
mental astronomy, 'as no was the first to place OBJ
servation n sure basis, and left behind him tho
germs Of many OF our modern instruments and
methods" Tho second book Is devoted to the telc
scope and the science OF optics. The author regards
the telescope as not boicg "a thing In the ordinary
scnse-it is combination OF things" each Of which
was known and used before they were combined TO
form the telescope. Hence he finds "dilcu to give
the credit OF the invention of the telescope TO any
particular person" From a study Of the lens we
taken to that OF its numerous adaptations in re-
fracting telescopes, ard the refracon. dispersion
conveyance, decomposition and decomposition of
light Thcn its reflection is considered and the angle
OF Incidence is proved equal to that Of reflection,
and the foci OF the mirror are shown in rela
= I'M m Iioh raj al
telescope is next explained, and numerous diagrams
illustrate in the clearest tie principles that
govern its construction and use. One OF these show
that tho proper form for reflector is the curve OF an
ellipse. chapter cyopeces deals with the di-
tcrcnt forms OF lenses used and the mode Of correc
tion for errors incidental to their uiacture &c,
as well OF determining their true magniyng power.
AS one OF the chiof difficulties to he overcome IN
the construction oil optical instruments is that which
in the nutacture Of their several important
parts, tho author explains In q chapter on
the ..Producton OF Lenses and spccula" how these
parts made 1t Is only OF late years that Tho pro-
ducton OF pure flint glass OF sufcC1s to satisfy
the wants OF optical instrument makers has given
such advantages to modern science. Now the work is
advanced Tar to admit OF tho production of discs
OF twenty Ave, twcnty-six aud even twenty eight
inches. Glasses Of the last mentioned sizes are
enna obser vatories respectively. The utmost care
must pc taken In the manufacture OF lenses for any
defects in the glass; such veins striD would be
fatal. In making rehcctors the same amount OF dif-
Guilty be overcome, and the particular obstacles
to success mentioned in detail by the author
who shows his cntiro familiarity with every
stage in the manufacture OF these Instruments
The third book Is devoted TO the description and ex-
PLANTATION OF the mechanism OF time aud space meas
urcs. Beginning with the clock as 1t first con-
sruccd we follow It through every stage of its I'M
provcment its present perfection. To the mechan-
ican this part Of Professor LockyeTs work will prove
highly interesting because OF the pains taken by tho
author to leave nothing unnoticed that add to tho
symmetry Of his descrp pt0ns Tho fourth book dis.
cusses "Modern Meridionai Ooservatious and treats
In their order OF he transit circle and its applica-
tons in modern observations, the transit clock and
chronograph" with modern electrical appliances for
establishing and distributing the mean timc and
"sGrecnwich time and the use made of It," OF the
lattor subject may remark that the ball OF the
Western Union Telegraph Company's building
on Broadway is regulated by mean Washington
timo determined in that city at the Observatory.
The sixth book has a special subject-''The Equa-
toral''-and describes the various thods OF mount
Ing that instrument and large tcescopes lhe adjust.
ments OF the equaora" The several observatoricg In
Europe America and Australia; "the sderostat" " or
an instrument by which the image of the other
planet Is kept before the equatorial mirror driven
by cockwork, ana thus precluding the necessity OF
moving the ponderous telescope itself, as to keep
the object in constant view ana tho ordinary work
the equatorial in determining the positions of vari
Gus heavenly bodies Throughout these chapters we
find selection Of illustrations that give value
not easily ound,in other works ON astronomy; and
when wo turn TO the sixth book on "Astron omi cal
Physics" equally impressed by tho excellence
OF the material presented The delicate experiments
and processes for determining the light and heat OF
the show how patiently the men OF science have
abored aud laborng on the details that combine
to make up tho wonderful whole Of their progress to
success. II may to the reader unversed In tho
possibilities OF scientific research that attempt at
measuring the degree OF heat impaired our earth
by distant star pushing investigation beyond
reasonable limits, yet perusal of the work before