after wassamo had been among these curious people several months , the old sand - spirit said to him , " son - in - law , you must not be surprised at what you will see next ; for since you have been with us you have never known us to go to sleep . it has been summer when the sun never sets here where we live . but now , what you call winter , is coming on . you will soon see us lie down , and we shall not rise again till the spring . take my advice . do not leave the lodge . i have sure knowledge that that knavish island spirit is on the prowl , and as he has command of a particular kind of storm , which comes from the south - west , he only waits his opportunity to catch you abroad and do you a mischief . try and amuse yourself . that cupboard , " pointing to a corner of the lodge , " is never empty ; for it is there that all the offerings are handed in while we are asleep . it is never empty , and-- " but ere the old sand - spirit could utter another word , a loud rattling of thunder was heard , and instantly , not only the old spirit but every one of his family , vanished out of sight . when the storm had passed by , they all reappeared in the lodge . this sudden vanishing and reappearance occurred at every tempest . " you are surprised , " said the old spirit , " to see us disappear when it thunders . the reason is this : that noise which you fancy is thunder , is our enemy the island spirit hallooing on his way home from the hunt . we get out of sight that we may escape the necessity of asking him to come in and share our evening meal . we are not afraid of him , not in the least . " just then it chanced to thunder again , and wassamo observed that his father - in - law made extraordinary dispatch to conceal himself , although no stranger , at all resembling in any way the island spirit , was in view . shortly after this the season of sleep began , and one by one they laid themselves down to the long slumber . the old spirit was the last to drop away ; and , before he yielded , he went forth and had his last sport with the sand - hills , and he so tossed and vexed the poor hills , and scattered them to and fro , and whirled them up in the air , and far over the land , that it was days and days before they got back to any thing like their natural shape . while his relations were enjoying this long sleep , wassamo amused himself as best he could . the cupboard never failed him once : for visit it when he would , he always found a fresh supply of game , and every other dainty which his heart desired . the rest of the old spirit seemed to have done him much good , for he was very cheerful ; and , first putting his head forth from the window for a puff at a sand - hill , which was his prime luxury in a morning , he said to wassamo , " son - in - law , you have been very patient with our long absence from your company , and you shall be rewarded . in a few days you may start with your wife to visit your relations . you can be absent one year , but at the end of that time you must return . when you get to your home - village , you must first go in alone . leave your wife at a short distance from the lodge , and when you are welcome , then send for her . when there , do not be surprised that she disappears whenever you hear it thunder . " he added , with a sly look , " that old island spirit has a brother down in that part of the country . you will prosper in all things , for my daughter is very diligent . all the time that you pass in sleep , she will be at work . the distance is short to your village . a path leads directly to it , and when you get there , do not forget my wants as i stated to you before . " 
the old island spirit has a brother down in that part of the country .
why did the old spirit say to not be surprised whenever the wife disappeared at the sound of thunder ?
why did the old spirit say to not be surprised whenever the wife disappeared at the sound of thunder ?