Magnetic variation in the United States

Magnetic Variation in the United States: Being a Compilation of Observations Made in Maerical from the year 1640 to the Present Date; Tabulated and Arranged for the use of Surveyors, with a brief account of the nature of Terrestrial Magnetism, its various theories as to the Origin, its Change in Intensity and Direction, and the progress of Magnetic Observation.

by J.B. Stone, Ph.B, C.E., Formerly instructor in Mathematics in the Sheffield Scientific School of Yale College

New York; 1878

Approximately 5" X 7 1/2"; 139 pages

Contents:

Part I:

Preface
Discovery of Variation and Dip
Researches of Halley, Humboldt and Ross
Table of Variation in London from 1576 to 1865
Change and Reversion of Change in Variation
"Magnetic Crusade" of 1835
First Compilation in America
Cause of Terrestrial Magnetism
Theories of Mayer, Gauss, Ampere and Norton
Magnetic Storms - Loomis' Conclusions
Magnetic Intensity, Remarks and Table
Accuracy of the Surveys by the Compass
Lack of Information Concerning Variation in Text Books on Surveying
Method of Ascertaining Variation by Theodolite and Compass
Formation of Variation Tables of Any Locality
Authors Method of Interpolation
Author's Request for Reports on Observations
Part II:

Description of Tables

Part III:

Tables of Variation, Dip and Intensity

Index

On the back of the contents page there is an advertisement for Heller & Brightly Engineering and Surveying Instruments at 33 N. Seventh St., Philadelphia. There is also an advertisement for Brandis & Teckritz Instruments with a nice picture of a surveying device on the page previous to the Index.