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Rh and he finally clinched the proof of what had been already substantially demonstrated by several others, viz. that germ-free air did not initiate putrefaction, and that accordingly “ spontaneous generation ” as ordinarily understood was a chimera (1875–1876). One practical outcome of these researches is the method now always adopted of sterilizing by a succession of gentle warmings, sufficient to kill the developed micro-organisms, instead of by one fierce heating attempting to attack the more refractory undeveloped germs of the same. This method of intermittent sterilization originated with Tyndall, and it was an important contribution to biological science and industrial practice. For the substantial publication of these researches reference must be made to the Transactions of the Royal Society; but an account of many of them was incorporated in his best-known books, namely, the famous Heat as a Mode of Motion (1863, and later editions to 1880), the first popular exposition of the mechanical theory of heat, which in 1862 had not reached the textbooks; The Forms of Water, &c. (1872); Lectures on Light (1873); Floating Matter in the Air (1881); On Sound (1867, revised 1875, 1883, 1893). The original memoirs themselves on radiant heat and on magnetism were collected and issued as two large volumes under the following titles: Diamagnetisrn and Magne-crystallic Action (1870); Contributions to Molecular Physics in the Domain of Radiant Heat (1872).

It was on the whole the personality, however, rather than the discoverer, that was greatest in Tyndall. In the pursuit of pure science for its own sake, undisturbed by sordid considerations, he shone as a beacon light to younger men—an exemplar of simple tastes, robust nature and lofty aspirations. His elevation above the common run of men was conspicuous in his treatment of the money which came to him in connexion with his successful lecturing tour in America (1872–1873). It amounted to several thousands of pounds, but he would touch none of it; he placed it in the hands of trustees for the benefit of American science—an act of lavishness which bespeaks a noble nature. Though not so prominent as Huxley in detailed controversy over theological problems, he played an important part in educating the public mind in the attitude which the development of natural philosophy entailed towards dogma and religious authority. His famous Belfast address (1874), delivered as president of the British Association, made a great stir among those who were then busy with the supposed conflict between science and religion; and in his occasional writings—Fragments of Science, as he called them, “ for unscientific people ”—he touched on current conceptions of prayer, miracles, &c., with characteristic straightforwardness and vigour.

As a public speaker he had an inbom Irish readiness and vehemence of expression; and, though a thorough Liberal, he split from Mr Gladstone on Irish home rule, and took an active part in politics in opposing it.

In 1876 Tyndall married Louisa, daughter of Lord Claud Hamilton. He built in 1877 a cottage on Bel Alp above the Rhône valley, and in 1885 a house on Hindhead, near Haslemere. At the latter place he spent most of his later years; his health was, however, no longer as vigorous as his brain, and he suffered frequently from sleeplessness. On the 4th of December 1893, having been accidentally given an overdose of chloral, he died at Hindhead.

TYNDARIS, an ancient city on the northern coast of Sicily, about 13 m. W.S.W. of Mylae (mod. Milazzo) and 5 m. E. of the modern town of Patti. It was founded by Dionysius the Elder in 395, who settled there 600 Peloponnesian Messenians on a site cut out of the territory of Abacaenum (1 m. north of the modern Tripi). It was thus almost the last Greek city founded in Sicily. It was one of the earliest allies of Timoleon. In the First Punic War it was dependent on Carthage, but expelled the garrison in 254 and joined the Romans, under whom it seems to have flourished. Cicero calls it “ nobilissima civitas," though it seems to have suffered especially under Verres. It was one of the points occupied by Sextus Pompeius, but was later on taken by Agrippa, who used it as a base of operations. Augustus probably made it a colonia. Pliny mentions that half of it was swallowed up by the sea, though he does not give the date of this event (Hist. nat. ii. 206). It was probably, however, due to a fault in the limestone rock of which it is composed, and the action of the sea. The site is a remarkably fine one, and it is surprising that it was not occupied sooner. It is an isolated hill (920 ft.) with projecting spurs, rising abruptly on the seaward side, and connected by a comparatively narrow isthmus with the lower ground inland. It thus commands a magnificent view, including even the summit of Etna, while opposite to it on the north are the Lipari Islands. Considerable remains of the city walls, built of rectangular blocks of stone, exist on the south side; on the west their foundations are traceable. Remains of several towers may be seen, and the site of the main gate, which was in a recess on the south (the land) side, is clearly traceable, .the walls defending it on each side being well preserved. Outside it are several tombs of the Roman period. The walls follow the upper edge of the plateau, and do not seem to have included the spurs to seaward. Their remains indicate that it was the north and north-east portion of the city that fell. This fact renders it doubtful whether the church of the Madonna di Tindari, at the east extremity, marks the site of the acropolis. Along parts of the north side, where the line of the wall should run, is a line of débris, which may belong to a reconstruction after the catastrophe described by Pliny. Within the walls are considerable remains of a building generally known (though not correctly) as the gymnasium, constructed of masonry, with three narrow halls, each about 90 ft. long, the central hall being 21 ft. wide, the other two 14 ft. Below it to the north are remains of a building with several mosaic pavements, and to the west is a small theatre, the internal diameter of which is 212 ft., and the length of the stage 80 ft. There are traces of many other buildings within the city area, including a considerable number of underground cisterns. An important collection of objects found on the site is preserved in the Villa della Scala (1½ m. to the west), belonging to Baron Sciacca, the owner of the site itself.

(T. As.)

TYNE, a river in the north-east of England, fiowing eastward to the North Sea, formed of two main branches, the North Tyne and South Tyne. The North Tyne rises in the Cheviot Hills, at their south-western extremity, near the Scottish border. The valley soon becomes beautifully wooded. At Bellingham it receives the Rede, whose wild valley, Redesdale, was one of the chief localities of border warfare, and contains the site of the battle of Otterburn (1388). The South Tyne rises in the south-eastern extremity of Cumberland, below Cross Fell in the Pennine Chain, and flows north past Alston as far as the small town of Haltwhistle, where it turns east. The valley receives from the south the picturesque Allendale, in which the lead mines were formerly important. The two branches of the Tyne join at Warden, a little above the town of Hexham, with its great abbey, and the united stream continues past Corbridge, where a Roman road crossed it, in a beautiful sylvan valley. The united course from the junction to the sea is about 30 m. The length from the source of the North Tyne is 80 m., and the drainage area is 1130 sq. m. In its last 15 m. the Tyne, here the boundary between Northumberland and Durham, is one of the most important commercial waterways in England. Sea-going vessels can navigate up to Blaydon, and collieries and large manufacturing towns line the banks—Newburn, Newcastle-upon-Tyne, Wallsend and North Shields on the Northumberland side; Gateshead, Jarrow and South Shields on the Durham side, with many lesser centres, forming continuous lines of factories and shipbuilding yards. The growth of the great shipbuilding and engineering companies, now amalgamated, of which the Armstrong firm at Elswick is the most famous, necessitated the dredging of the river so as to form a deep waterway. At high-water spring tides there are 40 ft. of water at Shields Harbour at the mouth, and 31 at Newcastle, 8 m. up river. Dangerous rocks outside the mouth have been partially removed and the remainder protected, and the Tyne forms a very safe harbour of refuge.