PART II.] On Polar Magnetic Variation. posite latitudes and longitudes. It is evident, that the half of the west division will give the farthest south, and that of the east, the farthest north part of the magnetic equator, constantly changing on account of the movement of the poles in contrary directions. This will give on the section, the present south point of the magnetic equator, nearly at d of Fig. 1. The pole n, properly speaking, is on the west side of the section, Fig. 1, but is assumed there, to demonstrate the action of the south east pole, on the south end of the needle. Suppose the north west pole 5, not to exist, the dip of the needle at d would be the angle hdb; and supposing there were no South east pole n, the dip at d would be the angle adr. As these two poles, at an equal distance froin d, neutralise the effect of each other, the needle will be horizontal on the tangent adb. In moving from the point d of the magnetic equator, to the northward, or southward, the needle is found to incline downwards, or dip to the nearest magnetic pole; while the other, or more distant, will attract the higher, and repel the lower end, inversely, as the square of the distance. At the point P, where the needle will stand perpendicularly over the pole 5, the effect of the pole n will be inconsiderable, as it will be very nearly in the line of the needle in that position. If we could at all times find the precise place of each magnetic pole, a requisite correction could be calculated, and applied to the apparent dip of the needle. An error of one degree, either in the place of the pole, or in the complement of the dip, will be found by trial, to make a difference of sixty miles in the depth of the pole, and of 42 in the length of the transverse diameter, 5, 6, of the real polar orbit. It remains to have made known what may be the number of degrees of latitude which the pole may be distant from N, the earth's north pole, when in the situations 2 and 4 of its orbit, supposed, for illustration's sake, to be on the parallel of 80° of fig. 3. The moving pole will arrive under the meridian of 10° west longitude, in 180 years, reckoned from 1817, or in the year 1997. It will then be found by the dipping needle, to be at 4, after describing one fourth part of its orbit, or some unknown curve, such as P4 of fig. 3. The points 4 and 2 becoming 597 thus made out, after a long period, the conjugate diameter 2, 4, of the orbit will be obtained. The lives and property of a great proportion of maritime nations depend in a great measure, on the solution of a problem of vast moment; and a serious responsibility attaches where delay will prevent the accomplishment of a national object. The pole is now moving in a northeast direction, as proved, by comparing the accurate observations of intrepid navigators. Ere long it will pass on, under uncomeatable regions, for a long period of years. The process, while it can be followed, is obvious, safe, and facile. A run of a few degrees from the north coast of America, in such vessels as Sir John Franklin had, would lead to P, the former place of the pole, and where it would now no longer be found; but, probably, at some point, such as a of fig. 3. The latitude and longitude of a, where the needle would stand perpendicular, would be carefully taken. In five years more, the position a would be visited, when the dip would indicate that the magnetic power had moved on to n. After another period, it might be found at v, beyond which any farther pursuit might be impracticable; and would be unnecessary, as the nature of the polar orbit, and rate of movement, would thus be distinctly made out. The readiest mode of finding these points in the polar curve, would be to move on the line of no variation at the time, till the needle stood perpendicular on the point sought after. The orbit of the southeast pole would be discovered by a similar procedure; and if ice prevented it at any point of the line of no variation, oscillations of the needle, compared with similar ones in a similar İatitude and longitude on the line of no variation in the northern hemisphere, would by analogy, furnish the place of the south-east magnetic pole.. The east variation, equally as the west, is occasioned by the position of the north-west pole P, in reference to the earth's pole N; and not by any imaginary pole in the north-east quarter. For instance, the people at D, have an east variation NDP; and they will have no variation, when the pole comes under their meridian, which is the same as that of London. The inhabitants at B, have an east variation, NBP, and will have no variation, 598 On Polar Magnetic Variation. when the pole will twice come under their meridian, at 4, the first quarter, and at 2, the end of the third quarter of the whole orbit, P4m2 of figure 3. The inhabitants at e, had no variation with the pole at P, but will have an increasing west variation, as the pole moves in its curve over the points a, n, and v. Thus it appears that the single pole P, accounts for every description of variation; and in the southern hemisphere, although the south end of the needle is that principally acted on, still the variation is reckoned from the north end of the needle, but the dip there, is necessarily reckoned at the south extremity, in contradistinction to the north dip. It is to be noticed, that every magnetised needle is naturally a dipping needle; and that it is rendered a horizontal needle by being balanced and attached to a card. Each end of the needle will point to its relative pole only when the needle lies in the plane of the two magnetic poles. In every other situation each pole will prevent the needle from pointing exactly to either; and the attraction and repulsion of the more distant pole will be always, according to what has been stated, showing strongly the necessity of the indispensable process recommended. The dip of the needle has been diminishing from the period of the discovery of this phenomenon by Norman. As due attention was not paid in former times to the coincidence of the centre of gravity and centre of motion, recorded observations, though inaccurate, are still sufficient to show the fact of a diminution of dip, which I shall attempt to explain by a rationale, founded on statements sanctioned by a theory resulting from experiments and calculation. It is requisite to refer to plain and linear plates, because "Segniùs irritant animos demissa per au rem, Quam quæ sunt oculis subjecta, fidelibus." Granting that Cavallo, in 1775, observed the dip with tolerable accuracy, we find at London its amount to be 72° 3′, to be compared with the present dip of 70°. This for 54 years gives an annual decrease of 2' 16." 6. The question necessarily arising is, when did the decrease commence, and when will the increase begin? Let fig. 2 be a section through the parallel of latitude AB of fig. 1, and 34° 30' [XCIX. from the equator; and having in its plane the transverse diameter, 5, 6, of the interior polar orbit, 2, 5, 4, 6, of fig. 2. The section is to be supposed parallel to the equator, and standing at right angles to NS, the axis of one hundred west longitude. Suppose radii passing from C, the earth's centre, through the cardinal points, 5, 4, 6, and 2, they would terminate on the surface at P, 4, m, and 2, of fig. 3; giving the four principal points of the exterior polar orbit, on every part of which the needle will stand nearly perpendicular, when the magnetic pole in its real interior orbit is on the radius or semidiameter of such point. There being no data for ascertaining the length of the conjugate diameter 4, 2, the number of miles which the magnetic power moves annually in its real and sensible, or apparent orbit, cannot be obtained till the important experimental process described shall have been followed. The number of miles cannot probably exceed eight in the exterior orbit, and which will measure half a degree on the equator, because the pole moves through the whole amount of the equatorial degrees, in 720 years. To a person at G, at the upper part of section, fig. 2, the dip will be greatest when the pole is at 2 of its orbit; and will diminish while it is moving during 360 years through the west half of its orbit, 2, 5, 4; and will increase while moving through the eastern semiorbit, 4, 6, 2. To those situated at R, the effect will be the reverse; and to both it will be similar, when the pole is at 4 and 2. To those situated at E and W, the dip will increase when the pole is moving inwards from 2 to 5, and from 4 to 6, in the opposite quarter-orbit. The dip will diminish while the pole is moving outwards towards the circumference, from 5 to 4, and from 6 to 2 of the opposite quarter of the orbit. When at the points 2, and 4, the dip will be similar; and when at 5 and 6, it will be apparently the same. The case is different when the observer is not, as here, situated in the plane of the polar orbit. At present, the magnetic pole or power is moving eastward in its interior orbit, from 5, the utmost point of westing in fig. 2, towards 4; and the quarter of its interior curve equal to 5, 4, will correspond with the fourth part of the exterior orbit found by the dipping On Polar Magnetic Variation. PART II.] needle, or P4 of fig. 3. That the pole is moving in this curve, or in some similar one, is proved by the experienced diminution of what is termed the VARIATION that is to say, the angle of variation NLP, is found now to be less than it was when the pole was at P, the farthest point to which it moved in its constant course eastward. It is evident that when the pole is in the position 4 of fig. 2, it will be nearer to the surface of the earth, on the side on which Loudon is situated, than it will be at 2, the opposite part of the interior orbit. It follows from this, that in London the dip of the needle will be at its maximum when the pole is at 2, and at its minimum when it arrives at 4; and consequently that the dip will diminish while the pole, as at present, is describing the western half, 2, 5, 4, of its orbit, and increase while it is moving through the other or eastern half, 4, 6, 2, or 4, m, 2, of fig. 3, which indicates the corresponding orbit on the surface. There will be a point between 5 and 4, and between 6 and 2, where the diminishing and increasing dip will be equal. It must be also manifest, that to inhabitants who are nearer to the point 2, than to the place 4 of the orbit, the dip will be of a differing description; or in general, that it will depend on the greater or less contiguity to, or distance from, the relative extremities of the conjugate diameter, 4, 2, of fig. 2, or 4, 2, a curve of fig. 3, on the surface. From not knowing nearly the length of the conjugate diameter 4, 2, it cannot at present be determined, whether the greatest diminution of the dip will be at 4, and the greatest increase at 2 of fig. 2; but these circumstances will take place when the pole is contiguous to, or at the parts 2 and 4 relatively, in the polar orbit. The diurnal variation minutely described by Canton, and observed first by me in the southern hemisphere, as stated in the Philosophical Transactions, is now decidedly reduced to the action of the solar heat, the great source of magnetism, and found to be a modification of, and intimately connected with, galvanic electricity. The magnetic fluid pervades all all substances; is equally active in vaspace, cuo and in pleno; and is so subtle, that no test can discover in what proportion it is incorporated with atino and 599 spheric air. It is constantly flowing Mankind is born to wonder and adore." JOHN MACDONALD. 600 Rev. Wm. Ainsworth, and Samuel Sunderland, Esq. [XCIX. MR. URBAN, Lightcliffe, Dec. 30. Fion, I gather that, in the year ROM some papers in my posses1632 the Rev. William Ainsworth (before noticed in pp. 290, 498), was living at Crownest, in the chapelry of Lightcliffe, in the parish of Halifax. This appears to have been his own estate; but, in a few years afterwards, I find it in the hands of another possessor. "Res angusta domi" may probably have obliged him to dispose of his little property, and this circumstance may explain the use of the term "unfortunate," which he applies to himself in the conclusion of his dedication to his patron. In 1647 he was presented by the Vicar of Halifax to the Perpetual Incumbency of Lightcliffe, which he held until 1650. "Samuel Sunderland, Esq." one of Mr. Ainsworth's patrons, was born in this parish in 1600; he went to London, where he carried on the business of a Woollen-draper, in which he was eminently successful; and he was an Alderman, and paid the fine exempting him from serving the office of Sheriff. After he had relinquished his commercial pursuits, he resided at Harden near Bingley; and died in Feb. 1676, s. p. He was a great benefactor to public charities in this part of the county, and particularly to the Free Grammar-school at Hipperholme, in this parish, as will appear from the following inscriptions: "Libera Schola Grammaticalis Hipperhomiæ a Mattheo Broadley, armigero, primitùs fundata, post a Samuele Sunderland aucta, qui ambo patria chari, et pauperibus benefici, hoc legatum famæ suæ monumentum posteris reliquêre, 1661." Over the entrance to the HeadMaster's house: "S1. Sunderland, Arm", dedit, 1671." On the façade of the present school, erected in 1783: "Literarum ergo et virtutis scholam Hipperholmiæ, instituit et dotavit Mattheus Broadley, Armig. 1661; stipendium auxit Samuel Sunderland, Armig. 1671; et quorundam benevolorum liberalitate hoc novum ædificium publicæ utilitati dedicatur, 1783." * Matthew Broadley was a native of Hipperholme. He lived in London, where he acquired a large fortune in trade. His will is dated Oct. 15, 1647. Ainsworth's "Triplex Memoriale," contains several strong complaints of the poverty of the Clergy in those days; particularly at p. 78, where he says: "The Ministry in this Church of England is, for the most part, the poorest trade Ministers having neither a competency while that any man drives, the inferiour sort of they live, nor provision made for their families after their death, contrary to the practice of other reformed Churches. Every man thinks he is at liberty to pay to the Minister, or forbeare, though he be content to be bound in every thing else. Men would have Ministers to burne their lamps, but will afford them no oyle to keep in the light; like Pharaoh's hard task-masters, they think we should make brick without straw.' And a little further: "The poorest Ballad-singer and Piper in the country live better of their trades than Ministers do." I shall only observe, that if this was the case in the succeeding reign, it is not to be wondered at that so many Curates suffered themselves to be ejected from the Chapels in this neighbourhoodt. It is said, that Mr. Ainsworth taught school, notwithstanding which he declares, that by reason of the late civil storms, he was as poorly provided of accommodations for study, as Cleanthes was for writing his philosophical notes, when, having wrought all day long in the vineyards, he wrote at night on bare bones instead of paper. Yours, &c. OLICANENSIS. In p. 498, for Rooker read Rookes. A. D. observes, "In a late highly improved edition of Debrett's Baronetage, the family of Strickland of Boynton, is deduced from a Roger Strickland of Marske, in the county of York. Any particulars of this Roger would greatly oblige. William Strickland, son of the above-named Roger, and said to be the first of the family who settled at Boynton, appears to have married a daughter of Sir Walter Strickland, of Sizergh in Westmoreland; what relations, if any, were they to each other? This William died at an advanced age in 1597.” + There are twelve Perpetual Curacies in the parish of Halifax, of which the Vicar is the patron; and the Curates preach at the parish Church on the first Wednesday in every month, in rotation, in conformity with the will of Nathaniel Waterhouse. PART 11.] [601] REVIEW OF NEW PUBLICATIONS. The History and Antiquities of the Conventual Church of St. James, Great Grimsly, with Notes illustrative and explanatory. By the Rev. G. Oliver, Curate, &c. 8vo. pp. 52. MR. Oliver is distinguished for la borious research, and he only errs when he charitably adopts other people's illegitimate children. In his history of Initiation we had occasion to notice his patronage of the helio-arkite theory, and here again we have to particularize other erroneous premises, for which he is not to blame. In page 9 it is stated, "that with respect to the Saxon style it is asserted that there is not a single specimen of a complete Saxon church now in existence in this kingdom; but there are parts of religious structures, which were doubtless erected before the Conquest." Now we know, that the church of Kilpeck in Herefordshire is affirmed, in the Anglia Sacra, to have been consecrated in the time of the Conqueror, by Herwald, Bishop of Landaff, who also consecrated, in the time of Edward the Confessor and Harold, "Henullam, Dubric, and Lantilio, in uno cemeterio," (Anglia Sacra, ii. 671.) Kilpeck we have examined, and can safely allegate, that it has a quite different aspect from other churches, and has undergone no other alterations than perhaps a wooden porch, or some such trifling thing. If investigations were made of various Welch churches, mentioned in history, we are sure that seIveral would be found anterior to the Conquest, which have undergone little or no change; and, oddly enough, the leading difference, viz. that the commencement of mullions in the windows marks an æra, has either not been noticed or very slightly. According to such observations as we have been able to make, the striking difference of the Saxon and Norman (though the rule may not be without exceptions) is, that in the former the arch is very lofty and the pillar short; and in the Norman vice versa. If in Domesday there frequently occurs the mention of priests, the existence of churches also follows of course; and if such churches exhibit GENT. MAG. Suppl. XCIX. PART II. D marks of the Saxon style, by what authority are they Normanized. We by no means blame Mr. Oliver; but we know the notion which has been inculcated, that every architectural remain is Norman, in defiance of authentic history, which gives us dates of the actual edification. It has been noted, that when power falls into the hands of the vulgar, it is exercised in a most violent pernicious manner. We venerate the memory of Gervase Holles, esq. more than once mayor of Grimsby, and one of its representatives in Parliament; for excellent are his collections still preserved in the British Museum.* It appears that his superior mind was intolerable to the lower orders of freemen, and that a successor in the mayoralty, a Mr. Booth, was much influenced by him. An unfortunate fellow, named Proctor, who happened to be churchwarden, was mulcted in the enormous penalty of 201. merely for saying, "that there were two mayors." This happened in the year 1639, and "In the same year, Mr. Proctor, the churchwarden, informed the Court, upon his oath, that Mr. Paul Willet, minister and twelveman, required him, the sayd Samuel Proctor, to present William Booth, Maior, and Gervase Holles, esq. for laughing in the Church, or else he would present him. P. 22. We are inclined to suspect, from the ensuing ordinance, that the members of the Corporation were in the habit of attending church in their every day working dress; for, by an ordinance in 1592,"the Bayliffes and Twelve are ordered to sytte where they are appoynted, and in decent apparell." The rank of the husband also extended to the wife; for in the same ordinance it is further commanded, that "the alIdrisses, the wives of the Twelve and xxiiij, do syte according to the appoyntment." p. 23. In p. 28 Mr. Oliver quotes old Fuller's explanation of the collar of SSS, * Mr. Oliver quotes those in the Harleian department. There are others as valuable in the Lansdown collection. |