In these days of accurate hydrography and cartography the navigator seldom has to worry about his charts. True, there may be changes in soundings and the depth of certain areas of the ocean may remain to be correctly determined and there still may be a few reefs and islands shown as P.D. There is never any doubt, however, that the latitude and longitude of coasts and islands, as charted, are substantially accurate.
Prior to the laying of the first transatlantic cable, the method employed to establish secondary meridians was the observation of moon culminations, and in 1866 the French government organized several parties which in the next several years visited many points in America, Polynesia, Japan, China, and India to permanently establish secondary meridians.
In commenting on the objections to this method the late Professor Asaph Hall of the Naval Observatory said:
It should be noticed that the moon’s motion among the stars being nearly thirty times slower than the rotation of the earth on its axis, an error in the observation or in the position of the moon will appear in the resulting longitudes multiplied by a factor nearly equal to thirty.
By means of chronometers transported across the Atlantic, as well as by observations of moon culminations, occultations, and eclipses, astronomers had sought to establish a secondary meridian at Washington, by measuring the difference of longitude between it and Greenwich, but the results were entirely unsatisfactory, showing differences of three and a half to four seconds of time, fifty to sixty miles.
For many years the officers of the U. S. Coast Survey and the Army Corps of Engineers, as well as the astronomers at the U. S. Naval Observatory, had been employed in simplifying and perfecting the methods of finding differences of geographical longitude by the electric telegraph and of determining the geographical latitudes by zenith telescope.
As soon as the Atlantic cable was in operation in 1866, the superintendent of the Coast Survey, took advantage of the opportunity to connect the longitudes of the western hemisphere with the meridian of Greenwich by way of Ireland and Newfoundland. In 1869-70 a similar determination was made by a different observer through the French cable from Duxbury, Massachusetts, to Brest. Again in 1872 a measurement was made through the same cable using the island of Saint Pierre in the Gulf of St. Lawrence as an intermediate station. One of the very first of the astronomers to successfully introduce this method was Captain J. M. Gilliss, U. S. Navy, who used it to determine the difference of longitude between Santiago and Valparaiso, Chile.
In the spring of 1873 the lines of the West India and Panama Telegraph Company were completed and Commodore R. H. Wyman, U. S. Navy, hydrographer to the Bureau of Navigation, submitted a plan to the Navy Department for an expedition which should seek to determine as accurately as possible the latitudes and longitudes of points in that part of the world connected by cable.
Authority was readily granted by the Navy Department and the telegraph company generously gave the use of its lines free of toll charges stipulating only that its employees should be recompensed for overtime.
The iron steamer Fortune, of 306 tons, was selected for the work and Lieutenant Commander Francis Matthews Green was ordered to command the expedition. Commander Green was one of the so-called Civil War “mustangs,” a Massachusetts man whose father before him was a shipmaster. He was a prime seaman of a most incisive scientific turn of mind who had been a deep student of the matter for a number of years and who had suggested the plan to Commodore Wyman. On account of unavoidable delays due to various causes the Fortune did not sail until November, 1874, returning in April, 1875, when she was replaced by the Gettysburg, a more commodious vessel. The same officers, however, were in the party and some improvements in equipment dictated by experience were made.
In 1873 a combination transit instrument and zenith telescope was designed by Mr. J. A. Rogers and the construction of two of these instruments was undertaken in the repair shop of the Hydrographic Office. After the first expedition the transit threads were replaced by glass diaphragms, on which lines, to take their Pace, were ruled with great accuracy by Mr. W.A. Rogers of the Harvard observatory. The instruments were constructed with great care by Mr. Edward Kahler under the supervision of Mr. J. A. Rogers. Mr. Rogers also designed portable observatories ingeniously constructed so as to be easily and quickly set up and dismounted.
Portable piers were also devised but later it was found expedient to build brick piers for mounting the transit instruments.
Four break-circuit-chronometers were furnished by Messrs. Negus, New York, adjusted to keep sidereal time. For registering the times of transit of stars, or the occurrence of time signals, an electric chronograph was furnished each party. Two beautiful instruments were furnished by Messrs. William Bond and Son, of Boston, for this second expedition.
It is not within the scope of this article to escribe each and every instrument nor its method of operation, but it is interesting to note that Sir William Thompson (Lord Kelvin) invented a beautiful device for telegraphing weak impulses over submarine lines.
Throughout the two years’ work, the same general system was pursued; the two observatories, with their instruments and equipment, alike in every particular, being under the special charge of Lieutenant Commander Green, and Mr. Miles Rock, with Lieutenant J. A. Norris, U. S. Navy, and Mr. C. W. Bartlett, as assistants.
In 1875 the work comprised the measurements from Panama to Aspinwall; from Aspinwall to Kingston, Jamaica; Kingston to Santiago; Santiago to Havana; and Havana to Key West. In 1876 the measurement was begun at Kingston and carried to St. Thomas, then from St. Thomas to Antigua; St. Thomas to Port of Spain, Trinidad; Port of Spain to Barbados, Port of Spain to Martinique; St. Thomas to San Juan. Double measurements were taken between St. Thomas and St. Croix; the observers and instruments at each place at one measurement being transferred to the other. This was done as one method of determining the personal equation between the observers.
In later years the work was continued by the U. S. Navy in France, Spain, and the Far East.
The work of the observers was not without adventure and peril. In Port-au-Prince, Haiti, the party was only saved from attack by a mob by a colossal bluff by Commander Green. The Commander accompanied by one or two members of the expedition had called upon the President. On leaving the palace they were beset by a hostile mob which threatened them with cacomaque clubs, stones, and other missiles. Commander Green held up his hand for attention and pointing to the Gettysburg at anchor off the mole said: “Do you see that ship? Her guns are loaded and manned. It is now eleven o’clock. My orders are that if we are not on the mole at eleven fifteen they are to open fire on your town at once.” Needless to say the party was allowed to depart unmolested.
In a certain European country the observers found the position of a certain point as determined by the royal astronomer some two miles out of position. How to break the news to him was the problem. Commander Green wrote him a courteous note saying that the observer’s position did not correspond with the official one and asked him to examine the work sheets to correct their error as they could not find it. The astronomer did so and said, “My God, gentlemen, you are right and I have been wrong these many years!” Later that day he was found dead in his home—a suicide.
What recognition was given these officers and scientists for an accomplishment of untold benefit to every maritime nation and to every seafarer? The firms of Negus and Bond are still in existence and known throughout the world, but what of the observers? Their names are not even remembered. They deserve to be inscribed on the rolls with Alexander George Findlay, Matthew Fontaine Maury, Captain Matthew Flinders, Rear Admiral John Elliott Pillsbury, and others.
In Kingston, Jamaica, near the Victoria market stands a statue of Admiral Vernon, Royal Navy—“Old Grog” gazing placidly across the Caribbean in the general direction of Cartagena, the scene of his triumph. On the pedestal of the monument is a bronze tablet commemorating the determination of the longitude of Kingston by a party from the U. S. Navy under the command of Commander F. M. Green, U. S. Navy. That’s all!
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A general in chief is not relieved of responsibility by an order from a minister or a prince far from the field of operations and knowing badly or not knowing at all the last state of affairs: (1) Every general in chief who undertakes to execute a plan which he thinks bad or injurious is criminal; he ought to make representations, to insist upon a change, finally to resign rather than be the instrument of the ruin of his own people. (2) Every general in chief who, in consequence of orders from a superior, delivers battle with a certainty of losing it, is equally criminal. (3) A general in chief is the first officer of the military hierarchy. The minister, the prince, gives directions to which he must conform in his soul and conscience; but these directions are never military orders and do not exact a blind obedience. (4) Even a military order is to be blindly obeyed only when it is given by a superior who, being on the spot at the moment of giving it, knows the state of affairs.—Darrieus.