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MARYLAND GEOLOGICAL SURVEY 429
Pennsylvania and parts of adjacent States. "1 Observations were
made at 22 points within Pennsylvania; they did not in every case
embrace the three elements. Professor Bach e made these observa-
tions during his summer vacations from 1840-43 and at private ex-
pense.
When Bach e became Superintendent of the Coast Survey, mag-
netics was incorporated in the work of the Survey. Since then
magnetic observations have been made in every state of the Union by
the Coast Survey, and the drawing of isomagnetic maps, and the
furnishing of the data for allowance of the secular variation, have
become regular functions of the Survey. Owing to its limited appro-
priation, the Survey cannot undertake, however, the making of obser-
vations in such number as would fulfil modern requirements of a
magnetic survey. It can at best confine itself to the establishment
of secular variation stations in each state, i. e., stations, as permanent
as possible, at which observations are made with great refinement and
at which observations may be repeated after the lapse of a certain
number of years, say about 10 years. Detailed surveys will at pres-
ent have to be undertaken by the states separately, which course may
have its advantages, but likewise has its disadvantages.
Magnetic observations, more or less complete, and magnetic tours,
more or less extensive, had been made previous to Bache's work,
referred to above, e. g., by Long (1819), Nicollet (1832-36), Locke
(1838-43) and Loomis (1838-41). The last made the first general
collection of magnetic observations for this country and has the honor
of having drawn the first magnetic maps. To be sure, these maps,
covering the eastern part of the United States, owing to the scantiness
of the material, were only rough approximations; nevertheless, when,
16 years later, a more complete map was made by the Coast Survey,
1 By an oversight, Mr. Schott fails to make any mention of this work of
Professor Bache in his article entitled " Magnetic Survey of North America, "
prepared for the Chicago Meteorological Congress of 1893. See Part II of
the Report of that Congress, published as Bulletin No. 11 of the Weather
Bureau. The records and results of Bache's survey are contained in Smith-
sonian Contributions to Knowledge No. 166.
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