OPERA. 



305 



specific gravity, 2-091. The present species is 

 treated of by many mineralogical writers under that 

 of quartz ; while others have subdivided its varieties 

 into numerous species. The chief of these varieties, 

 sub species, or species, as they have been regarded 

 by different authors, are, 1. noble opal, which exhi- 

 bits brilliant and changeable reflections of green, 

 blue, yellow, and red ; 2. fire opal, which simply 

 affords a red reflection; 3. common opal, whose 

 colours are white, green, yellow, and red, but 

 without the play of colours ; 4. semi-opal, the 

 varieties of which differ fcom those of common opal 

 in being more opaque ; 5. wood opal, which appears 

 in the shape of trunks, branches, and roots of trees ; 

 6. hydrophone, a variety without transparency, but 

 assuming it if thrown into water ; 7. hyalite, which 

 occurs in small reniform, botryoidal, and sometimes 

 stalactitic shapes, and is transparent ; 8. menilite, 

 which occurs in tuberose masses, and is opaque ; 9. 

 siliceous sinter, which is merely a deposit from a hot 

 spring. Three varieties of opal, 1. hyalite, analyzed 

 by Bucholz, 2. precious opal, and 3. menilite, both 

 analyzed by Klaproth, have yielded, 



Silica 1. 92'00 

 Water 6-33. 



2. 90-00. 

 10. 



3. 85-50. 

 II. 



The last contains, like several other varieties, a small 

 proportion of iron, alumina, lime, and carbon. 

 Before the blow-pipe, water is disengaged, the 

 mineral decrepitates and becomes opaque, and shows 

 the properties of pure silica. Opal is less frequently 

 met with in nature than quartz. Generally it forms 

 short, irregular veins, which, for the most part, are 

 found in porphyry. It accompanies calcedony in the 

 vesicular cavities of amygdaloidal rocks, and even in 

 agate balls. Menilite is found in adhesive slate. 

 Some varieties are met with in metalliferous veins, 

 and in petrifactions in sandstone. Almost the only 

 locality of precious opal known is at Czarwenitza, in 

 Hungary, where it is found in porphyry. Lately, it 

 has been met with in the Faroe islands, and also near 

 Gracias a Dios, in South America. Fire opal comes 

 from Zimapan, in Mexico. Common opal is found 

 in large quantity in Hungary, Saxony, and the Faroe 

 islands. An apple-green variety is found at Kohe- 

 mutz, in Silesia, which is called chloropal. Hyalite 

 is found in amygdaloidal rocks in Bohemia and 

 Hungary, and also in the United States, in Georgia, 

 lining cavities in the buhr-stone. Menilite occurs 

 imbedded in adhesive clay at Mevil Moutant, near 

 Paris. Wood opal is found at Kremnitz and Telko- 

 banya, in Hungary, and in many districts of Transyl- 

 vania. Precious opal is considered as a very precious 

 gem, and is generally cut with a convex surface. Its 

 value depends upon its size, purity, and the vivid 

 colours which it possesses. The phenomenon of the 

 play of colours has not hitherto been satisfactorily 

 explained. According to Hauy, it is the consequence 

 of fissures in the interior filled with thin films of air, 

 which reflect coloured light, according to the law of 

 Newton's coloured rings. If this were the fact, 

 opal would present nothing else but a kind of iri- 

 descence, and the beauty of opal would be owing, as 

 Hauy expresses it, only to its imperfections. But 

 these colours often keep constant directions within 

 single parts of the mass ; and in specimens not cut 

 in the usual convex form, but presenting even faces, 

 it is often possible to observe distinct images reflected 

 exactly as in the moonstone, or in corundum. The 

 play of colours, seems, therefore, to be connected 

 wkh the regular structure of the mineral. 



OPERA. The opera is a musical drama. The 



music makes an essential part of it ; and in this it is 



distinguished from other dramas accompanied by 



music. Song and music may be said to be the poetry 



v. 



of the opera, and, though the opera remains a drama, 

 and never ought to lose this character, yet, as music 

 is lyrical, the opera must be principally directed to 

 the expression of feelings and passions. Compara 

 lively little display of character and action can be 

 expected from it. An opera, like every work of art, 

 must bear the stamp of unity ; one character must 

 prevail through the whole, as the solemn and grave 

 in Mozart's Magic Flute (though there are naif pas- 

 sages interspersed in it,) or the glowing, vivid colour- 

 ing of Figaro, or the heroic elevation of G luck's 

 Alceste. It is further necessary to give individuality 

 of character by means of the music, and the lyrical 

 monologues (airs, cavatine, ar/osos) and dialogues 

 (duettos, terzette, &c.) must alternate in pleasing 

 variety. But our limits do not allow us to give a 

 description of the various parts requisite to these 

 exquisite productions. According as the serious or 

 the comic character prevails in the opera, it is termed 

 opera seria or opera buffa. There is also a style 

 mezzo stilo between both, the limits of which it is, 

 of course, impossible to define. Grand opera is the 

 name given to that kind which is confined to music 

 and song. The recitativo is an essential part of this. 

 By operetta is understood a short musical drama of a 

 light character. The Italians have a kind of musical 

 dramas called intermezzo. (See Interlude.) The 

 French vaudeville belongs to this species of compo- 

 sitions, but not the German melodrama, in which 

 music, indeed, is introduced either by itself or in 

 connexion with the dialogue, but no singing takes 

 place. 



Origin of the Italian Opera. About the year 1594, 

 three young noblemen of Florence, who were at- 

 tached to each other by a similarity of tastes and 

 pursuits, and a Jove of poetry and music, conceived 

 the idea of reviving the chanted declamation of the 

 Greek tragedy : they procured the poet Rinuccini to 

 write a drama on the story of Daphne, which was set 

 to music by Peri, the most celebrated musician of the 

 age, assisted by count Giacomo Corsi, who, though 

 only an amateur, was also, for the period, a good 

 musician : the piece, like the Mask of Comus, was 

 privately represented, and in the palace of Corsi. 

 The interlocutors, or singers, were the author and his 

 friends ; and the orchestra of his first opera consisted 

 but of four instruments, viz. a harpsichord, a harp, a 

 viol di gamba, and lute. There was no attempt at 

 airs ; and the recitative if such it could be called 

 was merely a kind of measured intonation, which 

 would appear to us insufferably languid and monoto- 

 nous ; yet it caused, at the time, an extraordinary 

 sensation, and was frequently repeated. Four years 

 afterwards, the first public opera, entitled Euridice, 

 written by the same poet, and set by the same musi- 

 cian, was represented at the theatre of Florence, in 

 honour of the marriage of Mary de' Medici with 

 Henry the Fourth of France. On this occasion, the 

 introduction of Anacreontic stanzas, set to music, and 

 a chorus at the end of each act, were the first imper- 

 fect indications of the airs and choruses of the modern 

 opera. Monteverde, a Milanese musician, improved 

 the recitative, by giving it more flow and expression; 

 he set the opera of Ariadne, by Rinuccini, for the 

 court of Mantua ; and in the opera of Glasone, set 

 by Cavili and Cicoguini, for the Venetians (1649,) 

 occur the first airs connected in sentiment and spirit 

 with the dialogue. According to another story of 

 the origin of the opera, John Sulpitius, about 1486, 

 exhibited little dramas, accompanied with music, in 

 the market-place at Rome, and also before the pope 

 and some cardinals. The commencement of the 

 opera seria at Rome reminds us of the wagon of 

 Thespis and his lees-besmeared company of strollers. 

 The first performance of this kind, consisting of 



