238 



On the Magnetic Inclination in the Azores. [Dec. 16,. 



The results are as follow : — 



I. Island of St. Michael. 



In the garden of Senhor Jose do Canto, Santa Anna, Ponta- 

 Delgada. Approximate position : lat. 37° 45' K, long. 25° 40' W. 



The spot was that selected for the "Challenger" observations: 

 Mr. do Canto has now marked it by a small (stone ?) pillar. 



Local time. Needle 1. Needle 2. Mean. 



Aug. 23, 1880. 12.0 to 3.30 p.m. 62° 40'-0 62° 40' -5 62° 40'-2 K- 

 The "Challenger" observations in 1873 gave 63° 56''8 K* 



II. Island of Terceira. 



At Angra : in the ground near the monument to Dom Pedro IV, 

 8 paces to the north of the Obelisk. Approximate position : lat.- 

 38° 39' 1ST., long. 27° 14' W. 



Local time. Needle 1. Needle 2. Mean. 



Sept. 16, 1880. 11 a.m. to 12.12 p.m. 64° 10'*5 64° 10'-1 64° 10'-3" 



III. Island of Faval. 



AtHorta: 32 paces E.N.E. (magnetic) to the front of the Clock 

 Tower to the north of the town. Approximate position : lat. 38° 32' 

 K, long. 28° 38'- 30 W. 



Needle 1. Needle 2. Mean. 



Sept. 1, 1880. 12.30 to 1.40 p.m. 63° 38' ; 5 63° 38\5 63° 38'-5 



Before leaving Lisbon for the Azores I made a set of observations 

 near Moita, at the Quinta do Esteiro Furado, belonging to Mr. T. 

 Creswell, which it may be desirable to include here. The station was 

 identical with that on which I made the series of determinations of 

 Photo-chemical Intensity, published in the "Philosophical Trans- 

 actions " for 1870. (" On the Relations between the Sun's Altitude 

 and the Chemical Intensity of Total Daylight in a Cloudless Sky," 

 Roscoe and Thorpe, "Phil. Trans.," 1870, p. 309.) The position 

 was, approximately, lat. 38° 40' EL, long. 9° W. Hence it is prac^ 

 tically in the same parallel as the Azores. 



Needle 1. Needle 2. Mean. 



Aug. 3, 1880. 10.30 a.m. to 12.45 p.m. 59° 03'-0 59° 03'-5 59° 03 /- 2 1ST, 



* Communicated by Captain Eyans, through Mr. Whipple. 



