The principal difference between the artificial and the natural geyser-tube is that in the latter the effect is not necessarily produced by two distinct sources of heat like the two fires of the experimental apparatus, but by the continual influx of heat from the bottom of the shaft, and the differences between the boiling-points of the different parts of the column owing to the different pressures of the superincumbent mass. This may be thus illustrated: AB is the column of water; on the right side the figures represent approximately the boiling-points (Fahr.) calculated according to the ordinary laws, and the figures on the left the actual temperature of the same places. Both gradually increase as we descend, but the relation between the two is very different at different heights. At the top the water is still 39° from its boiling-point, and even at the bottom it is 19°; but at D the deficiency is only 4°. If, then, the stratum at D be suddenly lifted as high as C, it will be 2° above the boiling-point there, and will consequently expend those 2° in the formation of steam. GEZER (the Kazir of Tethmosis [Thothmes] III.'s list of Palestinian cities and the Gazri of the Amarna tablets), a royal Canaanite city on the boundary of Ephraim, in the maritime plain (Josh. xvi. 3-10), and near the Philistine border (2 Sam. v. 25). It was allotted to the Levites, but its original inhabitants were not driven out until the time of Solomon, when "Pharaoh, king of Egypt" took the city and gave it as a dowry to his daughter, Solomon's wife (1 Kings ix. 16). Under the form Gazera it is mentioned (1 Macc. iv. 15) as being in the neighbourhood of Emmaus-Nicopolis ('Amwas) and Jamnia (Yebnah). Throughout the history of the Maccabean wars Gezer or Gazara plays the part of an important frontier post. It was first taken from the Syrians by Simon the Asmonean (1 Macc. xiv. 7). Josephus also mentions that the city was "naturally strong" (_Antiq._ viii. 6. 1). The position of Gezer is defined by Jerome (_Onomasticon_, s.v.) as four Roman miles north (_contra septentrionem_) of Nicopolis ('Amwas). This points to the mound of debris called _Tell-el-Jezari_ near the village of Abu Shusheh. The site is naturally very strong, the town standing on an isolated hill, commanding the western road to Jerusalem just where it begins to enter the mountains of Judea. This identification has been confirmed by the discovery of a series of boundary inscriptions, apparently marking the limit of the city's lands, which have been found cut in rock--outcrops partly surrounding the site. They read in every case in [Hebrew: nur] [Hebrew: taham][1], "the boundary of Gezer," with the name _Alkios_ in Greek, probably that of the governor under whom the inscriptions were cut. The site has been partially excavated by the Palestine Exploration Fund, and an enormous mass of material for the history of Palestine