14 EXPEDITION TO POINT BA1UIOYV, ALASKA. 



Lanily probably) show viscidity. It is desirable, therefore, that preference be given to tlieso 

 standards over any other .standards Cor extremely low temperatures, and in establishing tlio 

 meteorological observatory at which the. greatest cold is expected, special attention should bo 

 given to the ether and carbon di sulphide thermometers. 



" Sni/1/i'xt/v/ix in thi'ir nuc. Before mounting these thermometers in their stations, they should 

 be earefully swung or jarred so that no spirit can be detected (with a magnifying glass) adhering 

 to their upper ends. They should be inclined (with the bulb end nearest the ground) as far as it 

 is sale, and have the index stand in its place, by its own friction against the side of the tube. NO 

 that 'he drainage may be as perfect as possible.* 



"All mirlinii* should be wortled in inillinieters, and it should be remembered that the accom- 

 panying tabular corrections (see the correction cards) are meant to give only approximate, 

 temperatures. A careful comparison of all the thermometers from 1 to lli kas been made between 

 and 90 and Nos. 1, 5, and 9 have been kept by the observatory for experiments at temperatures 

 below F. 



"These are probably the best thermometers ever sent into the Arctic regions, and special 

 care should be taken to insure the safe return of the records, and. though less important, tho 

 instruments." 



IV. SPECIAL INSTBUCTIOKS PREPARED in inn VXITKD STATKS COAST \\n >;i .UMIVKV 



FOR OTC.SEKVATIONS IN TEKKKSTK 1 A I , MAG.NKTISM AT I'Ol.VI 1SAKKOW AND LADY FKAMv- 

 I.1X HAY. 



[These instructions will be applied, when suitable, to the observations ordered in preceding 

 pages, but they will also furnish a guide to the minimum number of observations to be taken in 

 case of accidents occurring to prevent full compliance with the plan proposed by the International 

 Polar Commission.] 



As soon as the quarters of the expedition have been fixed upon, a magnetic house will be 

 erected, in which the regular magnetic observations, as described below, will be made: other 

 observations will be made when on boat or sledge trips. 



Instruments. For use at the magnetic, observatory, there will be provided a magnetometer, 

 for absolute and differential declination and for horizontal magnetic intensity, to be permanently 

 mounted on a stone pier. In connection with this instrument a meridian or a/inmth mark will be 

 established a short distance on" the observatory, and visible from it through an opening in the 

 wall. The astronomical bearing of this mark will be carefully determined by means of an alt- 

 azimuth instrument and solar or stellar observations. 



In the same house, but on a separate pier, will be mounted a Kew dip circle, and in the case 

 of Point Harrow, a third instrument, a binlar magnetometer, \\ill also be permanently mounted 

 on its pier. At Point Barrow the magnetometer (or unifilar) and the bitilar instruments will be 

 mounted in the magnetic meridian and at a distance of not less than twelve feet, and the dip 

 circle will be mounted equidistant from these instruments, forming an equilateral triangle. At 

 Lady Franklin Bay the two instruments will be mounted in the plane of the magnetic prime 

 vertical, and not less than twelve feet apart. No iron is to be used in the construction of these 

 buildings, and they should be, not nearer than fifty yards to any other building, or double that 

 distance to any large mass of iron. Special reading-lamps (of copper) must be provided for use 

 with the instruments, and they must be tested to make sure that they do not affect the position 

 of the magnets. The use of candles stuck into wooden blocks is preferable to using lamps. 



When on boat or sledge journeys the party will carry a chronometer, a small alt-azimuth 

 instrument with circles of about three inches diameter (as constructed by Fan Hi \ Co., of 

 Washington, or by (Jasella, of London), provided with a magnetic needle or compass mounted 

 over its vertical axis, and a dip circle. 



ObxcrrtifiuHx nt the !>> iixinent atntioii. Hourly observations will be made, for declination and 

 diurnal variation, with the magnetometer on three consecutive days about the middle of each 



* This mi'thod mnlm-ms to tli:i ( Inllowi'il ;il :i!l signal .stations with minimum llN-nimmotcrs. rx< t'l't :IM li> ik-jMvo 

 of inclination, win-rein lhs<; suggestions should l>n most riiirl'ullv followed. 



