studying the construction and use of maps. The places of the zones, the lay of the continents, the positions of the oceans, and perhaps the lands of the more famous or more familiar peoples, may be noted so far as to enable the young student to refer more readily to his maps as he comes to need them in his historical studies. So also physical geography will demand study after chemistry, geology and other sciences have prepared the learner to understand its grand groupings and generalizations. And for all these some preparation may be made in the oral lessons on common things given to children in primary instruction. The landscape with its hills and valleys, its rocks, rivulets and soil may help to make familiar many of the simple notions and words used by the geographer. It is difficult to see how this isolated and barren geography should have won and retained so large a place among the common school studies, unless it is because it furnishes so much work for the pupils and is so easy for the teachers. If the pupils must remain six hours in school, they must be furnished some employment of their time, and the work of looking up places on the maps and drawing maps certainly serves to keep them busy many an hour. And the teacher who is too ignorant to teach the elements of physiology, physics or botany, or other sciences intimately connected with the daily life of men, may still be read to a class, the questions to be answered from the atlas. The conclusion from all here written is not that geography shall be studied less, but more; never, however, as a separate study, but always as a part of some other study with which it holds natural and necessary connection. It has been called a conglomerated science, borrowing its facts from astronomy, history, geology, botany, zoology, meteorology and political sciences. May it not rather be said. to be the local or territorial element of all these sciences, necessary to their existence and needful to their comprehension. More especially, it is a part of history, and with chronology constitutes the historical element of all the sciences. Geography should therefore be a part of all studies, both in common school and college. The atlas and the dictionary alike constitute a part of the outfit of every student, and are needed on every study table. The time heretofore given to mere geographical facts, places without events or relations, may well be given to history and science, with the map added. History has suffered as much from its divorce from geography as geography has from its isolation from history. Let the two be kept in close companionship, and we shall make both better historians and better geographers. Let history be studied on the map, and every event and place will thus be better known and remembered. JOHN M. GREGORY, LL.D. THEIR CAUSE. PART I. Among the wonders of the world the tides of the Bay of Fundy are unquestionably entitled to a very prominent place, not only in consequence of their great height alone, but for their extraordinary velocity and force as well. Nowhere else on the surface of our planet are there to be found such tides as occur here twice every lunar day, and twice every lunar month. When the sun and moon are either in conjunction or in opposition the ordinary tides are often exceeded fifteen or twenty feet, while once a year, when the full or new moon occurs at or near the nodes, and the moon is in perigee and the earth at or near perihelion, this last may be still further exceeded four or five feet. One would suppose the naked truth here astonishing enough without any resort to exaggeration, yet oftentimes gross misstatements have crept into the geographical descriptions of New Brunswick and Nova Scotia. The writer here calls to mind an excellent text-book of geography in use in New England some twentyfive years ago, in which it was stated that at the head of the bay just referred to the tide often reached a height of over one hundred feet, and that when the ebb tide ended and flood tide commenced, the speed of the waves was so great, that cattle feeding on the sea-weed, which for many square miles is here uncovered at neap-tide, are often drowned ere they can possibly reach a place of safety. Now, there is a substratum of truth in these statements, though they are exaggerated, as the writer, whose home was for twenty-one years on the very shore of the bay, can well testify; and to present a few facts concerning these tides in particular, with some preliminary remarks on tides in general, is the object of this article. As is generally known, the moon's attraction is the prime cause of the tides, though the sun aids more or less the moon in the work performed; but his effect, on account of his great distance, is only one-third of hers. Every lunar day, a period of twenty four hours and fifty-four minutes, there are two flood and two ebb tides. A tide begins to form under any particular meridian as soon as the moon. reaches that meridian, but the bulk of the tide follows a considerable time thereafter, so that the highest point is not just under, but some little distance behind the moon; and here it is well for the reader to remember that high tide is not caused alone by the direct, lifting-up force of the moon, which is very little, but by its tangential force-that is, by its pulling force on all the water on the side of the earth turned towards the moon, which causes the ocean to close up or heap up under it. Now this tangential force, or pulling towards the position beneath the moon, is necessarily greater than the direct force, for it is exerted not directly in opposition to the earth's gravity, but at an angle to it, which angle constantly increases from the moon's position until it becomes a right angle at 90 degrees distance from it. The reader will perceive that the moon, like a human being, finds it much easier to roll than to lift a heavy weight, and hence can do much more work rolling than lifting. And here comes a puzzle to many minds. Not only is there a high tide formed under the moon, but there is one at the same time on the opposite side of the globe. How can this be? This second high tide is just as much the effect of the moon's attraction as the first. This attraction tends to move the centre of the earth's attraction a little towards the moon, on the straight line, which joins the respective centres of the earth and moon. The effect of this is to diminish the earth's attraction for the water on the side turned towards the moon, and thus temporarily to diminish its specific gravity; so that, bulk for bulk, it does not weigh what water does 90 degrees distant, where the earth's attraction is unaffected. Now, the result of this is to heap up the water where its specific gravity is least to a height sufficient to balance the heavier water at the quadratures. To make this still plainer, let us conceive of a gigantic balance, with one scale-pan at 180 degrees distant and the other 90 degrees distant in longitude from the moon's meridian position. A mass of water placed in the first scalepan would not balance an equal mass placed in the other, since the attraction of earth in the former position by virtue of the earth's centre having been practically removed further off is less than in the latter position. Now, while the scale-pans are in the position supposed, let water enough be taken from the second scale-pan and put into the first to make the two balance, and it will be evident that while we have diminished the weight of one and increased the weight of the other, we have heaped up the water in one and lowered it in the other, and that though we have different masses, we have precisely the same weights. This is just what is essentially done in respect to the tides-the moon, through the medium of the mobility of the water and its own attraction, taking from one place and heaping up in another. But there is an interval of 12 hours and 27 minutes between one high tide and the next, or 24 hours and 54 minutes between high tide to-day and the corresponding one to-morrow. Why is this? The reason is, the moon revolves around the earth from west to east in 27.3216 solar days, while the earth in its diurnal revolution travels the same direction, but much faster; namely, in 23 hours, 56 minutes, 4.09 seconds, known as a sidereal day. The interval known as a mean solar day of exactly 24 hours is the mean of all the solar days of the year, this later day being the time required for the sun in leaving a certain meridian position to-day to reach the same to-morrow. For explanation of the fact that a solar day is longer than a sidereal, we refer the reader to a work on astronomy. With the above facts in mind, suppose at 3 P. M. on any particular day the moon crosses the meridian of Greenwich, or any other particular meridian, when the earth has made its circuit of 23 h. 56 m. 4.09 s., or .99727 of a solar day, the moon has gone in its orbit only 13.14 deg., or one-twentyseventh of 360 deg., and now before the meridian which was beneath the moon yesterday can be beneath the moon to-day the earth must catch up with the moon and cancel the 13.14+ deg., the distance the latter is ahead. In other words, there is a race between the earth and the moon in the diurnal revolution of the former and the monthly of the latter, and the former catches the latter in fifty-four minutes. See note below. In addition to the four tides caused by the moon every lunar day, there are also four tides one-third in magnitude to the former caused by the sun every solar day. Now, when the sun and moon are either in conjunction or in opposition, the former of which always occurs at new moon and the latter at full moon, the respective sets of tides are united and are proportionally increased in magnitude. But the moon in its orbit is sometimes quite near the earth and at other times quite far off, varying from 225,719 miles at perigee to 251,947 at apogee, a difference of 26,228 miles, or considerably more than 1-10 of its distance, making materially a difference in its effect. So the sun at the time of perihelion is between three and four millions of miles nearer the earth than at aphelion, also varying the intensity of the sun's effect. The perihelion point of the earth is reached in January and perigee point of moon is reached once in every 27 days. Again, the moon revolves in an orbit inclined to the ecliptic something over five degrees, and only when it is at or near one of its nodes that is, the point where the moon's orbit crosses the ecliptic-is it most advantageously placed to act in conjunction with the sun. Now the time of the year in which on the whole all these favorable conditions are most nearly obtained is in the early spring, which, by the way, is also the time when violent winds may come in as an aid to the force exerted by the moon and sun, and the result is that the highest tides of the year occur at this time. One point more is necessary to be presented here before concluding Part I and introducing the specific case of the Tides of the Bay of Fundy, as will be done in Part II, and it is this, that the birth-place NOTE. For those who love mathematical exactness in problems like these, the writer presents the following: Data. Sidereal day in terms of solar day, .9972696 nearly. Earth travels 360 deg. in sidereal day and the moon the same in its revolution around the earth. 1. To find distance traveled by moon in sidereal day (.9972696) 360 deg. 27.32166148 13.1404081 deg. distance traveled. 2. To find how far the earth must travel in its diurnal revolution in order that the moon may make the same meridian passage to-day as was made yesterday: Earth's gain of movement on moon = 360 deg. 13.1404081 deg.: 346.8595 deg. If the earth, then, gains in its race with the moon 346.8595 deg., it will require as much time to make up or cancel 13.1404081 deg. as the quotient arising from the latter divided by the former equal to .037884 of a solar day, or almost of the tides may be considered as being in the Pacific, west of the American coast and within five degrees of the equator, from which point a vast wave (vast only in extent, not in height), highest under the moon and gradually diminishing in height to both poles, moves forward across the Pacific at the rate, near the equator, of 900 miles per hour, or about 100 miles less than the speed of the earth in its diurnal revolution at that point. On reaching the shores of Asia and Australia a part of the tide keeps on south of the eastern continent and serves to reinforce the Atlantic tides which, unlike those of the Pacific, have their birth far south, namely, off the western coast of Cape Colony in South Africa, instead of near the equator, and in consequence of the narrowness of the Atlantic and the effect of the great initial wave from the Pacific, the tide does not travel due west, but northwest, coming, therefore, from the southeast instead of from the east, a most important point in considering the high tides of the Bay of Fundy. Just here, too, it must be remembered that the obstruction in the way of the tidal wave may not only change its direction but its speed as well; so that a tide in some bays and estuaries actually travels opposite to the moon's motion and often at a speed reduced to only a few miles per hour. Indeed, the famous maelstrom between two of the Loffoden islands off the western coast of Norway, and other marine whirlpools like this, are caused by the meeting of two tidal waves coming from different directions. Sunol Glen, Cal,, February 26, 1887. GRANVILLE F. FOSTER. HOW TO TEACH SPELLING. I shall present, as plainly as possible, a method of teaching spelling which I have found very successful in primary grades, more especially the 7th. To treat the subject systematically, I shall divide it into four heads: 1st, studying spelling; 2d, written spelling; 3d, oral spelling; 4th, dictation and language exercises, as a means of teaching orthography. First and most important topic: "How to teach children to study spelling." I believe that spelling should be taught through reading, as pupils should understand the use and meaning of a word first, thus following the natural order of an idea preceding the sign of it. In following this well-recognized principle, I always teach the reading lesson before the words at the top of it. To begin with the first lesson in the Second Reader: we will suppose that the class have read it. In the tabulated spelling you know there are 20 words. I would never think of giving so many new words to a class. I generally take 10, and sometimes only 8, when they are "catchy." One reason we fail is that we try to do too much at first; and I may add here that |