Atmospheric Cerenkov data, recorded at Gulmarg, India, during the 2-ye
ar period 1988-1989 in the direction of Cygnus X-3, have been searched
for the presence of a periodic pulsar modulation, employing both the
Rayleigh power and the epoch-folding (chi(2)) techniques. No evidence
is found for pulsations at either similar to 12.59 ms or similar to 9.
22 ms, the two period values around which the detection of pulsed sign
als has been reported by three atmospheric Cerenkov groups, but not by
at least two other groups, including one using a higher-sensitivity C
erenkov imaging telescope.