the pill but gave it to his dog. The man, having swallowed his, fell into a profound sleep: during which he seemed much agitated by dreams. The dog was affected in a similar manner. When the man awoke, he congratulated Gassendi on the favorable reception he had met with from his sable highness. It was with difficulty Gassendi convinced him that the whole was a dream, the effect of soporific medicines, and that he had never stirred from one spot during the whole night. 4. That diseases, especially the night-mare, the hypochondria, hysteric passion, and madness, are another source of spectres, we have the strongest reason to affirm. Persons subject to the nightmare often imagine that they see spectres. This is still more the case with hypochondriac and hysteric persons, and those who are in any degree deranged in their intellects. Instances in proof of this we need not quote, as every person connected with these unfortunate people must have met with proofs of it. 5. Drunkenness also has the power of creating spectres. Its natural effect in most cases is to derange the understanding, to throw it off its guard, and to give full scope to that passion which has a natural disposition to gain an ascendancy; and sometimes it excites passions which scarcely seem to exist at any other time. It makes some men licentious, some furious, some all benevolence and kindness, some from being cowards it renders undaunted heroes. It seldom, if ever, excites fear; and therefore it may be thought strange that men should imagine they see ghosts when intoxicated. But it must be remarked that the ghosts which the drunkard sees, he sees not with the same alarn and terror as men who are sober. He is not afraid of them. He has the courage to converse with them, and even to fight with them, if they give him provocation. A man returning home intoxicated affirmed that he had met with the devil; and that after a severe encounter he had vanquished him and brought him to the ground, to which he had nailed him fast by driving his staff through his body. Next morning the staff was found stuck with great violence into a heap of turfs! 6. Many apparitions of spectres have no other origin than the artifices of the waggish or self-interested. Dr. Plot, in his Natural History of Oxfordshire, relates a marvellous story, to which the doctor gave full credit, but which after all turned out to be the invention of the memorable Joseph Collins of Oxford, otherwise called Funny Joe, who having hired himself as secretary to the commissioners under the name of Giles Sharp, by knowing the private traps belonging to the house, and by the help of pulvis fulminans and other chemical preparations, and letting his fellow servants into the scheme, carried on the deceit without discovery to the very last; insomuch that Dr. Plot, in his Natural History, relates the whole for fact, and concludes in this grave manner : That though tricks have been often played in affairs of this kind, many of the things above related are not reconcileable with juggling; such as the loud noises, beyond the power of man to make without such instruments as were not there; the tearing and breaking the beds; and throwing about the fire; the hoof treading out the candle; and the striving for the SPECULARIA, among the Romans, were a kind of window casements, used before glass was introduced for this purpose. They consisted of transparant stones, called lapides speculares. See below. SPECULARIS LAPIS, in the old system of mineralogy, a genus of talcs, composed of large plates visibly separate and of extreme thinness; and each fissile again separated into a number of plates still finer. See TALC. Of this genus there are three species:-1. The white shining specularis with large and broad leaves, commonly called isinglass and Muscovy glass; its lamella, or leaves, are extremely thin, elastic, and transparent; it makes not the least effervescence with .quafortis; and is not easily calcined in the fire. It is imported in great quantities; the miiature-painters cover their pictures with it; the antern-makers sometimes use it instead of horn; and minute objects are usually preserved between two plates of it for examination by the microscope. 2. The bright brown specularis with broad leaves; a very valuable species though inferior to the former. 3. The purple bright specularis with broad leaves, which is the most elegant of all the talcs, and not less beautifully transparent than the first kind. The lapis specularis is found in many parts of the world. The island of Cyprus abounds with it. It is very common also in Russia, and has of late been discovered to abound in the Alps, the Appennines, and many of the mountains of Germany. The ancients used it, instead of glass, in their windows.-Hill's History of Fossils, p. 72. Some consider the lapis specularis to have been a species of gypsum, and composed of the acid of vitriol and calcareous earth. It came into use at Rome in the age of Seneca (Ep. 90), and, soon after its introduction, was applied not only to give light to apartments, but to protect fruittrees from the severity of the weather; and it is recorded that the emperor Tiberius was enabled, principally by its means, to have cucumbers at his table during almost every month in the year. Dr. Watson apprehends it is still used in some countries in the place of glass; however, it is well known that it was so used in the time of Agricola, for he mentions (De Nat. Fos., lib. v., p. 257) two churches in Saxony which were lighted by it. Agricola esteemed it to have been a species of plaster-stone; and in speaking of it he remarks that, though it could bear, without being injured, the heat of summer and the cold of winter, yet the largest masses of it were wasted by the rain. However, it differs from plaster-stone in this property, that it does not, after being calcined and wetted with water, swell and concrete into a hard stony substance.-Watson's Chemical Essays, vol. ii. p. 297, &c. SPECULATE, v. n. & v. a. SPECULATION, n. s. SPECULATIVE, adj. SPECULATIVELY, adv. SPECULATOR, N. s. Fr. speculer; Lat. speculor. To meditate; contemplate; to take a view of any thing with the mind; consider attentively: speculation is examination; power of sight; mental view or scheme: speculative is contemplative; theoretic; notional: the adverb corresponding a speculator is an observer, or one who forms new theories. This is a consideration not to be neglected, or thought an indifferent matter of mere speculation. Lesley. In all these things being fully persuaded, that what they did, it was obedience to the will of God, and that all men should do the like; there remained, after speculation, practice whereunto the whole world might be framed. Hooker. If all other uses were utterly taken away, yet the mind of man being by nature speculative, and delighted with contemplation in itself, they were to be known even for mere knowledge sake. They who have, as who have not, whom their great stars Id. Throne and set high? servants Thy bones are marrowless; thy blood is cold; Shakspeare. Some take it for a speculative platform, that reason and nature would that the best shouid govern, but nowise to create a right. Bacon's Holy War. Consider the quantity, and not speculate upon an intrinsical relation. Digby on Bodies. Thenceforth to speculations high or deep I turned my thoughts; and with capacious mind Considered all things visible. Milton. Man was not meant to gape or look upward, but to have his thoughts sublime; and not only behold but speculate their nature with the eye of the understanding. Browne. Although lapidaries and questuary enquirers affirm it, yet the writers of minerals, and natural speculators, conceive that stones which bear this name to be a mineral concretion. Id. The SPECULUM for reflecting telescopes is made of a kind of white copper consisting of thirty-two parts fine red copper, one of brass, fifteen of grain tin, and three of white arsenic. The process given by the late J. Edwards, who was rewarded by the Board of Longitude for disclosing it to the public, is that generally followed still, and is thus given in the Nautical Almanac for 1787:-Melt the copper in a large crucible, employing some black flux composed of two parts of tartar and one of nitre; when melted add it to the brass and silver. Let the pure be melted in another crucible. Stir the whole well with a dry spatula of birch, and pour off the fused metal immediately into a large quantity of cold water. The sudden chill of the water will cause the fluid metal to divide into an infinite number of small particles, which will cool instantly. 2. If the copper be completely saturated, the fracture of one piece of this mixed metal will appear bright and of a glossy look, resembling the face of pure quicksilver. But if it is of a brown reddish color it wants a little more tin. To ascertain the required proportion melt a small quantity, known by weight, of the mixed metal with a known very small part of tin; and, if necessary, repeat the trial with different doses till the fracture of the new mixture looks as already described. Having now ascertained the necessary addition of tin that is required, proceed to the last melting of the whole metal, together with the additional proportional dose of tin; fuse the whole, observing the same cautions as before, and you will find that the mixture will melt with a much less heat than that for the first fusion. Have ready as many ounces of white arsenic in coarse powder as there are pounds in the weight of the metal; wrap up the arsenic in a small paper, and put it, with a pair of tongs, into the crucible; stir it well with the spatula, retaining the breath to avoid the arsenical fumes or vapors (which, however, are not found to be hurtful to the lungs), till they disappear; take the crucible off the fire, clear away the dross from the top of the metal, pour in about one ounce of powdered resin, with as much nitre, to give the metal a clean surface, and pour out the metal into the moulded flasks. 3. The speculum should be moulded with the coucave surface downwards, and many small holes should be made through the sand upwards to discharge the air. The moulding sand from Highgate near London, used by the founders, is as good as any for casting these metallic mirrors. See TELESCOPE. The cast metal should be taken out from the sand of the flasks as soon as it has become solid, and while it is yet red-hot, and the face must be kept downwards to prevent it from sinking. Holding it in that position by the git, force out the sand from the hole in the middle of the mirror with a piece of wood or iron, and place the speculum in an iron pot with a large quantity of hot ashes or small coals, so as to bury the speculum in them a sufficient depth. If the sand is not forced out of the hole, in the manner above directed, the metal, by sinking as it cools, will embrace the sand in the middle of the speculum so tight as to crack before it becomes entirely cold. And if the metal is not taken out of the sand, and put in a pot with hot ashes or coals to anneal it, the moisture from the sand will always break the metal. Let the speculum remain in the ashes till the whole is become quite cold. The git may be easily taken off by marking it round with a common fine half-round file, and giving it then a gentle blow. The metal is then to be rough ground and figured. Another composition.-Another has been employed with great success by Rochon, director of the marine observatory at Brest. Of this composition the principal ingredient is platinum; but we think it unnecessary to add any farther description of Rochon's process, as the high price of platinum will, in all probability, for ever prevent it from coming into general use for the speculums of telescopes. For the grinding of the speculum a very complicated process is recommended in Smith's Optics, and one not much more simple by Mr. Mudge, in the sixty-seventh volume of the Philosophical Transactions: but according to Mr. Edwards, whose speculums are the best, neither of these is necessary. Besides a common grindstone all the tools that he made use of were a rough grinder, which serves also as a polisher, and a bed of hones. When the speculum was cold he ground its surface bright on a common grindstone, previously brought to the form of the gage, and then took it to the rough grinder. This tool is composed of a mixture of lead and tin, or of pewter, and is made of an elliptical form, of such dimensions that the shortest diameter of the ellipse is equal to the diameter of the speculum, and the longest diameter is to the shortest in the proportion of ten to nine. This rough grinder may be fixed upon a block of wood, in order to raise it higher from the bench; and, as the metal is ground upon it with fine emery, a hole or pit must be made in the middle of it as a lodgement for the emery, and deep grooves be cut out across its surface with a graver for the same purpose. By means of a handle, fixed on the back of the metal with soft cement, the speculum can be whirled round upon this grinder so rapidly that a common laborer has been known to give a piece of metal, four inches in diameter, so good a face and figure as to fit it for the hones in the space of two hours. When the metal is brought to a true figure it must be taken to a convex tool, formed of stones from Edgedon in Shropshire, between Ludlow and Bishop's Castle. The common blue hones, used by many opticians for this purpose, will scarcely touch the metal of Mr. Edward's speculums; but where they must be employed, for want of the others, as little water should be used as possible when the metal is put upon them; because they cut better when but barely wet than when drenched with water. The stones, however, from Edgedon are greatly preferable; for they cut the metal more easily, and, having a very fine grain, they bring it to a smooth face. These stones are directed by Mr. Mudge to be cemented in small pieces upon a thick round piece of marble, or of metal made of tin and lead like the former composition, in such a manner that the lines between the stones may run. straight from one side to the other; so that placing the teeth of a very fine saw in each of these divisions, they may be cleared from one end to the other of the cement which rises between the stones. As soon as the hones are cemented down, this tool must be fixed in the lathe, and turned as exactly true to the gage as possible. It should be of a circular figure, and but very little larger than the metal intended to be figured upon it. Mr. Edwards recommends it to be made about one-twentieth part longer in diame ter than the speculum, because he has found that it does not then alter its focus; and he dissuades the use of much water on the hone pavement at the time of using it. When the metal is brought to a very fine face and figure by the bed of stones it is ready to receive a polish, which is given to it by the elliptical rough grinder covered with pitch. With respect to the consistency of this pitch Mr. Mudge and Mr. Edwards give very different directions. Whilst the former says that it should be neither too hard nor too soft, the latter affirms that the harder the pitch is the better figure it will give to the metal. Pitch may be easily made of a sufficient hardness by adding a proper quantity of resin; and, when it is hardened in this way, it is not so brittle as pitch alone, which is hardened by boiling. Mr. Edwards advises to make the mixture just so hard as to receive, when cold, an impression from a moderate pressure of the nail of one's finger. When the elliptical tool is to be covered with this mixture it must be made pretty warm, and every where of about the thickness of half-acrown; and to give it the proper form it must, when somewhat cool, be pressed upon the face of the mirror, which has first been dipped in cold water, or covered over with very fine writing paper. All the superfluous pitch is now to be taken away from the edge of the polisher with a penknife, and a hole to be made in the middle accurately round with a conical piece of wood. This hole should go quite through the tool, and should be made of the same size, or somewhat less than the hole in the middle of the speculum. Mr. Edwards says that he has always found that small mirrors, though without any hole in the middle, polish much better, and take a more correct figure, for the polisher's having a hole in the middle of it. The polisher being thus formed it must be very gently warmed at the fire, and divided into several squares by the edge of a knife. These, by receiving the small portion of metal that works off in polishing, will cause the figure of the speculum to be more correct than such squares had been made. Mr. Mudge directs the polisher to be strewed over with very fine putty; but Mr. Edwards prefers colcothar of vitriol. Putty, says he, gives metals a white no lustre, or, as workmen call it, a silver hue; but good colcothar of vitriol will polish with a very fine and high black lustre, so as to give the metal finished with it the complexion of polished steel. The colcothar of vitriol should be levigated between two surfaces of polished steel, and wrought with a little water; when it is worked dry add a little more water. When the colcothar has been wrought dry three or four times it will acquire a black color, and will be sufficiently fine to give an exquisite lustre. This levigated colcothar must be put into a small phial and kept with some water upon it. When it is to be used, every part of the pitch-polisher must be first brushed over with a fine camel's hair brush, which has been dipped in pure water, and rubbed gently over a piece of dry clean soap. The washed colcothar of vitriol is then to be put upon the polisher, in a large quantity at once, so as to saturate the pitch and form a fine coating. With respect to the parabolic figure to be given to the mirror, Mr. Edwards assures us that a very little experience in these matters will enable any one to give it with certainty, by polishing the speculum in the common manner, only with cross strokes in every direction, upon an elliptical tool of the proper dimensions. Mr. Edwards, in a letter to Dr. Maskelyne, published since his directions thus given, makes the following addition to his former directions, which, as it is short, we will here subjoin. 6 Make the brilliant composition first of copper and tin. Melt the proportional quantity of silver and brass in a small crucible by itself. When you put the brilliant composition the second time into the crucible, add also the lump of brass and silver melted together before in a separate crucible; and, when the whole is now fluid, add the proportional quantity of arsenic, and then pour it off into the flasks, after the scoria is taken off, and a little powdered resin is thrown into it.' The reason assigned is, that as copper requires more heat to melt it than either silver or brass does, if the brass were put into the high heat of melting copper, its lapis calaminaris would calcine, which will not be the case when the ingot is made liquid by the lower heat of the second melting. The best fuel that Edwards found for melting the metal was coal-coke, as prepared by the malsters, which casts no smoke, and is more lasting than charcoal: he also found that the blueish hue of crown-glass, used for the eye-piece, best corrects the yellowish color of objects, as shown by a speculum, and particularly when No. 47 is the composition chosen. In trying the figure of the great speculum, Mr. Edwards rejects the diaphragms of Mr. Mudge as unnecessary, and adopts a more simple method, thus: when the specula and eye-piece are in their places, he fixes a circle (of white paper probably) of half an inch, or an inch in diameter, at the distance of from fifty to 100 yards, and gives it a broad black annular margin, by way of contrast; then, when the telescope is adjusted nicely to distinct vision thereby, the screw that moves the small mirror must be turned either way, until a dark haze surrounds the circle, or field of view, which will become broader and broader the farther the screw is turned; now, if the haze is more distinct, and the edge of it better defined, when the screw turns to the right hand, or brings the small speculum nearer, from the point of distinct vision, than when the motion is in a contrary direction, the figure of the great speculum is spherical; but if, on the contrary, the edge of the haze is better defined by the opposite motion, then the figure is hyperbolical; and, lastly, if, at equal distances on each side of the true focal point, the appearance of the haze is the same, the figure is known to be properly parabolic, and fit for its office. The small speculum, in the Gregorian construction, being placed to receive converging rays from the large one, is required to be spherical, as we have before said; but in the Newtonian construction it is made plane, and of an oval shape, to reflect the rays to the eye, placed at an angle of 90°. Mr. Edwards says he received his instruction how to grind and polish one of these from his friend Dr. Herschel, when he lived at Bath. To grind one of the elliptical specula flat, a small tool of lead with emery is first used, and then two or more considerably larger ones are used; both the tools and bed of hones should not be less than six inches in diameter. The figure of the tools is not considered to be completed till the speculum can be first highly finished upon one of them, and afterwards be applied to another, without receiving any change: the last half dozen strokes should be in the direction of the longer axis of the ellipsis. When this is perfected, it must be polished upon the pitch-polisher, of a circular form, the diameter of which is greater than the transverse axis of the speculum by one-tenth. As Mr. Edwards speaks of Dr. Herschel as his friend, and as the doctor has not, that we know of, yet published the composition of his metal and mode of grinding, polishing, and figuring it, we may conclude that he practises Mr. Edwards's process, and particularly as Mr. Edwards gives us the following information in the postcript of his pamphlet:-Dr. Herschel chiefly makes use of a Newtonian reflector, the focal distance of whose great mirror is seven feet, its aperture 6.25 inches, and powers 227 and 460 times, though sometimes he uses a power of 6450 for the fixed stars. Note, if the metals of a Newtonian telescope are worked as exquisitely as those in Dr. Herschel's seven-feet reflectors, the highest power that such a telescope should bear, with perfect distinctness, will be given by multiplying the diameter of the great speculum by 74; and the focal distance of the single eyeglass may be found by dividing the focal distance of the great mirror by the magnifying power: thus, 6.25 × 74 462, the magnifying 7 X 12 and power; 0.182 of an inch, will be 462 the focal length of the single eye-glass required.' See TELESCOPE. Mr. Little recommends the following proportions:-32 parts of the best bar copper, 4 parts of the brass of pin-wire, 16 of tin, and 14 of arsenic. Silver he rejects, as it has an extraordinary effect of softening the metal; and he found that the compound was not susceptible o the highest polish, unless it was extremely brittle. He first melts the brass, and adds to it about an equal weight of tin. When this mixture is cold, he puts it into the copper, previously fused with black flux, adds next the remainder of the tin, and lastly the arsenic. This mixture he granuates, by pouring into cold water, as Mr. Edwards did, and fuses it a second time for casting. SPECULUM, in surgery, an instrument for dilating a wound, or the like, to examine attentively. See SURGERY. SPEECH, n. s. Sax..гpæcan, to speak. SPEECH LESS, adj. The power of articulate utterance, or of expressing thoughts by words; language; talk; mention: the adjective corresponding. There is neither speech nor language, but their voices are heard among them. Ps. Common Prayer. A plague upon your epileptick visage! Smile you my speeches as I were a fool. Shakspeare. King Lear. What was the speech among the Londoners, Shakspeare. Do you think me a swallow, an arrow, or a burlet? Have I, in my poor and cold motion, the expedition of thought? I speeded hither with the very extremest inch of possibility. Shakspeare. Now if this suit lay in Bianca's power, How quickly should you speed. Make me not sighted like the basilisk: Id. He fell down, foamed at mouth, and was speech- I've looked on thousands, who have sped the better less. I kneeled before him; Id. Twas very faintly he said rise; dismissed me The acts of God to human ears Milton. Cannot without process of speech be told. There is none comparable to the variety of instructive expressions by speech, wherewith man alone is endowed, for the communication of his thoughts. Holder on Speech. He that never hears a word spoken, it is no wonder he remains speechless; as any one must do, who from an infant should be bred up among mutes. Id. A single vision transports them; it finds them in the eagerness and height of their devotion; they are speechless for the time that it continues, and prostrate when it departs. Dryden. Accidence. In speech be eight parts. The constant design of these orators, in all their speeches, was to drive some one particular point. Swift. Though our ideas are first acquired by various sensations and reflections, yet we convey them to each other by the means of certain sounds, or written marks, which we call words; and a great part of our knowledge is both obtained and communicated by these means, which are called speech. Watts. There is a prurience in the speech of some, Wrath stays him, or else God would strike them dumb: His wise forbearance has their end in view, Cowper. SPEED, v. n., v. a., & Pret. and part. pass. SPEED'ILY, adv. [n.s.sped and speeded. SPEED'Y, adj. Sax. rpidian; Belg. spoeden. To make haste; move with celerity: succeed to despatch in haste; hasten; assist: as a noun substantive, quickness; celerity; hurry; success: speedy is, quick; nimble; swift: the adverb corresponding. O Lord, I pray thee send me good speed. Genesis xxiv. 12. ' If any bring not this doctrine, receive him not into your house, neither bid him God speed. Peter. By my regard, but killed none so. Id. Winter's Tale. His horse full of windgalls, sped with the spavins, and rayed with the yellows. Shakspeare. He that rides at high speed, and with a pistol kills a sparrow flying. Id. Henry IV. The prince, your son, with meer conceit and fear Of the queen's speed, is gone. Post speedily to your husband, Shew him this letter. Shakspeare. Id. King Lear. How near's the other army' ? -Near, and on speedy foot: the main descry Stands on the hourly thought. Id. He was chosen, though he stood low upon the roll, by a very unusual concurrence of providential events, happened to be sped. Fell. When they strain to their utmost speed, there is still the wonted distance between them and their aims: all their eager pursuits bring them no acquests. Decay of Piety. If prayers Could alter high decrees, I to that place Would speed before thee, and be louder heard. Milton. Satan, toward the coast of earth beneath, Down from the' ecliptick sped with hoped success, Throws his steep flight in many an airy wheel. Id. Earth receives id. As tribute such a sumless journey brought The mightiest still upon the smallest fed. More. Waller. His flying hat, his wings upon his heels. Dryden. The lukewarm blood came rushing thro' the wound. With a speeding thrust his heart he found; With all his harness soon the god was sped; Lucina Id. Reached her midwife hands to speed the throes. Id. |