A reappraisal of several extensive phenomena of the high galactic latitudes

This is the first of two papers dealing with the extensive high latitude phenomena. The relationships between the diffuse and filamentary gaseous nebulosity, the giant radio loops and the high, medium and low velocity neutral hydrogen are considered in the light of recent observations. The existence of other giant loops is also suggested.A further article (by K.H.E.) will present some very accurate measurements of the radial velocities of the nebulosities in the vicinity of Loop 2. These will be compared to some neutral hydrogen features in that region.