108 Land Magnetic Observations, 1905-10 



The experience gained has shown the desirabiUty of light instrumental outfits. It is not always 

 possible to secure good pack mules, and the heavier the outfit the slower the progress which can 

 be made with these animals. It will frequently happen that men packers are more suitable, in 

 which case heavj' outfits are a great hindrance. For work in the interior, it is preferable to 

 carry camping outfits. A hammock was found to be the most convenient bed, particularly as 

 it did not weigh more than 5 or 6 pounds; blankets are necessary in the mountains. Knee-lace 

 boots are a necessity for both riding and tramping. A speaking knowledge of Spanish is decidedly 

 desirable, as few English-speaking people are met with in the interior. Work should be attempted, 

 as far as possible, only during the so-called dry season, from about December to early May. 



Throughout the trip every possible courtesy was shown me. Sefior Barrios, minister of 

 foreign affairs of Guatemala, kindly supplied me, through our minister to Guatemala, with a 

 letter of introduction to various government officials. In British Honduras, the colonial officials 

 were extremely kind. I am particularly under obligation to Dr. H. Clement, resident commissioner 

 at Punta Gorda, who rendered substantial assistance, as also to others who showed their interest 

 in various ways. 



H. W. FisK, ON Magnetic Work in the Bermuda Islands, July and August, 1907. 



According to instructions, I left Washington, July 2, bound for Bermuda, in company with 

 the Harvard University biological party in charge of Professor E. L. Mark. My outfit con- 

 sisted of magnetometer No. 3, dip circle No. 172, pocket chronometer Kittel No. 254, Hamilton 

 watch No. 56, observing tent No. 9, camera No. VII, and miscellaneous appurtenances. 



At Bermuda, it was my good fortune, through the kindness of Professor Mark, to have quarters 

 with the biological party at Agar's Island, and we are indebted to him for other courtesies. 



Five primary stations were established, the base station at Agar's Island (occupied three times), 

 Ireland Island, Spectacle Island (near Gibbs' Hill), St. George, and Nonsuch Island. None of 

 the Challenger stations could be positively identified except the one near the "Dockyard" and 

 that unfortunately was no longer available, owing to possible disturbing influence from the great 

 steel floating dock about 400 feet away. The Challenger stations at Cricket Ground (Somerset), 

 Tatem's Point, Spanish Point, Cobbler's Island, Clarence Cove, Spectacle Island (primary), 

 Hawkins Island, Wreck Hill, Ducking Stool, Mount Langton (pedestal), in the absence of 

 detailed information, could be only approximately occupied. About 77 secondary stations were 

 established, which with the primary ones make a total of over 80 stations. At about 45, all 

 three elements were observed more or less completely; at the remainder, deflections only were 

 obtained. It did not seem advisable to make any serious attempt at running out ranges, as the 

 country was thickly wooded and densely populated. The roads were very crooked, thus pre- 

 venting the obtaining of long ranges on them; only along exposed coast lines were extended ranges 

 possible. Diurnal variation observations were made, covering three entire days and a morning 

 and evening of two others. 



There are numerous caves of considerable size in the group; in some of these, magnetic ob- 

 servations could be made with more than 100 feet of rock and earth above, affording opportunity 

 for further investigations on local disturbances. The openings in some of the caves permit of 

 running azimuth lines directly into them by means of the theodolite. Observations could there- 

 fore be made on and below the surface in the same vertical line There are also some shoal places 

 where, in quiet weather, a tripod could be placed in shallow water and observations made at 

 some distance from the mainland. This was done at North Rock, 10 miles from land on the 

 north edge of the plateau. 



H. W. FisK, on Magnetic Work in the West Indies and the Guianas during 



July to December, 1908. 



The work was in pursuance of instructions of July 7, 1908, and of October 23, 1908. The 

 instrumental outfit consisted of magnetometer No. 4, using the short deflection bar, and Lloyd- 

 Creak dip circle No. 189 supplied with four needles, tripod, tent, and other accessories. The 

 expedition started from New York on July 11, 1908, sailing on the steamer Orinoco of the Royal 

 Mail Steam Packet Line, for Bridgetown, Barbados. Kingston was reached on evening of July 16; 

 as the steamer sailed at 10 o'clock the next morning, only a few hours were available for observing. 



