is, without much doubt, on the northern peninsula of Michigan, near where mining is carried on so extensively at the present time. Native copper is occasionally found in the valley of the Connecticut River and in New Jersey, but in quantities too small to have furnished even the supply which we know to have been in possession of the aborigines of New England. On Keweenaw Point, however, in Northern Michigan, not only is there an endless amount of native pure copper which savages could use without melting, but there are numberless excavations made by natives in searching for the metal before historic times.

This portion of Michigan lay in the track of the great ice-movement which characterized the glacial period. By this means boulders were transported from this region as far as the southern parts of Ohio, Indiana, and Illinois. I have, indeed, found boulders (though none containing copper) from the vicinity of these mines which had been carried by the ice to the Kentucky hills, a few miles south of Cincinnati. It is not surprising, therefore, that occasionally masses of this copper should be found in connection with the gigantic boulders which had been transported by ice to the vicinity of the mounds in the Ohio Valley. A piece of Lake Superior copper weighing five or six pounds was found by Prof. Brainard, of Cleveland, in the glacial deposits of Medina County, O. Dr. John Locke, of Cincinnati, reports in his possession "a flattened piece of copper, weighing several pounds, which was found in the earthworks at Colerain, Hamilton County, O., having a spot of silver as large as a pea forming part of the mass." The presence of silver in such form is pretty positive evidence that the mineral came from Lake Superior, as it is not known to exist in this condition in any other mines.

Considering the rude tools with which the prehistoric miners of Northern Michigan were compelled to work, their operations were really very surprising. Their mauls were nothing but pebbles from the beach, grooved for withes, which they used as handles. With these rude implements they broke away the rocky portion of the vein containing the copper, and dug trenches, in some places ten feet deep, and extending a long distance. Occasionally they encountered a mass of copper too large for them to manage; and after working upon it ineffectually for a long time, left it surrounded with their tools and crude mechanical contrivances, to tell the story of their disappointment.

Near Copper Falls, according to Col. Whittlesey, there was discovered in 1854, a prehistoric trench, dug in the solid rock to a depth of ten feet and following the copper veins for thirty feet. From the bottom of the trench in one place a flat piece of copper, from five to eight inches thick, was found to project upwards for eighteen inches, the granite upon each side having been removed by stone hammers to that depth. The upper edge of the copper "had been beaten by the stone mauls so severely that a lip, or projecting rim had been formed, which is bent downward over the sides. A large number of broken mauls were found in the place, and around it on the surface." It is not surprising that the efforts of these ancient miners were ineffectual in the present instance, as this mass of copper proved to be about nine feet in length, being,

therefore, still imbedded, and when they left it seven feet below the rocky bottom of their trench. There are neither marks of a cutting tool nor of fire upon these masses of copper.

At the Minnesota mine in the vicinity of Ontonagon River, a group of rude ancient trenches shows the position of the copper vein for more than two miles, and the excavations are some of thirty feet in depth. In one of these there was found when first discovered, in 1847, a detached mass of copper weighing nearly eight tons, which lay "upon a cob-work of round logs, or skids, six to eight inches in diameter, the ends of which showed plainly the stroke of a small ax or cutting-tool, about two and a half inches wide." These skids were of oak, and, on drying, shrank and cracked as water-soaked timber which has been long buried, is sure to do, and possessed little strength. "The mass of copper had been raised several feet on the timbers by means of wedges." "Its upper surface and edges were beaten and pounded smooth, all the irregularities taken off, and around the outside a rim or lip was formed, bending downwards." Charcoal and ashes were found in all these trenches. One of the stone mauls from this vicinity weighed thirty-six pounds, and was provided with a double groove, being, doubtless, intended to be used by two men.

In one of the pits a rude ladder was found, formed of an oak tree trimmed so as to leave the stumps of the branches projecting, on which men could readily descend or ascend to or from their work. Wooden levers were also found among the rubbish, preserved by the water, which covered them continually. On the edge of the excavation in which the mass of copper described was found, there stood an aged hemlock, the roots of which extended across the ditch. I (Colonel Whittlesey) counted the rings of annual growth on its stump, and found them to be 290. Mr. Knapp mentions another tree which had 395. The fallen and decayed trunks of trees of a previous generation were seen lying across the pits. According to Mr. Foster, the number of ancient hammers taken from these excavations alone exceed ten cart-loads.

"In cleaning out one of these pits the workmen came upon the remains of a wooden bowl, which, it was inferred from the splintery fragments of rock imbedded in the rim, must have been employed in baling out water." From the uniformity with which marks of fire are found in these trenches, it is plausibly inferred that the rock vein was heated, and water dashed upon it to destroy its cohesion, and make it crumble more easily under the blows of the rude mauls wielded by the ancient miners. "This method was practiced by civilized nations before the invention of gunpowder, and is even at this day in the mining districts of the Hartz and Altenberg." At Isle Royale, on Lake Michigan, some of the ancient mining pits are fifty feet in depth, and according to Foster and Whitney, there is scarcely a productive vein in all the copper region that does not give evidence of having been worked in prehistoric times.-Chicago Advance.

METEOROLOGY.

REPORT FROM OBSERVATIONS TAKEN AT CENTRAL STATION, WASHBURN COLLEGE, TOPEKA, KANSAS.

The last ten days of February were somewhat milder than the second decade, but it remained quite wintry through February, and the mean temperature was only 20°. There have been no days, since February 20th, when the temperature fell below 10°, and since March 1st the lowest temperature was 14°. Very little rain or snow has fallen. The heaviest snowfall of the winter occurred February 23d when about six inches fell. Northerly winds have been prevalent but the total wind travel has been rather below the average at this season.

Altogether the season is backward, and a cold, late spring seems likely to be the sequel to a long severe winter.

ENGINEERING.

THE NICARAGUAN CANAL.

J. W. MILLER.

Just at this time, when attention is directed to the Central American war, perhaps the attitude of the national government may be better understood and its importance to us more fully realized after reading the following relating to the proposed Nicaraguan Canal, written by J. W. Miller, superintendent of the St. Louis, Ft. Scott & Wichita Railroad Company. Mr. Miller was in the naval service, and twice made survey of the Nicaraguan and Panama routes, prior to his journey round the world with Gen. Grant. A man of unusual intelligence and culture, with powers of observation that make his notes of special value at this time, from which liberal extracts are taken:

Few persons seem at all aware how simple an engineering feat the canal problem present ot Nicaragua. The summit level is the lake, only one hundred feet above tide-water. From its southeastern end flows the San Juan River, which can be used for more than sixty miles of its length, leaving only forty-five miles for a canal. This canal runs through a low alluvial land, no excavations are necessary, no tunnels have to be bored, while the last seven miles before reaching the Atlantic is simply ditch work through the swamps and lagoons, where there is already an average of seven feet of water.

To return to the upper part of the San Juan. Sixty miles are to be utilized by damming the stream. This idea has been ridiculed by various engineers on the score that freshets would wash away the dams-a natural though hasty conclusion to be reached by any one conversant with the immense destructive force produced by tropical water rainfalls. But note that at Nicaragua alone freshets do not occur, for the lake is in an immense basin, one hundred miles long by thirty broad, into which the old surrounding country is drained, the river San Juan being simply an outlet, never rising more than six feet during the entire year. Contrast this gradual rise with the "cataract" which would be formed in the Chagres River if the Panama Canal were built. Slack water navigation is, therefore, feasible on the San Juan, and feasible nowhere else upon the Isthmus, for at no other point is there a constant level reservoir. "But," we are told, "the locks will necesserily be of such size that traffic will be suspended through the time taken to fill and discharge them, and ships endangered by the breaking of flood-gates." Mr. Menocal has gotten over these objections in his ingenious method of admitting and discharging the water of the locks. If not, Captain Eads' railway can be used in connection with the canal. None of the short canals around the dams are to be more than two miles long, and marine railways

METEOROLOGY.

REPORT FROM OBSERVATIONS TAKEN AT CENTRAL STATION, WASHBURN COLLEGE, TOPEKA, KANSAS.

The last ten days of February were somewhat milder than the second decade, but it remained quite wintry through February, and the mean temperature was only 20°. There have been no days, since February 20th, when the temperature fell below 10°, and since March 1st the lowest temperature was 14°. Very little rain or snow has fallen. The heaviest snowfall of the winter occurred February 23d when about six inches fell. Northerly winds have been prevalent but the total wind travel has been rather below the average at this season.

Altogether the season is backward, and a cold, late spring seems likely to be the sequel to a long severe winter.