14 CONTENTS

PAGE

DESCRIPTIONS OF MAGNETIC STATIONS IN MARYLAND........................

498

Stations occupied by the Maryland Geological Survey in 1896............

498

Stations occupied by the Coast and Geodetic Survey between the years

1845 and 1 896....................................................

503

Miscellaneous Stations..............................................

508

ESTABLISHMENT OF SURVEYOR'S MERIDIAN LINES..........................

508

Meridian Lines established by the Maryland Geological Survey..........

508

Simple Methods for Determining a true Meridian Line.................

511

I. To determine the true meridian by observations on Polaris at

Elongation, with the Engineer's or Surveyor's transit........

511

II. To determine the true meridian by observation on Polaris at

Elongation with plumb-line and peep-sight..................

516

III. To determine the true meridian by observing the transit of

Polaris and another star across the same vertical............

517

IV. Determination of the azimuth of Polaris and true meridian at

any hour, the star being visible, and the correct local mean

time being known........................................

520

The Determination of the Magnetic Declination by the Surveyor........

529

INDEX....................................................................

531