down so permanently are more subject to quakes than the older The prediction of earthquakes is by no means a chimerical proposition, in broad outlines, at least.

Before leaving this interesting subject may I be pardoned for saying the Seismological Tables published by the Dominion Observatory are universally used in America and to some extent elsewhere.

As a by-product of the seismograph we have found that it records the pulsation of the ocean waves, i. e., we in Ottawa record every wave of the Atlantic that impinges on the coast from Cape Hatteras to Newfoundland. The period of these waves varies from about 4 to 8 seconds, and on the seismogram they look like sawteeth. These pulsations are transmitted through the crust of the earth. We have been able to link up these microseisms, called micros for short, with areas of low barometer on the Atlantic Coast. At Ottawa we are about 500 miles from the nearest sea coast, and it seems incredible that we receive through the earth these pulsations of the ocean. We have built and installed at Chebucto near Halifax an instrument which I christened "undagraph" or wave writer, which counts and records every wave of the broad Atlantic reaching the coast of Nova Scotia there, and that record or undagram we correlate with the corresponding seismogram at Ottawa.

The next subject in geophysics of which the Dominion Observatory has charge is terrestrial magnetism. That means the determination of the three magnetic elements, declination or variation of the compass as known to the public, inclination or dip and the magnetic intensity. Our work extends from the Atlantic to the Pacific and we have occupied some five hundred stations at each of which these magnetic elements have been determined. The variation of the compass is the element most wanted-the surveyor needs it, so does the explorer, the navigator and many others. When the poet writes "as true as the needle to the pole," he is guilty of poetic license of a serious kind. If a sea captain were to accept that statement he would never reach his destination. In our work we find for instance on the east coast of Canada the needle points 35° to the west of true north and on Vancouver Island 25° to the east, that is, a range of 60° over Canada, twothirds of a right angle. It is very obvious that for those that use a compass it is very essential that its declination from true north be known. Unfortunately this is not a constant quantity, but is subject to an oscillating daily change and a slow secular one, both of which are quantities that we determine and apply.

In order to assure accuracy we standardize our instruments twice annually. The most accurate time is furnished by means of a pendulum clock. But why does the pendulum vibrate, or

pendulate, to coin a necessary verb? "It can't help itself" would scarcely be a scientific reply. It is the attraction of the earth that tends to restore it to its normal suspended position, the line of action of the earth's gravitational force. This force is affected by the rotation of the earth and the combined effect we call gravity.

The earth is not a sphere; hence points on the surface are at varying distances from the center. Again the centrifugal force due to rotation is greater in the equatorial regions than north and south thereof; in short, for every latitude there is a particular force of gravity, so that a pendulum that would swing or vibrate seconds in Ottawa would not do so here in Brooklyn. It would lose time here. You see you haven't got as much pull here (I am not speaking in a political sense) as we have in Ottawa, but you are more apt to fly off the handle, to use a cant expression, because nearer the equator. From the above statements it becomes evident that the pendulum, an invariable pendulum, gives us a means for determining the relative force of gravity on the earth, and thereby the accurate figure of the earth, its ellipticity, its flattening, as well as anomalies in the distribution of matter in the crust of the earth. This line of investigation is carried on too by the Dominion Observatory and we have about fifty stations distributed over Canada. The period of the pendulum, that is, the time of swing, which is about half a second, is determined to the one tenth-millionth of a second of time; let me repeat ten-millionths of a second of time, and this order of accuracy is shown when observations are repeated at the same place and the interagreement is limited to the units of the seventh place of decimals.

We now know the figure, i. e., ellipticity, with a high degree of accuracy so that we can readily compute what the theoretical force of gravity should be for any given latitude; hence observations there will show the divergence or anomaly for that place, which means that there is an anomalous distribution of matter in and about the crust of the earth. When we speak of crust of the earth, we mean a thickness of about seventy-five miles, which brings us to the stratum of equilibrium or compensation.

All mountains practically float in the earth, the ten or twenty thousand feet or more that they tower above sea-level are not supported by the crust it couldn't do it but they float like an iceberg does in the ocean, which displaces as much water as its own mass above and below water.

These gravity observations have disclosed some interesting facts about what is hidden underground, by the amount of gravitational force or pull that the hidden mass or masses exercise. If there are huge deposits of iron ore, for instance, gravity would be increased, while large deposits of oil or gas or salt would have the opposite

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effect. The pendulum thus becomes a scientific divining rod. We may well say-a peculiar concatenation-from the stars we bring to earth accurate time, and that time we use to express gravity, and from the latter divine oil. Perhaps it is fairer to state that the positive statement of the pendulum is when there is an excess of gravity, oil can not be present, for that always involves a defect of gravity.

But there is a more delicate and more sensitive instrument for measuring differential gravity, and that is the torsion balance, by means of which actual areas can be mapped out underground occupied by oil or gas or salt, which has recently been achieved in Europe, especially in Hungary. I am glad to state that such an apparatus is now being built for the Dominion Observatory, and it will be, I believe, the first in America for that purpose.

I shall refer to one other geophysical investigation in which we were engaged. Sir George Darwin many years ago concluded that the earth was subject to daily physical tides, beside those of the ocean, i. e., that the earth was squeezed, was deformed by the action of the moon, which is the main factor in our ordinary tides.

Darwin tried to measure the minute quantity, but failed on account of disturbing factors on the surface of the earth. Hecker of Potsdam succeeded by having his instrument in a deep shaft beyond the effects of the daily heating of the earth, in obtaining a value, but there was the anomaly, found too by the Russian Orloff, that apparently the earth was more readily squeezed in a north and south direction than in an east and west direction. The question was referred to Professor Love, probably the foremost exponent in questions of elasticity, but no satisfactory solution was obtained. It was believed that possibly the situation of the observing stations with reference to the ocean might play a part by the gravitational effect of the tide or heaped-up waters upon the horizontal pendulum which was the instrument used, and also by this same mass of water bending the ocean floor and producing slight tilting of the instrument. To settle this the International Seismological Society decided to establish several stations widely differing in their positions with reference to oceans. Canada was assigned a station. The war intervened, and we never met again. However, the problem was attacked by Michelson of the University of Chicago and brilliantly carried out on the grounds of the Yerkes Observatory and in quite a different manner, by observing in 500-ft. 6-in. pipes partly filled with water the change of level. For measuring the minute quantities an interferometer was used, that is, the wave lengths of light were the measuring

rod. It was found that the earth responds practically instantaneously to the action of the moon. The earth as a whole has about the rigidity of that of steel. The surface of the earth rises and falls about a foot twice a day, due to lunar and solar attraction. We are sitting on a long "teeter"-6,000 miles long, with a period of a little over twelve hours-unconsciously teetering. It doesn't seem much, yet in it is bound up the constitution of our earth, and of all objects in the universe what concerns man more than the earth?

And now I have done. I have given you a brief outline of "Astronomy in Canada" the title of my address, together with other scientific work carried on by the Dominion Observatory. Euclid's definition of a point is that which has position but no magnitude with Canada it is about the reverse with much emphasis on magnitude. We are trying to give it position—a prominent place on the map of a progressive world-a place in the sunand I am sure you good people to the south of us, who have been basking in sunshine these years, will welcome the kindred spirit from the north, where we are trying to advance knowledge and advance the various fields of development in which we are engaged, so that our work may be a credit to Canada and a benefit to mankind.

THE TAR-BABY STORY AT HOME

By Dr. W. NORMAN BROWN

THE JOHNS HOPKINS UNIVERSITY

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BOUT thirty years ago the late Dr. Joseph Jacobs pointed out that the "Wonderful Tar-baby Story" of Uncle Remus has a parallel in a tale of the Buddhist Jātaka-book, where the most salient feature of the Negro story, the "Stick-fast motif, occurs.1 Since then students of folk-tales have discussed that story with an almost undue respect for his enticing theory that it originated in India, passed to Africa in very early, perhaps prehistoric, times, spread over that great continent, and at last came to our shores deep-rooted in the souls of our Negro slaves.

What is more, since Dr. Jacobs first expressed his opinion, additional evidence has become available seeming to support at least the first part of his thesis, namely, that India is the ultimate home of the story, although other parts of his proposition have been variously modified." For example, it has been suggested that the story did not reach Africa until comparatively recent times, say the sixteenth century, when it was taken there by Portuguese sailors. Latest, a well-known American folklorist has found the Tar-baby story in the Cape Verde Islands attached to the "Master Thief" cycle of tales-a cycle first presented to the Occident by Herodotus in his account of the robbery of King Rhampsinitus' treasury. On the basis of this discovery, she has suggested a theory that the Tar-baby was originally a part of the Master Thief tale, that they both came from India to Western Asia and Africa, and proceeded thence to Africa. There the Tar-baby feature was clipped or detached from the larger story and has since maintained an independent existence. The idea is ingenious, but it is too much. based on unprovable hypotheses to be convincing.

1 Pañcāvudha-jātaka (Jātaka 55). Dr. Jacobs' remarks may be found in the following of his books: The Earliest English Version of the Fables of Bidpai, Introduction, p. xliv; The Fables of Esop (Caxton's edition), vol. 1, pp. 113 and 136; Indian Fairy Tales, story of "The Demon with the Matted Hair."

2 E. g., see Dähnhardt, Natursagen 4, 27ff.

3 E. C. Parsons in Folk-Lore, 30: 227. Her theory is untenable: (1) Herodotus' tale is not necessarily to be derived from an Indian source, for it

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