WILD'S SELF-REGISTERING BAROMETER (BAROMETER screw. four hours. At the end of every day this part of the roll is detached and put by to be bound up in book form in the records of the office in which the instrument is kept. The roll of paper is on a reel, n, passing between two rollers, g and k, as seen in Fig. 3. By these perfectly simple devices, instead of obtaining only three daily recorded observations, the observer at every station gets a continuous and perpetual record for every second in the day. That is to say, instead of getting, as by the common barometer (observed three times a day), observations for three seconds in twenty-four hours, he gets them for as many seconds as there are in twenty-four hours, or 86,400. Thus it follows that the value of the self-registering barometer, as compared with the ordinary one, is as 86,400 to 3! The marvelous accuracy and exquisite nicety with which all the observations forwarded to General Myer by the observers are marked ought to assure the public that nothing is wanting to give reliability to the published results and the "probabilities" issued from his offices. A self-registering barometer, as well as other instruments of equal sensitiveness, will be used by all the observer-sergeants. It is scarcely possible for this invaluable instrument to suffer derangement or to get out of order. A third most beautiful and sensitive self-registering instrument is that of Mr. Peelor, of Johnstown, Pennsylvania, used with great success and satisfaction by the Signal Service. This needs no battery, no electricity, to work it. A simple clock-work is all that is required, and its operations are as exquisitely accurate and trustworthy as the best navy chronometer. of one of these is presented on page 414, showing the synchronous readings, on a given day and at a given place, of the thermometers (wet and dry bulb), the hygrometer, and the barometer, all upon one sheet of paper. A barograph and thermograph made by Mr. Beck, of London, similar to those used in the Kew Observatory, are on trial in the Signal Office, and good results are hoped from them. Their beautiful machinery might also be mentube as it floats in the mercury, and also that tioned and described, but our space fails. Inof the arm, I, which supports it at G, is exactly deed, our limits have allowed mention to be balanced by the arm, II, to which is attached a made only of the most novel instruments emsliding weight, III, adjustable by a small thumb-ployed by the signal offices. A specimen record K is a steel crayon-holder fixed to the balance I II, and to which is fixed a crayon, c, whose point is seen in Fig. 3 to impinge upon a sheet of paper, l l. This sheet is moved by clock-work. When the atmospheric pressure is increased, the tube A is forced to rise a little We have already spoken of the beautiful out of the mercury in which it floats, and as it adaptation of Professor Hough's meteorograph rises at G the arm I is elevated. The crayon- to the work of printing its own registrations. holder, being fixed on the balance at the ful- The mechanics of meteorology have been adcrum, ƒ, by two little screws, swings a little to vanced one step higher than this, and the registhe left, and the crayon which it carries with trations of the automaton are instantly and perit makes a mark on the paper beneath it, which fectly photographed. The sheet of paper, suitmark indicates the rise of the barometer, or the ably prepared for photographic impressions, is increase of atmospheric pressure. If the press- made to slide, by means of clock-work, before ure decreases, the pencil, of course, moves in the a gas flame. The mercury in the tubes proopposite direction, and shows the barometric tects a portion of the paper from the action of fall. The roll of paper on which the record is the light of the lamp, while above the mercury made by this automatic instrument is divided the rays of the lamp fall unobstructed upon the into rectangular parts, each one of which ex-paper, and, making their impression, reveal the hibits the atmospheric variations for twenty- exact height of the mercury in the tubes. The "photograph of a storm," page 415, shows the movements of the mercury in the two thermometers and barometer for twelve hours. This process, by which the weather is photographed, is employed by General Myer, and these necessarily exact records will prove most attractive pictorial representations of the great storms in the atmospheric ocean for the study of meteorologists all over the world. PRESENT OPERATIONS OF THE SERVICE. Although the Signal Service is yet in its infancy, and must be patiently nursed and cherished by the people for some years before it can expect to do and discharge its full mission. Under General Myer's indefatigable care and skillful management it has already achieved much good, and more than compensated the public for the expense of its establishment. Since it was instituted last summer "the chief signal officer has," to quote the words of the New York World, "thoroughly organized and equipped a system which now embraces in its scientific Bulb.) DRAPER'S PHOTOGRAPHIC REGISTER OF BAROMETER AND THERMOMETERS AT NEW YORK, APRIL 28, 1870. (The upper line of the Thermometers is the Dry Bulb, the lower line is the Wet grasp every part of the land from Sandy Hook to the Golden Gate of California, and from Key West to the Dominion of Canada." Three times every day synchronous observations are taken and reports made from the stations-one at 8 A.M., one at 4 P.M., and the third at midnight. These observations are made by instruments all of which are perfectly adjusted to a standard at Washington. They are also all taken at the same moment exactly, these observations and reports being also timed by the standard of Washington time. The reports from the stations are transmitted in full by telegraph. By a combination of telegraphic circuits, the reports of observations made at different points synchronously are rapidly transmitted to the different cities at which they are to be published. They are, however, all sent of course to the central office in Washington. These reports are limited to a fixed number of words, and the time of their transmission is also a fixed number of seconds. These reports are not telegraphed in figures, but in words fully spelled out. There are now about forty-five stations for which provision has been made, and which are in running order. These have been chosen or located at points from which reports of observations will be most useful as indicating the general barometric pressure, or the approach and force of storms, and from which storm warnings, as the atmospheric indications arise, may be forwarded with greatest dispatch to imperiled ports. These stations are occupied by expert observers furnished with the best attainable instruments, which are every day becoming more perfect, and to which other instruments are being added. The reports of observers are as yet limited to a simple statement of the readings of all their instruments, and of any meteorological facts existing at the station when their tri-daily report is telegraphed to the central office in Washington. Each observer at the station writes his report on manifold paper.* One copy he preserves, another he gives to the telegraph operator, who telegraphs the contents to Washington. The preserved copy is a voucher for the report actually sent by the observer; and if the operator is careless and makes a mistake, he can not lay the blame on the observer, who has a copy of sheets. The pen is a dry stylus, and being pressed on *Thin paper with black carbon paper between the the upper sheet, it makes a similar mark on the sheets beneath it. his report, which must be a fac-simile of the one he has handed to the operator. The preserved copy is afterward forwarded by the observersergeant to the office in Washington, where it is filed, and finally bound up in a volume for future reference. When all the reports from the various stations have been received they are tabulated and handed to the officer (Professor Abbé) whose duty it is to write out the synopses and deduce the "probabilities," which in a few minutes are to be telegraphed to the press all over the country. This is a work of thirty minutes. The bulletin of "probabilities," which at present is all that is undertaken, is made out thrice daily, in the forenoon, afternoon, and after the midnight reports have been received, inspected, and studied out by the accomplished gentleman and able meteorologist who is at the head of this work. The "probabilites" of the weather for the ensuing day, so soon as written out by the Professor, are immediately telegraphed to all newspapers in the country which are willing to publish them for the benefit of their readers. Copies of the telegrams of "probabilities" are also instantly sent to all boards of trade, chambers of commerce, merchants' exchanges, scientific societies, etc., and to conspicuous places, especially sea-ports, all over the country. While the Professor is preparing his bulletins from the reports just furnished him by telegraph the sergeants are preparing maps which shall show by arrows and numbers exactly what was the meteorologic condition of the whole country when the last reports were sent in. These maps are printed in quantities, and give all the signal stations. A dozen copies are laid on the table with sheets of carbon paper between them, and arrow stamps strike in them (by the manifold process) the direction of the wind at each station. The other observations as to temperature, barometric pressure, etc., etc., are also in the same way put on them. cer. These maps are displayed at various conspicuous points in Washington-e. g., at the War Department, Capitol, Observatory, Smithsonian Institution, and office of the chief signal offiThey serve also as perfect records of the weather for the day and hour indicated on them, and are bound up in a book for future use. Every report and paper that reaches the Signal Office is carefully preserved on file, so that at the end of each year the office possesses a complete history of the meteorology of every day in the year, or nearly 50,000 observations, besides the countless and continuous records from all of its self-registering instruments. When important storms are moving, observers send extra telegrams, which are dispatched, received, acted upon, filed, etc., precisely as are the tri-daily reports. One invaluable feature of the system as now organized by General Myer is that the phenomena of any particular storm are not studied some days or weeks after the occurrence, but while the subject is fresh PHOTOGRAPH OF A STORM.-(Print from Photographic Register from Noon, December 13, 1870, Inch per Hour.) WAR DEPARTMENT WEATHER-MAP (SIGNAL SERVICE, U.S. A.), SATURDAY, APRIL 8, 1871, 7.35 A. M., WASHINGTON. The Numerals denote: 1st, The State of the Thermometer; 2d, That of the Barometer; and 3d, The Force of the Wind. It is not thought wise to undertake more than can be securely accomplished. The synopses and "probabilities" are all that intelligent shippers and careful seamen require. Shippers will not send their vessels to sea if the weather synopsis indicates threatening or alarming weather. Travelers can consult the "probabilities" before leaving home; and any severe storm that menaces any city or port is now specially telegraphed thither, and the announcement is made by bulletins posted in the most public places. in mind. To the study of every such storm, | have been most beautifully verified and conand of all the “probabilities” issued from the firmed. office, the chief signal officer gives his personal and unremitting attention. As the observations are made at so many stations, and forwarded every eight hours, or oftener, by special telegram from all quarters of the country, the movements and behavior of every decided storm can be precisely noted; and the terrible meteor can be tracked and "raced down" in a very few hours or minutes. A beautiful instance of this occurred on the 22d of February last, just after the great storm which had fallen upon San Francisco. While it was still revolving around that city, its probable arrival at Corinne, Utah, was telegraphed there, and also at Cheyenne. Thousands of miles from its roar, the officers at the Signal Office in Washington indicated its track, velocity, and force. In twenty-four hours, as they had forewarned Cheyenne and Omaha, it reached those cities. Chicago was warned twenty hours or more before it came. Its arrival there was with great violence, unroofing houses and causing much destruction. Its course was telegraphed to Cleveland and Buffalo, which, a day afterward, it duly visited. The president of the Pacific Railroad has not more perfectly under his eye and control the train that left San Francisco to-day than General Myer had the storm just described. By the modest estimate of the signal officers, the following is a table showing percentage of "probabilities" that have been verified. Fully verified. 50 per cent. 25 " 66 66 25 " It must, however, be borne in mind that the failures have often been due to lack of information from points where as yet no observer-sergeant is stationed. FUTURE AIMS. fidence it has in the people that they will patiently await the development of solid science, meantime leaving no stone unturned to hasten forward the observations which may lead to a more exact acquaintance with the habits, movements, and tracks of our American storms. Great progress has in a very short time been made in this knowledge, and every day new light is dawning upon the science of storms. The Signal Service has, up to this time, acted upon the wise maxim of "making haste slowly," and undertaking to do nothing which was While the observers now in the field are per- not in its power to do safely and securely, withfecting themselves in their work, the chief sig-out risk of failure. It has acted upon the connal officer is training other sergeants at the camp of instruction (Fort Whipple, Virginia), who will go forth hereafter as valued auxiliaries. It has been fully demonstrated by the signal officer that the army of the United States is the best medium through which to conduct most efficiently and economically the operations of the Storm Signal Service. Through the army organization the vast system of telegraphy for meteorological purposes can be, and is now being, most successfully handled. "Whatever else General Myer has not done," says the New York World, "he has demonstrated that there can be, and now is, a perfect net-work of telegraphic communication extending over the whole country, working in perfect order, by the signal-men, and capable of furnishing almost instantaneous messages from every point to the central office at Washington. Think of a single jump by wire from San Francisco 2700 miles eastward three times a day! When General Myer undertook to put this system in working order, the telegraph companies said it was impossible-no such thing had ever been heard of in telegraphing. It is now a grand fuit accompli, as much as the passing of the Suez Canal by ships or the escaping from Paris by balloons."* At present the signal officer aims only to give a synopsis of each day's weather, and a statement of what weather may be expected or will probably occur. The "probabilities" so far • New York World, March 5, 1871. VOL. XLIIL-No 255.-27 The instruments of the service have been bought on trial. They are undergoing the most varied experiments. In a short time, it is hoped, they will be greatly improved and perfected, and then the chief signal officer's results will be more satisfactory to himself, and his labors will be greatly facilitated. The celerity with which important results have already been attained by this officer has surprised and startled both himself and the friends of the great movement. As soon as possible, therefore, the Signal Of fice will have its signal posts along the lakes and on our Atlantic sea-board, where cautionary signals will be displayed, warning vessels of approaching gales and storms, and also a signal for clear weather. These will be displayed by day and by night, by a very simple and suitable contrivance now being perfected by General Myer. In New York already arrangements have been made for displaying the signals to shipping in the harbor from a lofty structure on the roof of the Equitable Life Insurance Company's office, the best station that could be chosen. The display of these storm |