The analysis of the dual magnetic field profile obtained by the ISEE mission provides a unique opportunity to study the earth's magnetospheric boundaries. A survey of the magnetopause thickness over the dayside magnetosphere is carried out by using the magnetic field measurements from the twin ISEE 1 and ISEE 2 magnetometers. Since reliable measurements are possible only for small separations (⟨1000 km) between ISEE 1 and 2 our data set is restricted to only thirty magnetopause crossing in the range of local time from 0800 to 1700 and at GSM latitude from 2¿ to 35¿. We find that the magnetopause is in constant rapid and irregular motion wiht velocities ranging, in 80% of the cases, from 10 km/s to 80 km/s and with the current sheet thickness ranging from 400 to 1000 km. The thickness seems much better ordered by dipole magnetic latitudes than by GSM latitude. Near the magnetic equator the magnetopause current sheet is thinnest, about 500 km on average. This observation suggests that reconnection is initiated in the equatorial regions rather than in the polar cusps.