Class
Book
Pla&A
lb fold out. opposite Taga 614
OUTLINES OF
ASTRONOMY
BY
SIR JOHN F. W. HERSCHEL
PART TWO
NEW YORK
P. F. COLLIER & SON
M C M I I
By Transfer
Maritime Comm.
SEP 3 1949
U-J
CONTENTS
CHAPTER XI
OF COMETS
Great Number of Recorded Comets — The Number of those Unrecorded
Probably much Greater — General Description of a Comet — Comets without Tails, or with more than One — Their Extreme Tenuity —
Their Probable Structure — Motions Conformable to the Law of Gravity— Actual Dimensions of Comets — Periodical Return of Several —
Halley's Comet — Other Ancient Comets Probably Periodic — Encke's
Comet — Biela's — Faye's — Lexell's — De Yico's — Brorsen's — Peters's —
Great Comet of 1843 — Its Probable Identity with Several Older Comets
— Great Interest at Present Attached to Cometary Astronomy, and its Reasons — Remarks on Cometary Orbits in General — Great Comets,
PART II
OF TEE LUNAR AND PLANETARY PERTURBATIONS
CHAPTER XII
Subject Propounded — Problem of Three Bodies — Superposition of Small
Motions — Estimation of the Disturbing Force — Its Geometrical Representation— Numerical Estimation in Particular Cases — Resolution into Rectangular Components — Radial, Transversal and Orthogonal
Disturbing Forces — Normal and Tangential — Their Characteristic Effects— Effects of the Orthogonal Force — Motion of the Nodes — Conditions of their Advance and Recess —…