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This is assuming that the ball were miles a second. Its momentum would acted upon by no force other than that carry it past this point, and its course of gravity. If it encountered resistance, would then become one of ascent say that of air, it would finally come to from the centre. Now would come in rest at the earth's centre, and there it the principle that to stop a moving body would remain, without visible support, requires the same expediture of force being attracted by the earth's mass with as that which gave it its motion. The equal force in every direction.
only force operating in this case would That this would be the result will be- be that of gravity, which would now come apparent upon examining the cir- pull at the upward-flying ball, to check cumstances of the case. To begin with, its motion, with exactly the same inthere can be no question that the ball tensity and under the same conditions as would fall to the earth's centre. The when it was drawing it downward. As force which drew it downward would
a consequence, the ball would rise before not be a constant one, however, but one it parted with all of its motion to a continually lessening in intensity until, height exactly equal to that from which at the earth's centre, it became nil. The it fell. It would rise to the surface of reason of this is that when the ball was the earth on the farther side, where it below the earth's surface the portion of would rest for a brief space of time, and the earth's mass which lay above it then, gravity still having a hold upon it, would attract it upward, and only the it would fall back towards the earth's portion which lay below it — that is, be- centre, again shoot past that point, and, low a plane passing through it perpen- ascending on the other side, would return dicular to the direction of its fall to the point from which it fell originally. would attract it downward. The rela- The movement of this ball is essentially tive intensities of these two attracting the same as that of a swinging penduforces can be calculated for any given lum. Now, if a pendulum is struck position of the ball. The force which dexterously when just at the end of its would be efficient for drawing the ball swing, in a direction perpendicular to the downward would be, of course, their dif- plane in which it swings, it will be set ference. Without attempting to give to swinging in two ways simultaneously here the demonstration, the simple fact and its visible path will be an ellipse, may be stated that at every point in its or, if the blow is just sufficient to make descent the ball would be pulled down- it swing in the new direction to the same ward by a force proportional to its dis- extent as in the first, the path will be a tance from the earth's centre. At the circle. This ellipse or circle will be start the whole force of gravity would described by the bob of the pendulum act in a downward direction, giving to in the same time as it requires for makthe ball an acceleration of thirty-two ing one complete oscillation. Similarly feet a second. When it had reached a our cannon ball would make its double point midway between the earth's surface passage through the earth in the same and its centre, the acceleration would be time as it would take in circling round sixteen feet a second. At three-quarters the earth, just clear of its surface, as a of the way down it would be reduced to satellite. To escape falling to the earth, , eight feet a second, and at the centre it it would need to travel at the rate of a would become zero.
little more than five miles a second, and The ball would descend with accele- the period of its revolution round the rated velocity and would reach the earth's earth would be one hour and twenty centre with a velocity of about five minutes, very nearly. G. S. J.
HOW WORRY AFFECTS THE BRAIN
ODERN science has brought to It is believed by many scientists who
light nothing more curiously have followed most carefully the growth
a pharmaceutical journal, that scores of markable still, it has been the deaths set down to other causes are able to determine, from recent discov- due to worry, and that alone. The eries, just how worry does kill.
theory is a simple one - so simple that
any one can readily understand it. stronger, is an irritant at certain points, Briefly put, it amounts to this: Worry which produces little harm if it comes at injures beyond repair certain cells of the intervals or irregularly. Occasional worbrain; and the brain being the nutritive rying of the system the brain can cope centre of the body, the other organs be- with, but the iteration and reiteration of come gradually injured, and when some one idea of a disquieting sort the cells of disease of these organs, or a combination the brain are not proof against. It is as of them, arises, death finally ensues. if the skull were laid bare and the sur
Thus does worry kill. Insidiously, face of the brain struck lightly with a like many another disease, it creeps upon hammer every few seconds, with mechanthe brain in the form of a single, con- ical precision, with never a sign of a “let stant, never-lost idea; and as the drop- up" or the failure of a stroke. ping of water over a period of years will Just in this way does the annoying wear a groove in a stone, so does worry idea, the maddening thought that will gradually, imperceptibly, but no less not be done away with, strike or fall surely, destroy the brain cells that lead upon certain nerve cells, never ceasing, all the rest — that are, so to speak, the and week by week diminishing the vitalcommanding officers of mental power, ity of these delicate organisms that are health and motion.
so minute that they can only be seen Worry, to make the theory still under the microscope.
NOISE AS A DANGER SIGNAL.
OISE, says the
the "American on our railroads there should be tests for Machinist," is, like dirt, a hearing as well as for sight, although we nuisance. Much noise, like have not heard of them. Sound is conmuch dirt, is a great nui- stantly telling the stationary engineer of
sance. As dirt is matter out the condition of his engine, and noise of place, so noise is sound out of place. tells of its maladjustment or derangeDirt demands removal, and so is the ment. Noise tells of the unwelcome great promoter of cleanliness. Noise is presence of water in pipes and valve perhaps more insistent than dirt, and so chests, as well as in the cylinder, of the has also its beneficent function, especially incorrect action of valves, of abnormal in the running of machinery. For many changes of speed, of defective lubricaof the improvements and much of the tion anywhere, of the displacement and perfection of modern machinery, noise rubbing of parts, of nuts or screws workonly is to be thanked. Noise has done ing loose, of connections or bearings that and is constantly doing much for lubri- need taking up.
need taking up. An engineer that can cation, from the squeaking wheel-barrow hear noises in his engine room and be and the baby carriage to the line shaft content under their continuance should or the loose pulley in the shop, and so be promoted to the outside of the door. clear to the top. Noise has saved the An ear sensitive to noise, with a prolives of half the steam-engines and of per detestation of it, is one good qualifimany engineers.
cation for a foreman or superintendent. When things are running all right there Noise means at least discomfort, makes will be sounds, generally rhythmical, men nervous and irritable, and will never and therefore more or less musical, but allow them to do their best. We worked never noise. As soon as things go wrong, once for a long time contiguous to some there is noise at once. The knock in the rattling gearing, and we know what we cylinder must be attended to or the head are talking about. We passed through flies out. There are other noises about a foundry the other day where they had an engine which tell an engineer at once a very noisy power-driven sand shifter of minor disarrangements and give the at work which must have had anything opportunity of correction before wear or but a good effect on the men,
and ceraccident occurs. A deaf engineer would tainly did not increase the amount of necessarily be an almost worthless and work done, and we could not help wonderan unsafe one. Probably many persons ing how the powers that be could permit do not appreciate the value of good hear- such a nuisance. There are many preing to an engineer. It is probable that ventable noises that might be stopped.
For the benefit of those whose acquaintance with the Question Department begins with this issue, it may be well to say that Self CULTURE readers are expected to look up in the Encyclopædia Britannica each day the answer to the question given for that day. This will seldom require more than one hour, but in the event that one evening's leisure does not suffice, it will be easy to continue the investigation the following evening while the subject is still fresh in the reader's mind. The conscientious pursuit of the home study involved in this department will lead to the possession of a large and varied stock of general information.
o vary the interest in these series of questions, as well as to increase the educational benefits arising from their daily study in tracing them to the sources of the history, it is designed, for a while, to group the questions under specific countries, and to withhold reference to the pages in
the Britannica, or in the New Supplement thereto, where the answers may be sought. In the present series of questions (for the month of December), it may suffice to say that answers will be found either under the general article on France, in the E. B., or under the historical personages or specific events referred to in the questions.-ED. S. C.
FRANCE AND FRENCH HISTORY
Dec. 1. France has been a Republic since Dec. 17. Tell what you can about Joan of the overthrow of Napoleon III. Give the date Arc and her deeds. and cause of the Emperor's overthrow.
Dec. 18. What was the character and aims Dec. 2. In whom, and in what bodies, does of Louis XI.? the present Constitution vest the Executive and
Dec. 19. Relate what you know of the reLegislative power?
ligious wars of the sixteenth century, and give Give the area, in English miles, of the date of the Massacre of St. Bartholomew. France, and its present population.
Dec. 20. Under what circumstances did Dec. 4. What is the present effective strength Henry of Navarre become King, and in what of the French army? What the strength (Jan. great battle did he defeat the Holy Catholic 1896) of the French navy? *
League ? Dec. 5. Give the length, in inches, of the
What was the social condition of French mètre, and the equivalent value of the France under the regency of Marie de Medicis? franc.
What distractions in the Kingdom Dec. 6. Into how many administrative de- brought Cardinal Richelieu into power? partments is the France of to-day divided ?
Dec. 23. Who was Louis XIV.'s great finance Dec. 7. Name the chief articles of French minister?
Dec. 24. What was the immediate cause of Dec. 8. When was Paris made the capital of the great exodus of the French Protestants (the all France?
Huguenots), at the close of the seventeenth cen. Dec. 9. Give the Roman name applied to tury? France in Cæsar's day, and state who were the Dec. 25. In what cause was the battle of Franks who conquered the country in the fifth Blenheim (Höchstädt) fought? State the apcentury.
proximate losses of the Allies, and also the Dec. 10. Give the periods of the régime Losses of the French and Bavarians. of Charles Martel, mayor of the Palace, who Dec. 26. Under what sinister feminine influfounded the Carlovingian dynasty.
ences did Louis XV. fall ? Dec. Il. Relate what you know of Charle
Dec. 27. What was the condition of the magne and his period. When did he become
French people on the eve of the Revolution ? King of the Franks, and when was he crowned
Dec. 28. State what you know of Turgot, Emperor of the West ?
Necker, Mirabeau, Talleyrand, Guizot, and Dec. 12. When did the Northmen (Nor- Thiers. mans) become permanent settlers in France ?
Dec. 29. What brought Charlotte Corday Dec. 13. Under whom did the Feudal Mon- (D’Armans) to the block? Justify the epithets archy in France have its rise ?
applied to her as “the angel of assassination" Dec. 14. What was the influence on France and “the Joan of Arc of the Revolution." of the Crusades?
Dec. 30. Who were the parents and who the Dec. 15. Give the date of the English inva- husband of Marie Antoinette, and against what sion of France, and state when Calais was taken excesses, in the turmoil of the time, did she by Edward III.
disastrously protest? Dec. 16. Cite the chief events of the Hun- Dec. 31. What immediately led to the res dred Years' War.
toration of the Bourbons? * For answers to some of the above questions that refer to the recent history of France, it will be necessary to consult the New Supplement to the E. B., in 5 volumes [The Werner Company], 1897.
SOME NOTABLE WOMEN OF THE CENTURY: 1.—MARY SOMERVILLE, THE SCIENTIST*
QUARTER of a century has been able to bestow. The universities of
knowledged their indebted crowning glory of civilization, and there
It is notably true of this period that If he desired to watch the stars in their from scores of illustrious names the vari- onward courses, or to wrest from the ous seats of learning received new life rock the secret of its age or birth, every and became conscious of an inspiration available aid was placed at his disposal. vastly greater than any they had hitherto The prevailing sentiment regarding * See sketch (brief facts in Mary Somerville's
woman's development at this time is life) in the Encyclopædia Britannica, Vol.
dutifully reflected by Mrs. Anna Letitia XXII, page 260.
Barbauld, in a letter written to her niece.
“The line of separation," she writes, direction of her life and made her the “between the studies of a young man most remarkable woman of her time. and a young woman is this: A woman The memory of days which are in any is excused from all professional knowl- respect remarkable acquires peculiar edge. Men study in order to qualify charm when viewed through the perthemselves for the law, for physic, for spective of quiet years, and one experivarious departments in political life, for ences a unique pleasure in reading the instructing others from the pulpit or pro- personal recollections of this gifted fessor's chair. These all require a great woman. We learn how, as a child, she deal of severe study and technical knowl- wandered along the seashore, collecting edge, much of which is in no wise valua- shells, pebbles and flowers; how she ble in itself, but as a means to that passed evenings in gazing at the starlit particular profession. Now, as a woman heavens; how she amused herself in a can never be called to any of these pro- garden frequented by birds, observing fessions, it is evident that you have them until their habits were familiar to nothing to do with such studies. A her. The first ten years of her life were woman is not expected to understand the passed without the aid of books — unless mysteries of politics because she is not we except the book of nature, whose called to govern,
She is not required to leaves she was already beginning to turn. know anatomy because she is not to per- This excellent foundation for the form surgical operations; she need not superstructure of wisdom seems to have embarrass herself with theological knowl- been most unwittingly laid, and was in edge because she will neither be called fact the result of neglect rather than preupon to make or explain creeds.
vision. Suddenly, however, her father “A woman should have such a tincture awoke to a consciousness of the fact that of general knowledge as to be able to en- a girl should at least know how to read gage gracefully in conversation.
In no and write and keep accounts, and Mary subject is she required to be deep, of was sent away to school. none should she be ignorant. If she
We learn from her record how, though knows not enough to speak well she perfectly erect and well formed, she should at least know enough to keep was enclosed in stiff stays, with a steel from speaking at all, and the modesty busk in front, while bands drew her which prevents an unnecessary display shoulder blades back until they met, and of what she does know will cause it to be how another steel rod with a semicircle supposed that her knowledge is greater which passed under the chin was clasped than it is. As she will never obtrude to the busk in her stays. In this conher knowledge, none will ever be sensible strained attitude she had to prepare her of any deficiency in it, and her silence lessons, and the chief task given her was will seem to proceed from discretion to “learn by heart” daily a page of rather than from a want of information.” Johnson's Dictionary.
Johnson's Dictionary. She returned to It is proper to state, in passing, that her home at the age of eleven, and, aside Mrs. Barbauld could not so clearly have from instruction in music, seems to have stated the popular idea of woman's edu- been left to her own devices. When cation had she not herself overstepped thirteen years old, she for the first time the boundaries she prescribes. She was met with a friend who encouraged and an excellent classical scholar, but dared gave direction to her love for study. not counsel her niece to a like disregard
A little later, while out in company of prevailing sentiment; hence, her letter, with her mother, she met a lady who presenting as it does the compromise be- tried to interest her in some manner of tween this sentiment and a personal de- fancy work. While turning the leaves sire for intelligence, affords as perfect a
of a book of designs her eye caught key to the spirit of the time as we can sight of what appeared to be an arithhope to find.
metical question, but, on turning the In this whirl of contending influences page, she found strange-looking lines began the life of Mary, daughter of Ad- mixed with letters, chiefly x's and y's: miral Sir William Fairfax. She was born Said her friend, replying to her eager inat Jedburgh, Scotland, in the year 1780, quiry: “It is a kind of arithmetic; they and disclosed at an early age a hunger call it algebra. I can tell you nothing for knowledge that changed the whole about it.”