Imágenes de páginas
PDF
EPUB

them up

liarly eligible ; and he apprenticed his son, then a youth, to the trade. There the family-home was reared, and continued many years. While the Lord was honoured, and the cause of true religion promoted, the success of the business proved that “godliness” was “profitable unto all things ;” the “promise” being fulfilled both as to "the life that now is,” and to “ that which is to come.”

The new Methodist establishment was an annoyance to many, and was viewed by them with jealous dislike; but the new business-establishment was an important addition to the trading and industrial resources of the town. It has furnished labour and its corresponding profit to many of the inhabitants, from that time until now.

A member of the family, yet living, venerable in years, met with a remarkable instance of the intolerance which in a past age was displayed toward those who ventured to worship God otherwise than in modes by law established. This lady began, about the year 1819, in connexion with a companion, to collect for the Wesleyan Missions. In their canvass they were met by the then Vicar-General of the Chapter, and Chairman of the bench of Magistrates. He gave them a severe reprimand, and forbid their going a step farther, alleging that he had the power, as a magistrate, to take

“under the Vagrant Act,” and that he should certainly put the law in force if they did not desist, and keep their pernicious papers to themselves ! He declared, that he knew for a fact that the Missionaries, for whom they were begging, were dissipated men, and not worthy of support. Of course, these ladies took no notice of the imperious mandate, but persevered in their work; and the moral force of their conduct had an abiding influence in the town.

In the year 1835 a new chapel was required. A serious illness befell the son of the above-named Mr. Neepe; but he earnestly prayed that he might recover, to do some special work for God. He did recover, accomplished his purpose, and died. That work was the erection of a new chapel. Much opposition was encountered, and twice were the Trustees involved in Chancery-suits concerning land. Providence kindly favoured their efforts

, and at length another site was secured in a central situation, where the edi: fice was built in 1840, and opened by the late Rev. Drs. Bunting and Newton, and the Rev. S. D. Waddy. This chapel has recently undergone renovation : a new organ has been introduced, and other improvements have been made. It was re-opened in April, 1863, by the Rev. William Arthur and Charles Haydon. The results were worthy of the united efforti of a church, which, although not numerically large, possesses and display a living power. Planted and preserved in the midst of opposition, thi Methodist Society in Southwell has faithfully witnessed for Christ, and for experimental religion, through more than one generation; and still recog nises its solemn responsibility to maintain and diffuse the light of Christian holiness. Nottingham, November, 1863.

1.

51

BY STAFF-COMMANDER F. J. EVANS, R.N., F.R.S.,

SUPERINTENDENT OF COMPASSES TO THE ADMIRALTY.* Wrapt as the early history of the Mariner's Compass is in obscurity, there is sufficient evidence to prove that at a very remote period among the Eastern nations the directive power of magnetized iron was known; and that it was turned, by the Chinese, to purposes of distant travel, if not to extended navigation. The time of its introduction among the Western nations of Europe is comparatively recent; the merit of the invention of the compass in its present arrangement of box, bow), and supporting pivot, being assigned to a Neapolitan citizen, about the year 1302. But recent literary research indicates that it must have been in use, under similar conditions, at least a century earlier, by the mariners of England and France.

Between the remote date recorded in the Chinese annals (said to be about 2600 years B.c.) of the application of the freely-suspended magnet to purposes of travel, and that just given, little or nothing is known of its history. The successive powerful nations that existed near the shores of the Mediterranean sea have left no records of its employment; and we may certainly draw the inference, that in the lengthened and circuitous voyage of St. Paul, which resulted in shipwreck on the island of Malta, the “shipmen” had not the advantage or consolation to be derived from this guiding monitor.

By some it may be considered puerile to seek after records which add so little to our real knowledge. But, considering the powerful aid the Mariner's Compass has rendered to civilization, and the material progress that has been made in the well-being of mankind from the days of Columbus and Vasco de Gama,—by opening up the navigation of vast and distant oceans, and the consequent discovery of rich and fertile lands,--the interest of the intelligent seaman cannot fail to be enlisted toward whatever relates to so priceless an auxiliary to his labours.

It is somewhat remarkable tbat the compass-valuable as it is to us, and honoured in song as it has been from the days of the Troubadours to those of Dibdin, the sailors' bard— has not at all periods received the same meed of honour from those most interested in its use. In the seventeenth century several treatises were written relating to the discovery of longitude to be attained by magnetic observations of the dip and variation of the compassneedle. From the interest created at the time we may infer that at that period the value of the compass to navigation was thoroughly appreciated ; and we find that, in immediate connexion with the development of certain magnetic laws directly affecting it, a special voyage of research to the South Atlantic Ocean was undertaken by the illustrious Halley, under the direction of the British Government, in 1701.

* “ Life-Boat Journal," vol. v., No. 50.

In the middle and toward the close of the eighteenth century, much attention was paid to the fabrication of magnets, and the art of infusing high magnetic power into them had attained a great degree of excellence. Notwithstanding this progress, we find, in the beginning of the nineteenth century, the celebrated navigator Flinders describing the compasses of the Na as “the worst-constructed instruments of any carried to sea ;” and in 1820 that able philosopher, Peter Barlow, in an official Report to the Board of Admiralty, on the compasses of the Royal Navy, stated that more than one half of those he had examined (150) “ should be considered as mere lumber, and ought to be destroyed.”.

It would be an interesting subject of inquiry, to trace the causes leading to the decline of the compass in the estimation of seamen, which brought about such a falling off in its fabrication. In the time of our scientific navigators of the last century, Cook, Vancouver, Phipps, and others, great attention was devoted to the determination of purely magnetic observations, partly with the practical view of the results being ultimately useful in obtaining the longitude. The dip of the needle, for example, was frequently observed at sea ; and the variation of the compass was certainly determined in many distant parts of the world with considerable accuracy, as is verified by recent investigation. Singularly enough, the discrepancies in the variation of the compass, as then observed at sea, under different circumstances of the position of the instrument, and the direction of the ship’s head, (which we can now trace to the action of the iron in the ship magnetized by induction from the earth,) were considered as due to inherent errors of manufacture ; and its character for accuracy was, of course, looked on with suspicion. The art of navigating by lunars and chronometers was now cultivated by the higher class of seamen ; the check on the compass was consequently more perfect, and the navigator was again more independent of it. Among the general mass, the golden rule of “the three L's,” or strict attention to the lead, latitude, and look-out, was the common formula of navigation, without even an allusion to the poet's “unerring guide." The compass was now probably at its lowest ebb in the tide of professional opinion: for we actually find it treated as a hardware article, specially manufactured in the Minories and its neighbourhood, with other ships' stores, and stowed away indiscriminately with iron hooks and thimbles, deck-scrapers, hook-blocks, and other choice miscellanea of the boatswain's storeroom. This is no fanciful picture, but what is well known to those conversant with the naval service little more than a quarter of a century past.

Let us turn to the present day, and take for example what we find recorded, at the opening of the year 1863, relating to a compass designed for

* It is scarcely necessary to say that this state of things no longer exists. From the time of Barlow's Report there has been progressive improvement; and there is ample testimony, from many disinterested and leading authorities, that the chief compasses of the Royal Navy have attained a high degree of excellence; and, indeed, have been adopted as models by other first-rate navies of the world.

the Life-Boat Institution. It is described as very portable, compact in its details, serviceable in its arrangements, and exact as a philosophical instrument; in fine, as “found to answer admirably in every respect.” Now, although this excellent character cannot be applied to the compasses in general use in the mercantile navy, still much improvement has taken place in late years, both in the manufacture, and in their treatment on board ship.

The improvement as a sea instrument may in part be traced to the introduction of steam ; a vessel being thus enabled to make as much progress on a direct course in a few hours as would formerly have taken days to accomplish. The improved sailing powers, also, of nearly all classes of ships, and the competition and emulation in making quick passages, have further tended to place the compass as an indispensable auxiliary to the sextant and the chronometer. Greater issues depend on its correct action, than in those days when time was of little importance to the seaman, and when, on the approach of apprehended danger, the ship’s head was turned away from the obstacle, and a more propitious season quietly awaited. The seaman of to-day, without disregarding the good old “three L’s,” is obliged to give a more prominent position to his compass. The progress of our knowledge of terrestrial magnetism, one of the most important branches of physical xience, has also been most marked in the last half century.

The extensive introduction of iron into the construction and equipment of ships, (which, by increasing the errors of the compass, diminishes materially in some directions of the ship's head its directive power, and thus renders a sluggish compass, or in other words an inferior compass, useless, or even worse than useless,) has necessitated not only the employment of compasses of superior manufacture, but also some knowledge of the laws which affect them by the action of the ship’s iron.

The question may now be asked—What are the essentials of a good compass ? Before answering this question, it may be advisable to give some account of the features of a bad compass; and this we shall do by making a few extracts from the Report of the late Professor Barlow on the contract compasses of the Navy in 1820. It will be seen how closely his description applies to those of the genuine old stamp,—forming too frequently, at the present time, the miserable equipment of our coasting craft, and, indeed, of some of our noble foreign trading ships.

Mr. Barlow considered, after his extended examination, that “the causes of error may be reduced to the three following :

"1. The errors which naturally appertain to the form of the needles usually employed in those instruments.

"2. To imperfect workmanship.
“: 3. To the manner in which the compasses are kept in store.

“With respect to the imperfections in workmanship, it is needless to enter into detail. The cards are, many of them, elliptical, rather than circular ; true centering seems to be entirely disregarded ; and the pivot capping, which ought to be agate, seems in many instances to be only

common glass. The balance also in various cards is only preserved by a very liberal distribution of sealing-wax, which increases the weight of the card, and prevents its traversing, particularly where the needle has but slight directive power.

“With respect to the first of the above sources of error, it is to be observed that the needles are commonly of a form approaching very nearly to a parallelogram ; and, consequently, the accuracy of the bearing of the card will depend upon the north and soutli point of the needle coinciding with the geometrical axis of the figure....... This source of error may be avoided by suspending the needle edgewise, instead of flatwise.”

On the third source of error there are the following valuable remarks, which apply well to the conservation on ship-board :—“It is a well-known fact, if two magnets be brought near and parallel to each other, with their poles inverted, or if they be laid across each other, or be in any other irregular manner brought into contact, or within each other's influence, the power of each will be impaired, and perhaps ultimately destroyed. Now, in the store, the boxes containing the cards, &c., are all placed and piled on each other indiscriminately, without any regard being paid to the directions of the needles within them : consequently, there is a perpetual decomposition of the magnetic influence going on, which would ultimately derange and destroy the action of the most perfect instrument; and to this cause is doubtless to be attributed the very weak directive force of many of the needles which I examined.”

We now proceed to the consideration of the essential qualities of a good compass.

These we consider to be the combination of great sensibility and stability with simplicity of construction. By sensibility and stability it is to be understood that the needle is freely to submit to the earth's magnetic force, with power sufficient to obey steadily that force under the varying motions of a ship, without the aid of friction or other mechanical impediment;steadiness (or rather sluggishness) produced by the latter causes being obtained, as is now well known, at the expense of accuracy.

The principal modern improvements may, probably, be reduced to the introduction of compound needles, arranged on sound philosophical principles, and the manufacture and fitting of liquid compasses. By the latter are meant those compasses in which the card and suspension are immersed in fluid ; and which, in any excessive motion of a ship or boat, appear to be indispensable. We propose, however, to confine our attention chiefly to the simple form of compass ; premising, that the essential points of construction are equally applicable to the liquid compass.

The chief points to be attended to in the construction of the Mariner's Compass are :-(1.) Great directive power of the needle, with little weight, and consequently little friction on the point of suspension. (2.) Permanency of the magnetic power or force in the needle. (3.) Accurate adjustment of the several parts of the compass.

There are numerous records, within the last century, of the labours of

« AnteriorContinuar »