midnight on the 4th of December
40sec . of the 1st of December of the ensuing year . 5th . It will meet the moon four days after its discharge , precisely at midnight on the 4th of December , at the moment of its transit across the zenith . The members of the Gun Club ought , therefore , without delay , to commence the works necessary for such an experiment , and to be prepared to set to work at the moment determined upon ; for , if they should suffer this 4th of December to go by , they will not find the moon again under the same conditions of perigee and of zenith until eighteen years and eleven days afterward . The staff of the Cambridge Observatory place themselves entirely at their disposal in respect of all questions of theoretical astronomy ; and herewith add their congratulations to those of all the rest of America . For the Astronomical Staff , J. M. BELFAST , _ Director of the Observatory of Cambridge .