, 1872-11-06
THE NEEDLE.

tllzlng ueIgnb0Fe.
| THE NEEDLE.
A Synopsis of Magnetic Survey of
the Plains by Or. r. c. I1i1gard---
| PoIntings of the Compass in Co1ora~
do, Kansas, and Missouri.
From, the Denrer Nescs, Oct. 19.
We are privileged this morning to give the
] practical substance OF the results obtained by
| Dr.. T. 9. Hugard, formerly Of St. Louis, who is
! conducting the Bache magnetic survey Of the
States and Territories. This important survey
is carried On under the joint truHteeship Of the
Smithsonian Institution, the United States Coast
proceeds Of the legacy Of Professor Bache, the
late Superintendent Of tile United States Coast
| Survey.
( Proceeding from Go1conda, on the Ohio
River, in Southern Illinois, in October, 1871, the
survey was carried through the northern line Of
the Ohio states, by Vincennes, Indianapolis,
Richmond, Indiana, Columbus, Ohio, to near
] the "neutra1 Ine,'' or the line which embraces
al! the points where the pointing is due north.
It ought to be- at once understood that in all
passes through Eastern Ohio and North Caro-
1ina), the pointing Of the compassionate
is westward, and vest Of that line
eastward. The neutral line has been steadily
travelling, from Annapolis, in 1901, to Raleigh,
| N. c., in 1880, and is at present moving west
! ward at an Increased rate.
The exploration in the winter Of 1870 to III, OF
the Mississippi Valley, through New Albany,
near Louisville; Edgedeld, near Nashville,
Grenada, Miss; jackson, Hiss. Victsburg, Nat
| chez, Baton Rouge, New Orleans, the Plaquemine
Plantations, and the mouths Of the MISSISSIPPI
! pi River (S0uth"est Pass and Pass q E 'Outre),
established the important fact that the variation
| -east-was about one-half Of degree 1esa than
! had been anticipated from the scanty data OF q
| few previous observations, exact astronomical
md magnetic observations having only been car
ried out along the Atlantic, gulf, and Pacific
United States coast survey, as such, Professor
! Baehe, the late Superintendent, having
personally engaged in series Of inland mag
netic observations, it was judged advisable to
continue this system on tho proceeds OF his lega-
cy for the prosecution Of scientific observations
| in general, on an extended scale.
! It is q fact worthy Of notice. that in the
axis OF tho Mississippi Valley the lines Of
run nearly north and south: 50 that New
| Orleans and the City OF St. Louis, Missouri,
| have about the same pointiug-seven de-
grees east. On the Pacldc shore, on the con-
trary, aud inland, the lines Of equal pointing run
nearly east and soest; whereas the entire area
Of the intervening tract, inclusive Of Missouri,
] Kansas, and Colorado, remained essentially un-
The funds having been deficient, DR.. Hill
gu'ed 9s the s thus bs far SeR a
the st. Louis & Kansas, the Kansas Pacific
! and the Denver g. Rio Grande Railroad Conpa-
nies,-from St. Louis to Herman, No. sedalia,
Kansas City, salina, Ellis, Wallace, Denver. aud
Hughes, Boulder, and Cheyenne, etc. At the
] former places, as we'll es at Dubuque, Iowa,
Wenona, Macon, and Highland, H.; and at
Cairo, H.; corresponding observations were
taken, md at most places meridian or true
noon tine WAS determined within the limits Of
the instrumental accuracv.
In order to make the following data, for which
ne arc indebted to DR.. Hilgard, practically ayal~
able, due Eegardmust be had OF the trend Of the
On the Pacific Coast is brought to about tie
Same line as Wallace, Colorado; and Pueblo
! about three e-fourths Of q degree east (tn point
Of Of tbg nsads ahs DIP or 9sbar ncno 81
tho magnetic force when free to act, is
! likewise subioined ninety degrees meaning the
| vertical. The eliminating vortex Of the mag
ct present assumed in Boothia Felix, On the
Polar Circle. It will thus be understood that
| while the neutral line WIS once at Cleveland,
Ohio, the pointing st Boston was eleven degrees
soest, and at Victoria, Vancouver's Island, about
| twenty-three degrees east!
In the following table the variation given i'm
plies the mean variation Of the whols twenty
four houra that very uniformly takes places at
about o'clock P. NJ. The range OF daily varia-
ton, it is well known, between O'Clock in the
in thu West, usually amounts to. from ten to
eighteen n.i,iutes Of angle. Keeping all these
facts in mind, the following table Of results will
| be found generally useful to surveyors and tray
ellers, especially in the plains:
| Places. Variation East. Dip.
st. Louis, Missouri. deg. % min SO deg. IS min.
Herman, Assour4.... deg. Y min. So deg. q min.
sedalia Missouri. deg. q min .68 deg. 80 min
Kansas City, Missouri 10 deg 46 min .69 deg. 06 min
anhattan Kansas. 10 deg. sc min 68 deg. 48 min.
Ellis, Kansas deg. 26 min. ..67 deg. 81 min.
Wallace Eausas .la deg 26 min. 81 deg. 81 min.
Denver Colorado. II deg. IS min. 81 deg. 40 min.
Pueblo, Colorado. 13 deg. 80 min &c deg. q min.
In the latter case, the influence Of the de-
crease in latitude becomes very marked, owing to
the trend of isogonic lines. The latitude of
Pueblo was determined at about S8 deg, II
| min.; that Of Denver at 80 deg., a min; all
| these determinations, however, leaving slight
margin OF possible error Of about one-haH to
! one minute Of angle.
As it is desirable to correct the magnetic
| maps as at present in use, q similar survey
ought to be at once instituted along the
Union Pacific route, in order to fully har-
monize the magnetic Systems Of the Pacific, the
Mississippi, the Atlantic CoaBt, aud Canada, in
which latter section the British Government is
carrying similar survey, as it has heretofore
been conducted, by Captain Sabine, all along the
accessible coasts of the globe. Almost until
| now, the magnetic survey Of the interior remains
private enterprise Of the heads OF the leading
governmental and legated scientific institutions
OF the country.
! Strong Language.
When N. Vauillot heard that Gariba1di didn't
| die after Montana, he said: "We have a1vavs