T. A. Lyons

“ Instead of confining the case to the impossibly small area of two square miles, let us suppose a gradual fall of the barometer from one part of the ocean to the other—such a fall, in fact, over such an area as often comes within the experience of every naval officer—and it stands to reason that waves of the ocean, like those of the air, only smaller and more sluggish, are consequent upon every change of the barometer. ”

“ Suppose a ship to leave New York at noon of any day, and that her "run" is accurately kept until noon of the next day, when the latitude and longitude by account are found. The ship may not really be in this position: currents may have borne her along or athwart her course, yet we can not discover them; they act on log-chip and vessel alike: but let the position "by observation" be determined for the same instant that it is "by account," and we have at once a standard of comparison whereby the treacherous streams are made known. ”

“ The third phase of the problem on land is entirely excluded from the ocean. There we can not establish fixed stations and spread a web of electric wire over them, with some guiding genius ensconced in the midst. We can not (as is done every morning in the United States, England, France, and Germany, for the limits of each country) say what the weather will be, and how the winds will blow, for the ensuing twenty-four hours, in the Indian Ocean, the South Seas, or the North Atlantic. ”

“ Now, the atmosphere that encircles our globe is but an ocean of less density than the watery element that surges upon its surface; like that, it moves, contracts, and expands according to well-known physical laws, and these laws constitute the rules whereby the person at the central station operates on his known quantities, solves the equation, and obtains for a result the forecast of the weather for the next few hours. ”

“ A consideration of the rotation of the earth is of assistance only in determining the general direction of the great ocean-currents.
A few other entries of the log-book require a passing notice. The direction of the wind is indicated by a vane in connection with a compass, and its force is estimated according to the following scale:
The above sail and speed, corresponding to various forces of the wind, are but approximations to what really takes place according to particular circumstances, such as model of ship, course steered with reference to the wind, condition of the sea, etc. ”

“ It is the log-books of ships of our own navy from 1855 to 1877—the large accumulation of twenty-two years—that are now undergoing compilation at the Hydrographic Office for the series of charts described: since 1877, by an order of the Navy Department, the compilation is made by the navigator of each cruising ship. Being an officer of many years' experience at sea, and having direct and daily supervision of the log-book, there is great advantage in having the data arranged in the requisite form, on the spot and at the time of its occurrence, by such a competent person. ”

“ Imagine this system of circulation once set up, and nothing is more natural than that it should continue while the earth revolves; indeed, a glance at any current chart of the world will suffice to show the force of this reasoning. ”

“ Some idea may be formed of the comprehensive scale of the journal of this society, when it is known that it contains observations three times in the day of the barometer, thermometer in the shade and in the sun, hygrometer, magnetic needle, direction and force of the wind, quantity of rain and of evaporation, the height of any neighboring water, the changes of the moon, the appearance of the sky, and the occurrence of meteors and of the aurora borealis. ”

“ When the observations of every square for each month are collected on sheets of Form D in the manner described, the reduction of the data is complete for the part of the ocean under consideration. The final step is to arrange the matter in shape for the engraver and printer. This is done on sheets of Form C—a blank eight inches by ten—which is a facsimile of one of the squares of the monthly charts enlarged to a size suitable for writing all the data in the proper spaces. The data for all the squares for one month are transcribed from Form D to Form C ”

“ A miniature chart of a five-degree square, but on a sufficiently large scale to allow of considerable accuracy, is printed on the Form, for plotting the ship's track: the position of the ship being determined at 8 a. m., noon, and 8 p. m. of each day, these points afford the data for tracing the track. Whenever currents exist, their set in points and their velocity in knots and tenths of a knot per hour are written on this little chart at each noon position; an arrow is also projected from the track to indicate their direction. ”

“ When full, it is to be transmitted to Washington at the expense of the office. A number of sailing charts and all the latest hydrographic information are supplied gratis as an inducement to keep the journal. Hundreds of them are already afloat on ships of various nationalities, and are being filled with valuable data regarding every sea known to commercial enterprise.
Before proceeding to describe the method of compilation, I shall dwell for a moment on one of the items of record in the log-book, viz., the ascertainment of the ship's speed. ”

“ To recur to the problem of the meteorologist of to-day, it assumes three distinct phases: first, from a number of observations extending through many years and over a large expanse of land or sea, to discover the laws of atmospheric phenomena; second, from an unbroken series of observations at any one place, through a sufficiently long period to eliminate all merely adventitious changes, to determine the climate of that place ”

“ In Boston, the east wind of spring and autumn is a source of annoyance to its inhabitants; it comes laden with moisture and—coughs. In California, it is an equally unwelcome visitor, but for a very different reason: it parches and all but cracks the skin. ”

“ As well lay railway-tracks over the ocean and expect ships to glide upon them! In matters pertaining to their profession, none are more tenacious of their opinions than sailors—and justly so: they form them after hard experience. ”

“ When calms or light, variable airs occur, the number of hours of each is counted, and the sum entered in its proper place. When a gale—that is, wind of a force of 8 and upward—happens, the number of hours it blew from any of the eight principal points of the compass (supposing it to have varied in direction) , together with the force during each period, are duly tabulated. ”

“ After stating the necessity of making observations on land coördinate with those at sea, in order to study the atmosphere in its entirety, he uses these prophetic words: "This extension of the system landward was proposed in the beginning as a part of the original plan. I have never ceased to advocate it since, and to couple with it a system of daily weather reports through the telegraph. As much as we have accomplished at sea, more yet can be accomplished through the magnetic telegraph on the land. ”

“ The "knots" reel off slowly or rapidly according to the ship's velocity, and, when the last grain of sand runs out, the line is instantly stopped. The number of knots and tenths run out denotes the speed at the moment of making the experiment, and, according to the conditions of wind, sea, and sail for the whole hour, the speed is deduced for the hour, and so entered in the columns.
To draw in the line, a quick, strong jerk on it frees the plug, when the chip floats horizontally, and can be hauled aboard with little resistance. ”

“ Similarly for each point from which the wind blew while the ship was in the square.
As the entries regarding the wind in the log-book are hourly estimates of both its direction and force, for the hour—an interval that permits little variability in either quantity—accuracy to this degree is insured in both the compilation and charts. There is no averaging the force or direction for longer periods than an hour, and, as far as I am aware, this is the only system pursued by any nation wherein these items are compiled with such detail. ”

“ The observations of the temperature of the air, of the sea-water, and of the barometer, are all similarly plotted, each on a sheet by itself. In every instance the symbols are in different colors, to distinguish the data peculiar to each month. ”

“ The laurels to be anticipated from such extension of our beautiful field of research would crown the results already obtained, and probably entitle the whole to be regarded as among the most splendid achievements of the age. ”

“ Even with the inducements now offered, and notwithstanding that the undertaking is mainly for their benefit, only a very small percentage of all the masters of merchant-vessels will take the trouble to keep a meteorological journal with the requisite accuracy and care. Were it not for the excellent log-books of our ships of war, our knowledge of the phenomena of the ocean would indeed be most meager and inaccurate.
⁠2. Supposing the data obtainable, the organization essential to dealing with it in such detail would be immense: a lifetime would hardly suffice to reach a practical result,
⁠3. ”

“ Having a due regard for the conformation of the ground over which his prognostics extend, he well knows that, according to the relative variation of pressure, temperature, and moisture, there will be a corresponding variability of weather: that if the pressure is great at one place and slight at another, the air will as naturally flow from the former toward the latter as water will down an inclined plane ”

“ With a properly devised system of meteorological observations to be made at certain stations wherever the telegraph spreads its meshes, and to be reported daily by telegrams to a properly organized office, the shipping in the harbors of our seaport towns, the husbandman in the field, and the traveler on the road, may all be warned of every extensive storm that visits our shores, and while yet it is a great way off. ”

“ The solution of the third phase of the problem is the one productive of most immediate benefit to all, how much soever their callings may differ; and this universal interest warrants my stating its conditions more at length than I have done with the other two. This phase may be likened unto an algebraic equation—a combination of known and unknown quantities, which, being operated upon according to certain rules, gives a desired result.
First, to determine the known quantities, a variety of instruments must be read and recorded at stated periods. ”

“ The solution of the first phase is all but complete: the great governing principles of our atmosphere are now quite well known—it is only the details that need defining. That of the second phase can scarcely be said to be more than begun: in only a few places on the globe have accurate observations been continued for a long enough period to reliably define their climates ”

“ The observations of each year are summed up and compared with those which precede, in copious and most laborious tables of mean and extreme results, and many very interesting essays upon various branches of meteorology are interspersed throughout the volumes of the society. ”

“ As, however, these observations were collected by a multitude of vessels and during a continuous series of 81 years, several vessels were observing at the same time in different parts of the ocean. Surely, this is an abundance of facts that must render indisputable the information contained in the more frequented squares: more would be mere accumulation, without perceptibly affecting the mean results. ”

“ This means that if the hours all the vessels spent in the square were added together, the total would be 1,110 hours, or 46 days 6 hours; this is the whole period of observation in this square for this month; it is composed of fragments of February collected from many years. An hour is the unit of observation, and a vessel had to be a whole hour in a square in order to have it constitute an observation. In this square, then, there were 1,110 observations of the wind: of this number, it was 226 hours from the N. W.; 85 hours from the N. N. W.; 76 hours from North, etc. ”

“ In order to discover the extent of this phenomenon, the hours of its recurrence, and the amplitude of the alternate rise and fall, the daily record of the barometer is carefully examined, and, whenever the phenomenon is found clearly defined, the hours of the two extreme lowest and two extreme highest readings, together with the readings themselves, are noted and tabulated on the blank. To save repetition, I will state here that all compilations of the barometer are reduced to 32° Fahr. and sea-level. ”

“ Arriving, then, at the eastern shores of the continents to the westward of those from which it started—at the North and South American shores, for instance, having started from Europe and Africa—and being banked up by constantly arriving volumes of water, it would be forced to the northward and to the southward along the coast-line of each continent ”

“ To collect data for it sufficient to give trustworthy results, would require a fleet of cruisers almost as large as the combined merchant marine of the world—all to be assiduously engaged for many years. ”

“ In both places, the relative prevalence of this wind is a fact important to know. In Buffalo, the storms that sweep in from the lakes are disagreeable in the extreme; in Texas, the fierce blast of the norther is often very destructive. ”