456 



IIXI'EDITION TO POINT HARROW. ALASKA. 



Station, I'glaamif, 



"The three magnetic instruments were mounted on wooden piers, the season being too far 

 advaneed to place masonry. Posts 12 inches square were set into the fro/en earth to a depth of 

 1 foot, and lamented into their place by pouring water around them and allowing it to free/.e. 

 Tin 1 piers answeivd every purpose, were perfectly solid, and did not change their position in the 

 slightest decree, and when the observatory was taken down this summer I found the ice around 

 their base unmelted. As soon as the weather was warm enough, brick piers capped with stone 

 were placed, and the instruments are now all in position on permanent piers." This operation 

 occasioned an interruption in the hourly observations from July '22 to July ;!0, IS82. This first 

 series dosed with Scplem1>er 9, 1S82; it includes term-day observations, also hourly observations 

 of dipping needle deflected by a constant weight as a substitute fora vertical force measure: these. 

 latter observation-! of relative total force, while of small value as differential measure, may never- 

 theless supply means for computing changes in the intensity which otherwise would have, been 

 wanting. 



The supply party in the Leo arrived off Uglaamie August 20, 1882, with the J-Jrooke mag- 

 netometers : they were mounted on brick piers, in a building especially erected for them, and their 

 relative position was in strict conformity with the plan contained in the instructions. So long as 

 thawing weather continued these piers lacked somewhat in stability, but the frost soon rendered 

 them immovable. These instruments having been adjusted, the hourly series of observations com- 

 menced September 12. issi>, and were continued without interruption to August :.'?. ts,s.".; the term- 

 day observations and those 

 for absolute measures were con- 

 tinued throughout the second 

 year of the occupation of the 

 place. 



It has already been men- 

 tioned that in consequence of 

 unfavorable conditions be- 

 tween August 22 and August 

 29, 1883 (when the, station was 

 abandoned), no verification of 

 the magnetic works could be 

 made by 31 r. II. A. Marr, but 

 on the return voyage some, 

 magnetic, observations were se- 

 cured at ("nalashka. and after 

 the return of the instruments 

 to Washington some additional 

 verification work was done by 

 Sergeant Maxfield in January 

 and February. 1SSI. 



The accompanying sketch 

 shows the location of the mag- 

 netic observations and the po- 

 sition of the instruments. 



The first position of the 

 magnetic observatory was a 

 little to the westward of the 

 new position shown on the 



sketch ; the change was made 

 in July, 1SS2. 



