ABSTRACT OF MAGXETJCAL OBSERVATIONS. 



45 



IV. ABSTRACT of MAGNETICAL OBSERVATIONS made at LAND STATIONS, 

 prefaced with descriptive references to the Observation spots. 



1. KEW OBSEBVATOBT, 



2. LISBOS, 



fLat. 51 28' 6"K. 

 (Long. 18 46-5 w. 



In the small wooden house at the end of the garden where the 

 Unifilar Magnetometers are examined. 



fLat. 38 43' 1 3-1" H. 

 (Long. 9 8 20-5 w. 



At the Magnetic Observatory in the new " absolute " house attached 

 to the Observatory of the Infante Dom Luiz. 



3. GIBRALTAR, 



f Lat 36 

 ' a ' \ Long. 5 



8' 24' 

 20 24 



'. 



Lat. 36 7' 36" 

 'ong. 5 21 24 



a. On the neutrax ground near the Spanish lines, close to the 300 

 yards stone. Soil sandy. 



b. On the walk above the Grand Parade, near the site where the 

 officers of the Austrian frigate " Xovara " made observations ; which 

 latter is now occupied by two heavy guns. The site was selected with 

 a view to comparing the results at the two epochs, but the whole 

 parade is so surrounded with guns and shot that no reliance can be 

 placed on the observations. The Horizontal Force notwithstanding 

 is the same as on the neutral ground ; the Inclination less by 13'. 



4. MADEIRA, . 



fLat 32 38' 0" s. 

 - 1 Long. 16 55 30 w. 



f Lat 32 38' K. 

 (Long. 16 55 w. 



a. The place selected on the first visit, in February 1873, was a 

 little off the new road to the west of Fort Pontinha and near Casa 

 Branca, but the local disturbance was so great as to destroy all hope of 

 satisfactory results. At one foot above the ground the Inclination was 

 48 46' x., whilst on the observing stand, 3^ feet above the same spot, 

 it was 5618'x. 



The Declination at this place differed 4 from that found on board 

 the ship. 



b. On the second visit in 1873, a place was found on the new road, 

 on the Alameda near the bridge over the Rio Secco, although the 

 ground was of a promising nature, yet even here the Inclination differed 

 as much as 40' in two places 20 yards apart. 



The Standard compass was set up at about 20 yards from the 

 Unifilar position. 



