KXPHUITION TO POINT lIAl.'ltnW, ALASKA. 15 



month; besides I!ICKI> observations, extending over seventy-two hours, there will be made :it any 

 convenient intermediate time t<i<-h day (of the three) one set of deflect ions, followed immediate! y 

 by a set of oscillations for the determination of the horizontal intensity. At Point I'arrow the, 

 bifilar will be read immediately after the nnifilar. There will also be made at any intenncii 

 time twit day (of the three) a set of dip observations. In connection with the declination, the 

 mark will be read once each day (unless the instrument should aecidently be disturbed), but it 

 suflices to determine the magnetic axis of the declination magnet on one of the Hirer- days. Tim 

 instrumental constants of the magnetometer will be determined before leaving Washington, and 

 the observers will use the Coast and (ieodctic Survey magnetic blank forms for their n-conK or, 

 incase no special forms are provided, they will use, .small (octavo) note, books; they will al>r: 

 compute, as soon as the observations arc completed, each month, the magnetic mean declination, 

 diurnal range, and turning hours, also the horizontal force in absolute measure (Knglish units) 

 and the dip. tabulating the results for each day. 



I'A-fra observations on other than the three days about the middle of each month will bo 

 made (luring all occurrences of auroral displays, but as they are likely to be very numerous at 

 Point Harrow, observers there may confine their extra observations to the more conspicuous 

 displays only. On these occasions the declinometer (and the bifilar at Point P.arrow) will be 

 read, say, every ten minutes, or at shorter or longer intervals, as the state of the needle may 

 appear to demand, the object being to establish a connection between the appearances of the 

 aurora and the motion of the magnetic needle. 



When landing OH a boat journey, or during a sledge journey at suitable stations (not less than 

 ten or fifteen miles apart), the time, latitude, and azimuth will be determined by the alt azimuth 

 instrument, and the declination by the same instrument (the, hour and minute of the observation 

 is to be noted, in order that the diurnal variation may be allowed for): the dip will also be 

 observed, and in case time, is pressing, reversal of circle, reversal of face of needle, and reversal 

 of polarity may be dispensed with, but the needed correction to the result, from the single 

 position of the instrument, must be ascertained at the permanent station. Observations of 

 deflections (with magnetic needle and with weights) will be made with the dip circle, as arranged 

 for relative and absolute total force, the data for the latter to be supplied at the permanent 

 station. 



It is highly desirable, especially in the case of the, Lady I<"ranklin Bay party, that all stations 

 within reach and formally occupied by other parties for magnetic purposes be revisited, in order to 

 furnish material from which to deduce the secular change during the. interval; besides, all oppor- 

 tunities should be taken when lauding on the way up to secure observations for declination, dip, 

 and iiitensity the latter best by oscillations of the intensity magnet. The winter quarter* of 

 the late English expedition should be connected magnetically with the present quarter.*. 



[All magnetic observations will be made on Gottingen time, as provided for by the Hamburg 

 Conference. | 



Ail magnetic records will be kept strictly in conformity with "Notes on Measurement* of 

 Terrestrial Magnetism," United States Coast Survey, Washington, 1877, and other records in con- 

 nection therewith should be equally clear and complete, and all computations should be made by 

 the observer in separate books. Duplicates of all records will be made, compared with ilu- 

 original, and the latter returned, annually, if practicable, to the Chief Si-n,il Ofiicer for tin- 

 Superintendent of the Coast and (ieodetic Survey, Washington, !>. ('. The observers should also 

 provide themselves with copies of the "Admiralty i Manual of Scientific Knqniry." the "Arctic 

 Manual and Instructions," 1375, and "Aurora-, their characters and spectra." by .1. II. ('apron. 

 1880, also with "Terrestrial and Cosmieal Magnetism," by K. Walker, iNiii, and any other work 

 they may require for their information. 



V. ADDITIONAL SPECIAL iKsriirrrioivs. 



The rules prescribed in "Instructions for the Expedition toward the North Pole." as pub- 

 lished (in pamphlet) by authority of the Hon. (ieorge M. Jtobeson, Secretary of the Nav,\.and 

 those, contained in "Suggestions Relative to Objects of Scientific Investigation in Knssiau 

 America," both of which are furnished, will be followed as closely as circumstance* permit. 



