principal, if not the only, instances of rock inscriptions in the northern parts of this continent described by writers of the time of the French régime, and though, with others known to the English, like the Dighton Rock, they were probably conspicuous from their prominent position or from their location on routes of travel, and therefore early remarked and described, yet in artistic conception and workmanship they doubtless did not differ materially from scores of others that have been discovered since. Naturally the work of this kind that was executed in caves came to the notice of civilized man much later, for such places would be somewhat out of the way and more or less inaccessible without special effort, and, indeed, as possible resorts of wild beasts or venomous reptiles, would not be sought by the traveler unnecessarily. But a notable ex

FIG. 1.-DAYTON'S BLUFF CAVE.

ception to this rule was a cave within the limits of the capital city of Minnesota, which for over a century has had a somewhat undeserved celebrity, which was given to it by Capt. Jonathan Carver in 1766-'67. In his description he mentions the incised figures as follows: "I found in this cave many Indian hieroglyphics, which appeared very ancient, for time had nearly covered them with moss, so that it was with difficulty I could trace them. They were cut in a rude manner upon the inside of the wall, which was composed of a stone so extremely soft that it might be easily penetrated with a knife-a stone everywhere to be found near the Mississippi." The construction of a railroad some years ago, which necessitated the demolition of the front part of this cave, together with the confusion made by the intrusive names of modern visitors and idlers,

ruined the aboriginal pictographs in it, of none of which is a copy known to have been made. Ten years ago there were plainly to be seen snakes, birds, men, animals, fish, and turtles, some of which were intaglios and others outline figures, and they were clearly of the same style and probable age of those discovered in recent years in caves along the valley of the upper Mississippi. Since October, 1888, several caves, rock shelters, and fissures have been visited between a point a few miles below Lansing, Iowa, and St. Paul, Minn., and thoroughly explored for pictographs, of which the best specimens were carefully copied. Seven of the caves are here described, in the order of the descent of the river. from north to south, and at least one good representative pictograph from each, reduced in facsimile, is furnished by way of illustration.

Dayton's Bluff Cave, St. Paul, Minn.—At the foot of Dayton's Bluff, which skirts the river in the lower part of the city, 50 feet northeast of Commercial Street, about midway between Plum and Cherry Streets, and a little over 400 feet above Carver's Cave (already cited), is a moderate sized cave, only one third the length of that one, facing to the southwest similarly. It is about 35 feet in length, measuring on the present floor to the edge of the water in the rear that in a few feet meets the descending slope of the roof; in width about 24 feet, and, at present, 10 feet high. In it are pictures of men, birds, and animals, cut into the side-walls and roof, all of which are outline figures. The one illustrated here (Fig. 1), which is on the left hand as one enters, and quite near the floor, represents a man with uplifted hands, and is about one foot in length.

La Moille Cave, Winona County, Minn.This is the most interesting place of its kind yet discovered. It is on the south side of Trout brook, about a mile southeast from La Moille railroad station. The valley is somewhat of an amphitheatre, being walled in on two sides by bluffs from 300 to 500 feet high, with the land rising in high plateaus to the west and northwest. On the south side of the valley, where the brook runs near the foot of the bluff, there is a rock escarpment of Potsdam sandstone rising about 30 feet, which is perpendicular, and at this point there is an archway 27 feet wide and 9 feet high. Above the archway a large pine tree stands on the verge of the rock. From the entrance to the back part of the cave the distance is 45 feet; the length of the cave proper, which runs parallel with the outer face of the rock is 70 feet. The roof is bell-shaped, sloping from a central point toward the bottom on all sides, and at the highest point it is 15 feet above the ground at the entrance. The floor is not level, the eastern side being the highest. Flowing from the heart of the bluff are two springs, one from the southeast and the other from the southwest, which unite on the west side of the cave, and thence flow into Trout Brook, 30 feet from the entrance. The southeast stream emerges from a low passage-way, which is about 12 feet broad and from 2 to 3 feet high, extends beyond the main cave 30 to 40 feet, and then becomes narrower and much lower. When the Mississippi river overflows its banks the back water enters the cave, and at extreme

daughters, while the pennant at the top may be the family or tribal ensign.] In this instance an attempt has been made to show the wing-feathers, which (though it is not an uncommon thing to see them delineated in this region) are on a far more elaborate scale than is usually attempt

delineated. Other specimens of the serpent family are represented in this cave, and are much finer and more perfect, especially as regards the rattles (in snakes of that class), and they are also larger. Similarity in size governed partly the selection for illustration of the two here given.

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ed. The groove extending back from the head may be intended to represent a snake with open mouth, but as there is no similar specimen to be found among the numerous snakes (30 or more) carved upon the roof, it is not unreasonable to surmise that it may be intended to symbolize speech. The two snakes (Figs. 4 and 5) are on the west slope of the roof, and represent two

FIG. 6. SAMUEL'S CAVE.

types, one of which is a rattlesnake. They are grooved out from one-half inch to one inch in depth, and are perfectly smooth. In the bottom of the main groove are smaller ones, which are probably intended to represent the darker colorings on the back of the particular kind of snake

Some of them have forked tongues protruding from the mouth, which may be intended to represent speaking rather than hissing.

Samuel's Cave, La Crosse County, Wis.— This cave, unlike the others here described, is not in the immediate valley of the Mississippi, but is about 9 miles by road from the city of La Crosse, on the northwest quarter of section 20, town 16, range 6. It is near the foot of a hill that rises about 70 feet above the valley, and until within a few years its existence was unknown, the entrance having been covered by the gradual accumulation of debris washed from the slope above. On the side walls and lower slope of the roof are outline figures, as well as paintings having a bluish-black color. The latter are covered with a thin glazing or coating deposited from disintegrated limestone. There are outline carvings representing men, animals, birds, etc. The one here illustrated (Fig. 6) denotes an elk, probably, and covers a space about one foot square.

Reno Cave, Houston County, Minn.-This is on the northwest quarter of section 35, town 102, range 4, near Reno, locally known as Caledonia Junction. It is about 150 feet above the clough, in a ledge 30 feet in height. There are sarvings representing birds, men, etc., both on the face of the ledge and in the cave. The grotesque figure, or rather caricature, here illustrated (Fig. 7) represents a man with large hands, and somewhat after the style of some of the Mexican carvings.

Allamakee County, Iowa, Cave No. 1.Above Kain's Station, on the northeast quarter of section 26, town 100, range 4 W., is a ledge extending along the slough for about 150 yards, which is about 25 feet in height above the water. In this ledge are a cave, several fissures, and some shelters. The figure (Fig. 8) illustrated represents a human head with horns or feathers, and covers a space about 9 by 12 inches. The

cave was used as a dwelling-place at some early period, for there are numerous fragments of partially burned bones, broken pottery, etc., bedded

Allamakee County, Iowa, Cave No. 2.On the northwest quarter of section 18, town 99, range 3 W., is a ledge of rock about 200 feet above the river, in which is a small cave. Among the pictures in it are several representing the human head, also snakes, animals, and canoes, or crescents. In one case the groove forming the outline of one of the heads (human) has been painted a bluish-black color, and apparently the paint is the same as that used in the Samuel's cave near La Crosse. The specimen illustrated (Fig. 9), which is about 6 by 15 inches, may represent some kind of bird.

In

Allamakee County, Iowa, Cave No. 3.-On the northeast quarter of section 3, town 98, range 3 W., three or four miles below Lansing, is a ledge about fifty feet high, standing about 100 feet above the river. this ledge are two narrow caves or fissures, known as the "Indian cave," on the walls of which were formerly a large number of carvings representing men, animals, snakes, birds, human feet, birds' and animals' tracks, human faces, crescents (canoes?) and others of doubtful character. Many of these have been wantonly defaced until they can scarcely be traced. The one here given (Fig. 10), which is about 14 by 19 inches, probably represents some kind of bird.

FIG. 7.-RENO CAVE.

FIG. 8.-ALLAMAKEE CAVE, No. 1.

in the earth covering the floor. At the various other points that are mentioned above are to be found representations of hands, feet, men, birds' claws, and other objects.

FIG. 9.-ALLAMAKEE CAVE, No. 2.

In copying these cave-drawings, it has been an object to get only the best specimens, for it is an impossibility to get all of them, and often it is hard to tell where there is a beginning or an end

ing. There is no way now of determining how all this carving was done, for the grooves of themselves show no other indication than the rubbing process. As for style and merit, these selected and representative pictographs must speak for themselves; and as regards their meaning, it is purely a matter for conjecture, and the reader may draw his own conclusions as

FIG. 10.-ALLAMAKEE CAVE, No. 3. to whether religious or mythological ideas entered into their construction, or whether they were but casual records or idle work. Their antiquity, however, is great, as was proved by excavations made in the Samuel's cave shortly after its discovery in 1878-the only cave of the upper Mississippi that, up to this time, has been formally brought to the notice of antiquaries.

CHEMISTRY. Chemical Philosophy. One of the most notable contributions of the year to this branch of chemistry is the lecture by the distinguished Russian chemist Mendeleeff, at the Royal Institution of Great Britain, in which he attempts to apply to chemistry the dynamical principle of Newton's Natural Philosophy. Having traced an analogy between the grouping of atoms and the arrangement of celestial bodies in stellar systems, the author assumes that chemists have during the last ten years sought and found systems of conservation or dynamical equilibrium similar to those which prevail in the visible world, and by which the position of the heavenly bodies in the universe is determined. Where one-sided affinities only were at first detected, secondary or lateral ones have also been found, and even those which are diametrically opposite; yet, as

among these, dynamical equilibrium establishes itself, not by excluding one or other of the forces, but by regulating them all, so the chemist finds in the flame of the blast-furnace, the formation of salts, and with especial clearness in double salts, and in the crystallization of solutions, not a fight ending in the victory of one side, as used to be supposed, but the conjunction of forces; the peace of dynamic equilibrium resulting from the action of many forces and affinities. Carbon combines with oxygen under the influence of heat, and is dissociated from it by heat. In the case of the solution of common salt in water, it is necessary to take into account, on the one hand, the formation of compound particles generated by the combination of salt with water, and on the other hand, the disintegration or scattering of the new particles formed as well as of those originally contained. A dynamic equilibrium is formed, of particles tending to combine and also to fall asunder. Chemical reactions which formerly appeared to act victoriously along one line have been proved capable of acting as victoriously along an exactly opposite line. It is insufficient to suppose that statical equilibrium reigns alone in chemical systems or chemical molecules. Numerous considerations compel us to renounce this idea; and appeals to dynamic principles constitute, in the author's opinion, the foundation of the modern teaching relating to atomicity, or the valency of elements. Starting with Newton's third law of motion (of action and reaction), it is possible to preserve for chemistry all the advantages arising from structural teaching, without being obliged to build up molecules in solid and motionless figures, or to ascribe to atoms definite limited valencies, directions of cohesion, or affinities. The case of substitutions is selected for present consideration by the author, and is discussed with particular reference to the illustrations that may be drawn from the carbon_compounds of the doctrine that if a system of atoms or a molecule be given, then in it, according to the third law of Newton, each portion of atoms acts on the remaining portions in the same manner and with the same force as the second set of atoms acts on the first. It is inferred directly from this consideration that both sets of atoms forming a molecule are not only equivalent with regard to themselves, as they must be acccording to Dalton's law, but also that they may, if united. replace each other. The review results in the conclusion that by the principle of substitution

that is, by the third law of Newton-" we are able to deduce, in the simplest manner, not only the individual composition, the isomerism and relations of substances, but also the general laws which govern their most complex combinations, without having recourse either to statical constructions, to the definition of atomicities, to the exclusion of free affinities, or to the recognition of those single, double, or treble ties which are so indispensable to structurists in the explanation of the composition and construction of hydrocarbon compounds. And yet, by the application of the dynamic principles of Newton, we can attain to that chief and fundamental object

the comprehension of isomerism in hydrocarbon compounds, and the forecasting of the ex