Dubuque, Sept 20th 1852
Capt. Andrew Talcott
Chief Engineer
Iowa Minnesota Boundary Survey
Sir,
I have the honor to present herewith the observations,
calculations, Etc for determining the azimuth of guide lines No’s 1 & 2
from the Mississippi River to Station Washington, with the offsets from
the same to the parallel of 43* 30’ N. Lat.
It will be seen by reference to the report that the whole
of guide lines 1 & 2 with the exception of the last six miles was checked
by setting up the zenith and azimuth instrument at three points, and
corrections made for any deflections which were found to exist.
The running of the guide line was assigned to Mr. G. A.
Stuntz and the running and marking on the parallel to Mr. J. S. Sheller.
The work previous to your arrival was much retarded by
the unseasonal rains and scarcity of grass, making the transportation of
supplies slow and difficult.
In accordance with instructions left by you mounds have
been erected at the intersection with the parallel of the meridians of
Stations Jefferson, Adams and Washington.
The mound at Station Adams fell upon the soft and
marshy ground to the South of the guide line, but at Stations Jefferson
and Washington the position of the mounds and the large size of the
stones, which formed their bases was such to serve them against removal
or injury.
At Station Washington the post used for transit observations
was removed and a large stone substituted in its place.
The whole of the field work including that between the
monument and the Mississippi River (which was left unfinished in the
spring, on account of the height of the water ) was finished by the ninth
Transcribed by Don Borcherding Jan 2011
Page 1
of September, and the field notes returned to the office of the Surveyor
General by Mr Sheller, under whose superintendence the whole of the
parallel was chained and marked.
The difference between the latitude of the established by
Captain Talcott and that by Capt. Lee (according to offsets from the
guide line No. 2) being 64.4 links, the latter being to the North, it is
provided for by lessening the offsets on the guide line No. 3, 52.2 links.
Thus throwing the curve further to the North, (the offsets being South)
and diminishing the offsets, ( which are South) on guide line No. 2 ,
throwing that portion of the curve further South.
The corrections in the offsets for guide line No. 3 commenced
at No. 52, where the correction is one link, and increased to No. 1 where
the correction is 52.2 links, the intermediate corrections increasing in
arithmetical progression the difference being one link.
I remain, Sir
Very respectfully
Your obedient servant.
Signed, Isaac W. Smith
Asst. Engr. I. M. B. Survey
Note: The remaining 12.2 links of the difference of latitude by direct
observation at Station Washington and that given by the guide line from
the iron monument was corrected by deducting progressively from 1 to 12
links from the southern offsets measured from stations 39 to 50 in chains
on Guide Line No. 2.
Transcribed by Don Borcherding Jan 2011
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Records of Observations Etc. made by
Isaac W. Smith
Principal Assistant I. & M. Bd. Survey
B
D
C
M
A
The zenith and azimuth instrument was mounted on a stump at the point
represented by A in the figure above 5.76 chs South of the parallel. M
representing the Iron Monument erected by Capt. T. J. Lee Top. Engr’s
and M. D. the parallel.
The meridian A B through the point A was then determined by the
following observations.
Station 1 near Monument
Date Star
Apr 14 Polaris
h
5 54 02
5 00 04
5 52 22
4 38 44.5
Apr 15 Polari s 5 54 23
Mean of results
Mean of Verniers for Elongation
z
a
E
W
46* 28’ 30” 3* 02’ 31” 68* 43’ 50”
44* 29’ 00” 21*14’ 55” 87* 56’ 00”
46* 29’ 20” 1* 39’ 45” 68* 14’ 50”
42* 51’ 55” 28* 16’ 10” 94* 56’ 40”
46* 28’ 50” 2* 02’ 30”
64* 38’ 20”
Meridian
66* 41’ 00”
66* 41’ 05”
66* 41’ 05”
66* 40’ 30”
66* 40’ 55”
66* 40’ 55”
h = Sid interval from meridian transit to elongation
z = zenith distance
a = azimuth
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The following transit of high and low stars were also taken on the
meridian determined by the elongations of the preceding page.
Date
1
M S
Apr 14 53 54.5
5 59.0
11 40.0
16 46 38.0
18 56.5
Station 1
Mean of Wire
2
3
4
5
M S
H M S
M S
M S
H M S
54 18.5 3 54 51.5 55 25.0 55 36.5 3 54 51.2
6 15.5 4 06 31.5 6 47.5
7 03.5 4 06 31.5
11 55.5 4 12 11.5 12 27.5 12 43.0 4 12 11.5
47 07.0 3 47 35.0 48 04.0 48 33.0 3 47 35.4
19 12.0 5 19 27.0 19 43.0 19 59.0 5 19 27.4
Name of Star
aUrsa Majors
S Leones
S Hydra
aUrsa Majors
B Corni
Reading of Meridian by Transit (a ursa majors and S Leones) 66*40’ 30”
“
“
“ ( a ursa majors and S Hydra ) 66* 40’ 57”
“
“
“ ( a ursa majors and B Corni ) 66* 40’ 40”
Mean of results of above 66* 40’ 42”
“
“
by elongations
66* 40’ 55”
The Meridian by high and low stars west 13”
The reading from the eastern and western elongations of Polaris differing
5” from the mean by elongation was adopted.
Reading of Meridian
66* 41’ 00”
B
D
C
M
A
A signal was then placed on a stump at the point C the initial point of
the Guide Line No. 1 which is 3 chs 59 links North of the parallel and 76
links west of the Monument. The distance A. C. is 32.15 chs.
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The azimuth of the line A C was determined as follows:
Reading of signal on meridian
66* 41’ 00”
“
“
at C
140* 30’ 10”
Azimuth of A C corrected from A to C at A 73* 49’ 10”
“
“
“ C 253* 49’ 30”
The instrument was then taken to C and the following readings taken,
Reading for C A from C
206* 09’ 10”
Azimuth of C A “ C
253* 49’ 30”
Reading of Meridian at C
312* 29’ 40”
“
“ Guide Line C B
142* 29’ 40”
Azimuth of Guide Line from N to E 270* 00’ 00”
B
D
A
M
C
E
Previous to marking the parallel the guide line was tested as follows.
A B M C E represents the guide line as run
A initial point of guide line
B 358.00 ch
W of A
M 240.00 ch west of B. 598.10 ch. W of A
C 680.00 ch “ “ M. 1278.10 ch W of A
E 1000.00 ch “ “ C 2278.10 ch W of A
D a signal 18 links N of C visible from M & E
By putting up the zenith instrument at B. M. & D. the following
deflections were found in the line.
At B
2’ 20” South front sight on M
“ M
1’ 55” South “
“ “ D
“ D
7’ 05” South “
“ “ E
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The deflection at D was caused by mistaking the point of the forward
signal in setting up the smaller instrument with which the line was run
and the line from D to E being visible in several points was found to be
straight.
The zenith instrument being mounted at D the following observations
were taken determine the azimuth of the line D M.
Saturday May 1st
Eastern Elongation of K Ursa Minoris
Reading of verniers for elongation
163* 34’ 00”
Azimuth at elongation
1* 33’ 45”
Reading of Meridian
162* 00’ 15”
“ “ Signal on D M
251* 43’ 40”
Azimuth of D M from N to E
89* 43’ 25”
The instrument was then taken down on account of rain, and on the
night of the 2nd of May was again put up.
Eastern Elongation of Polaris
Reading of Verniers for Elongation
164* 00’ 30”
Azimuth at Elongation
2* 02’ 30”
Reading of Meridian
161* 58’ 00”
“
“ Guide Line Signal
251* 41’ 40”
Azimuth of Guide Line E from N to E
89* 43’ 40”
“ “ “ by elongation of Ursa Minoris
43’ 25”
Mean of results
89* 43’ 32”
No Polaris was at the eastern elongation after daybreak the signal M on
the guide line 8.5 miles distant was visible and the azimuth of the line
accurately measured immediately after the observation.
The portion of the line from A to B about 4.5 miles was assumed to be
correct, a great portion ot it being laid off with the zenith instrument
from A and the remainder ( one or two miles) being run with great care.
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The azimuth of D M from D being 89* 43’ 32” and B. M. deflecting 1’
South at M. the azimuths of A. B. B. M. and M. C. are as follows.
Azimuth
is from
Azimuth of Prime
Error to the
Of line
N. to E.
verticel starting at A South
A.B. at A
270* 00’ 00” 270* 00’ 00”
00’ 00”
B.M. “ B
269* 53’ 59” 269* 56’ 19”
2’ 20”
M.C. “ M
269* 49’ 46” 269* 53’ 50”
4’ 10”
C.E. “ C
269* 35’ 32” 269* 46’ 51”
11’ 20”
The corrections for the above deflections were calculated by plane
trigonometry.
Station 2.
Station 2 is 2282.15 chs. West of the iron monument erected by Capt.
Lee, Top. Engrs, and 4.82 chains north of the parallel.
The following are the observations by which the azimuth of guide line
No. 2 was determined.
Name
Station 2
Mean of the reading of verniers Signal
Of
Elongation
on Guide
Stars
h
z
a
E
W Meridian Line
h.m.s * ‘ “ * ‘ “ * ‘ “ * ‘ “ * ‘ “
Ursa min
“ “
“ maj
“ “
B cephei
Polaris
5.47.08
5.55.22
3.09.45
2.29.27
4.38.44
5.54.23
46.24.20
46.27.20
32.17.40
26.07.00
40.51.50
46.28.50
4.41.50
1.33.45
53.08.50
62,16.20
28.16.10
2.02.30
238.12.00
235.04.20
233.30.09
30.35
180.21.40
30.30
170.13.50
30.10
261.46.20
30.10
205.33.10
30.40
Reading of meridian by the mean of the above
233* 30’ 22”
“
Signal on Guide Line West
143* 29’ 30”
Azimuth of Guide Line No. 2 counted from N to E
269* 59’ 08”
In the above table; a = Azimuth of Star at elongation
Z = Zenuth dist “
“
H = Sid interval from meridian transit to elongation
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The azimuth of Guide Line No. 2 by elongations
269* 59’ 08”
“ mean of results by transits of high & low stars 269* 59’ 19”
Difference
11”
The Azimuth adopted was
269* 59’ 20”
The signal on the Guide Line used in determining the azimuth was 11
miles distant from Station 2 at the point at which the signal was placed
the zenith instrument was mounted, and a back sight being taken to
Station 2 the line was tested to a point 8 miles west, or 19 miles from
Station 2, and thence extended to Station Washington with the smaller
transit. This latter instrument had from some cause been much injured,
rendering it necessary to run the line with great care to avoid injury, and
to test nearby the whole of it with the zenith instrument. No deflections
however were found in Guide Line No. 2.
In the spring of the year the water was so high on the Mississippi River
as to render it extremely difficult to produce the guide line east through
the river bottom. It was therefore deferred until the return of the party in
the fall. The line was then run and the parallel marked as follows.
Guide Line No. 1
C
E
B
3.60 chs
D M
3.60 chs
F
C. is the initial point of Guide Line No. 1 3.59 chs. N of the parallel and
76 links west of the monument. M represents the monument.
The instrument was put up at C and a signal placed at E (on the
extension of the guide line) on the bluffs east of the Mississippi.
A signal was then placed 36o links South of E. at F. The line D. F. is
therefore parallel to C. E. and is consequently a prime vertical running 1
link South of the monument.
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A deflection of 1’ 30” was then made to the North and the guide line run
to the west bank of the river. This section of the guide line runs 1’ 30” N.
of the prime vertical.
The Azimuth from N. to E. =
80* 58’ 30”
Commencing one link South of the parallel, the distance to the first
mound east is 1 ch 90 lks. The offsets are calling the first mound east of
the monument (1 ch 90 lks) No. 0.
For No. 0
0.9 links N
No. 4
2.2 links S
1
0.6 “
S
5
1.7 “ S
2
1.6 ‘
S
6
0.8 “ S
3
2.1 “ S
7
0.6 “ N
The distance from Monument to W bank of river 256.14
½ Breadth of the river at intersection of line
8.08
Distance from monument to meridian of Sta. 1
32.15
“ “ Meridian of Sta 1 to Meridian of Sta 2
2250.00
“ “ “
“ 2 “ “ of Sta Washington 2001.85
“ “ the middle of the Channel of the
The Mississippi to Station Washington
4548.23
Transcriber’s Note: This report was transcribed from the Micro film (M-618) in the
Library at the Minnesota Historical Society Building in St Paul. Original pages 6 – 10 of
the Records of Observations were not transcribed. They contain tables of Astronomic
Observations at Station 2 which were taken by Smith May 7th -10th 1852.
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