340 



COMEDY COMETS. 



place not only without condensation, but where gase- 

 ous iuaUcr is actually produced from solid mutter. ;is 

 in the inflammation of gunpowder. Besides, the 

 evolution of light, if it were derived from the gas, 

 should be proportional to the quantity solidihed, 

 whcrea- it depends chiefly on the combustible. The 

 first of these objections to Lavoisier's theory, which 

 is yet generally received, h;is been partly removed 

 by modifying the definition so as to extend it to seve- 

 ral other Ixxlies. hence called supporters of coniLiis- 

 ti'i. (See (7i finical Classification anil X<nnrm-luture.) 

 'Hie definition which we have given of this pheno- 

 menon at the beginning of this article is merely a 

 description. The question arises, Whence come the 

 light and heat ? They are generally referred to the 

 condensation which is almost alwaysa necessary con- 

 sequence of a chemical combination ; but we have 

 already seen that, in some cases, they are produced 

 where the component parts actually pass from a so- 

 lid to a gaseous state. It seems probable, in the 

 present state of our knowledge, that they may be at- 

 tributed to the disengagement of the electric fluid. 

 " In every chemical combination," says Berzelius, 

 " there is a neutralization of opposite electricities, 

 and this neutralization produces the heat and light in 

 the same manner as it does in the Leyden jar or the 

 galvanic battery." But to this it may be objected, 

 uiat, if electricity were the cause of the disengage- 

 ment of the heat and light, they would always bear 

 a fixed proportion to each other. This is not the 

 case : the combustion of oxygen and hydrogen dis- 

 engages a very great quantity of caloric, but very 

 little light ; that of phosphorus and oxygen produces 

 opposite results. There is, then, no theory of com- 

 bustion at present received, which will explain all 

 the circumstances of this phenomenon. If there be 

 any one general cause, it must beone which, like af- 

 finity, is modified by the nature of the agents and the 

 peculiar circumstances of their mutual action. 



COMEDY. See Drama. 



COMENIUS, JOHN AMOS, a benefactor of man- 

 kind, by the improvements which he introduced into 

 education, was born March 28, 1592, in the village 

 of Comna, near Brumau, in Moravia ; hence the 

 name which he assumed : his real one is not known. 

 His parents, belonging to the Moravian denomina- 

 tion, had him educated at Herborn. In 1616, he re- 

 ceived an appointment as teacher, in Fulnek, which, 

 in 1618, was plundered by the Spaniards. Comenius 

 lost his papers, and all that he possessed, and fled 

 to Poland, where, in 1632, he was elected bishop of 

 the Moravian and Bohemian Brethren in Lissa. In 

 1631, he published, at Lissa, his Janua Linguarum 

 reserata, a work which was translated, within 

 twenty-six years, into twelve European languages, 

 also into Persian, Arabian, and Mongolian. In 

 this, he laid down a new system for teaching 

 languages to children by the use of visible signs, 

 in order to facilitate the learning of words. His 

 Orbis pictus, or the Visible World, was first pub- 

 lished, in 1659. at Nuremberg. In 1641 he was in- 

 rited to England, in order to introduce a better or- 

 ganization into the schools ; but, as the civil war pre- 

 vented the accomplislunent of this plan, he went to 

 Sweden, where the chancellor Oxenstiern became 

 his patron. In 1656, he returned to Lissa, where he 

 once more lost all his books and manuscripts on the 

 burning of the town after the retreat of Charles X. 

 Comenius died at Amsterdam, Oct 15, 1671. In the 

 latter part of his life, he gave himself up to religious 

 dreams, after the fashion of that time, and revered 

 Bourignon (q. v.) as a prophetess. Adelung gives 

 the number of his works as 92, but there are only 54 

 now extant. 



COME SOPRA (Ital. ; as above or as before) ; an 



allusion to the manner of performing some former 

 passage, the style of which performance has been id- 

 ready denoted. 



COME STA (Ital.; as it stands) ; an expression 

 implying that the performer is not to embellish the 



*>a!>e with any additions of his own. 



COMETS. Of natural appearances, there are few 

 that have been regarded with more superstitious ap- 

 prehensions than those bodies which occasionally ap- 

 pear in the sky, luminous, like the stars, but gener- 

 ally distinguished from these by a tail, or train o ' 

 fainter light, bearing some resemblance to a tuft or 

 lock of liair. Of this, the Latin name is coma, and 

 in consequence, these bodies are called comets, to 

 distinguish them from the other luminaries, which, 

 whether near or remote, apparently fixed or mov- 

 able, have not this train-like accompaniment. Co- 

 mets are one of the three classes into which astrono- 

 mers divide those celestial bodies that adorn the sky 

 during the night. The stars, which retain their re- 

 lative positions with regard to each other, and are at 

 so great distances from the earth, that no means or 

 instruments hitherto invented can measure them, are 

 one class, and a class not apparently connected 

 with our sun, or deriving light or heat from that lu- 

 minary. The planets, which change their relative 

 positions among the stars, and of which our earth is 

 one, form the second class. They are solid bodies, 

 and not luminous in themselves, but shine merely by 

 reflecting the light of the sun. The masses of the 

 planets, their magnitudes, and their motions, have 

 been all determined with the greatest accuracy ; and 

 the place that any one of them will occupy at any 

 proposed point of time, can be calculated with the 

 greatest ease, by any one acquainted with practical 

 astronomy. The planets are, in their motions, go- 

 verned by one uniform law. In the early ages, the 

 planets were held to have certain influences upon in- 

 dividuals and nations. The comets, which are more 

 singular in their fonn, and more varied in the times 

 of their appearance, were still better adapted for su- 

 perstitious purposes ; and, accordingly, we find that 

 their visits have been attempted to be connected with 

 the great, more especially the calamitous, events of 

 nations. The appearance of a comet is, however, no 

 more a prodigy, and has no more influence upon the 

 fate of men or of nations, than the appearance of the 

 moon, or of a deciduous leaf upon a tree in spring. 

 They are so distant, and either their motions are so 

 rapid, or their substance is so rare that none of them 

 have been found to have any material action upon 

 such of the planets as they have come near, although 

 the planets have had a considerable influence upon 

 them. What the comets are, or what purposes they 

 serve in the economy of creation, we do not know. 

 As far as observation has gone, they are subject to 

 the same laws as the planets, revolving about the 

 sun in orbits or paths, with this difference, that their 

 orbits are much more eccentric, or differ much more 

 from circles, than the orbits of the planets ; and thus, 

 while they approach much nearer to the sun at one 

 time of their revolutions, they recede corresponding- 

 ly farther from it at another. The time since men 

 had rational opinions on the subject has, however, 

 been too short for verifying, by observation, the 

 theory as applicable to the whole, or even the greater 

 number of these bodies that have, from time to time, 

 made their appearance. 



Tycho Brahe was the first who expressed a decid- 

 edly rational opinion on the subject of comets. Find- 

 ing, by careful observation, that the comet of 1577 

 had no diurnal parallax, which he could detect, that 

 is, that its place, when viewed from the surface of 

 the earth, was not different from what it would have 

 been if viewed from the centre ; he properly concluded 



