226 



Ocean Magnetic Observations, 1905-16 



Dead Reckoning. 



The data for the dead reckoning (D. R.) are the ship's courses and the log-readings, 

 the corrections to these, the astronomic positions, and the times or places for which posi- 

 tions are required. The times, places, courses, leeway, and log-readings are taken from 

 the ship's log-book and entered on Form 42 below. In the column headed "Ship's Time" 

 are entered the ship's times at the various places whose geographic positions are required, 

 either for scientific results or for navigational reasons. The places are stated or else indicated 

 by symbols or abbreviations, which will readily be recognized. The first entry refers to the 

 last position of the day before. In the specimen form it is the place where two-star observa- 



Date: Sat., Aug. 23, 1913 

 Vessel: Carnegie 



Geographic Positions at Sea: Dead Reckoning 



(Form 42) 



Wind: SSE, SE, S, SSW 

 Com'd'r: W. J. P. 



Comp'r: H. R. S. 

 Reviser: W. J. P. 



Ship's Time 



h m 



7 04 p. m., * * yesterday 



5 38 a. m., D obs'ns 



8 03 a. m., alt. 



9 18G. M. Noon 

 Noon 



2 42, H and / obs'ns 

 4 00, o alt. 



6 20, D obs'ns 



7 06, * * alt. 



Compass 



N 22E 

 N 22E 

 N22E 

 N22E 



N22E 

 N22E 

 N22E 



N22E 



Decl'n 



-24 

 -24 

 -24 

 -24 

 -25 

 -25 

 -25 

 -25 



Dev'n 



Lee- 

 way 



True 

 Couise 



358 

 3.58 

 358 

 358 

 357 

 357 

 357 

 357 



Log 

 Readings 



31.2 

 83.4 

 94.8 

 100.8 

 13.8 

 25.9 

 31.3 

 40.6 

 44.1 



Dis- 

 tances 



miles 



52.2 



11.4 



6.0 



13.0 



12.1 



5.4 



9.3 



3.5 



N 



52.2 



11.4 



6.0 



13.0 



12.1 



5.4 



9.3 



3.5 



miles 



W 



miles 



1.8 

 0.4 

 0.2 

 0.4 

 0.6 

 0.3 

 0.5 

 0.2 



Diff. 

 Long. 



2.3 W 

 0.5 W 

 0.3 W 

 0.5 W 

 0.8 W 

 0.4 W 

 0.7W 

 0.3 W 



Yesterday at 

 Run to D obs'ns 



By D. R. 



(Adjusted) 

 Run to © alt. 



h m 



7 04 p. m. 

 5 38 a. m. 



5 38 a. m. 

 5 38 a. m. 



8 03 a. m. 



By D. R. 8 03 a. m. 



(Adjusted) by obs. 8 03 a. m. 

 Run to G.M." Noon 9 18 a.m. 



By D. R. 



(Adjusted) 

 Run to 



9 18 a. m. 

 9 18 a. m. 

 Noon 



By D. R. at Noon 



By obs. (adjusted) Noon 

 Run to HI obs'ns 2 42 p. 



By D. R. at 



(Adjusted) 



2 42 p. m. 

 2 42 p. m. 



Latitude 



o / 



37 59.0 N 

 52.2 N 



39 28.9 N 

 (39 29.2 N) 



Longitude' 



39 46.9 W 

 02.3 \V 



39 .50.3 W 



(39 49.8 W) 



By D. R. 

 Run to o alt. 



h m 



2 42 p. m. 



4 00 p. m. 



By D. R. 4 00 p. m. 



(Adjusted) by obs. 4 00 p. m. 

 Run to D obs'ns 6 20 p. m. 



By D. R. 



(Adjusted) 

 Run to * * alt. 



By D. R. 



By obs. 



6 20 p. m. 



6 20 p. m. 



7 13 p. m. 



7 13 p. m. 

 7 13 p. m. 



Latitude 



o r 



39 28.9 N 

 05.4 N 



39 34 3 N 



(39 34.7 N) 



09.3 N 



39 43.6 N 



(.39 44.2 N) 



03.5 N 



39 47.1 N 

 39 47.8 N 



Longitude' 



o / 



39 50.3 W 

 00.4 W 



39 50.7 W 



39 50.1 W 



00.7 W 



39 50.8 W 



(39 49.1 W) 



00.3 W 



39 51.1 W 



39 48.8 W 



'Longitudes are to be increased by 1'4 on account of sea rate of chronometer, determined finally, September 12, 1913. 



tions made in the evening of August 22 have determined both latitude and longitude. 

 The ship's magnetic courses by the standard compass are entered in the second column 

 under "compass." The magnetic decUnations given in the next column are taken from 

 navigation charts corrected, as necessary, for the error indicated by the magnetic results 

 of preceding days; the minus sign indicates west decUnation. The deviation at the 

 standard compass is zero, as noted in the fourth column. The leeway is taken from the 

 log-book, where its estimated magnitude is recorded every 4 hours, or at every change 

 of wind or course. In the specimen form, the wind coming from SSE to SSW and the 



