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going theorems, the complement of the altitude if not previously known, will render this operawill be 81° 32' 30', and Pd the distance from the tion very inaccurate. pole being 109° 5', and the horary distance from 94. But the most exact way for taking the dethe meridian, or the angle d P Z, 36o.
clination of a plane, or finding a meridian line, To log. sin. 74° 51' -1.98464
by this instrument, is, in the forenoon, about two Add log. sin. 36° 0' -1.76922
or three hours before twelve o'clock, to observe
two or three heights or altitudes of the sun; and And from the sum -1.75386
at the same time the respective angular polar Take the log. sin. 81° 32' -1.99525
distances. Write these down; and in the after
noon watch for the same, or one of the same altiRemains -1.75861 = log.sin. tudes, and mark the angular distances or dis 35°, the azimuth distance sought.
tance on the quadrant; the division or degree 91. When the altitude is given, find from exactly between the two noted angular distances thence the hour, and proceed as above. This will be the true meridian, and the distance at praxis is of singular use on many occasions; as,
which it may fall from the centre of the divi1. In finding the declination of vertical planes sions, will be the declination of the plane. The more exactly than in the common way, especially reason for observing two or three altitudes and if the transits of the sun's centre are observed by angles in the morning is, that in case there applying a ruler with sights, either plain or tele- should be clouds in the afternoon, we may have scopical, to the wall or plane whose declination the chance of one corresponding altitude. is required. 2. In drawing a meridian line, and
OF THE RIGHT PLACING OF DIALS. finding the magnetic variation. 3. In finding the bearings of places in terrestrial surveys; the
95. The plane on which the dial is to rest transits of the sun over any place, or his hori- being duly prepared, and every thing necessary zontal distance from it, being observed; together for fixing it, you may find the hour with tolera with the altitude and hour; and thence deter- ble exactness by a large equinoctial ring-dial, mining small differences of longitude. 4. In ob- and set your watch to it. And then the dial serving the variations at sea, &c.
may be fixed by the watch at your leisure.
96. If you would be more exact, take the OF FINDING THE Declination, Inclination, sun's altitude by a good quadrant, noting the AND RECLINATION OF Planes.
precise time of observation by a clock or watch.
Then compute the time for the altitude observed; 92. The declination, inclination, and reclina- and set the watch to agree with that time, action of planes are frequently taken with a suffi- cording to the sun. Hadley's quadrant is very cient degree of accuracy by an instrument called convenient for this purpose: for by it you may the declinator or declinatory:
take the angle between the sun and his image 92.* The construction of this instrument, as reflected from a basin of water; the half of somewhat improved by Mr. Jones, is thus : On which angle, subtracting the refraction, is the a mahogany board is inserted a semicircular arch altitude required. of ivory or box-wood, divided into two quadrants 97. This is best done in summer; and the of 90° each, beginning fronı the middle. On the nearer the sun is to the prime vertical, the east or centre of this arch turns a vertical quadrant, west azimuth, when the observation is made, so which is divided into 90°, beginning from the much the better. Or, take two equal altitudes of base; on which is a moveable index, with a the sun in the same day; one any time between small hole for the sun's rays to pass through, seven and ten in the morning, the other between and form a bright spot on a certain mark. The two and five in the afternoon; noting the moments lower extremity is pointed, to mark the linear of these two observations by a clock or watch: direction of the quadrant when applied to any and if the watch shows the observations to be at other plane; as this quadrant takes off occa- equal distances from noon, it agrees exactly with sionally, and a plumb-line hangs at the centre, the sun: if not, the watch must be corrected by for taking the inclinations and reclinations of half the difference of the forenoon and afternoon planes. On the plane of the board is inserted a intervals; and then the dial may be set true by compass of points and degrees, with a magnetical the watch. needle turning on a pivot over it. See Decli 98. For example, suppose you had taken the NATORY.
sun's altitude when it was twenty minutes past 93. The addition of the moveable quadrant VIII in the morning by the watch; and found, and index considerably extend the utility of the by observing in the afternoon, that the sun had declinator, by rendering it convenient for taking the same altitude ten minutes before IV; then equal altitudes of the sun, the sun's altitude, and it is plain, that the watch was five minutes too bearing, at the same time, &c. To apply this fast for the sun : for five minutes after XII is instrument in taking the declination of a wall or the middle time between VIII h. 20 m. in plane : Place the back part of it in a horizontal the morning, and III h. 50 m. in the afterdirection to the plane proposed, and observe noon; and, therefore, to make the watch agree what degree or point of the compass the N. part with the sun, it must be set back five minutes. of the needle stands over from the north or the 99. In many cases, where the situation is south, and it will be the declination of the plane suitable, it is very desirable to have a true merifrom the north or south accordingly. In this dian line for the regulation of clocks and watches; case, allowance must be made for the variation we shall, therefore, here insert Mr. Ferguson's of the needle (if any) at the place; and which, method of constructing one.
Make a round hole, about a quarter of an inch through the small hole in the plate. And always, diameter, in a thin plate of metal; and fix the for some time before the observation is made, plate in the top of a south window, in such a the plummet ought to be immersed in a jar of manner that it may recline from the zenith at an water, where it may hang freely; by which means angle equal to the colatitude of your place, as the line will soon become steady, which otherDearly as you can guess: for then the plate will wise would be apt to continue swinging. face the sun directly at noon on the equinoctial days. Let the sun shine freely through the hole Of The Double HorizonTAL, THE BABYLONIAN into the room; and hang a plumb-line to the
AND ITALIAN Dials. ceiling of the rooin, at least five or six feet from the window, in such a place as that the sun's 100. Sometimes a stereographic projection of rays, transmitted through the hole, may fall upon the hour circles, and the parallels of the sun's the line when it is noon by the clock; and hav- declination, is added to the gnomonic projection, ing marked the said place on the ceiling, take on the same horizontal plane; the upright side of away the line.
the gnomon being sloped into an edge, standing Having adjusted a sliding bar to a dovetail perpendicularly over the centre of the projection: groove, in a piece of wood about eighteen inches so that the dial, being in its due position, the long, and fixed a hook into the middle of the shadow of that perpendicular edge is a vertical bar, nail the wood to the above-mentioned place circle passing through the sun, in the stereoon the ceiling parallel to the side of the room in graphic projection. The months being duly which the window is; the groove and the bar marked on this dial, the sun's declination, and being towards the floor: then hang the plumb- the length of the day at any time, are had by inline upon the hook in the bar, the weight or spection; as also his altitude, by means of a plummet reaching almost to the floor; and the scale of tangents. But its chief property is, that wbole will be prepared for further and proper it may be placed true, whenever the sun shines, adjustment.
without the help of any other instrument. This done, find the true solar time by either of 101. The Babylonian and Italian dials reckon the last two methods, and thereby regulate your the hours, not from the meridian as with us, but clock. Then, at the moment of the next noon by from the sun's rising and setting. Thus, in Italy, the clock, when the sun shines, move the sliding an hour before sun-set is reckoned the twentybar in the groove, until the shadow of the plumb- third hour; two hours before sun-set the twentyline bisects the image of the sun, made by his second hour; and so of the rest. And the shadow rays transmitted through the hole, on the floor, that marks them on the hour-lines, is that of the wall, or on a white screen placed on the north point of a stile. This occasions a perpetual variaside of the line; the plummet at the end of the tion between their dials and clocks, which they line hanging freely in a pail of water placed bo- must correct from time to time, before it arises to low it on the floor.- But because this may not be any sensible quantity, by setting their clocks so quite correct for the first time, on account that much faster or slower. And in Italy, they begin the plummet will not settle immediately, even in their day, and regulate their clocks, not from sunwater; it may be farther corrected on the follow- set, but from about mid-twilight, when the Ave ing days, by the above method, with the sun and Maria is said ; which corrects the difference that clock; and so brought to a very great exactness. would otherwise exist between the clock and the
The rays transmitted through the hole will dial. The improvements which have been made cast but a faint image of the sun, even on a white in all sorts of instruments and machines for meascreen, unless the room be so darkened that no suring time, have rendered these dials of little sunshine may be allowed to enter but what comes account.
IN DE X.
AHAZ'S DIAL, the most ancient on record, 2.
DIALLING, defined, 1. History of, 2. 7. Illustra
tion of its principles, 18. 24. By the globe, 25. 38.
By spherical trigonometry, 68–91.
by them, 42.
North, 46. East, 47. West, 48. Universal, 49. 53. Declination, &c. of, 92. Right placing of, 95. Double horizontal, 100. Babylonian, 101.
BABYLONIAN DIALS, 100.
CLAVIUS, the first writer on the art of dialling, 6.
DECHALES, a writer on dials, 6.
East Dials, 47.
FERGUSON, Mr. James, a writer on dialling, 7. His
method of making a meridian line, 99.
GLOBE, terrestrial, dialling by, 25.
PICARD's method of dialling, 6. GNOMONS, a universal dial with several,
PLACING of dials, 95.
PLANES, declinations, &c. of, 92-94. Hire, M. De La, his method of dialling, 6. HORIZONTAL Dials, 11. Construction of one, 28. Quirinus, the firs Roman Q.al erccted at the temple 44. Double, 100.
of, 5. HOUR CIRCLE, defined, 14, 15. Hour Lines, geometrical method of drawing, 44
RECLINATION of planes, 92. 94. 47.
RECLINING DIALS, 13.
ROMANS, not early acquainted with dials, 5.
South DIAL, construction of a, 45.
STILE of a dial, 9. ITALIAN DIALS, 100, 101.
STURMIUS, a writer on dialling, 7.
SUBSTILE of a dial, 9. Its distance from the meriLONDON, how to construct a dial for the meridian of,
dian, 16. Its place, 35. How to find its distance, 28.
36, 37. MARTIUS PHILIPPUS, erects a dial at Rome, 5.
Thales, a diallist, 3.
TRIGONOMETRY, Spherical, dialling by, 68.
VALERIUS MESSALA erects a dial at Rome, 5.
VerticAL DIALS, 11.
UNIVERSAL DIALS, description and use of, 49. 58. OZANAM, a writer on dialling, 6.
WELPERUS. a writer on dialling, 6. PAPIRIUS CURSOR, the first Roman diallist, 5. WEST DIAL, construction of a, 48. PATERSON, a writer on dialling, 7.
WOLFIUS, a writer on dialling, 6.
DIALLING in a mine, called also plumbing, The Tuscan language is greatly admired for its is the using of a compass, which the miners call elegance, and the meanest inhabitants of Florence dial, and a long line to know which way the load speak a dialect which the rest of Italy are proud to
Johnson. or vein of ore inclines, or where to shift an airshaft, or bring an adit to a desired place.
Dialect is an appellation given to the lan DIALLING LINES, or DIALLING Scales. See guage of a province, in so far as it differs from DIALLING, Index.
that of the whole kingdom. The term is parDialling Sector is a sector having upon it, ticularly used in speaking of the ancient Greek, besides other lines, the dialling lines, the con
whereof there were four dialects, each of which struction of which is shown under DIALLING. was a perfect language in its kind, that took It is evident that some advantage will be ob- place in certain countries. In Great Britain, tained in the practice of dialling by having the besides the two dialects of English and Scotch, line placed on a sector. See Sector.
almost every county has a dialect of its own, all Dialling Sphere, is an instrument made of differing considerably in pronunciation, accent, brass, with several semicircles sliding over one and tone, although one and the same language. another, on a moving horizon, to demonstrate the DIALECTICS, in the literary history of the nature of the doctrine of spherical triangles, and ancients, that branch of logic which taught the to give a true idea of the drawing of dials on all rules and modes of reasoning. See Logic. Zeno manner of planes.
Eleates was the first who discovered the natural DIALLING Trigon, an instrument invented by series of principles and conclusions observed in Mr. Benjamin Martin, consisting of two graduated reasoning, and formed an art thereof in form of scales and a plane, used by some in the practice a dialogue; which, for this reason, was called of dialling.
dialectica. The dialectica of the ancients is DI'ALECT, n. s.
Fr. dialecle; Span. dia- usually divided into several kinds: The first was lecto; Ital. dialetto; Lat. dialectus; Gr. dialer
the eleatica, that of Zeno Eleates, which was Too, from dia and lėyw, to speak. Language; and contentionum. The first consisting of rules
threefold; viz. consecutionum, colloqutionum, style; the mode of expression peculiar to a certain district.
for deducing or drawing conclusions. The When themselves do practise that whereof they such universal use in philosophy, that all reason
second, the art of dialogue; which became of write, they change their dialect; and those words they shun, as if there were in them some secret sting.
ing was called interrogation: then, syllogism
Hooker. being laid aside, the philosophers used dialogue, In her youth
and required the respondent to conclude and There is a prone and speechless dialect, argue from the several concessions made. The
last part of Zeno's dialectics, episun, was conShakspeare. Measure for Measure. tentious, or the art of disputing and contradicting; If the conferring of a kindness did not bind the though some, particularly Laertius, ascribe this person upon whom it was conferred to the returns of part to Protagoras a disciple of Zeno. gratitude, why, in the universal dialect of the world, The second is the dialectica megarica, whose are kindnesses still called obligations ? South. author is Euclid, as of Megara. He gave much
Such as moves men,
into the method of Zeno and Protagoras; though case as a cementto hold the stones together. Thay there are two things appropriated to him: the wore bracelets and other ornaments about their first, that he impugned the demonstrations of dress : and their cups and table-furniture were others, not by assumptions, but conclusions; of the same kind. The green stones were found continually making illations, and proceeding to succeed best, and the emerald and chrysolite from consequence to consequence: the second, were most in esteem for this purpose. Pliny that he set aside all arguments drawn from com says of them: Nihil jucundius aurum decet, parisons of similitude as invalid. He was suc Nothing becomes gold better.' ceeded by Eubulides, from whom the sophistic DIAL'OGIST, n. s. 3 Gr. διαλογος; δια way of reasoning is said to be derived. In his
Di'ALOGUE, n. s. & v. n. I and loyos, a word. time the art is described as manifold : mentiens, A speaker in a conference; a conference or confallens, electra, obvelata, arcevalis, cornuta, and versation between two or more persons. Το calva. See Sophism.
hold a conference. The third is the dialectica of Plato, which he
Will you hear the dialogue that the two learned proposes as a kind of analysis to direct the hu
men have compiled in praise of the owl and cuckow ? man mind, by dividing, defining, and bringing
Shukspeure. things to the first truth; where being arrived, it
Dost dialogue with thy shadow ? applies itself to explain sensible things, but with
Timon. a view to return to the first truth where alone it
In easy dialogues is Fletcher's praise ; can rest. Such is the idea of Plato's analysis. He moved the mind, but had not power to raise. The fourth is Aristotle's dialectica: containing
Dryden. the doctrine of simple words, delivered in his
With the stars book of Prædicaments; the doctrine of propo And the quick Spirit of the Universe sitions, in his book De Interpretatione; and He held his dialogues ; and they did teach that of the several kinds of syllogism, in his
To him the magic of their mysteries. Byron. books of Analytics, Topics, and Elenchuses. DIALYSIS, in grammar, a mark or character,
The fifth is the dialectica of the Stoics; which consisting of two points (-) placed over two they call a part of philosophy, dividing it into vowels, because otherwise they would make a rhetoric and dialectic; to which some add the diphthong, as Mosaic, Phaeton, &c. definitive, whereby things are justly defined ; DIAMASTIGOSIS, a festival of Sparta, in comprehending likewise the canons or criterions honor of Diana Orthia, which received that name of truth. The Stoics, before they treat of
ano rov uasıyovv, from whipping, because boys syllogisms, have two principal places; the one were whipped before the altar of the goddess. about the signification of words, the other about These boys, called Bomonicæ, were originally the things signified. On occasion of the first, free-born Spartans, but in the more delicate ages they consider abundance of things belonging to they were of mean birth, and generally of a slathe grammarian's province: what, and how vish origin. This operation was performed by many letters; what is a word, diction, speech, an officer in a severe and unfeeling manner; and &c. On occasion of the latter, they consider that no compassion should be raised, the priest things themselves, not as without the mind, but stood near the altar with a small light statue of as in it, received in it by means of the senses. the goddess, which suddenly became heavy and Accordingly, they first teach, that nil sit in in- insupportable if the lash of the whip was less ritellectu, quod non prius fuerit in sensu ; 'what- gorous. The parents of the children attended ever is in the mind came thither by the senses;' the solemnity, and exhorted them not to show and that aut incursione sui, as Plato, who meets themselves, either by fear or groans, unworthy of the sight; aut similitudine, as Cæsar hy his Laconian education. These flagellations were effigy; aut proportione, either by enlarging as a so severe, that the blood gushed in profuse torgiant, or by diminishing as a pygmy; aut trans rents, and many expired under the lash of the latione, as a Cyclops; aut compositione, as a whip, without uttering a groan, or betraying any Centaur; aut contrario, as death; aut privatione, marks of fear. Such a death was reckoned very as a blind man.
honorable, and the corpse was buried with much The sixth is Epicurus's dialectica : who had solemnity with a garland of flowers on its head. recourse to certain canons, the collection whereof The origin of this festival is unknown. Some be called Canonica ; and as all questions in phi- suppose that Lycurgus first instituted it to inure losophy are either de re or de voce, he gave the youth of Lacedemon to bear labor and faseparate rules for each.
tigue, and render them insensible to pain and DIALECTICK, n. s. Alalektien. Logic; wounds. Others inaintain, that it is a mitigation the art of reasoning. See Dialect.
of an oracle, which ordered that human blood DIALEC'TICAL, adj. Logical ; argumen- should be shed on Diana's altar; and according tative.
to their opinion, Orestes first introduced that Those dialectical subtleties, that the schoolmen barbarous custom, after he had brought the staemploy about physiological mysteries, more declare tue of Diana Taurica into Greece. There is the wit of him that uses them, than increase the another tradition which mentions that Pausanias, knowledge of sober lovers of truth.
Boyle. as he was offering prayers and sacrifices to the DIALITHA, in the writings of the ancients, gods, before he engaged with Mardonius, was a word used to express the elegant ornaments suddenly attacked by a number of Lydians who of the Greeks and Romans, composed of gold disturbed the sacrifice, and were at last repelled and gems. They also called these lithocellawith staves and stones, the only weapons with cemented stones or gems; the gold being in this which the Lacedemonians were provided at that
moment. In commemoration of this, therefore, Lop a bough of a tree, and one shall behold the grain the whipping of boys was instituted at Sparta, thereof (by some seret cause in nature) diamonded ani after that the Lydian procession.
or streaked in the fashion of a lozenge. Fuller. DIAM'ETER, n. s.
Gr. διά and μετ
Certainly the price and virtue of things consist not DIAM'ETRAL, adj. pov,
a measure. The
in the quantity: one diamond is more worth than DIAM'ETRALLY, adv. line which, passing many quarries of stone. Bp. Hall. Contemplations, DIAMET'RICAL, adj. through the centre of The diamond is by mighty monarchs worn, DIAMETÓRICALLY, adv.) a circle, or other cur
Fair as the star that ushers in the morn.
Blackmore. vilinear figure, divides it into equal parts. Di
The lively diamond drinks thy purest rays, ametral and diametrical is describing or
Collected light, compact.
Thomson. relating to a diameter; also, in a figurative sense, directly opposite; or perhaps, to the
Shakspeare opens a mine which contains gold and
diamonds in inexhaustible plenty, though clouded by greatest length opposed, as are the points of a circumference touched by the ends of a diameter. with a mass of meaner minerals.
incrustations, debased by impurities, and mingled
Johnson. Diametrally and diametrically are also synony
The Diamond is a genus of siliceous earths, mous.
called adamas gemma by the Latins, demant by The space between the earth and the moon, accord. the Germans and Swedes, and diamant by the ing to Ptolemy, is seventeen times the diameter of French, and is the hardest of all stones hitherto the earth, which makes, in a gross account, about one
discovered. See ADAMAS. It was thought by hundred and twenty thousand miles. Raleigh.
the ancients that the diamond became soft He made an instrument to know
and malleable, by steeping it in hot goat'sIf the Moon shine full or no.
blood. Diamonds are found only in the East Tell what her diameter to an inch is,
Indies, and in Brasil in South America. The And prove that she's not made of green cheese.
diamond mines are in GoLCONDA, V15APOUR,
BENGAL, and the island of BORNEO. See these He persuaded the king to consent to what was dia articles.' In the mines of Golconda are found a metrically against his conscience and his honour, and, great number of stones from ten to forty carats, in truth, his security.
and upwards; and it was here that the famous Christian piety is, beyond all other things, diame diamond of Aurengzebe, the great mogul, was trally opposed to profaneness and impiety of actions.
found, which before it was cut weighed 793 ca
rats. The stones of this mine are not very clear; Thus intercepted in its passage, the vapour, which their water is usually tinged with the quality of cannot penetrate the stratum diametrically, glides the soil : being black where that is marshy ; red along the lower surface of it, permeating the horizon- where it partakes of red; and sometimes green tal interval, which is betwixt the said dense stratum and that which lies underneath it. Woodward.
and yellow, where the ground is of these colors.
Another defect is a kind of greasiness appearing That the longer diameter of an ellipsis may be shortened, till it shall differ little from a circle, is of its lustre. There are usually not fewer than
on the diamond, when cut, which takes off part indisputably true.
60,000 persons, men, women, and children, at DIAMETER. The line, which passing through work in this mine. When the miners have found the centre of a circle, or other curvilinear figure, a place where they intend to dig, they level anodivides it into equal parts. The impossibility ther somewhat bigger near it, and enclose it with of expressing the exact proportion of the diame- walls about two feet high, leaving apertures from ter of a circle to a circumference, by any re
space to space, to give passage to the water. ceived way of notation, and the absolute neces. They dig twelve or fourteen feet deep, and till sity of bringing it as near the truth as possible, they find water. Then they cease, and the water has induced some of the most celebrated men thus found serves to wash the earth two or three in all ages to endeavour to approximate it. The times, after which it is let out at an aperture first who attempted it with success was the ce- reserved for that purpose. This earth being well lebrated Van Cuelen, a Dutchman, who, by the washed and dried, they sift it in a kind of open ancient very laborious method, carried it to thirty- sieve, as we do corn; then thresh it, and sift it six decimal places; these he ordered to be en- afresh; and lastly, search it well with the hands graven on his tomb-stone, thinking he had set to find the diamonds. The miners work naked, bounds to improvement. However, the indefa- except that they have a thin linen cloth before tigable Abraham Sharp carried it to seventy-five them. They have also inspectors, to prevent places in decimals; and since that time it has their concealing diamonds; which, however, been carried much further.
they frequently do, by swallowing them when DI'AMOND, n. s.
Fr. and Dut. diamant; not observed. Di'AMONDED, adj. ) Ital. Span. and Port. dia Diamonds are commonly clear and pellucid, mante ; Teut. demünt, from Lat
. adamas, adaman- yet some are met with of a rose color, or inclintis ; Gr. aðapas, adapavros, i. e. a privative, ing to green, blue, or black, and some have black and dapağw to subdue, because too hard to break specks. Tavernier saw one in the treasury of or mould into shape. See the article below. A the mogul, with black specks in it, weighing precious stone. Diamonded is, shaped like a about fifty-six carats; and he informs us, that diamond.
yellow and black diamonds are produced in the I see how thine eye would emulate the diamond : mines at Carnatica. Mr. Dutens also relates, thou bast the right arch ben brow.
that he saw a black diamond at Vienna in the Shakspeare. collection of the prince de Lichtenstein. Some