Latitude constant latitude and constant longitude, which are constructed with reference to the rotation axis of the Earth. The primary reference points are the poles where the axis of rotation of the Earth intersects the reference surface. Planes which contain the rotation axis intersect the surface at the meridians; and the angle between any one meridian plane and that through Greenwich (the Prime Meridian) defines the longitude: meridians are lines of constant longitude. The plane through the centre of the Earth and perpendicular to the rotation axis intersects the surface at a great circle called the Equator. Planes parallel to the
The Blood Line anything in the way that, say, some of the sacrifices in "Children of Earth" did.' He also criticised the effect of the cliffhanger, saying 'so it turns out that this huge world-changing event was just a "trial run" for an even bigger plan on the part of the bad guys? Does anyone (other than Davies) think that what the series needs is to get even bigger?' The Blood Line "The Blood Line" is the tenth and final episode of "", the fourth series of the British science fiction television series "Torchwood". It was first broadcast in the United States on