landward at the ebb. At sixty miles away from the Atlantic coast the deflection due to tidal action of this kind is probably quite as great as the greatest deflection due directly to the moon. These flexures are not confined to the surface, but must extend in almost equal degree beyond the depth of the deepest mine. Until the atmospheric pressure and the state of the tides at each moment can be accurately known for a great distance around any given spot, the experimental determination of the lunar disturbance of gravity is out of our reach; our instrument, even in the most favorable site, must needs record incessant variations of which no satisfactory account can be given. A gravitational observatory must, therefore, for the present content itself with registering the more or less irregular tremors of the earth that are allied with earthquake-move ments. English and Metric Measures.-The fol. lowing comparative summary of English and French (or metric) standards of measures and weights will be useful: The English inch is equivalent to 2:54 centimetres; the foot to 30.48 centimetres; the yard, to 94.44 centimetres; the mile to 1609 33 metres; the nautical mile, to 1852-30 metres. The square inch is equivalent to 6:45 square centimetres; the square foot, to 929-01 square centimetres; the square yard, to 8364 13 square centimetres, The cubic inch is equivalent to 16-387 cubic centimetres; the cubic foot, to 28 516 cubic decimetres; the cubic yard, to 764.535 cubic decimetres; the pint, to 0.567 cubic decimetre; the gallon, to 45-410 cubic deci metres. The English grain is equivalent to 64.799 milligrammes; the ounce avoirdupois, to 28.349 grammes; the pound, to 453-590 grammes; the ton, to 1016.050 kilogrammes. The foot-pound is equivalent to 0.13825 kilogrammetre; the French horse-power, to 75 kilogrammetres a second; and the English horse-power (550 foot-pounds a second, or 33,000 foot-pounds a minute), to 76 kilogrammetres a second. The metrical unit of pressure is the kilogramme per square centimetre. We may also count by centimetres of mercury or by timetres high, or to 1033 kilogr square centimetre. The English square inch corresponds with 70-3 per square centimetre. False Fangs in Harmless Sna blowing-viper or puffing-adder of t States, although it is timid and una and can rarely be provoked to then does no particular harm, reputed a dangerous and venomo because it has long, fang-like teeth. It belongs to the genus which is so called on account of usual and irregular dentition. It same group as the Xenodons, or tooths, of tropical America, which supposed there to be poisonous, for no better reason than our Nor can genera are. Dr. Stradling all to bite him, and suffered no ill eff the wound. Mrs. Catharine C. Hop in "Land and Water,” that she examined one of these strange snakes for the purpose of seeing t when she observed that they ar or what are called in the viperin hinged teeth-that is, they are so the snake can erect or depress pleasure by a volitional movemen jaw. It is known, she says, that n gland exists in this snake, “and it on venturing to feel the teeth, in let me know it had a larger pai judge of their relative sizes, that th tucked away in case I took too ma ties." NOTES. A STEP toward fixing a system form standards of time was made convention of railroad managers w held at St. Louis, April 11th. H were agreed upon at fifteen degrees tude apart, to which the clocks in be made to conform. Four standa tricts respectively appertaining to th made: Eastern time, to agree with the 75th meridian; central time, o slower, to be regulated by the 9 ridian; and two other standards, three hours slower than Eastern tin fixed by the 105th and 120th m All changes in time will be made at the works; an industrial or technical school, which is attended by about eighty fitters and boiler-makers, and by the clever young men in all the departments; and a mining-school, with two hundred students. In the steel department all the young men under eighteen are required to attend the night-school, and those who willfully absent themselves are liable to expulsion. At the great zinc-works near Liége, also, the apprentices are required to attend evening-schools. THE agricultural of France have been substitution of the madder in dyeing, the the phylloxera. The will have to be give again be made prof wrought by the silkphylloxera, now that discovered, may be r expedite the recovery culture, an extensive has been arranged, by drawn from the river distributed to all the o THE Davenport (Iowa) Academy of Sciences has recently received from the Rev. J. Gass a number of the peculiar "curvedbase" mound-builders' pipes. One of them is a finely carved stag's head, representing the antlers bent around the bowl, in relief; another is an eagle, perched and holding some small animal in its claws; two others are neatly carved birds; another is a finely sculptured black bear; a sixth is supposed in the Mississippi, now to represent a fox, with the face turned backward; a seventh is a nondescript animal. Others are plain. The bear is cut MR. GEORGE SUTTO traces the causes of th ern rivers to the great bring on extensive sto local influences, now in summer or winter a cur. Whenever four from a black stone; the other pipes are in suddenly over the se ash-colored pipestone or red catlinite. Up to the present date, we understand, there have been received in answer to the official letter of inquiry to the members of the British Association, as to whether they intended to go to Montreal or not, replies in the affirmative from three hundred and forty. Among these are a good many who may be said to be really representative of English science, but, as might be expected, the younger men are present in a larger proportion than the older.-Nature. PIERRE CARBONNIER, the distinguished French pisciculturist, has recently died. He was the author of several monographs on the natural history and cultivation of fishes, and contributed many papers to scientific journals. He was also director of the Aquarium of the Trocadéro at the French Exhibition of 1878. MR. W. S. BARNARD, of the Department of Agriculture, observes that ants may do valuable service as destroyers of larvæ and insects, particularly of the cotton - worm, which appears to be fiercely attacked by all the species. Even the smallest ant all alone will assault and worry the worm, and the insects appear plentiful in all the fields. They dispatch the younger worms very quickly, but the older ones more often escape. Ants are, however, detrimental, though indirectly, to vegetation, in that they protect aphides or plant-lice by keeping off the insects that would prey upon them. This they square miles of the C sixty-three feet will be at Cincinnati; and if t frozen and heavily co flood will be much hig ple of the river valleys to avoid disaster from forehand the height to rise, and this may be taining how much rain nal-Service Office could tion by systematically lishing measurements points in all parts of th large rivers. AN Association of A was organized at Spring in April last, of which was chosen president, Martin and A. S. Pack dents, and Professor S. F College, secretary. Tw were enrolled. The Ass name of the "Society of Eastern United States." A NOTEWORTHY fea third annual meeting of graphical Society, at I presence, as the hero of youthful African explore mann, and by his side eighty-nine years old, w and Nubia seventy years and the other Red Se years later. IN CHANGES IN NEW ENGLAND POPULATION. BY NATHAN ALLEN, M. D., LL. D. N the history of a nation or a people there are sometimes impo changes taking place, so gradually and quietly that they are s ly perceptible at the time. It may require a series of years or se generations to work out the problems involved, but they may b lowed with results of great magnitude. Some changes of this character have been taking place in our England population, which we purpose here briefly to notice. I earlier history of New England there were few changes in the dence of her people. As agricultural pursuits constituted their cipal occupation, the same farms and lands continued to a great e in the same families from generation to generation. Prior t Revolutionary War very little emigration took place out of New land. In the early part of the present century many persons rem to New York and some to Ohio. From 1810 to 1830 this emig continued steadily to increase, not only to those States but t States and Territories farther west. To such an extent had this gration been carried on that, in 1840, the United States censu ported nearly half a million of persons born in New England were living in other States. Whenever new lands were thrown into market by the Govern or by means of railroads, or some new mining interests, then a “ ern fever" started up, and great numbers might be seen West." While we have no means of ascertaining the exact nu removing from New England, during any one year or period of the United States census gives, every ten years, the birthplace people residing in every State at the time the count was made. |