336 



THE CENTURY BOOK OF FACTS. 



known that the Greeks used magnifiers of glass 

 which they called " reading-glasses," and rude 

 lenses of crystal have been found in Egyptian 

 ruins. 



Mirage. Mirage (sometimes called Fata 

 Morgana} is the appearance in the air of the 

 image of some distant object, seen either in 

 connection with the object itself, above or be- 

 low the latter, or suspended in the air, the ob- 

 ject being invisible. It is a very curious but 

 sufficiently common phenomena, and in the 

 Asiatic and African plains it is frequently 

 observed. When the weather is calm and the 

 ground hot, the Egyptian landscape appears 

 like a lake, and the houses look like islands in 

 the midst of a widely-spreading expanse of 

 water. This causes the mirage, which is the 

 result of evaporation, while the different tem- 

 peratures of the air strata cause an unequal re- 

 flection and refraction of light, which give 

 rise to the mirage. Travelers are frequently 

 deceived, but the camels will not quicken their 

 usual pace until they scent water. 



The Fata Morgana and the inverted images 

 of ships seen at sea are not uncommon on Eu- 

 ropean coasts. Between Sicily and Italy this 

 phenomenon is seen in the Sea of Reggio with 

 fine effect. Palaces, towers, fertile plains, with 

 cattle grazing on them, are seen, with many 

 other terrestial objects, upon the sea the 

 palaces of the Fairy Morgana. The inverted 

 images of ships are frequently perceived, and 

 many most extraordinary but perfectly authen- 

 tic tales have been related concerning the re- 

 flection and refraction of persons and objects 

 in the sky and on land, when no human beings 

 nor any of the actual objects were within the 

 range of vision. 



Mirrors. In ancient times mirrors were 

 made of metal ; those of the Jewish women of 

 brass ; mirrors of silver were introduced by 

 Praxiteles, 328 B. C. Mirrors or looking- 

 glasses were made at Venice, -A. D. 1300 ; and 

 in England, at Lambeth, near London, in 

 1673. The French excelled in their manu- 

 facture of them in the last century. Various 

 methods of coating glass by a solution of silver, 

 thus avoiding the use of mercury, so injurious 

 to the health of the workman, have been made 

 known, by M. Petitjean, in 1851 ; by M. Cimeg, 

 in 1861, and by Liebig and others. 



Mother-of -Pearl. The shells of many 

 molluscous animals display a brilliant pearly 

 and iridescent luster, resulting from the peculiar 

 manner in which the layers of calcareous 

 matter of which they are composed have been 

 successively formed. Such shells, even when 

 small in size, form bright and, especially to 

 the untutored eye, attractive ornaments, and 

 as such are used for necklaces and similar 



purposes. When the shells are of sufficient 

 size to cut and shape for purposes of utility, 

 they become articles of some commercial 

 importance under the name of Mother-of- 

 Pearl. This term, though applicable to all 

 pearly shells, is in commerce principally 

 applied to the shells of the bi-valve pearl 

 mussel, which is the principal source of the 

 commercial product. 



The largest and steadiest consumption of 

 mother-of-pearl is in the button trade, and 

 much is also consumed by cutlers for handles 

 of fruit and dessert knives and forks, pocket- 

 knives, and other forms of cutlery. It is also 

 used in the inlaying of Japanese and Chinese 

 lacquers, European lacquered papier-mache 1 

 work, trays, toys, and as an ornamental inlay 

 generally. In an innumerable variety of 

 small and fancy articles, mother-of-pearl is 

 also employed, its use being limited only by 

 the moderate dimensions and thickness of 

 material obtained, and its rather brittle 

 nature. 



The carving of pilgrim shells, and the 

 elaboration of crucifixes and ornamental work 

 in mother-of-pearl is a distinctive industry of 

 the monks and other inhabitants of Bethlehem. 

 Among the South Sea Islands the shell is 

 largely fashioned into fishing hooks, a purpose 

 for which its brilliant, conspicuous appearance 

 seems to render it suitable without the addi- 

 tion of any bait or other lure. 



Music. Lucretius ascribes its invention 

 to the whistling of the winds in hollow reeds. 

 Franckinus, to the various sounds produced by 

 the hammers of Tubal-Cain ; Pontique and 

 others to the ringing of birds ; and Zarlino to 

 the sound of water. It is however agreed that 

 music was first reduced to rules by Jnbal, 1800 

 B. C. The flute and harmony or concord in 

 music was invented by Hyagnis, 1506. Vocal 

 choruses of men are first mentioned 56 B. C. 

 The first six musical notes are said to have 

 been invented by Guy Aretino, a Benedictine 

 monk of Arezzo, about 1025. The notes of 

 present use were perfected in 1338. Musical 

 pitch was settled in France in 1859. Pythago- 

 ras maintained that the motion of the twelve 

 spheres must produce delightful sounds ' inau- 

 dible to mortal ears, which he called the music 

 of the spheres. Saint Cecilia, a Roman lady, 

 is said to have excelled so eminently in music, 

 that an angel was enticed from the celestial re- 

 gions by the fascinating charms of her melody ; 

 this hyperbolical tradition has been deemed 

 sufficient authority to make her the patroness 

 of music. She died in the third century. 



Nails. It is only since 1810 that machin- 

 ery has been employed to any extent in the 

 manufacture of nails. Previous to that date, 



