below. I have seen a master, or more properly 'mistress,' thus served several times, each time returning in a dogged sort of resistance to the will of her servitor. These inert mistresses, too, apparently know something of the bitterness of bondage to a capricious domestic help!" In the course of the migration, one queen was seen to resist carriage so vigorously that she was finally dropped, and, refusing to give the slave a hold on the mandibles, was seized by the wing and dragged off. "The lucidus ants seemed to have no volition in or direction of this movement. I released a number from their porters during various stages of the transit, and they always wandered about with a confused, aimless, and irritated manner until again seized and borne off by slaves." Some of the ants were colonized in Philadelphia, and observed more closely. The masters were never seen to work. "The colony was changed several times in order to incite to new work in mining galleries and rooms; clusters of lucidus were placed by themselves; they always remained idle. The slaves wrought with the greatest industry and energy as long as there was any need: the masters would crowd into the galleries, and move about in an aimless way, but I never could trace any attempt either at directing or aiding in the work. So, also, I never saw one attempt to eat. . . . Yet they are in good condition, and evidently well fed. They are doubtless fed by the workers, who must disgorge the food." But Dr. McCook could not see this going on. The lucidus ants and the workers both seemed fond of the light, even of the artificial warmth and light of the gas-light globe, where they would "congregate in the comfortable glow." The association of the two species in their singular relations has resulted in developing the warlike faculties of lucidus at the expense of its disposition to labor; but has not operated to degenerate the soldierly courage and faculty of Formica Schauffussi, the working ant, for the individuals of this species will spring to repel a hostile attack as freely and fiercely as their masters, and will do it independently, too; and they are quite as able as ready to wage sucessful warfare. The lucidus ant appears to be spread over the whole continent, except perhaps in the far south.
Improved Electric Motor.—A new form of dynamo-machine has recently been devised by Mr. C. F. Heinrich, which the "Telegraphic Journal" pronounces an important advance upon previous constructions. The main improvement is in the form of the armature, which the inventor has been led to adopt by a careful study of the Gramme ring and the way in which currents are induced in it. He finds that the inner side of the ring (that farthest from the field magnet) produces on the coil a current opposed to the one induced on the part of the coil immediately in front of the poles of this magnet, and to this extent weakens the current and causes heat in the coil. When the field magnet is powerful and the ring thin, this effect is reduced, but the inductive action of the farther side of the ring is not wholly eliminated. He therefore makes the ring channeled, or of horseshoe cross-section, the coils of wire being wound on the outside only. This removes the metal from the inner portion, and at the same time allows such a free circulation of air around the wires of the coil where they cross the base of the horseshoe that heating is effectually prevented. The ring is mounted and revolved between the poles of the field magnet in the same way as on the Gramme machine.
Geological Features of Behring Strait.—Some curious geological features are noticed in Mr. W. H. Dall's report of his last summer's work in the coast and geodetic survey of Alaska and the vicinity of Behring Strait. The country is not wholly without attractions, for when, on the 20th of August, the surveying-vessel, the Yukon, anchored behind Cape Lisburne, on the American shore of the Arctic Ocean, nearly two hundred miles north of Behring Strait, the air was balmy, the sun was warm and bright, no snow or ice was visible, and the banks were covered with flowers, among which daisies, monk's hood, and forget-me-nots were conspicuous. At Point Belcher, too, the vegetation was quite dense. Beds of good coal, belonging to the true Carboniferous period, are found at Cape Lisburne, from which the revenue cutter Corwin was satisfactorily coaled several times. Large lumps of coal lay on the beach at
