The electron microscope provides an ideal environment for the structural analysis of small volumes of amorphous and polycrystalline materials by collecting scattering information as a function of energy loss and momentum transfer. The scattering intensity at zero energy loss can be readily processed to a reduced density function G(r), providing information on nearest neighbour distances and bond angles[l]. Figure 1(a) shows the G(r) for glassy carbon, a turbostratic form of graphite. The three nearest neighbours in glassy carbon (labelled 1-3 in figure 1) are at 1.42 Å, 2.44 Å and 3.75 Å respectively. These distances correspond to the first three nearest neighbours in a graphite sheet and are expected in glassy carbon which is know to have good in-plane graphitic order. In figure 1(b) the G(r) of cathodic arc deposited tetrahedral amorphous carbon is shown. This material contains a high fraction of diamond-like bonding[2] and has a 1st nearest neighbour peak at 1.52 Å.