Fitzroy's Hydrographic Surveys

200 NATURE [FEBRUARY 6, 1932 are mostly still the foundation of the present-day Letters to the Editor. charts of this area. The Argentine Government surveys have super [The Editor does not hold himself responsible for seded them between the Rio do la Plata and the Gulf opinions expressed by his correspondents. Neither of St. George, but the charts of the east coast of can he undertake to return, nor to correspond with Patagonia southwards, with the exception of the plans the writers of, rejected manuscripts intended for this of the ports, still incorporate these surveys. The or any other part of NATURE. No notice is taken charts of Tierra del Fuego are also largely founded of anonymous communications.] on the Beagle's work. In Magellan Strait the larger portion of the Beagle's work has been superseded, the FitzRoy's Hydrographic Surveys. Main Strait being taken from later British and foreign tVITH reference to the article in NATURE of Dec. 26, government surveys, but the adjacent waters are still 1931-pages 1065-1067-on "The Voyage of the partly from the Beagle's surveys. Beagle ", and more especially with reference to the For the west coast of South America from Magellan paragraph on page 1068 on FitzRoy in "News and Strait to about latitude 40° S., that is, including all Views ", it is not, I think, generally known either the Chonos Archipelago, Chiloe Island, etc., our Ad how much hydrographical surveying Capt. FitzRoy miralty charts are compiled from the Chilean Govern and his staff carried out during this five yearn' voyage ment charts, and thence northwards to Valparaiso from 1831 until 1836 or how long this work has stood. -approximate latitudn 33° S.-FitzRoy's surveys First, it may be mentioned that in 1825 France and have been modified by later Chilean and other work ; England undertook to survey the coasts of South whilst only a few of our plans of Chilean ports and America. The French examined the coasts of Brazil ; anchorages are now produced from the results of the English those of Patagonia, Tierra del Fuego, FitzRoy's work. Chile, and Peru. However, northwards from Valparaiso to the River The surveys carried out by the officers of the Guayaquil, all the Admiralty charts of the Chilean Adventure and Beagle from 1826 to 1831 embraced coast and of all the Peruvian coast are from Capt. part of eastern Patagonia south of the Gulf of St. FitzRoy' s surveys, and almost all the plans of Peruvian George, the greater part of the Strait of Magellan, ports likewise. Tierra de! Fuego, and the west coast between Magellan This very large amount of work must have called Strait and Golfo de Penas. Thirty-three charts and for the greatest energy and zeal on the part of Capt. forty-five plans of this work were received in tho FitzRoy, his officers, and ship's company, more especi Hydrogrnphic Department. ally when one bears in mind the fact that these At the end of 1831, as we know, the Beagle again survevs were all carried out either from boats or from sailed from England to continue the survey and then the ship under sail and with appliances which nowadays to run a chain of meridian dis'tances through the we would consider most crude. Pacific, Indian, and Atlantic Oceans, the ship being Finally, as regards the chain of meridian distances supplied with twenty-two chronometers for the pur round the world, it is recorded that these exceeded pose. twenty-four hours by thirty-three seconds only, in a In 1832 three tmck charts (Cape Verde Islands to period of five years. Bahia, etc.) and four plans (ports in the Azores, St. H. P. DOUGLAS, Paul's Rocks, etc.) were received at the Admiralty Vice-Admiral and Hydrographer. from the Beagle. Hydrographic Department, In 1833 seven charts of the south-east, south, and Admiralty, south-west coasts of Tierra del Fuego and two plans London, S.W.l, of parts of the Gulf of Penas were received of surveys Jan. 18. made in 1832. In 1834 nineteen charts and eight plans, also forty views of the surveys carried out in 1833, were received. These embraced the east coast of Patagonia from the Specific Heats of the Diatomic Gases. south shore of the Rio de la Plata to the Gulf of St. THE marked disagreement between the specific George, including all ports. heats of the diatomic gases as found by sound velocity In 1835 eleven charts, two track charts, and twelve measurements and those calculated on theoretical plans were received, the areas of the surveys being grounds has for long been a source of perplexity to mainly the east coast of Patagonia from the Gulf of statistical mechanists, especially in view of the appar St. George to Magellan Strait, the east coast of Tierra ently simple nature of the assumptions required in del Fuego, and the Falkland Islands, with plans of the calculation. The easiest of these assumptions to the ports and anchorages. attack would seem to be that of complete equilibrium In 1837, after the conclm,ion of the Beagle'8 voyage, between the various degrees of freedom of the mole Capt. FitzRoy forwarded eighteen charts of the coast cule as the sound waves pass. of Chile and thirty-four plans, eleven charts of the In two recent papers 1 Kneser has shown, by means coast of Peru and eleven sheets of plans, embracing of sound velocity measurements, that there is a lag the whole coast from the Chonos Archipelago, 47° S., in the transfer of energy between the vibrations of to the Guayaquil River, 3° S., and including all the the CO2 molecule and the other degrees of freedom ports and anchorages along the coast ; also six charts much greater than that which has been hitherto sus and eight plans of the Galapagos Islands, and three pected. In fact, he found that the period of relaxation charts and one plan of o1,her islands in the Pacific for the vibration concerned was of the order of 10-5 Ocean. of a second, in place of the usually assumed period of It will thus be seen that during the period of this the order of 10-10 of a second. Now, if one admits a 5 voyage no less than eighty-two coastal sheets, eighty value of 10- of a second for CO 2, why should one plans of harbours, and forty views were re<,eivod in not suppose that the period for oxygen may be of the the Hydrographic Department of the Admiralty from order of 10-4 of a second ? Unless we are to disregard FitzRoy's surveys. the sound velocity results in toto, we must make some These surveys of the coasts of South America were fundamental alteration to the theory, ancl this seems used for the production of the Admiralty charts and to be the easiest to make. I find that the results of No. 3249, VoL. 129] © 1932 Nature Publishing Group.

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