his alms into the cap of the young mendicant, though it is known, by the experience of years, we may fay, of ages, that the money thus collected is to be spent in riot and debauchery. Thus is the young mind degraded by thofe who fhould be the guardians of public virtue-an abfurd and pernicious custom gives a fanction to meanness and vice, for no better reason than because it is a custom,

But, with regard to a reform in education, long-established cuftom is not the only obftacle in the way. The immenfe eftablishments which have been formed upon the old plan give a weight and influence to the members of these establishments which they throw into the anti-reforming fcale. Poffefied of confequence and high emoluments, they dread, and they oppose all change, while, from their fituation, and the nature of our government, their oppofition will always have great effect. This, with the little attention paid to a matter of fuch high importance by the legislature, give but small hopes of a speedy reformation: but the progrefs of fociety has already had fome effect, and will perhaps gradually remedy the evil. In the meanwhile, we fubjoin a fhort specimen of Dr. Prieftley's Effay, in hopes that it will induce our readers to perufe the whole, and seriously to examine a subject where all are so intimately concerned:

It feems to be a defect in our prefent fyftem of public education, that a proper course of studies is not provided for gentlemen who are defigned to fill the principal stations of active life, distinct from those which are adapted to the learned profeffions. We have hardly any medium between an education for the compting-house, confifting of writing, arithmetic, and merchants'-accompts, and a method of inftitution in the abstract sciences: fo that we have nothing liberal that is worth the attention of gentlemen, whose views neither of these two oppofite plans may fuit,

6

Formerly none but the clergy were thought to have any occafion for learning. It was natural, therefore, that the whole plan of education, from the grammar fchool to the finishing at the univerfity, fhould be calculated for their ufe. If a few other perfons, who were not defigned for holy orders, offered themselves for education, it could not be expected that a course of studies should be provided for them only. And, indeed, as all those perfons who fuperintended the bufinefs of education were of the clerical order, and had themselves been taught nothing but the rhetoric, logic, and school divinity, or civil law, which comprifed the whole compafs of human learning for feveral centuries, it could not be expected that they fhould entertain larger or more liberal views of education; and ftill lefs that they should strike out a course of study for the ufe of men who were univerfally thought to have no need of ftudy; and of whom few were fo fenfible of their own wants as to defire any fuch advantage.

Besides, in thofe days the great ends of human fociety feem to have been but little understood. Men of the greateft rank, fortune,

and

and influence, and who took the lead in all the affairs of state, had no idea of the great objects of wife and extenfive policy; and therefore could never apprehend that any fund of knowledge was requifite for the moft eminent flations in the community. Few perfons imagined what were the true fources of wealth, power, and happiness, in a nation. Commerce was little underflood, or even attended to; and fo flight was the connexion of the different nations of Europe, that general politics were very contracted. And thus, men's views being narrow, little previous furniture of mind was requifite to conduct them.

The confequence, of all this was, that the advances which were made to a more perfect and improved state of fociety were very flow; and the prefent happier ftate of things was brought about, rather by an accidental concurrence of circumftances, than by any efforts of human wisdom and forefight. We fee the hand of Divine Providence in those revolutions which have gradually given a happier turn to affairs, while men have been the paffive and blind inftruments of their own felicity.

But the fituation of things at present is vastly different from what it was two or three centuries ago. The objects of human attention are prodigiously multiplied; the connexions of states are extended; a reflection upon our prefent advantages, and the steps by which we have arrived to the degree of power and happiness we now enjoy, has fhewn us the true fources of them; and fo thoroughly awakened are all the ftates of Europe to a fenfe of their true interefts, that we are convinced the fame fupine inattention with which affairs were formerly conducted is no longer fafe; and that, without fuperior degrees of wifdom and vigour in political measures, every thing we have hitherto gained will infallibly be loft, and be quickly transferred to our more intelligent and vigilant neighbours. In this critical posture of affairs, more lights, and fuperior industry, are requifite, both to minifters of state, and to all perfons who have any influence in fchemes of public and national advantage; and confequently a different and a better furniture of mind is requifite to be brought into the business of life.

This is certainly a call upon us to examine the state of education in this country, and to confider how thofe years are employed which men pass previous to their entering into the world; for upon this their future behaviour and fuccefs muft in a great measure depend. A tranfition, which is not eafy, can never be made with advantage; and therefore it is certainly our wisdom to contrive that the ftudies of youth fhould tend to fit them for the butinefs of manhood; and that the objects of their attention, and turn of thinking in younger life, fhould not be too remote from the defined employment of their riper years. If this be not attended to, they must neceffarily be mere novices upon entering the great world, be almoft unavoidably embarraffed in their conduct, and, after all the time and expence beftowed upon their education, be indebted to a series of blunders for the most useful knowledge they will ever acquire.'

The

The whole Effay is highly worthy of attention; and to those who imagine (though we think falfely) that it contains views inju rious to their interefts, we can only fay fas eft et ab hofte diceri.

To conclude, the author, in this volume, has collected from every quarter whatever could tend to make his work, what we really think it, a moft ufeful publication. It is with regret we add, fi fic omnia. There are fome inaccuracies in the language, and in general the diction does not seem to have been much attended to; but it is fufficiently perfpicuous.

ART. II. A Treatife on Practical Aftronomy. By the Rev. S. Vince, A. M. F. R. S. 4to. 18s. fewed. Cambridge, printed: Cadell, London. 1790.

THIS

HIS work is fuited to the practical genius of the English nation. Though fcience has fallen from its former dignity and importance, this country ftill maintains its preeminence in the arts. Within these thirty years vaft improvements have been introduced into the aftronomical inftruments, and the mode of conducting obfervations has been almoft totally changed. Partial defcriptions have been occafionally published; but a treatife, which contained a complete detail of the implements of a modern obfervatory, was ftill wanting. Mr. Vince has undertaken this task, and performed it with great judgment. His defcriptions are fimple, clear, and popular, and his directions and remarks are diffufe, and even minute. He explains the principle of the conftruction of the inftruments, and details their uses and adjustments. He has availed himself of the affistance of Dr. Maskelyne and Mr. Ramsden, and has rendered his descriptions, by means of accurate engravings, intelligible even to those perfons who have not had the fortune to fee the inftruments.

In Chap. I. Mr. Vince explains the curious contrivance of Vernier or Nonius, by which minute portions are measured by the differences of proximate scales. His account feems to be rather inaccurate. The principle is this: If the unit of the fundamental scale be divided into n parts, and m+1 of these parts be divided by mn, it is evident that each of these will exceed the former by; or the original parts will virtually be fubdivided by m. In his illuftration, Mr. Vince fuppofes that the product of 24 by 25 is 500 inftead of 600. This remark would be too minute, had not the author felected the example for a particular purpose, and repeated the mistake.

mn

In Chap. II. he treats of Hadley's quadrant. This moft beautiful and ufeful inftrument was firft conftructed about the

year

1

year 1730. The inaccuracy of the foreftaff, and of Davis's quadrant, had long been felt; and the difficulty of obferving at fea was confidered as a barrier to the discovery of longitude. Sir Ifaac Newton, Dr. Wallis, and Sir Christopher Wren, discovered, towards the end of laft century, the principle which Mr. Hadley employed in conftructing his quadrant. The reflecting telescope enjoyed the fame fingular fortune. It was invented in 1670 by Mr. James Gregory, but was first constructed above fixty years afterwards by his countryman Mr. Short. The difcovery of Hadley's quadrant has been claimed by the Americans. An ingenious New-Englander, it is faid, conftructed by himself an inftrument of this kind at fea. Hadley's quadrant depends upon a curious optical principle. An incident ray of light makes with the fame ray, after a double reflection, an angle equal to twice the inclination of the mirrors. In the fore obfervation the angle which the mirrors make with each other is acute; in the back obfervation it is obtufe. In measuring the angle fubtended by near objects, a small correction must be made for the distance of the mirrors from each other. But when the objects are remote, their position with regard to each of the glaffes may be confidered as abfolutely the fame. Mr. Vince gives very full directions for the use and adjustment of this intrument. Many of these would naturally occur to the intelligent obferver. The back obfervation is the most liable to error, and its adjustment the moft difficult. Other methods of correcting it have lately been propofed by Mr. Dollond and Mr. Blair. Our author then gives directions for taking the altitude of the fun, moon, or stars, at fea, by the fore and back observations; also their distances and their altitude at land, by means of what is termed an artificial horizon. In determining the time from equal altitudes, the author proposes a neat formula. Let t= the tangent of the latitude, the tangent of the declination, s➡ the fine, and r the longeft, of the hour angle from noon, and d= the temporary variation of declination; the correction He closes with a short, diftinct account of the

is / d ( + ~ ). ±).

2

=

v=

method of discovering longitude at fea by the distance of the moon from the fun or a fixed ftar. Dr. Mafkelyne, our present aftronomer royal, was the firft who, by his ingenuity and induftry, properly reduced it to practice.

In Chap. III. Mr. Vince treats minutely of the telescopic wires. If these be parallel and vertical, the time of the paffage of a heavenly body is inversely as the cofine of the zenith diftance. From this principle, the time of the central tranfit of the fun may be determined; it may also be difcovered by obferving the approach of the one limb to the feveral wires, and afterwards

the

the receffion of the other. It is more difficult to afcertain the paffage of the moon, owing to her parallax, the irregularity of her motions, and the variation of her afpect.. Dr. Mafkelyne has, however, given a formula for this purpofe. The motion of a heavenly body in the field of a telescope is not exactly parallel to the horizontal wire, for it is affected by the change of declination and of refraction. The quantity of refraction be fides varies with the denfity and temperature of the atmosphere. If b denote the temperature in degrees of Farenheit, a the altitude of the mercury of the barometer in inches, z the zenith distance, and r the tabular refraction, it is found partly from experience, and partly from induction, that the true refraction is 475'XaX tangt.-3. Mr. Vince deduces feveral formulæ for 37b+12950

correcting the errors in the right afcenfion, occafioned by the irregular motion of the ftars over the crofs wires of the inftrument.

Chap. IV. is occupied about the tranfit telescope. This inftrument is dioptric; it has only one eye-glafs, which is convex; and hence it inverts the objects. It is connected to an horizontal axis, and fo adjufted as to move in the plane cf the meridian. Its principal use is to determine the right afcenfions of the heavenly bodies, and to correct the motion of the clock. The firft adjustment is to place the axis parallel to the horizon. This may be done by the fpirit level, by the plumb line, or by obferving if the pole ftar and its reflected image appear on the fame wire. If the telescope be at right angles to the axis, an object must appear in the fame pofition after the inftrument is inverted, and the wires must be moved till this take place. The next adjustment is to make the line of collimation move in the plane of the meridian. This may be afcertained by obferving whent the intervals of time between the tranfits of a circumpolar ftar, above and below the pole, are equal, or when thofe of two known ftars, differing confiderably in declination, are equal to their difference of right afcenfions in time. At night the wires are commonly illuminated by means of a lamp attached to the extremity of the telescope, the light of which is reflected down the tube. Mr. Ramfden makes the axis hollow and open at one end, where he places the lamp, and within the telescope he fixes a perforated plane mirror, making an angle of 45° with the tube. Mr. Vince describes the ufes of the inftrument for regulating the clock, and for determining the meridian transits, and the right afcenfions of the fixed stars.

In Chap. V. our author confiders the aftronomical quadrant. The telescope is moveable, and contains a fyftem of wires in the principal focus of the object-glafs. The limb is extended a

few