Page:American History Told by Contemporaries, v2.djvu/303

No. 96] would become the top, and the top would become the bottom : and this is called the topsey-turvey mode, which is nearly allied to the accidental, and frequently arises from it. .Very good — But are not salt-boxes sometimes single and sometimes double? . Yes. . Well, then mention the several combinations of salt-boxes with respect to their having salt or not. . They are divided into single salt-boxes having salt ; single salt-boxes having no salt ; double salt-boxes having salt ; double salt-boxes having no salt ; and single double salt-boxes having salt and no salt. . Hold ! hold ! — you are going too far. . We cannot allow further time for logic, proceed if you please to

. Pray Sir, what is a salt-box? . It is a combination of matter, fitted, framed, and joined by the hands of a workman in the form of a box, and adapted to the purpose of receiving, containing, and retaining salt. . Very good — What are the mechanical powers concerned in the construction of a salt-box? . The ax, the saw, the plane, and the hammer. . . . . . . . Have not some philosophers considered glue as one of the mechanical powers? . Yes ; and it is still so considered, but it is called an inverse mechanical power : because, whereas it is the property of the direct mechanical powers to generate motion, and separate parts ; glue, on the contrary, prevents motion, and keeps the parts to which it is applied fixed to each other. . . . . Is the saw only used in slitting timber into boards? . Yes, it is also employed in cutting boards into lengths. . Not lengths : a thing cannot properly be said to have been cut into lengths. . Into shortnesses. . Certainly — into shortnesses. Well, what are the mechanical laws of the hammer? . The time wastes fast ; pass on to another science.