“Fustrate!” exclaimed Bubble, nodding his head enthusiastically.  “I like fustrate!  Ge-ography!  Why, that sounds just like pie!  I—­I don’t mean that, Miss Hildy.  I didn’t mean to say it, nohow!  It kind o’ slipped out, ye know.”  Bubble paused, and hung his head in much confusion.

“Never mind!” said Hilda, kindly.  “Of course you cannot make the change all at once, Bubble.  But little by little, if you really think about it, you will bring it about.  Next week,” she added, “I think we must begin upon grammar.  You are doing very well indeed in spelling and geography, and pretty well in arithmetic; but your grammar, Bubble, is simply frightful.”

“Be it?” said Bubble, resignedly.  “I want to know!”

“And now,” said the young instructress, rising, and shaking out her crumpled frock, “that is enough for to-day, Bubble.  We must be going home soon; but first, I want to take a peep at the lower part of the old mill, that you told me about yesterday.  You have been in there, you say?  And how did you get in?”

“I’ll show ye!” cried Bubble, springing up with alacrity, and leading the way towards the mill.  “I’ll show ye the very place, Miss Hildy.  ’Tain’t easy to get in, and ’tain’t no place for a lady, nohow; but I kin git in, jist like—­like ’rithmetic!”

“Bravo, Bubble!” said Hilda, laughing merrily.  “That is very well for a beginning.  How long is it since the mill was used?” she asked, looking up at the frowning walls of rough, dark stone, covered with moss and lichens.

“Farmer Hartley’s gran’f’ther was the last miller,” replied Bubble Chirk.  “My father used to say he could just remember him, standin’ at the mill-door, all white with flour, an’ rubbin’ his hands and laughin’, jes’ the way Farmer does.  He was a good miller, father said, an’ made the mill pay well.  But his eldest son, that kem after him, warn’t no great shakes, an’ he let the mill go to wrack and ruin, an’ jes’ stayed on the farm.  An’ then he died, an’ Cap’n Hartley came (that’s the farmer’s father, ye know), an’ he was kind o’ crazy, and didn’t care about the mill either, an’ so there it stayed.

“This way, Miss Hildy!” added the boy, breaking off suddenly, and plunging into the tangled thicket of shrubs and brambles that hid the base of the mill.  “Thar! ye see that hole?  That’s whar I get in.  Wait till I clear away the briers a bit!  Thar! now ye kin look in.”

The “hole” was a square opening, a couple of feet from the ground, and large enough for a person of moderate size to creep through.  Hildegarde stooped down and looked in.  At first she saw nothing but utter blackness; but presently her eyes became accustomed to the place, and the feeble light which struggled in past her through the opening, revealed strange objects which rose here and there from the vast pit of darkness,—­fragments of rusty iron, bent and twisted into unearthly shapes; broken beams, their jagged ends sticking out like stiffly