162 
GENERAL SIR EDWARD SABINE ON TERRESTRIAL MAGNETISM. 
less satisfactory character, viz. that there are generally fewer available grounds for 
assigning “ secular change ” on tolerably sufficient and accordant evidence. 
I have now to offer again, and in increased measure, my most grateful acknowledg- 
ments to Captain Frederick John Evans, R.N., the present Hydrographer of the 
Admiralty, for his most valuable assistance in many ways, but preeminently in the 
superintendence of the formation and execution of the Maps (Plates 26-28) embodying 
the results. 
ZONE I.— LATITUDES, EQUATOR TO 10° N. 
Authorities. 
Denham MSS. in the Magnetic Office, received from the Hydrographic Office. 
Sabine Pendulum and other Experiments (1825). 
Allen MSS. in the Magnetic Office, received from the Author. 
Owen L. S. Kamtz ; MSS. in the Magnetic Office, Kew Observatory. 
De Clerval L. S. Kamtz ; MSS. in the Magnetic Office. 
Baikie MSS. in the Magnetic Office, received from the Observer. 
Yidal Sabine in Philosophical Transactions, 1849. 
Basevi Reports of the Great Trigonometrical Survey of India. 
Laplace L. S. Kamtz • MSS. in the Magnetic Office. 
Taylor & Caldecott . . Schlagintweit ; Scientific Mission to India and High Asia (Leipzig and London, 1861). 
Powell Schlagintweit ; Scientific Mission to India and High Asia. 
Franklin Schlagintweit ; Scientific Mission to India and High Asia. 
Ludlow MSS. in the Magnetic Office. 
Novara (Austrian Frigate) Reise um die Erde (Wien, 1862-65). 
Blosseville Schlagintweit ; Scientific Mission to India and High Asia (Leipzig, 1861). 
Belcher MSS. in the Magnetic Office, received from Admiral Sir Edward Belcher. 
Schlagintweit Scientific Mission to India and High Asia (Leipzig and London, 1861). 
Elliot Magnetic Survey of the Indian Archipelago, Philosophical Transactions, 1851. 
Bonite Yoyage de la Bonite (Paris, 1842). 
Bougainville L. S. Kamtz ; MSS. in the Magnetic Office, Kew. 
Stanley Contributions to Terrestrial Magnetism, Sabine in Philosophical Transactions, 1849. 
Prussian Ships .L. S. Kamtz; MSS. in the Magnetic Office, Kew. 
..^ f Mem. by Lenz in the Sci. Mem. of the Acad, of St. Petersburg ; and L. S. Kamtz, MSS 
l in the Magnetic Office, Kew. 
D’Urville L. S. Kamtz ; MSS. in the Magnetic Office, Kew. 
Duperrey L. S. Kamtz ; MSS. in the Magnetic Office, Kew. 
Erman Reise um die Erde (Berlin, 1841). 
FitzRoy Yoyage of the ‘ Beagle,’ 1849. 
Barnett L. S. Kamtz ; MSS. ; and MSS. received from the Observer (Capt. Barnett). 
Austin L. S. Kamtz ; MSS. in the Magnetic Office, Kew. 
Horne L. S. Kamtz ; MSS. in the Magnetic Office, Kew. 
