The largest induction coil ever made has lately been constructed for Mr. Wm. Spottiswoode by Mr. Apps. It has two primaries, of which the one used for long sparks weighs sixty-seven pounds and is formed of a bundle of iron wires 44 inches long and 3.5625 inches in diameter. The wire is 0.032 inch in diameter. This primary has 660 yards of copper wire 0.096 inch in diameter, and wound in 1,344 turns in six layers. The spark obtained with this primary is remarkably long in proportion to the battery power used. With five Grove's quart cells the spark was 28 inches, with ten cells 35 inches, with thirty cells 37.5 inches and 42 inches, and it is thought that even better results could be obtained. The insulation is so good that seventy cells have been used without injury. The condenser is smaller than usual, being of the size commonly used with a ten-inch coil. It has 126 sheets of tinfoil, 18 by 8-1/4 inches, separated by two sheets of varnished paper. The other primary is heavier than the above described, weighing 92 pounds. The secondary coil contains 280 miles of wire, in 341,850 turns. It is used for spectroscopes and for short sparks. The power of this instrument is really comparable to that of lightning. A block of flint glass three inches thick has been pierced with the 28-inch spark. * * * * * FRENCH PROPERTY OWNERS. The financial strength of the French is a constant marvel to other nations. Political economists point to the single standard of coinage or to the double standard, according as they consider France to adhere to one or the other of these systems, as the source of this strength. But the difference between that and other nations is probably more conspicuous in the management of government loans than in any other thing. The French government does not depend on syndicates. More than four million French men and women have subscribed to the public debt, and whatever arrangements are made with great bankers, the common people of France are always invited to take a part of the bonds at a fixed and fair price. That country is noticeably distinguished from Great Britain by the equally wide distribution of land. There are more than five million peasant proprietors in France, while the United Kingdom is owned by about 200,000 persons. In England one person in 130 probably owns land, as distinguished from mere house property, and outside of London one in 30 owns a house. In Scotland one in 400 is a landowner, and one in 28 has a house in his name. In Ireland one in 315 owns land, but only one in 120 has title to a house. * * * * * TRIGONOMETRICAL SURVEY OF NEW YORK.