M E L - M E L 841 media. They pass copiously through rock-salt, he tells us, but ft-cbly through alum, ami hence Melloni concludes that there are amongst the solar rays some which resemble those of terrestrial heat, and in general that the differences observed between solar and terrestrial heat in the transmission of rays are to be attributed merely to the mixture in different proportions of these several species of rays. An instrument like the thermo -multiplier could not of course remain a monopoly, and shortly after its completion we rind Professor James Forbes making use of it to prove the polarization of heat as well as to extend our knowledge of refraction. The brilliant researches of this experimentalist were, like those of Melloni, crowned with the llumford medal of the Royal Society. On September 2, 1839, Arago communicated to the academy of sciences a letter by Melloni, who had found that rock-salt acquires by being smoked the power of transmitting most easily heat of low temperature, or dark heat. Forbes had discovered a similar property in mica split by heat, and he now showed that rock-salt roughened and mica scratched possess similar properties to blackened rock-salt. Melloni on his part took up the subject of polarization, and decided in favour of the equal polari/ability of heat from different sources, a conclusion that did not then appear to Forbes to be in conformity with his experiments. It is very instructive to notice the loyalty which held both these experimentalists to the results of their observations. While Melloni ditfers from Forbes with regard to polarization, he will not allow the truth of a generalization proposed by Ampere, who had endeavoured rise to light. Melloni admits that many phenomena may be ex plained by this hypothesis, but he mentions some experiments in which he thinks that this theory will not hold. The brilliant generalize! from without has of course a different point of view from the laborious experimentalist within. They are all worthy of scientific honour for it is by the seeming conflict, but in reality the united efforts of workers such as these that the essential element of stability in the structure of scientific knowledge is finally secured. MELON (Cucumis Melo, L.), a most polymorphic species of the order Cucurbitacex, the varieties of which are grouped by Naudin under ten tribes, while several other plants of less known characters probably belong to it, 1 The melon is an annual herb with palmately-lobed leaves, and bears tendrils. It is monoecious, having male and female flowers on the same plant. The flowers have deeply five-lobed campanulate corollas and three stamens. Naudin observed that in some varieties (e.g.,oi. Cantaloups) fertile stamens sometimes occur in the female flowers. It is a native of south Asia " from the foot of the Himalayas to Cape Comorin," 2 where it grows spontaneously, but is cultivated in the temperate and warm regions of the whole world. It is excessively variable both in diversity of foliage and habit, but much more so in the fruit, which in some varieties is no larger than an olive, while in others it rivals the ponderous fruits of the gourd (Cucurbita maxima, L.). The fruit may be globular, ovoid, spindle- shaped, or serpent-like, netted or smooth-skinned, ribbed or furrowed, variously coloured externally, with white, green, or orange flesh when ripe, scented or scentless, sweet or insipid, "bitter or even nauseous, &c. Like the gourd, the melon undergoes strange metamorphoses by crossing its varieties, though the latter preserve their characters when alone. The offspring, however, of all crossings are fertile. As remarkable cases of sudden changes produced by artificially crossing races, M. Naudin records that in 1859 the offspring of the wild melons m. sauvage de 1 Inde (G. melo ayreslis) and m. s. d Afrique, le petit m. de Figari (0. maculatus?) bore quite different fruits from their parents, the former being ten to twelve times their size, ovoid, white-skinned, more or less scented, and with reddish flesh; though another individual bore fruits no larger than a nut. The offspring of m. de Figari after being crossed bore fruits of the serpent-melon. On the 1 For generic characters see Benth. et Hook., Gen. PL, i. 826 ; and for a full account of the species of Cucumis and of the tribes of melon, by M. Naudin, see Ann. des Sci. Xat., 4 ser., torn. xi. p. 34. 2 Naudin, I.e., pp. 39, 76; see also Gard. Chron., 1857, p. lu-5, and 1858, p. 130. other hand, the serpent-melon was made to bear ovoid and reticulated fruit. 3 With reference to the early cultivation of the melon, Naudin thinks it is probable that the culture in Asia is as ancient as that of all other alimentary vegetables. The Egyptians grew it, or at least inferior races of melon, which were either indigenous or introduced from Asia. The Romans and doubtless the Greeks were familiar with it, though some forms may have been described as cucumbers. Columella seems to refer to the serpent- melon in the phrase ut coluler . . . venire culat Jlexo. Pliny describes them as 2^ e P nes (xi x - 23 to xx. G) and Columella as melones (xi. 2. 53); see Pickering, Chron. Hist., of PL, 229. The melon began to be extensively cultivated in France in 1629, according to Olivier de Serres. Gerard (Herball, 771) figured and described in 1597 several kinds of melons or pompions, but he has apparently included gourds under the same name. Picker ing observes that the melon was carried by Columbus to America, and by the Portuguese to the Malayan Archi pelago. The origin of some of the chief modern races, such as " Cantaloups," " Dudaim," and probably the netted sorts, is due to Persia and the neighbouring Caucasian regions. The first of these was brought to Ptome from Armenia in the ICth century, and supplies the chief sorts grown for the French markets; but many others are doubtless artificial productions of West Europe. For cultivation of the melon, see art. HOUTICULTUUE, and also Gard. Chron., May 6, 1882, p. 596; and for references to French literature on the same see Naudin, ut supra, p. 82. MELOS (Att. Gr., M^Aos), the modern Milo, one of the Sporades of the ^Egean Sea, situated at the south-west corner of the archipelago, in 3G 45 N. lat. and 24 26 E. long., 75 miles due east from the coast of Laconia. From east to west it measures about 14 miles, from north to south 8 miles, and its area is estimated at 52 square mites. The greater portion is rugged and hilly, and the culminating point, Mount Elias in the wept, reaches a height of 2538 feet. Like the rest of the cluster to which it belongs, the island as a whole is of volcanic origin, with tuff, trachyte, and obsidian among its ordinary rocks. The great natural harbour, which, with a depth diminishing from 70 to 30 fathoms, strikes in from the north-west so as to cut the island into two fairly equal portions, with an isthmus not more than 1J miles broad, is evidently the hollow of the principal crater. In one of the caves on the south coast the heat is still so great that one cannot remain within more than a few minutes, and on the eastern shore of the harbour there is a remarkable cluster of hot sulphurous springs. Sulphur is found in abundance on the top of Mount Kalamo and elsewhere. In ancient times the alum of Milo was reckoned next to that of Egypt (Pliny, xxxv. 15 [52]), and millstones, salt (from a marsh at the east end of the harbour), and gypsum are still exported. The Melian earth (yij MqAws), employed as a picrment by ancient artists, was probably native white-lead. Orancre olive, cypress, and arbutus trees grow throughout the island, which, however, is too dry to have any pro fusion of vegetation. The vine, the cotton plant, and barley are the main objects of cultivation. Including the neighbouring islands of Antimilos (4 square mi es , Cimolos (16 square miles), and Polinos(5| square m.les), the total population of Melos was only 5538 m 1879. Antimilo, 5i miles north-west of Milo, is a mere uninhabited mass of trachyte, and is often cal ed Lno milo or Desert Melos. Cimolo*, or Argentina, l&s, than 1 mile to the north east, wasjamous in_antiquit y ft ~ 3 See also Nauto, in Xou^ch. sur 1. hyb. dans Us veg., p. 118, 1861.
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