WE have here another attempt to simplify the acquirement of a knowledge of some of the elementary facts of science, but though there is much to be commended, some points certainly require revision. With reference to the well-known experiment in which bits of straw, wood, or cork come together when thrown into a basin of water (p.22), the author has fallen into the common error of ascribing the effect to gravitation instead of to surfacetension. If a few wax-lights or other things not wetted by water be added, it will be found that a substance which is not wetted is repelled by a substance which is, and that only “birds of a feather flock together.” Again, with young students, loose or incomplete statements cannot be too carefully guarded against; the statement on p. 59 that 15 pounds or 30 inches of mercury is “equal to a square inch column of air to whatever height it may extend”is of this class.
Science of Every-day Life
By J. A. Bower, F.C.S. (London: Cassell and Co., 1889.)