EXPEDITION TO POTXT BARROW, ALASKA. 



595 



Observations for determining the ahxolute magnetic <l<'<-liitati<m Continued. 



(Date, August :il. IJ-H:-. 

 magnetometer No. 11. 

 and Maxfield.] 



(lot.tlngen time. Instrument, theodolite 

 Magnet L,, suspended. Observer* : Dark 



1 1 i.ii... SL-ptember 14, 1S82, local time, Instrument, U. a C. and G. 8. 

 anlfllumunetameterlfo.il. Magnet L /( suspended. Obwrven- 



Dark am! Maxneld.] 



Time. 



Mean 

 scale- 



Compntatinn. 



Time. 



Mean 

 scale- 



Compntation. 



H. 00 a. MI. 

 . 15 a. ui. 



8. 30 a. m. 

 H. 4."> a. m. 

 (I. 00 a. 111. 

 !t. 15 a. m. 



9. 30 a. m. I 



!>. 4") II. 1U. 

 10.0 I 11. 111. 



In. ir. ii. m. 



10. 30 II. ill. 



10. 4fin. m. 



11.00 p.m. 

 11. 15 p. m. 

 11.30p.m. 

 11.45]). m. 

 12. 00 p. m. 

 12. 15 p. m. 

 12. 30 p. m. 

 12. 45 p. m. 

 1. 00 p. m. 



Sum 



Mean ... 



<t 



r,C. 40 



IL>. 'jr. 



43.60 

 43.40 

 46. 50 



41;. r,:> 

 43.30 

 4.\ 00 

 45.75 

 41.75 



41.40 



45.30 

 42.30 

 44.20 



38. 50 



37.70 



39. 90 

 40.60 

 41.50 



Beading of tnarlc. 



o i 



At beginning of a. m. observa- < A. 359 51 

 tiom { B. 53 . 



At ml of p. m. observations . . j :IS " 



Mean. 



S3 

 359 52. 



8 a. m 



9 a. m 



10 a. m 



11 a. m 



12m 



1 p.m 



d. Heading of mark. 



42. 90 o < 



Hi. iin At beginning of a. m. ob- < A. 360 51 



.VI. 70 servations | B. 52 



36. 10 I At end of p. m. observa-) A. 359 5] 



40. KO i tions }B. 52 



41.7.-, 



Mean 359 ].. 



Value of oue division of scale... =3'. ( 



Scale-reading of axis 



Mean scale-reading of east and 

 west magnetic elongation 



diff. =" 



34.92 

 42.89 



Readings of the differen- 

 tial ii M i I i I :i r taken at 9, 

 10,11 a,m., and 12 m. 

 and at 1 p. m. 



7.97 



!)>. HI 

 42.89 



Line of de- 

 torsion... 15 

 A-f.. cir-CA. 354 11 

 ole . . . ) B. 09 



Reduction to axis + 2!>. 4 



A zimuth circle reads 354 10.0 



9 a. in . 



10 a. m . 



11 a. m . 

 12m ... 



1 p. m . 



538 

 553 

 510 

 521 

 525 



Magnetic meridian reads 354 39. 4 



d. 

 43.85 



529.0 

 521.7 



Mean reading of mark 359 52.0 



Azimuth of mark 46 36.0 



True meridian reads 313 16.0 



1. 98 = 7. 3 

 41.87 



Magnetic declination 41 23. 4 Ii 



Line of detor- 

 sion 15 



A. circle..^' 354 



Valueofonedivision of scale. 



Scale-reading of axis 



Mean scale-reading of east 

 and west magnetic elonga- 

 tion 



=3'. 119 



:;:. ii:, 



41. S7 



diff. ^ 



e.82 



Reduction to axis +0 25.2 



Azimuth circle reads 354 10.0 



Magnetic meridian reads 354 35. 2 



Mean reading of mark 359 51. 5 



Azimuth of mark !( 36. 



True meridian reads 313 15.5 



Magnetic declination 41 19. 7 



*Krom observations uf August 19 and September 30, 1882. 



[Date, September 30, 1882, local time. Instrument. U. S. C. and <}. S. 

 uninlarmaprnetometerMo.il. Magnet I,,, suspended. Observers: 

 Dark and Maxfield.] 



[Date, October 14, 1882, local time. Instrument, U. S. C. and G. S. 

 unin'larmapnetoinetCTNo. 11. Magnet L,, suspended. Observers: 

 Dark and Maxneld.J 



Time. 



8a.m.. 

 9 a. m.. 



10 a. 111.. 



11 a. m . . 

 12m..., 



1 p. m. . 



Mean 

 scale- 



readiniia. 



Computation. 



Time. 



d. 



41.40 



41.20 



39.85 



38.90 



37.90 



37.00 



Rc;ul ings of the differen- 

 tial unifilar at 8. 9, 10. 

 11a.m., and 12 MI. ami 

 at 1 p. m. 



Heading of mark. 



At beginning of a. m. ob < A. 359 52 



servaticne \ B. 50 



At end of p. m. observa- C A. 359 50 



tions JB. :> 



Mean. 



359 51 



8 a. m. 

 9 a. m. 



10 a. m. 



11 a. m 



12 IP ... 

 1 p. m- 



M.'.'IIL 



readings. 



d. 



49.00 



50.55 



32.00 



32.10 



34.40 



33.70 



Determination of axis of magnet. 

 Altn'te 



8 a. m . 



9 11. m . 



10 a. m . 



11 a. m . 

 12m.... 



1p.m. 



519 

 520 

 518 

 516 

 511 



d. 



ail. 7 

 +1.73 = 6.4 



41.10 



Rcwlinzaof the differeu- 



tiiil imifilar at 8, 9, 10. 



I ! a. MI and 11! in. and 



at 1 p. m. 



36.82 

 33. 25 

 88.00 



32. -Jf> 

 37.88 



86.41 



85, LM 



:i4. M 



S ii. ill . 



9 a. m . 

 10;i. m .. 

 Ha. m.. 

 12m 



1 p. m. - 



Computation. 



Shading of mart. 



359 



At beginning of a. m. ob- J A. 



servationB ( B. 



At end of p. m. obseiva-CA. 359 



ticuis } B. 



Mean . 



359 51 



533 

 548 



504 ' 

 509 



512 



Value of one division of scale 



Scale-reading of axis 



Meau scale re ;n! ing of E. and 

 W. magnetic elongation. 



diff.= 



3.1. 0,-i 

 36.8)7 



1. 89 



Reduction to axis 

 Azimuth circle reads 



+0 7.0 

 354 31.0 



Valueofonedivisionofscali 



Scale-readiiicofaxis ...... 



Mean calr-rc:iilinu ' t" K. and 

 W. miignetic rloiiiiiitiim. .. 



=3'.6 



41. 10 



Tss" 



d. 

 38. 02 520. 7 



.-.14. (i 



1. li. r . = 6. 1 



Magnetic incrhlian reads 354 38.0 



Mean reading of mark 359 51.0 



Azimutb ot' mark 40 36,0 



> Tidian reads 313 15.0 



Line of del or- 

 sion 15 



Az. circle f' n54 



Reduction to axis -fo -1 > 



Azimuth ciiclr rciuls 3M I'il.o 



Magmilic ridiiiure.nl.-. 3.H 5P. 5 



Mean icadin:; of nun I, 



Azimuth of mark K. of M... 4(> :\ . n 



'I'lile uieriilian i e ds.. ::l . 



Magnetic declination 41 23. 



: Mean oi results from the observations of September 30. and Oo 

 toberSl. 



Magnetic :!ec!inal., 



II :;:. -. K. 



