  From analysis of the DIRBE weekly averaged sky maps, we have detected
substantial flux in the 60 and 100 micron channels in excess of expected
zodiacal and Galactic emission. Two methods are used to separate zodiacal light
from more distant emission. Method I makes use of the time-dependence of the
North-South annual variation observed at the ecliptic poles. This method is
robust against errors in the inter-planetary dust (IPD) model, but does not
demonstrate isotropy of the background. Method II measures the ecliptic
latitude dependence of the dust over a range of ecliptic latitudes at solar
elongation e=90 degrees. This allows the excess to be determined in each week
of the DIRBE mission for high redundancy, but the results depend weakly on the
IPD model. Both methods give consistent results at 60 and 100 microns. The
observed signal is consistent with an isotropic background at the level \nu
I_\nu = 28.1 +- 1.8 +- 7(syst) nW/m^2/sr at 60 microns and 24.6 +- 2.5 +- 8
nW/m^2/sr at 100 microns.
  The IR excess detected at 140 and 240 microns by these methods agrees with
previous measurements, which are thought to be the cosmic infra-red background
(CIB). The detections at 60 and 100 microns are new. While this new excess is
not necessarily the CIB, we have ruled out all known sources of emission in the
solar system and Galaxy. We therefore tentatively interpret this signal as the
CIB and consider the implications of such energy production from the viewpoint
of star formation efficiency and black hole accretion efficiency. However, the
IR excess exceeds limits on the CIB derived from the inferred opacity of the
IGM to observed TeV photons, thus casting doubt on this interpretation. There
is currently no satisfactory explanation for the 60-100 micron excess.
