family of Proclidæ. See SPARTA. He died after a long and successful reign, during which the Messenian war was carried on, about A. A. C. 723. THEOR'BO, n.s. Fr. tuorbe; Ital. tiorba. A large lute for playing a thorough bass, used by the Italians. He wanted nothing but a song, And a well tuned theorbo hung Upon a bough, to ease the pain Butler. His tugged ears suffered, with a strain. THEOREM, n. s. Fr. theoreme; Greek THEOREMATIC, adj. Ο θεωρημα. A position THEOREMATICAL, laid down as truth; THEOREM'IC. comprised of or relating to theorems. Having found this the head theorem of all their discourses, who plead for the change of ecclesiastical government in England, we hold it necessary that the proofs thereof be weighed. Hooker. The chief points of morality are no less demonstrable than mathematicks; nor is the subtilty greater in moral theorems than in mathematical. More's Divine Dialogues. Many observations go to the making up of one theorem, which, like oaks fit for durable buildings, must be of many years growth. Graunt. Here are three theorems, that from thence we may draw some conclusions. Dryden's Dufresnoy. Theoremick truth, or that which lies in the conceptions we have of things, is negative or positive. Grew. Her thoughts were theorems, her words a problem, as if she deemed that mystery would ennoble 'em. Byron. A THEOREM, mathematically, is a proposition which terminates in theory, and which considers the properties of things already made or done; or it is a speculative proposition deduced from comparing together several definitions. A theorem is something to be proved, and a problem something to be done. THEORIUS, Gr. Otoplog, i. e. clear-sighted. A surname of Apollo, at Trazene.-Lempr. THEORY, n. s. Fr. theorie; Greek THEORETIC, adj. Jewpia. Speculation; THEORETICAL, scheme; plan or sysTHEORETICALLY, adv. tem, yet subsisting THE ORIC, N. S. only in the mind; not practice the adjectives and adverb correspond: theoric is used by Shakspeare for theory. If they had been themselves to execute their own theory in this church, they would have seen, being nearer. When he speaks, Hooker. The air, a chartered libertine, is still; Wherein the toged consuls can propose Bacon's Natural History. The theorical part of the inquiry being interwoven with the historical conjectures, the philosophy of colours will be promoted by indisputable experiments. Boyle on Colours. THEOSOPHISTS, from Orog, God and copia, wisdom, a fanatical sect of philosophers, who rose about the end of the sixteenth century, and pretended to derive all their knowledge from divine illumination. They ascribed this to the singular manifestation of divine benevolence, that they were able to make such a use of the element of fire, in the chemical art, as enabled them to discover the essential principles of bodies. Hence they were also called Fire-Philosophers. One of their chief leaders and ornaments was the celebrated Paracelsus, from whom they were called Paracelsists. THEOXENIA, a festival held annually in all the cities of Greece, but chiefly at Athens, in honor of all the gods. THERAMENES, a celebrated Athenian general, patriot, and philosopher. He defeated the Megarians, and suppressed a tumult in Athens; but the Athenians being at last completely subjugated by the Spartans, who demolished their walls and subjected them to thirty tyrants, all under Spartan influence, except Theramenes, who was the only one of the thirty that stood up for his country. The rest abused their power in the most cruel and arbitrary manner. Theramenes's patriotic opposition to these tyrants only ended in his own death. It is said that when he drank the bowl of poison, he But drank to the health of Critias, his accuser, but along with that compliment he imprecated a curse on the tyrant, which was soon after fulfilled. THERAPEUTE, a term that has been variously applied to those that are occupied wholly in the service of religion. A Jewish sect was so called from the extraordinary purity of its religious worship. With a kind of religious phrenzy, they placed their whole felicity in the contemplation of the Divine nature; and, detaching themselves wholly from secular affairs, transferred their property to their relations or friends, and withdrew into solitary places. How long this sect continued is uncertain; but it is not improbable that, after the appearance of Christianity in Egypt, it soon became extinct. THERAPEUTIC, adj. Gr. Jepaπevtikos. Curative; teaching or endeavouring the cure of diseases. The practice and thrapeutick is distributed into the conservative, preservative, and curative. Harvey. Therapeutick or curative physick restoreth the patient into sanity, and taketh away diseases actually affecting. Browne. Medicine is justly distributed into prophylactick, or the art of preserving health; and therapeutick, or Watts. the art of restoring it. THERAPNE, an ancient town of Laconia, on the west bank of the Eurotas, where Apollo Be ye therefore very courageous to do all that is written in the law, that ye turn not aside therefrom, to the right hand or to the left. Jos. xxiii. 6. Wide is the gate, and broad is the way that leadeth to destruction, and many go in thereat. Matt. vii. 13. We have forsaken all and followed thee, what shall we have therefore? Id. xix. 27. He hopes to find you forward, Shakspeare. Those which come nearer unto reason find a paradise under the equinoctial line, judging that thereunder might be found most pleasure, and the greatest fertility. Raleigh. The matter is of that nature, that I find myself unable to serve you therein as you desire. Bacon. Though we shall have occasion to speak of this, we will now make some entrance thereinto. All things without, which round about we see, We seek to know, and have therewith to do. Id. Davies. Between the twelfth of king John, and thirty-sixth Peter called to mind the word that Jesus said; of king Edward the third, containing one hundred and when he thought thereon he wept. and fifty years or thereabouts, there was a continual bordering war. Mark xiv. 72. As they were much perplexed thereabout, two men stood by. Luke xxiv. 4. Let not them that are in the countries enter thereinto. Luke. Id. Though grants of extraordinary liberties made by a king to his subjects do no more diminish his greatness than when one torch lighteth another, yet many times inconveniencies do arise thereupon. Id. on Ireland. Being come to the height, they were thereby brought to an absolute necessity. Within ourselves, we strangers are thereto. Id. Davies. When you can draw the head indifferently well, proportion the body thereafter. Peacham. Id. Id. Considering how the case doth stand with this present age, full of tongue and weak of brain, behold we yield to the stream thereof. Hooker. Every errour is a stain to the beauty of nature; for which cause it blusheth thereat, but glorieth in the contrary. Id. Some parts of our liturgy consist in the reading of the word of God, and the proclaiming of his law, that the people may thereby learn what their duties are towards him. Id. There have been that have delivered themselves from their ills by their good fortune or virtue. Id. Dare to be true; nothing can need a lie ; Herbert. There are delivered in holy scripture many weighty arguments for this doctrine. White. In human actions there are no degrees described, but a latitude is indulged. Bishop Taylor. Therewithal the execrable act Daniel. The leaves that spring therefrom grow white. Mortimer. He blushes, therefore he is guilty. Spectator. If the paper be placed beyond the focus, and then the red colour at the lens be alternately intercepted and let pass, the violet on the paper will not suffer any change thereby. Newton. Exiled by thee from earth to deepest hell, Pope. Solon finding the people engaged in two violent factions, of the poor and the rich, and in great confusion thereupon, made due provisions for settling the balance of power. Swift. The wrestlers sprinkled dust on their bodies to give better hold: the glory therefore was greater to conquer without powder. West's Pindar. THERESIENSTADT, or MARIEN THERESIENSTADT, a large town of the south of Hungary, in the palatinate of Bacs. In fact it is an assemblage of villages, consisting of perhaps 3000 cottages, inhabited by 22,000 inmates, partly of Servian, partly of Rascian descent. They depend for their support chiefly on the extensive town lands, the total extent of which is said to be 340 square miles. The town is open, but has large barracks, a Catholic church for the Servians, a Greek for the Rascians, and a Franciscan monastery for Catholics; these complete the list of its public buildings. Theresienstadt has a pretty active traffic in cattle, horses, wool, and hides. THERIACAL, adj. Gr. Inpiaka; Lat. the riaca. Medicinal; physical. The virtuous bezoar is taken from the beast that feedeth upon the mountains where there are theriacal herbs. Bacon. THERMÆ, hot baths or bagnios. Luxury and extravagance were in nothing carried to such heights as in the therma of the Roman emperors. Ammian complains that they were built to such an extent as to equal whole provinces; from which Valesius would abate, by reading piscinæ instead of provinciæ. And yet, after all, the remains of some still standing are sufficient testimonies for Ammian's censure; and the accounts transmitted of their ornaments and furniture, such as being laid with precious stones (Seneca), set round with seats of solid silver (Pliny), with pipes and cisterns of the same metal (Statius), add to, rather than take from, the censure. The most remarkable bagnios were those of Dioclesian and Caracalla at Rome, great part of which remain at this day; the lofty arches, stately pillars, variety of foreign marble, curious vaulting of the roofs, great number of spacious apartments, all attract the curiosity of the traveller. They had also their summer and winter baths. See BATHING. THERME SELINUNTIE, an ancient town of Sicily, near Selinus, famous for its hot baths; now called Sciacca. See SCIACCA. THERMÆUS SINUS, a bay of Macedon, on the coast of Therma or Thessalonica, afterwards called Sinus Macedonicus.-Strabo. THERMIDOR, the eleventh month in the Revolutionary French calendar. It begins on the 19th July, and ends on the 17th August. THERMODON, a river of ancient Boeotia, near Tanagra, called also Hæmon.-Strabo 11. THERMODON Or THERMODOON, a river of Cappadocia in the country of the Amazons; running into the Euxine Sea, near Themiscyra. It is now called Termeh. His heat raises the liquor in the thermometrical tubes. Cheyne. THERMOMETER. This instrument was invented about the beginning of the seventeenth century; but, like many other useful inventions, it has been found impossible to ascertain to whom the honor of it belongs. Boerhaave ascribes it to Cornelius Drebbel of Alcmaer, his own countryman. Fulgenzio attributes it to his master Paul Sarpi, the great oracle of the Venetian republic; and Viviani gives the honor of it to Galilæo. But all these are posthumous claims. Sanctorio claims this honor to himself; and his assertion is corroborated by Borelli and Malpighi, of the Florentine academy, whose partiality is not to be suspected in favor of a member of the Patavinian school. Perhaps the best way to reconcile these different claims would be to suppose that the thermometer was really invented by different persons about the same time. A common thermometer consists of a tube terminated at one end by a bulb, and closed at the other. The bulb and part of the tube are filled with a proper liquid, generally mercury, and a scale is applied, graduated into equal parts. Whenever this instrument is applied to bodies of the same temperature, the mercury being similarly expanded, indicates the same degree of heat. In dividing the scale of a thermometer, the two fixed points usually resorted to are the freezing and boiling of water, which always takes place at the same temperature, when under the same atmospheric pressure. The intermediate part of the scale is divided into any convenient number of degrees; and it is obvious that all thermometers, thus constructed, will indicate the same degree of heat when exposed to the same temperature. In the centigrade thermometer this space is divided into 100°; the freezing of water being marked 0°, the boiling point 100°. In this country we use Fahrenheit's scale, of which the 0° is placed at 32° below the freezing of water, which, therefore, is marked 32°, and the boiling point 212°, the intermediate space being divided into 180°. Another scale is Reaumur's, the freezing point is 0°, the boiling point 80°. These are the principal thermometers used in Europe. It may be proper to state that the spirit of wine thermometer is usually employed for very low temperatures, as mercury may be frozen in the atmosphere; whilst mercury, on the contrary, is best calculated for high temperatures, as its point of ebullition is little short of a red heat. The Royal Society, fully apprised of the importance of adjusting the fixed point of thermometers, appointed a committee of seven gentlemen to consider of the best method for this purpose; and their report is published in the Phil. Trans. vol. LXVII., part ii., article 37. They observed that, though the boiling point be placed so much higher on some of the thermometers now made than on others, yet this does not produce any considerable error in the observations of the weather, at least in this climate; for an error of 1° 30′, in the position of the boiling point, will make an error only of half a degree in the position of 92°, and of not more than a quarter of a degree in the point of 62°. It is only in nice experiments, or in trying the heat of hot liquors, that this error in the boiling point can be of much importance. In adjusting the freezing as well as the boiling point, the quicksilver in the tube ought to be kept of the same heat as that in the ball. When the freezing point is placed at a considerable distance from the ball, the pounded ice should be piled to such a height above the ball that the error which can arise, from the quicksilver in the remaining part of the tube not being heated equally with that in the ball, shall be very small, or the observed point must be corrected on that account according to the following table: The correction in this table is expressed in 1000th parts of the distance between the freezing point and the surface of the ice: e. g. if the freezing point stands seven inches above the surface of the ice, and the heat of the room is 62°, the point of 32° should be placed 7 × 00261, or '018 of an inch lower than the observed point. A diagonal scale will facilitate this correction. The committee observe that, in trying the heat of liquors, care should be taken that the quicksilver in the tube of the thermometer be heated to the same degree as that in the ball: or, if this cannot be done conveniently, the observed heat should be corrected on that account; for the manner of doing which, and a table calculated for this purpose, we must refer to their excellent report in the Phil. Trans., vol. LXVII., part ii., article 37. With regard to the choice of tubes, they ought to be exactly cylindrical. But, though the diameter should vary a little, it is easy to manage that matter in the manner proposed by the abbe Nollet, by making a small portion of the quicksilver, e.g. as much as fills up an inch or half an inch, slide backward and forward in the tube; and thus to find the proportions of all its inequalities, and thence to adjust the divisions to a scale of the most perfect equality. The capillary tubes are preferable to others, because they require smaller bulbs, and they are also more sensible, and less brittle. The most convenient size for common experiments has the internal diameter about the fortieth or fiftieth of an inch, about nine inches long, and made of thin glass that the rise and fall of the mercury may be better seen. The next thing to be considered is of what number of degrees or divisions the scale ought to consist, and from what point it ought to commence. As the number of the divisions of the scale is an arbitrary matter, the scales which have been employed differ much from one another in this circumstance. Fahrenheit has made 180° between the freezing and boiling water point. Amontons made 73°, and sir Isaac Newton only 34°. There is, however, one general maxim, which ought to be observed: that such an arithmetical number should be chosen as can easily be divided and subdivided, and that the number of divisions should be so great that there shall seldom be occasion for fractions. The number eighty, chosen by Reaumur, answers extremely well in this respect, because it can be divided by several figures without leaving a remainder; but it is too small a number: the consequence of which is that the degrees are placed at too great a distance from one another, and fractions must therefore be often employed. We think therefore that 160 would have been a more convenient number. Fahrenheit's number 180 is large enough; but, when divided, its quotient soon becomes an odd number. As to the point at which the scale ought to commence, various opinions have been entertained. If we knew the beginning or lowest degree of heat, all philosophers would agree that the lowest point of the thermometer ought to be fixed there; but we know neither the lowest nor the highest degrees of heat; we observe only the intermediate parts. All that we can do then is to begin it at some invariable point, to which thermometers made in different places may easily be adjusted. If pos sible, too, it ought to be a point at which a natural well known body receives some remarkable change from the effects of heat or cold. Fahrenheit began his scale at the point at which snow and salt congeal. Kirwan proposes the freezing point of mercury. Sir Isaac Newton, Hales, and Reaumur, adopted the freezing point of water. The objection to Fahrenheit's lowest point is that it commences at an artificial cold never known in nature, and to which we cannot refer our feelings; for it is what few can ever experience. There would be several great advantages gained, we allow, by adopting the freezing point of mercury. It is the lowest degree of cold to which mercury can be applied as a measure; and it would render unnecessary the use of the signs plus and minus, and the extension of the scale below 0. But we object to it that it is not a point well known; for few, comparatively speaking, who use thermometers, can have an opportunity of seeing mercury congealed. As to the other advantage to be gained by adopting the freezing point of mercury, namely the abolition of negative numbers, we do not think it would counterbalance the advantage to be enjoyed by using a well known point. Besides, it may be asked, Is there not a propriety in using negative numbers to express the degree of cold, which is a negative thing? Heat and cold we can only judge of by our feelings: the point then at which the scale should commence ought to be a point which can form to us a standard of heat and cold; a point familiar to us, from being one of the most remarkable that occurs in nature, and therefore a point to which we can with most clearness and precision refer in our minds on all occasions. This is the freezing point of water chosen by sir Isaac Newton, which of all the general changes produced in nature by cold is the most remarkable. It is therefore the most convenient point for the thermometers to be used in the temperate and frigid zones; we may say over the globe, for even in the hottest countries of the torrid zone many of the mountains are perpetually covered with snow. The principal thermometric scales in Europe are, as we have already stated, Fahrenheit's, which commences at the temperature produced by mixing snow and salt, and which is 32° below the freezing of water, so that the latter point is marked 32°, and the boiling point 212°, the intermediate space being divided into 172°; Reaumur's, in which the zero is the freezing point, and 80° the boiling point; and the centigrade, in which the space between the freezing and boiling of water is divided into 100°. Each degree of Fahrenheit's scale is equal to four-ninths of a degree on Reaumur's; if, therefore, the number of degrees on Fahrenheit's scale, above or below the freezing of water, be multiplied by four, and divided by nine, the quotient will be the corresponding degree of Reaumur. Fahrenheit. Reaumur. 16°. 80°. 68° 32° 36 X 4 1449 212° 32° 180 × 4 7209 To reduce the degrees of Reaumur to those of Fahrenheit, they are to be multiplied by nine, and divided by four. VOL. XXII, 80° x 9 = 720 ÷ 4 = 180 + 32°; =212. Fahrenheit. 100 × 9= 9005180 x 32 = 212°. M. Bellani has proved, by reference to direct experiment, that a mercurial thermometer made in the usual manner, and the freezing point of water marked on it from experiment, if it be laid aside awhile, and again plunged in melting ice, the mercury will stand higher than before; and that if it be put aside again, and then again tried, the mercury will be higher still, until, at the end of a certain time, a year or so, the effect of elevation will cease. It was found, from numerous experiments, that the result was not influenced by the various qualities of the glass used in the instrument; by the more or less perfect exclusion of air from the bulb or tube; by the constant horizontal, perpendicular, or inverted position of the instrument; by the open or closed extremity; by the longer or shorter time of remaining in the ice; or by the compression of the surrounding ice. Neither was it found to be peculiar to mercurial thermometers, but was exhibited by alcohol thermometers, though in a less degree. M. Bellani at last ascertained that the effect was due to a gradual and slow contraction of the glass after having been highly heated, which contraction, as long as it continued, diminished the bulk of the instrument, and consequently forced the fluid into the tube. This effect he illustrates in the following manner :-Take a Florence flask, or any similar thin glass vessel, such as a matrass with a long narrow neck, shortly after it has come from the glass furnace, it not having been annealed in the oven; introduce shot or sand into it till it almost sinks in water, seal it hermetically, and draw out one part of the neck until not more than a line in diameter, that part being about an inch in length; fasten a small basin on the top of the neck with wax, and then, putting the instrument in water of a certain temperature, 40° Fahrenheit, for instance, put weights in the cup till the surface of the water is at the middle of the narrow part of the neck; then lay the instrument aside for some days, or better still some weeks or months, and, after that time, again immerse it in the same water at the same temperature and pressure, and with the same weight; the instrument will now sink lower than before, in consequence of its diminished bulk from gradual contraction of the glass. It was found that, although the effect was greatest after the glass had been rendered soft by heat, yet that it occurred also when the elevation of temperature had not extended nearly to the softening of the glass, and indeed more or less upon every rise of temperature. Hence two kinds of irregularity in thermometers arise from the same cause. The one is manifested soon after the formation of the instrument, increases to a certain |