Page:Popular Science Monthly Volume 8.djvu/55

 Rh accomplished—not, perhaps, yet awhile. Society may not yet require them; the world could not at present afford to pay for them. The progress of engineering works, if we consider it, and the expenditure upon them, has already in our time been prodigious. One hundred and sixty thousand miles of railway alone, put into figures at £20,000 a mile, amounts to £3,200,000,000 sterling; add 400,000 miles of telegraph at £100 a mile, and £100,000,000 more for sea-canals, docks, harbors, water and sanitary works constructed in the same period, and we get the enormous sum of £3,340,000,000 sterling expended in one generation and a half on what may undoubtedly be called useful works. The wealth of nations may be impaired by expenditure on luxuries and war; it cannot be diminished by expenditure on works like these.

As to the future, we know we cannot create a force; we can, and no doubt shall, greatly improve the application of those with which we are acquainted. What we called inventions can do no more than this, yet how much every day is being done by new machines and instruments! The telescope extended our vision to distant worlds. The spectroscope has far outstripped that instrument, by extending our powers of analysis to regions as remote. Postal deliveries were and are great and able organizations, but what are they to the telegraph? Need we try to extend our vision into futurity farther? Our present knowledge, compared with what is unknown even in physics, is infinitesimal. We may never discover a new force—yet, who can tell?



OST amateur botanists have in the course of their walks come upon the peculiar leaves of the common sundew (Drosera rotundifolia), with the clear drops which the leaves bear glistening in the morning sun, and, on referring to their manuals, have noted the relationship which it bears to Venus's fly-trap (Dionæa muscipula), whose famous irritability is always a matter for mention.

In collecting the showy side-saddle-flower (Sarracenia purpurea), they have, of course, observed that its curious, trumpet-shaped leaves are usually half-filled with water and drowned insects.

In fishing from the stagnant pools, the inconspicuous, yellow blossoms, and rootless capillary leaves of the bladderwort (Utricularia vulgaris) they have doubtless noticed how they swarmed with insects and small crustaceans; and have accepted, with that unhesitating faith which our whole system of education begets and fosters, the statement that the little bladders are filled with air, and that their function is to float the plant at the time of flowering. 