THE MARCH OF PRACTICAL SCIENCE.
IT is idle to be continually repeating that this is a very wonderful age; but we may with good reason congratulate ourselves that science has now reached a point that insures to the human race an ever-increasing mastery over the powers and resources of nature, and that ought, with any kind of right management, to be productive of better modes of life from year to year, not for the few only but for all. At the last meeting of the British Association an address was delivered by Mr, Preece, President of the Section of Mechanical Science, which, though confined to the single subject of the recent advances in the practical applications of electricity, furnishes a vivid picture of the changes which scientific knowledge generally is working in the world. Things that to our forefathers were perfect types of the unknowable, are to-day, as Mr. Preece remarks, among the best-understood of natural phenomena, if not in relation to their ultimate cause, at least in regard to the laws of their operation. Among the various troublesome questions asked of the patriarch Job was one as to whether he could send lightnings, so that they might come and go at his bidding. Of course, Job had to give it up; but that was not because the problem was absolutely insoluble, but because he had not the scientific knowledge necessary to solve it. To-day lightnings are flying to and fro in most complete subjection to the will of man; and even the free lightnings of heaven have to a large extent been placed under bonds to do him no harm. Mr. Preece antedates, we observe, by five years the classical experiment of Franklin with the electricity of the clouds, placing it in 1747 instead of in 1752; but he is correct in stating that nearly a century elapsed after Franklin's great discovery before, as a working power, electricity was fairly mastered. Naturally the Church was opposed to the study of electricity in its beginnings; but that study has been too fruitful of beneficial results, and too victoriously successful all along the line, to remain under a ban of any kind. Churches themselves are now protected by lightning-rods against random thunderbolts, just as the clergy, in common with other classes, are protected by vaccination against small-pox. On the subject of lightning-rods, Mr. Preece's declaration that "as long as points remain points, as long as conductors remain conductors, as long as the rods make proper connection with the earth, lightning protectors will protect," is a word spoken in season; as also is the caution he goes on to give as to the neglect of the conditions upon which the whole efficiency of the system of protection against lightning depends.
It would be impossible within our limits to give anything like a satisfactory summary of the very interesting address to which we have referred. Two or three points may, however, be singled out for notice. The electric telegraph may now be said to have been in use for business purposes for half a century. The rate of transmission at the outset was five words a minute; today it is six hundred. Cooke and Wheatstone required five wires for their first needle instrument, which worked only at the rate of four words a minute; whereas one wire now conveys six messages simultaneously at ten times the speed. On the 8th of April, 1886, now nearly three years ago, when Mr. Gladstone introduced his Home-Rule Bill in the British House of Commons, no less than 1,500,000 words were sent over the wires from the Central Telegraph office in London. Mr. Preece seems to approve of the purchase of the telegraphs by the British Government. He