al tax, wantonly imposed by the dregs of the people, as would enable them to contribute handfomely towards the reduction of the national debt in times of peace, or otherwise supplying the exigencies of government.

Vales may be confidered in another light, which will appear very striking, if the incomes of certain claffes are compared with the rank those persons bear in the state.

How many hundred clergymen are there in England, who do not receive 251. a-year for the maintenance of them and their families? yet the meanest live ry-fervant in London, exclusive of vales, cofts his mafter 30 1. a-year; an hoftler or waiter in a well accustomed inn, fhall gain more by vales than the pay of a cap. tain of foot; and the porter of a minifter of ftate, who wears his livery, fhall have a greater income than a lieutenant colonel of dragoons.

From thefe, and many other confiderations, it feems highly neceffary to put a ftop to this practice.

But before any fuch regulation can be expected in private families, the example fhould be fet in a higher place. We have feen with pleasure the wife and virtuous example of economy which has already been established in that place [xxiii. 89]; and it is to be hoped that the fame wifdom and goodness which faw the propriety of thofe regulations, will give direc tions for this most neceffary one. Can there be a greater affront to majefty, than to fee all the avenues to the royal prefence befet with harpies of different orders, who, though otherwife plentifully provided for by the inunificence of a moft gracious prince, yet ftanding with their palms open to extort money, in name of Christinas-boxes, from thofe who pafs? many of whom can but ill afford it, yet must pay, or be exposed to petulent fneers. In like manner the royal palaces, and gardens, as well as thofe of private perions, are locked up by their feveral keepers; fo that neither foreigners nor fubjects can fee thofe works of taste and magnificence, but at a very great expence. This fhameful practice of giving vales hath been abolished in Scotland ever fince Whitsunday 1760. The juftices of peace and freeholders led the way in fome counties, by entering into refolutions, at their quarter-feflions, to give no vales upon any pretence whatsoever. This was followed by other counties, and by particular focieties, [xxii. 331.]

When these refolutions came to take effect, it raised a general mutiny amongst fervants in Scotland, particularly in Edinburgh and the neighbourhood, where many of them left their fervices all at once, and got into fhips in order to come to London in quest of new places and vales; but happily for the others, most of them were impreffed in the Thames, and fent on board the fleet before they had an opportunity of fetting foot on hore The account of this foon reached Scot land, which put a stop to the defection; and now fervants there, having no expec tation of vales, fettle quietly to their bu fineffes. Their wages have been mode rately raifed; they are become much more reasonable and tractable, as they now find they must trust to their own good behaviour for a fuitable encourage ment from their masters; and a perin may now travel from one end of that kingdom to the other, without having occafion to put his hand into his pocket, except when he lodges at an inn.

A refolution fo general is not to be ex pected in a country fo extensive and popu lous as England; it seems therefore high ly expedient that an act fhould pals in parliament to reftrain the pernicious c ftom of giving vales, by fubjecting the per on who gives them to a fine, fatis quoties, for every tranfgreflion of the law; and by enacting, that the man who takes them, fhall thereby become inliited to ferve his Majefty in his army or navy, leaving it to the juftice of peace before whom the complaint is brought, to ad judge the perfon to either of thofe fer vices he fhall think proper. [xxii. 13.]

In framing fuch a law, many other things may occur which deferve confide ration, fome of which shall be here flight ly touched.

The rates of wages, for example, fhould be fixed according to the different degrees of servants.

Perfons of great eftates do not refle upon the injury they do their fellow ci tizens by the exorbitant wages they give their fervants, and how fuch example diftrefs people of moderate fortunes. Be fides, it has another pernicious confe quence, of draining the country of necel fary hands, many of whom flock to Lon don in expectation of high wages; though, in ftrictnefs, no good reafon can be affigned why a fervant in London fhould be intitled to much higher wages than in the country; any difference in the expente

termining the longitude to one degree of a great circle, or 60 geographical miles; of 15,000 l. if it determines the fame to two thirds of that distance; and 20,000 l. if it determines the longitude to 30 miles xix. 606.], or one half of a degree. Encouraged by the hopes of gaining fo confiderable a reward, and willing to benefit mankind by their labours, many ingenious perfons have applied them felves to the folution of this famous problem, the difcovery of the longitude at fea; a problem which was formerly placed in the fame degree of probability with the fecret of prolonging life, the perpetual motion, and the fquaring of the circle.

Among the many candidates for this reward, Mr John Harrifon has generally been thought to stand foremost; an artist of very diftinguished abilities, and to whom the aftronomers of thefe days are indebted for that moft valuable difcovery of the compound pendulum, commonly called the grideron-pendulum. It was generally imagined, that if a clock or watch could be fo nicely conftructed as neither to be affected by the motion of the fhip, nor by the different state and temperature of our atmosphere, the problem would be folved in the fimpleft and moft practicable manner; fince nothing would be expected from the mariner but to determine the time of day at the thip in any part of the fea, and to compare that time with his watch, which had been firft adjusted to the meridian of the place from whence he took his departure, the difference being the difference of longitude. Accordingly Mr Harrifon bent his thoughts this way, and after many years labour and application, he is now of opinion, that he has brought his clock to the defired degree of perfection; that, by a combination of teel and brass bars, he has prevented his clock from being affect ed by the variable conflitution of the atmosphere and the difference of climates; -that by making ufe of a spring of fuch a determined length that it thall always act with an equal force, he has obtained a regular and uniform motion;-that he has removed any ill effects that might be occafioned by the friction of the feveral parts of this very complicated machine; -that, from the nature of the materials he has made ufe of, his clock will not require cleaning fo often as ordinary timekeepers; in a word, that his watch may be depended on to one second in a day. He has therefore ventured to lay

his propofal before the commiffioners of longitude; he has fubmitted his machine to a trial, and his fon, to whom he has intrufted the care of it, is appointed im mediately to fail to Jamaica for that purpofe [447.]. Accordingly, the clock is to be adjusted to the meridian of Portimouth, by obfervations to be taken with an exquifite equal-altitude inftrument, made by Mr Bird in the Strand. When the fhip arrives at Jamaica, the time of noon is to be determined by fimilar ob fervations, and compared with the clock, and the difference carefully noted; which difference, it is fuppofed, will give the difference of longitude within the limits required by the act of parliament. But this is not all. The fame experiment is to be repeated when the hip returns home; that a full, and, if posible, a fatisfactory trial may be made; and that it may be known whether any material dif ference will arife in this fecond determination of the longitude. Such is the me thod of trial which was propofed by Mr Harrison, if I am rightly informed, in a memorial drawn up by fome friend, and laid before the commiflioners on Tuesday Oct. 13. 1761, when his propofal was agreed to, and ordered to be carried into immediate execution.

But let us now inquire, how far this method is to be depended on, and whether it be fuch as feems to be pointed out by the act of parliament. It is enacted "That one half of the reward fhall be paid when the major part of the commil fioners agree, that fuch method extends to the fecurity of fhips within 80 geographical miles of the thore; and the other half, when a fhip, by the appointment of the commiflioners, fhall fail over the ocean from G Britain to any part in the West Indies, without lofing the longi tude beyond the limits mentioned."

We will fuppofe, that, upon trial of Mr Harrifon's clock, it appears, that the difference of longitude between Portmouth and Jamaica, and Jamaica and Portfmouth, agrees within one minuit, nay, is given to the very fame second: yet how fhall it be made appear to the commiffioners that the fhip did not lose its longitude? The clock may gain in returning nearly what it loft in going, or vice verfa; and the difference of time, therefore, will not fhew the true longi tude. The commiflioners, in this cate, will have no certain flandard by which to form a proper judgment, as the longi

tude

Sept. 1762. Of the inventions for tude of Jamaica has not hitherto been de termined with fufficient accuracy. At a meeting of the commiffioners, about the latter end of May, or beginning of June, 1761, it was agreed, that a trial of Mr Harrison's clock fhould be made; and alfo that the longitude of Jamaica fhould be determined and adjusted by actual obfervation; for which purpose, a gentle man of known abilities was appointed to make the observations at Portsmouth; and orders were given to Mr Bird to prepare two equal-altitude inftruments of equal length, and two reflecting telescopes of two feet focus. This expedition was poftponed for the present, by circumftances of a very public nature, which were not at that time forefeen; but ftill it is much to be lamented, that Mr Harrifon fhould fuffer himself to be fo far prevailed upon by his friends, as to propose the prefent method, which can never be fatisfactory, and which he laid afide fome years ago, as inadequate, upon the reprefentation of the greatest aftronomer of the age. His fon, indeed, is to be accompanied with another gentleman, as an affiftant; and they intend to take with them one of the reflecting telescopes, which exceed any of that length ever made before; but with what defign, I must not presume to determine. As they cannot expect to be at Jamaica before the middle of December, the feafon will be too far advanced for the observation of the eclipses of Jupiter's fatellites; and the prefent voyage will be undertaken with hardly any other view than to determine how far the clock may be depended on in long voyages. Many other objections to the prefent method might be produced, as, particularly, the manifeft impropriety of taking obfervations on land for determining the going of the clock; fince the true time at the fhip muft always be determined at fea, by taking altitudes with Hadley's quadrant. But I fhall at prefent content myself with faying, that the method now before us does not appear to me to be calculated to do juftice even to Mr Harrison; fince he has been prevailed on to undertake this voyage at a time when his watch is not brought to that degree of perfection which he is capable of giving it; and when he knows, or ought to know, that he is not allowed, by an amendment lately made of the 12th of Q. Anne, (if I am rightly informed), more than one trial.

Though the method of determining the

473

longitude by a clock has been generally thought to be the most simple and easy of all, yet I am of opinion that it can never be entirely depended on in very long voyages; and therefore the mariner must be obliged to call in to his allistance that method which is founded in nature, and which will fupply him with opportunities of determining his fituation at sea as often as he can defire. This is the method formerly propoled by that eminent philofopher and aftronomer Dr Halley, and fince adopted by Mr Tobias Mayer, a celebrated profeflor at Gottingen, who has conftructed a fet of lunar tables more easy to the calculator, and more accurate, than any hitherto publifhed. His tables indeed, as delivered to the commiffioners, though more accurate than those publifhed in the 2d volume of the Gottingen acts, were not found to reprefent the moon's place fufficiently within the limits which the act requires. But they have fince received farther corrections, and have been compared with a very confiderable number of obfervations by the Royal Aftronomer at Greenwich, and the editor of Dr Halley's tables; and they are never found to differ one minute from obfervation, and generally may be depended on within one half, or at most two thirds of that quantity.

But it may be faid, that this method is liable to one confiderable objection, i. e. the error in observation. To which it may be answered, that, with good inftru. ments, an experienced obferver will not be liable to an error of more than one minute: and that a ftill greater precision may be expected, if the moon's distance be obferved on the fame day from two different stars, one to the east, and the other to the weft of the moon; by which means almost every error both in the obfervation itself, and in reducing fuch obfervation, will be compenfated. The tables indeed are fomewhat imperfect; and when an obfervation is taken at fea, before it can be compared with a calculation made for the meridian of the place to which the tables are adjusted, it must be freed from the effects of parallax and refraction, by long and painful calculations; which cannot be expected from every common mariner. But if we confider, that the error of the tables is very fmall, in general not exceeding half a minute; that obfervations of this kind may be made at all times of the day, (fince the distance of the fun and moon

will answer the fame purpo e); and that the tedious method of trigonometrical calculation has been rendered unnecessary by the Abbe de la Caille, who has fur. nished us with a means to folve every poflible cafe by fcale and compafs, -I flatter myfelf that this method will go hand in hand with Mr Harrison's, and that they will illuftrate and confirm each other.

A third competitor for the longitudereward is Mr Chriftopher Irvine, who has invented what he calls a marine chair, an inftrument to render oblervations, and particularly thofe of the eclip fes of Jupiter's fatellites, more eafy and practicable on fhipboard. This gentle man certainly merits fome encouragement for his contrivance; but I cannot think that he can ever be intitled to the reward for the discovery of the longitude; fince, without good tables, his chair can be of little fervice. If the fatellite-tables could be brought to fuch a degree of perfection as to reprefent the eclipfes of the ift and 2d within one minute, they would be of confiderable benefit to the mariner. But this is not to be expected (particularly in the cafe of the 2d) from tables furnished with empiric equations, and adjusted by obfervation. The action of thole planets upon one another should firft be determined upon true geometrical principles, and the variable inclinations of their orbits carefully afcertained. When this has been done, the number of the eclipfes of the 1ft and 2ft fatellites visible in any one place is fo fmall, not exceeding at a mean 60 in a year; fo many of those few opportunities are loft by cloudy weather; and there being generally four months in the year with not above fix obfervations that can poflibly be made, (I inftance in the years 1760 and 1761, and include all the fatellites), I will venture to fay this method can never be of fingular and general service to the mariner. I need not obferve, that the flowness of the motion of the 3d and 4th fatellites will not fuffer their ecliples to be of the fame ufe with the other two; the difference between two obfervers in the fame place amounting, particularly in the cafe of the 4th, to 2, 3, or even 4 minutes.

The method of determining the longitude by ecliples of Jupiter's fatellites, was proposed by Mr Whifton in 178, when the tables did not represent the motions of the fatellites with that degree

of accuracy which we have reafon to ex pect from Mr Wargentin's laft tables. That gentleman (Mr Whiston) was fenfible that the mariner would not have fuf ficient opportunity of determining his longitude from ecliples of the two innermo? fatellites, and therefore called in to his afliftance their occultations both beyond and on this fide the body of Jupiter, and alfo their conjunctions. But from the obfervations of three accurate obfer.en employed by Mr Whifton, about that time, to make obfervations in three dif ferent places, it fully appeared, that little or no aflittance could be obtained from the occultations, and still lefs from the conjunctions, though made in the mot favourable circumstances, viz. when two of the fatellites were receding from each other in a contrary direction. As Mr Whiston had no contrivance like that of Mr Irvine, to take off the agitation of the vellel, he proposed to make use of a refracting telescope, having one broad eye-glais in the common focus of fevea object-glafles. This im-mechanical and unphilofophical apparatus was found to be of no fervice; and though we have reaton to expect much greater aflistance from the marine chair, yet ftill I believe it is al moft next to impoflible for an oblerver, feated on this chair, to keep the body of Jupiter within the field of a long reflecting telefcope: and I am told, by very experienced mariners, that Mr Irvine's chair must be greatly affected by that mo tion which the failors call the yawing the hip; a motion compounded of tw others, in the direction from fide to fide, and from head to ftern; a motion which muft effectually prevent the mariner from making any ufe of Dollond's micrometer, if he were defirous of meaturing the distance of the moon's limb from any neighbouring ftar. [xviii. 217. xxi. 636. xxii. 312.] [Gent. Mag.] ASTROPHILUS,

of

The act 2 Geo. III. cap. 18. palled laft feflion [219.], "for rendering mort effectual an act 12o Annæ, for providing public reward for fuch perfon or perfonsis ball discover the longitude at fea, with regard to the making experiments of pro potals made for difcovering the longi tude," upon a recital, That by the 2 12° Anne commiflioners were impowered to lay out 2000 l. in making experiments of propofals made for difcovering the lon gitude; that by an act 14° Geo. II. [iii. 189.] thefe commiflioners were inpowered to apply fuch part of the aferementioned