From the fact that this room lay directly over the small one occupied by Inez，in which was the wall cavity they had recently explored，they conceived the idea that the wall here might also be hollow.Pounding upon it，however，had no effect in determining this，for kiln—baked adobe is not resonantand it was impossible to discover from any surface indication whether there were eight feet of closely set blocks or less.Careful search for any sign of an opening proved futile.
Finally old Miguel said：
"Next room was room of Se？or Cristoval.Eet was room hees father live in，too；the old se？or who build thees part of house.If there ees way to get in wall，from upstairs，it ees there.""To be sure，"said practical Beth，catching at thesuggestion；"it was there that Major Doyle heard the baby cry."So on they all trooped into the blue room，where the wallwas likewise carefully inspected.While this was being done Rudolph looked at his watch and found it was after four o'clock."It will soon be daylight，"said he to his wife."What a night it has been ！It seems a month since we arrived here andfound Toodlums gone."Old Miguel had been silent and unobtrusivea in the vacant room，but here he was as eager in testing the wall as any one of them.
"You see，it's this way，"Patsy was saying；"if themajor could hear baby cry，through this wall，those inside could hear us，if we called to them.Who among us has the clearest，the most penetrating voice ？""Suppose I try？"squeaked Runyon，earnestly；but thosewho considered the remark at all merely gave him scornful looks.
"Let Rudolph call，"said Helen."I think his voice mightpenetrate the pyramids of Egypt."Rudolph went close to the wall and shouted："Hello，there！Baby！I—nez ！—eh—eh—what's the othergirl's name？""Mildred，"said Beth.
"Mil—dred ！"shouted Dolph；"Mil—dred！"
He paused between each name，which he roared so loudly that he nearly deafened those in the room，and everyone listened intently for a response.
No answer.
"Perhaps they're asleep—worn out，"said Uncle John.No one now seemed to doubt that the missing ones were imprisoned in the wall.
"Let Beth try，"suggested Patsy.
Beth had a clear，bell—like voice and from where she stood she called out the names of Inez and Mildred.Then，in the stillness that followed，came a muf？eda cry in return—a cry that set all their nerves quivering with excitement.
The mystery was solved at last.
Beth repeated the call and now the answer was clearer，though still indistinguishable.It was a voice，indeed，but whose voice they could not tell.But now，to their astonishment，came another sound，quite clear and distinct—the wail of a baby voice.
"That settles it ！"cried the major，triumphantly."Was Iright，or wrong？Was it a nightmare，or was I crazy？""Neither one，my dear sir，"replied the doctor."Youdeclared you heard a ghost."Arthur was capering about in frantic joy.
"She's alive—my baby is alive ！"he exclaimed.
"And probably she was sound asleep until your infernala yelling awakened her，"added the major.
"It wasn't our yelling，"said Uncle John，as delighted as even the father could be；"it was the yelling of whoever is inside，there，that frightened the baby.Thank goodness the dear child could sleep during all these weary hours，when we have been wearing our hearts out with anxiety.""We have yet cause for anxiety，"declared Patsy，"for little Jane is not rescued yet，by any means，and presently the poor thing will become very hungry and suffer for lack of food.We now know where baby is，but we can't get at her；nor can Mildred or Inez ？nd a way to get her out，or they would have done so long ago.""Very true，"agreed Helen Hahn，gravely."Unless wecan soon ？nd a way to get to them，all three will starve.""Why，we will pull down the wall ！"cried Arthur."Dynamite it！"piped Bul Run.
"Be sensible！"counseled Uncle John sternly."We are wasting precious time.Miguel，"turning to the ranchero，"get some of your men，with picks and crowbars，and fetch them here quickly."The Mexican，who seemed bewildered by the discovery of the missing ones，although he had himself been the ？rst to suspect where they were，started at once to obey this order.