are coming from the South, they are ofen arrested by them, leaving the fpace from thence to the zenith ferene; while to the East and Weft, where no fuch obftacles intervene, all is obfcured by a flying feud. From Eaft to South-eaft the fea is vifible, diftant about ten or twelve miles; a circumftance which, in fome particular cafes, is not without its ufe. But, what is more peculiarly happy, is the opportunity afforded by the light-houfe for obfervations upon terreftrial refractions, both by night and day this light-houfe is about, five miles diftant from the land, and about fifty feet high from the water. In particular fates of the atmosphere, and more efpecially upon approach of fevere weather, the Welsh mountains are diftinctly visible, particularly that ridge of hills which runs South-We&t to Point Braich-y-pwll, and bounds Caernarvon Bay in that direction.

inent.

To proceed to the particulars of this building. Fig. 1 is an elevation of the Eaftern front; and Fig. 2 the groundplan. E is the bafe of a folid pillar, fixteen feet fquare, of the mon folid mafonry, and raifed from the rock to fuch a height, that the centre of the equatorial inftrument, which it is to fupport, may look over every part of the building, and command the whole range of the horizon. This fubftantial pillar is furrounded by a circular wall, at a foot diftance, which is to fupport the turning dome and the floor of the room, which is not fuffered to touch the pillar itfelf, or the piers which arife from it for the fupport of the axis of the inftruAnd, for this purpofe, the floor is framed to as to let the piers pafs through untouched; whence no motion of the floor or furrounding wall can be communicated to the inftrument; and the temperature of the pillar is in fome meafure preferved by the furrounding wall. The turning dome is framed of wood: cach rib confifts of three parallel and equal pieces; the grain of the wood in them being fo difpofed, as to counteract each other's inclination to caft or warp. The frame is covered with canvafs, well foaked in drying-oil, tar, and white paint; and coated afterwards with white paint, wrought up to fuch a confiftence as to require being laid on with a trowel. The infide is covered with another thinner fheeting; and between the two, wood mois, if neceifary, will be introduced, to prevent the tranfmiffion of heat. The aperture for obfer

5

vation is two feet fix inches wide, and opens to fix inches beyond the zenith. As the dome is an hemifphere, the flide. which huts this aperture is made to move vertically through the zenith, with a movement fimilar to that of fome modern writing-tables. The flide paffing through the zenith defcends through the oppofite quadrant of the hemifphere within the dome; but as this flide exceeds ninety degrees of the hemifphere by fix inches, it would be impoffible, in opening the aperture, to make the flide deicend through its own length on the oppofite fide, as the wall-plate muft prevent it before its afcending extremity could reach the zenith. Therefore, to remedy this, a tranfverfe hinge is coutrived in the flide, about eight inches from that extremity, which thus defcends on that end which is next the zenith when the aperture is clofed. This hinge lets the eight hinges hang perpendicular to the horizon, when the flide has rifen fo much on the other fide; and the whole is thus allowed to defcend until the ze nith is laid open to obfervation.

Around this dome there is a platform, commanding one of the most extenfive and varied profpects that can be ima gined. On the South fide it overlooks the grounds of the Earl Bective: with a gentle declivity to the river, and from thence a varied picture of the rich feenery of the woods of the Phoenix Park, terminated in the back ground by the majeftic grandeur of the Wicklow mountains. To the South-eaft is the city of Dublin, diftant four miles, the femicircular bay with the fhipping, and the great South wall extending five miles into the bay, and terminated by the light-houfe: the ridge of rocky hills, called the Three Brothers, forming the head of Dalkey, and bearing Malpas's Oberfk on the highest point of the middle hiil: on the East and North-east, Clontarfe and its environs, the hill of Howth, and the inlands called Ireland's Eye and Lambay: to the North-weft the profpect is to uncommonly level and extenfive, as to gratify the aftronomer much more than the painter. To the South weft are the picturefque ruins at Calle-Knock; and to the Weft, the very extended and rich view of the counties of Meath and Kildare, in which latter Mr. Conolly's obelisk forms a grand and central object.

The room for making obfervations on the meridian is placed to the Weft of the building. In Ireland the Western winds

prevail,

here made as in the Equatorial Dome, to prevent the tranfmiffion of heat.

The fourth wing is defigned for occafional obfervations, fuch as eclipfes, occultations, &c. which, being confined to the planets, require only the range of that part of the hemifphere in which those can at any times be visible. Upon this account the center of the Southern Dome is fo far removed towards the South, that a line drawn from thence to the extremity of the Meridian Room fhall clear the greatest amplitude of any of the planets in this latitude. For, as to comets, they are always moft convenis ently obferved by the equatorial inftruments, and that has the entire horizon at command in this obfervatory

In this Southern wing, F. P. reprefent the basis of two pillars which rife into the dome; and, refting on folid mafonry, unconnected with the floor and furrounding walls, are to fupport a polar axis, carrying an achromatic tele Lcope, to which it is proposed to apply an helioftatic movement, which will carry it round, with an equable motion, in a fidereal day; nor is this a matter of fimple amusement, for many advantages arife from fuch an apparatus. Every practifed obferver is aware of the errors that muft neceffarily arife from the permanency of the effect of light upon the organ of fight. This makes it probable that we do not always fee a ftar in its true place in the field of a fixed telefcope. In the tranfit inftrument, for inftance, the image of the wire does not change its place in the eye, but is permanent; as that of a ftar approaches this wire, the last impreffion remains until the ftar has paffed the wire, and before the new impreffion is fenfible, As to the diftinctnefs of vifion to be expected from it, the following experiment will be fufficient for any perfon who doubts let a line be drawn horizontally upon a wall, at fuch a diftance from a telescope as that the obferver shall be able to read, through it, a tolerably fmall print; let the telescope be directed to a certain point in this line, and a man move a printed paper, having both large and fmall characters, along this line as equally as he can; when the paper comes oppofite the telefcope, the obferver will find that the greater characters alone are diftinct; but let him follow the paper with the telescope, and he will find the fmall characters diftin&t likewife. This in

ftrument promifes alfo the fairest trialto the wire micrometer, which has, I fear, too haftily been laid afide. The Prifmatic, the Caffegrain, the divided object-glafs, the divided eye-glafs mi- crometers, have all their particular difadvantages, deriving error from metaphyfical as well as phyfical fources; not that it is to be inferred that the wire micrometer is unexceptionable.

The dome of the upper room here is fimilar to that of the Equatorial Room, and is defigned for this one inftrument. Two obfervers in the fame room are too many far fuch obfervations as are to be made here. He must be a steady practifed obferver whofe imagination will not be affected when another, with a more perfect inftrument, gives evident figns of his obfervation being completed, while to the former it has not yet taken place. To avoid this inconvenience, the lower room is defigned to permit occafional obfervers to practife; and mafonry is contrived to support other telescopes with proper stability. The Northern wing may be applied to the ufe of a zenith fector, if required, or of a pillar quadrant, if that should be confidered as an expedient measure for determining refractions, and an appara、 tus of mafonry, fimilar to that in the Southern wing, is propofed for occafi onal obfervers.

Thefe are the particulars of the conftruction of this obfervatory, which will be a lafting monument to the honour of its Founder, Dr. Francis Andrews, late provoft, and a memorial to ages of the liberality and zeal of Trinity College.

As a new building is now erecting for the Four fuperior Courts of Justice at Dublin, the old edifice ufed now for thofe Courts, and which was completed in the year 1698, will probably be taken down: in order, therefore, to preferve fome memorial of that building for pofterity, I trouble you with an infide View of it, from the clock near the great gate of entrance to the screen of the Court of Chancery (fee plate 1. fig. 3): A. the area of the Court of King's Bench, with its curtain. B. area of the Court of Common Pleas. C. fcreen of the Court of Chancery. D. door leading into the lane called Hell. E. fteps of the Court of Exchequer. F. fprings of the octangular cupola, over the hall. Yours, &c. J. PRANCER. Vol. LVII. p. 1193, col. 2, l. 11, read “Henry Bruen, eiq.”

Mr.

you, he has no time to retrieve the lofs; and both he and the man of fortune, imagining the difficulties in the way to learning are now infurmountable, fit down in defpair. For encouragement of thefe gentlemen, Mr. Urban, the following additional circumftance or two in the life of Mr. James Collings is fent you by one who was intimate with him from his youth.

Mr. C. after being for a few years partner with Mr. Cox in his flock-office in the Royal Exchange, fucceeded him there. Without ever neglecting bufinefs, he not only read the polite Eng lith and French authors, but ftudied mathematics, natural and moral philofophy. Some ingenious men whom he occafionally met at a bookfeller's, having frequently difcourfed with him there, they agreed to form a little club †, and met once a fortnight, to difcuts the principles of fcience,-fometimes naming a book to be diftinctly canvaffed. If in their debates any ancient claffic was referred to, Mr. C. was at fault, and filent, having never learned a word of Greek or Latin. This leads us to the principal fact.

Mr. C. was now about 40; he daily attended his office at the 'Change, to which he rode nine or ten miles, from his houfe in Fryern-Barnet, and had no leisure but when he returned thither in the evening. Yet, thus circumftanced, he formed a vigorous refolution to learn Latin and Greek. He had, a little be fore, learned Italian by the help of English translations; and now took the fame method to learn Latin. He began with an caly profe author; and in about a year and a half could read not only Cicero, but Salluft and Livy, without any tranflation. Then he took up Ovid and Virgil. He knew nothing of dactyls and fpondees; but catched (to use his own words) a ringing of the numbers in bis ear; and understood the fenfe. Learning profody foon after, he read thofe poets with more pleafure, and proceeded to Horace and the reft. Then he began Greck in the fame manner, the Latin tranflations ferving as the English before. The progrefs he made was amazing. He told a friend (the writer of thefe lines), it was the moft delightful

See our Obituary for Feb. p. 181.

Mr. Collings, Mr. John Canton, and two or three more, were joined afterwards by Dr. Benjamin Franklin, Dr. Richard Price, and others.

purfait he had ever engaged in. There was scarce a celebrated claffic author, Latin or Greek, in profe or verfe, with whom he was not well acquainted. A learned member of the club faid, "Mr. C. has read more of the ancients, and understands them better, than any of us who were taught parfing and conftruction at fchool." Mr. C. ufed to fay, "if he were to renew the task, he would begin with the rudiments, declenfions, conjugations, &c." He was deficient in one point, pronunciation. He underftood metre; but, not having practifed making, fcanning, and capping verfes, he fometimes fpoke a Latin or Greek word with wrong quantity.

A little above twenty years ago, Mr. C. retired from bufinefs, with a handfome fortune, and a character unblemifhed, feafting on the fruits collected by his labour during many preceding years; never at a lofs for rational em ployment; happy in perufing the finest authors, and converfing with learned men, who efteemed him for his improv ing polite converfation, and the perpetual ferenity of his temper.

Now let any gentleman for whole fake this account is given, judge if it be not worth his while to exert himself for attaining fuch intellectual enjoyment, and prevent his finking, in the decline of life, to the infipidity of a faunterer, the ftupidity of a tipler, or the peevithnefs of a humourift. If he have not ambition enough to afpire after ornamental accomplishment, and the honour of being intimate with Horace and Homer, and to become learned, he may acquire great variety (almost every kind) of use. ful knowledge from books in his owe language. As Mr. C. did, let him choose what he will ftudy, and fome knowing friend will tell him what au

thors to read. his books.

Mr. C. had no tutor but

Mr. C. had a tender confumptive conftitution; but by ftrict care and fobriety protracted it beyond his fixty-feventh year. Latterly his fight failed him; but he was not by that lofs deprived of his favourite amufement: his excellent wife relieved his calamity; for the lady read to him any of his books in the learned languages.

School-boys learn from Cicero *, that Cato Major, the rigid Roman Cenfor, learned Greek with eagerness in his old age.

* De Senectute.

Mr.