EXPEDITION TO POINT HARROW, ALASKA. 



599 



Observation* for determining the absolute magnetic declination Coiitiuued. 



;Daie, April 30, 1883, local timo. Instrument, unifilar magnetometer ! [Date, May 14. 1883, local time. Instrument, nnitiUr magnetometer. 

 No. 11. Magnet L y/ suspended. Observers: Dark and Muxiield.] Magnet L,, auspended. Ol> I. and Maxdcld.j 



Time. 



8 :i. in. 



1) a. in. 

 Ill a. in. 

 11-a. m. 

 12 in . 



t |>. in . 



Mean I 

 d. 



52. I) 



:!ii. 

 20.0 

 22.0 

 00.0 

 10.5 



Brooke declinometer 



H';M! 



8 a. in 618 



;i a, m 555 



497 



11 ii. in 497 



12 in 419 



1,,. in 459 



d. 



507. 5 

 482. 1 





detor- 



sion 135 



5 A 



IB 



55 



Line of dctor- 

 sionat 11 a.m. 



Az. circle j A 



258 



35!) 



56 



Computation. 



Time. 



mark. 



At beginning of a. m. ob- ( A 

 servations f B 



At end of p. m. observa- C A 

 tions ) B 



359 



Mean. 



358 57.5 



8a. m 



8a. in 



10 a. m 



11 a. m 



12m 



1 p. m 



Mean 



Bcale- 



readinga 



d. 



37.0 



::;,. ;, 

 34.0 

 :n.7 

 31.4 



Determination of axis of magnet. 



Scale. 



Scale-read- 

 ings. 



24.0 

 42.9 

 24.2 

 43.0 

 25.4 

 41.9 

 24.8 



24. 

 47.5 



_>:.. 2 



44.8 



45.1 

 27.4 



Moan. 



Altn'te 



24.0 

 45.2 

 24.7 

 43.9 

 26.7 

 43.5 

 26.1 



24.35 

 44.55 



25.70 

 43.70 



20.40 



Axis. 



34.78 

 34.62 

 34.80 

 35.20 

 34.95 



Brooke declinometer 

 readings. 



8 a. m 487 



9a. m 480 



10 a. m 480 



lift, m 468 



12m 407 



1 p. in 462.5 



Seal.,. 



d. 



Value of one division of scale =*. ( 



475.1 

 476.1 



Seale-reading of axil 34.87 



Mean scale-reading of E. and 

 W. magnetic elongation. .. 16.54 



+ .27 = 1.0 





ditt.= 



18.33 



Reduction to axis. 

 Azimuth circle rend* 



-0 67. 6 

 349 55.5 



Line of detor- 



sion 250 



348 56 

 58 



Magnetic meridian leads 348 47.9 



Mean reading of mark 359 57.5 



Azimuth of mark E. of N... 46 36.0 

 True meridian reads 313 21. 5 



A , circle J A 

 \ B 



etor 

 Az. circle J A 



Line of detor- 



sion 297 



348 56 

 57 



Magnetic declination 35 26. 4 



Computation. 



Heading <if mart. 



359 



At beginning of a. m. ob-C A 

 aervatious ............ JB 



At end of p. m. observa- ( A 

 ) ir 



tious 



Mean 



359 57. '.'5 



Determination of ails of magnet. 



Scale-read- 

 ings. 



Mean. 



Altn'te 

 mean. 



30.0 

 37.0 

 28.4 

 39.0 

 28.8 

 37.3 

 28.1 



41.! 5 

 31.2 

 41.0 

 31.2 

 42.9 

 30.9 



30.10 

 39.25 

 29.80 

 40.00 

 30.00 

 40.10 

 29.50 



2''. !I5 



40.05 

 29.75 



Axis. 



:t4. 60 

 111. 72 



35.02 

 34.93 



Value of one division of scale =3'. 69 



Scale-reading of axis 34. 84 



Mean scale-reading of E. and 



W. magnetic elongation . . 33. 55 



difl'.= 



1.29 



Reduction to di -o 4.8 



Azinuith circle reads 348 56.8 



Magnetic meridian reads 348 52. 



Mean reading of mark 35!) >7. :' 



Azimuth of mark E. of N... 46 36.0 



True meridian reads 313 21.2 



Magnetic declination 35 30. 8 E. 



| Date May HI. 1883, local time. Instrument, uiiifilar magnetometer 

 No. 11. Magnet L,, suspended. Observers: Dark andMaxfiuld.} 



ir~A. 



[Date, June 14, 1883, local time. Instrument, nnitilar ina^iie 

 No. 11. Magnet L,, suspended. Observers: Dark and Maxliehl.] 



Time. 



Mean 



readings. 



Computation. 



Time. 



Mean 

 scale- 

 readings. 



Computation. 



8 a. 111 '... 



9 a. m 



lua. ill 



11 a. in 







I p. in 



d. 



37.8 

 40.0 

 32.0 



112. 7 

 111. 1 

 31.2 



Heading of mark. 



At iieginuiliK of a. m. ob- ( A 359 57 



servatiiuis jB 58 



At eml of p. m. observa- ( A 359 57 



tions )B 58 



Mean. 



359 57.5 



8 a. m. 

 9a.m. 



10 a. m. 



11 a. m. 



12 m ... 

 Ip. m. 



d. 



44.0 

 43.0 

 39.0 

 34.5 

 114.1 

 34.2 



IJronke tit i lir, 



readings 



9a.ni 499 



JO a. in 472 



lla.m 474 



12m 469 



1 p. in 469 



d. 



XI. 411 17ti. (i 

 47IJ. I 



-.14 =0.5 

 33. 26 



Scale. 



Determination of axis of magnet. 



Altn'te 



Scale-read- 

 ings. 



31.2 

 30.9 



27. 6 

 27. II 



22.4 I 



32.5 ! 



31.2 

 46.1 

 34.8 

 50.0 

 40.2 

 46.5 

 33.7 



Mean. 



31.20 

 3&50 

 31.20 

 38. SO 

 31.30 

 39.50 



31.20 

 38.50 

 31.25 

 39.00 

 30.55 



Axis. 



if. 



34. K. r . 

 34.85 

 34.88 

 35.15 



Brooke declinometer 



readings. 



8a.ni 499 



9a.m 500 



10a,m 486 



lla,m 470 



12m 471 



Ip.m 469 



Reading of mark. 



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



servations .............. i B. 



At end of p. m. obaerva-t A. 



tions .................... )B. 58 



Mean ................. 



Value of one division of scale 



Scale-reading of axis ....... 



Mean scale-reading of E. and 

 W. magnetic elongation . . 



diff.= 



34. 87* 

 1.42 



Reduction to axis 4n 



Azimuth circle reads 348 41.0 



Value. >f one division of scale =3'. ( 



Seal,, reading o! axis 34.95 



Mean smte-rMding of E. and 



W. magnetic elongation. . . 33.26 



d. 

 38.13 



1.84 

 36.29 



482.5 

 475.7 



6.8 



Magnetic meridian reads 348 46. 2 



Mean reading of mark 359 57. 



Azimuth of mark E. of N... 46 36.0 



True meridian reads 313 21.0 



Magnetic declination 35 25. 2 E. 



Line of detor- 

 siou 265 



'{ :MH 



l.ille ol' 



diff.= 



1.1 



06.2 

 348 54.0 



K.-dm'limi to axis 

 Azimuth circle re.iiis 



Mamti-l i, iiifi nli;m reads 348 47.8 



Mom reading of marl 359 57.5 



A/,imntli of mark !:. of X. .. 40 36.0 



True ineridhiii reads 313 21.5 



.Mai'iietV di'clination :; 



Lino of detor- 



sinn 300 



A.. circle{ A ; 348 40 



Line of tletor- 

 sion 28C 



* From observations nf M.iv "I and .Inly 1 I 



