Submarine vents sometimes break forth, locally raising the level of the sea-bottom, or even forming temporary islands or shoals.
The region was by no means a peneplain before its slanting uplift; its surface then was hilly and in the south mountainous; in its central and still more in its northern part it was overspread with lavas which flowed westward along the broad open valleys from many vents in the eastern part: near the northern end of the range, eruptions have continued in the present cycle, forming many cones and young lava flows.
The lavas are usually porphyrites, which occur in sheets, with intercalated bands of volcanic tuff that are sometimes strongly felsitic. One of the vents by which such materials were ejected occurs in the Braid Hills on the south side of Edinburgh.
But Brunhild is ill content; though she saw Siegfried do homage to Gunther at Isenstein she is not convinced, and believes that Siegfried should have been her husband; and on the bridal night she vents her ill humour on the hapless Gunther by tying him up in a knot and hanging him on the wall.
The vents rattled without producing heat.
Volcanic sulphur usually occurs as a sublimate around or on the walls of the vents, and has probably been formed in many cases by the interaction of sulphur dioxide and hydrogen sulphide.
This discovery was followed by that of the calculus of partial differences, the first trials of which were published in his Reflexion sur la cause generale des vents (1747).
It has been suggested that these spurs represent the sites of vents or fissures of eruption.
In order to obtain the acid, a series of basins is constructed over the vents, and so arranged as to permit of the passage of water through them by gravitation.
The two leading types of volcanic areas are the plateaus, in which sheets of porphyrites, basalts and even trachytes were emitted, sometimes with wide discharge of volcanic ashes, and the puys, or isolated vents, or scattered groups of vents, which discharged comparatively a small amount of lava and ashes.
The actual vents which were the sites of the small volcanoes still remain distinct, and the erupted lavas form high ground in the middle of Ayrshire.
When the otter "vents" or comes to the surface to breathe, his muzzle only appears above water, and when he is viewed or traced by the mud he stirs up, or by air bubbles, the hounds are laid on.
A dry and warm wind comes down from the snowy Elburz to Gilan in December and January, and much resembles the fhn of the Alps (Dr Tholozan, Sur les vents du Nord de la Perse et sur le foehn du Guilan, Corn pies rendus, Acad.
And a depth of 97 fathoms. Voyagers in 1828 and 1842 reported that steam still issued from numerous vents, but Otto NordenskjOld (Antarctica, London, 1905) found no exterior evidence of volcanic activity.
There was little explosive action, and few of the volcanic vents can now be traced.
These must either have been ejected by submarine volcanoes or drifted by the wind from active vents, as the fine ash discharged by Krakatoa was wafted over the whole globe.
At or about the main vents are numerous solfataras.
The springs, geysers and steam vents are scattered over it in the most irregular fashion.
In diameter, in the centre of which a smaller crater was later on built up (the basin is now known as the Campo di Annibale) with several lateral vents (the Lake of Albano, the Lake of Nemi, &c.).