six o'clock
But only those who have tried it , know how thoroughly one may get lost in the Adirondack woods in a very short time , or how loudly one may scream without being heard even by the friends who are searching for them . And they were searching for the lost girls . When the two failed to appear by half-past six , Mr. and Mrs. Rose became apprehensive for their safety . They knew the girls had gone for a long ramble in the woods , but it was the rule of the camp to be back for six o'clock supper , unless due notice had been given . `` They 're lost in the woods , '' Mrs. Rose declared , and though hoping the contrary , Mr. Rose agreed with her . They had telephoned to all the neighbouring camps and as no one had seen the girls that afternoon they felt sure of what had happened . `` We must make search parties , '' said Bob , while Bert looked thoroughly scared at the thought of his sister 's danger .