“Ha! ha! ha! whimsical enough,” cried the vicar; “but, unfortunately, your explanation is not the true one. The sign,” observed Mr. Twaddleton, “is not quite so uncommon as you seem to suppose; it was originally ‘_Pan and his Bacchanals_,’ but, by a very natural transition, the figure of the sylvan deity, which is certainly terrific[14] enough to sanction the mistake, has passed into that of the evil tempter; while the word _Bacchanals_, by one of those verbal corruptions so common in all languages, has been converted into the _bag of nails_.” “Very true,” said the Major; “whenever the vulgar are incapable of understanding the meaning of a word, they are sure to substitute for it some one which has the nearest resemblance to it in sound, and which is more familiar to them. I had but just now an excellent instance of this kind: my blundering servant Jacob insisted upon it that you were fond of _antics_; and before I left London, on sending him out to purchase a _Court Calendar_, what do you suppose he brought home?--a _Quart Colander_!” The vicar was much amused by the absurdity of the mistake. “I lately heard,” continued the Major, “of a Welsh squire, who, upon being questioned whether _Socinianism_ or _Arianism_ prevailed in his district, replied, that he could not answer that question, but that he knew there had been a great deal of _Rheumatism_.” But the good company of the Major and his newly acquired friend must not detain us any longer from our duty. Mr. Seymour and his young family have reassembled in the library, and it is necessary that we should immediately join them. Some of our readers may, perhaps, decline accompanying us upon this occasion; for the subject to be discussed, however necessary it may be, is certainly not so entertaining as many of those which have engaged our attention. If this be the case, they may make a short cut, and join us again at the beginning of the following chapter. The children had arranged themselves around the table, when their father observed, that it would be necessary for their future progress, to devote an hour or two to the consideration of several mathematical figures and terms. “As to mathematical figures,” said Tom, “if you allude to squares, circles, and figures of that description, and to parallel lines, angles, and so on, I can assure you that I am already well acquainted with them; for the work you have given us on PAPYRO-PLASTICS[15] has fully instructed me in those particulars.” “If that be the case,” replied Mr. Seymour, “you will not have any difficulty in answering my questions; but we must, nevertheless, go regularly through the subject, for the sake of your sisters, who may not be equally proficient in this elementary part of geometry: tell me, therefore, in the first place, what is meant by a _parallelogram_.” “A four-sided figure,” answered Tom. “That is true; but are there not some other conditions annexed to it?” “Yes; its opposite sides are parallel.”