  Measurements of the spatial and temporal coherence of single, femtosecond
x-ray pulses generated by the first hard x-ray free-electron laser (FEL), the
Linac Coherent Light Source (LCLS), are presented. Single shot measurements
were performed at 780 eV x-ray photon energy using apertures containing double
pinholes in "diffract and destroy" mode. We determined a coherence length of 17
micrometers in the vertical direction, which is approximately the size of the
focused LCLS beam in the same direction. The analysis of the diffraction
patterns produced by the pinholes with the largest separation yields an
estimate of the temporal coherence time of 0.6 fs. We find that the total
degree of transverse coherence is 56% and that the x-ray pulses are adequately
described by two transverse coherent modes in each direction. This leads us to
the conclusion that 78% of the total power is contained in the dominant mode.
