occurred first, a moderate shock not of any peculiar force and consisting of a single vibration; this was momentary. In about two minutes afterward a very sharp movement took place, giving the impression of a lateral motion from north to south. The table on which I had my elbow at the time seemed to recede about 1 to 2 inches, quiver an instant and return to its place: the beams of the houses creaked like the timbers of a ship in heavy weather. Doors and windows flew open. Those who were in bed at the time seemed to feel it much more, and the effect of the vibrations was to make many "C sea sick." This shock, they tell me, was the sharpest known here since 1826. I cannot learn of any damage done to buildings in the city.

The unquietness of the earth continued from the time mentioned until nearly 11 P. M., with a species of shuddering motion scarcely perceptible unless one were lying down. There was heard with each shock, a peculiar muffled rushing sound, not as clear and distinct as the movement of wind, but something like it. At the moment of the principal shock I looked at my watch and found the time to be ten minutes of ten-Bogota time. Time however, here, is not well regulated, as the observatory possesses no instruments and is neglected. The direction of the movement was very distinct from the north to the south. As earthquakes rarely have their centers in Columbia and are generally the result of action in Ecuador, it may be advisable to connect this observation with notices from that country. I believe there is but one volcano in action in Colombia-Puracè.

Some nights since we noticed for two hours after sunset in the west, and nearly in the range of Tolima, a well defined column or line of light, on the Cordillera. This bore about due west. The character of the light I could not determine.

Legation of the United States, Bogota, June 6, 1870.

ART. XLVIII-Discovery of a new Planet, the 112th, named Iphigenia, by Dr. C. H. F. PETERS, of the Litchfield Observatory of Hamilton College. Letter to the Editors, dated Clinton, Oneida Co., N. Y., Sept. 22, 1870..

I HAVE the pleasure to communicate the following observations upon an asteroid discovered on the night of the 19th inst.

The planet is about 11th magnitude, receives the number (112), and I have already given a name to it, Iphigenia, while that found on Aug. 14, (111), has been called Ate, with regard to the simultaneous events in Europe.

AM. JOUR. SCI.-SECOND SERIES, VOL. L, No. 150.-Nov., 1870.

ART. XLIX.-Geological Explorations in China; by Baron von RICHTHOFEN. In a letter to Prof. J. D. WHITNEY, dated Peking, Aug. 20th, 1869, and communicated by him for this Journal.

I PROMISED you, a few days ago, a more detailed account of the geological results of my travels in Manchuria and the province of Chi-li than I wished to give before having visited at least some of the localities near Peking examined before by Pumpelly. I have done this and am now acquainted with the most important formations occurring in the neighborhood of this capital.

The southern province of Manchuria has the name Shing-King and is divided by the Liao river into Liao-tung and Liao-hsi (meaning East and West of the Liao). The course of my travels from May to July was as follows: from Chifu by sea to Nin-chang, at the mouth of the Liao; thence by land down the western and up the southeastern coast of Liao-tung, to the frontier of Corea, then to the northeast, along this frontier, and to Mukden; from Mukden I went to Peking by Kin-chan and Yung-ping.

There are certain circumstances which render the geology of northern China difficult. In the first place the extent of the country is very great, and the character of the formations changes no less in the different provinces of it than it does in other regions of the globe. One is easily inclined, on a hasty tour of reconnoissance, to compare the strata in various regions on lithological grounds. But if I bear in mind the erroneous conclusions arrived at in the European Alps, by geologists who endeavored to determine the age of the sedimentary formations on the strength of their lithological resemblance to the formations of other parts of Europe, I think I cannot be cautious enough in this new country. Lithological analogy can here be used as a safe guide only when carefully traced from province to province and so on to remote regions. Then there is the apparent absence of any great geological events creating disturbances simultaneously over the whole region. Ancient deposition continued in one place while it was interrupted in another by the dislocation of those strata previously deposited. Another difficulty is the scarcity of fossils. I dare say that, with the exception of a few plants of the Coal-measures, I have discovered all localities of fossils now known to exist. Yet, if it is considered that I never received any knowledge of their existence (excepting Lake Tai-hu) not even the slightest hint, from either native or foreigner, but that I had to discover every fossil myself in hurrying through the country, it will still be found surprising, that the number of known fossiliferous localities is so great. I believe that China will, on a closer examination, contribute largely to the knowledge of the most ancient animal life on the globe. There is another difficulty caused by the recurrence, at different levels, of strata which bear a close similarity to each other. This relates chiefly to certain quartzose sandstones of a

reddish or yellow color when converted into quartzite. They have often a thickness of thousands of feet, and, as they are less affected by denudation than many other stratified rocks, they frequently compose mountain ranges for themselves, without offering any clue for determining their stratigraphical position. This is also true, though in a far less degree, of the limestones. In regard to these, as also to the knowledge of the occurrence of fossils, the analogy with the history of the exploration of the European Alps is striking. One cannot be astonished that the first explorer of Chinese geology, though a most admirable observer, should have distinguished only one great limestone formation in China, and referred it all to that age (namely, the Devonian) to which all the fossils then known (namely, those which are sold in drug stores) were believed to belong; just as "the Alpine limestone was until not very long ago a comprehensive term used to designate all the limestones occurring at different geological levels in the Alps. You may recollect that already my observations on the Yang-tse induced me to distinguish there at least three limestone formations. Since then I have come to the conclusion that it will not be difficult, on detailed examination, to establish in other regions a greater number at distinct levels.

It is for the various reasons mentioned, that I examined every mountainous country independently from what I had seen before, applying new terms for the different formations observed, and tried to establish the analogy between different regions only after having completed the exploration of each. The series of formations, as established on the Yang-tse, has found thereby a great deal of additional support and, I think, will prove to be a near approximation to the true order of succession.

In my two previous letters (March 1st and May 8th) I mentioned my having found Carboniferous fossils on the Yang-tse and in Shantung, in certain limestones and shales which occur there in close connection with the Coal-measures, or indeed form part of them. They mark there a very distinct and remarkable horizon. I did not find any corresponding fossils in Manchuria or Chili. There, however, I was fortunate enough to collect sufficient material for determining the age of a formation which corresponds, stratigraphically and lithologically, with the lowest ("Matsu ") limestone on the Yang-tse and the formation mentioned as No. 2 of Shantung in my letter of May 8th. It has a thickness of many thousand feet, and is, lithologically, exceedingly varied. It consists of endless alternations of red micaceous argyllite and brown sandstone, with strata of limestone, the former two prevailing in the lower half, the latter in the upper portion. The limestone itself presents a large number of varieties, and one can distinguish, on purely lithological grounds, several horizons, the order of succession of which is similar in wide regions. One of these horizons is marked by black oölitic limestone, which, together with some other conspicuous varieties of limestone, extends from the Yang-tse to Liao-tung and to Peking (twelve degrees of latitude and ten of longitude).

On the frontier of Corea, this oolitic limestone abounds in the remains of Trilobites and small brachiopods, chiefly of the Orthis and Lingula families. The sediments were there deposited in inlets of the ancient sea between ridges consisting chiefly of gneiss, granite and quartzite. The accumulation of the shells of trilobites which took place in these protected abodes is astonishing. I collected quite a number of species, but nothing adequate to the material which I saw, as several circumstances, chiefly the danger of being cut off by torrents swelled by the copious rains of the season, made it necessary to hurry over the most prolific localities. Yet, I hope that it will now be possible to determine the age of one of the most important formations of Northern China. It predominates, in bulk, over all other sedimentary formations of Lio-tung and extends thence into Corea. In Liao-tsi, it appears to have been removed by denudation to a great extent. It ap pears only in places, and even in these it is often covered by porphyries. Again it takes a dominent part in the structure of the country in the province of Chi-li, chiefly between Yungping-pu and Peking, becoming, however, more and more metamorphosed with the approach to the latter city. Its limestones (that is, its upper portion) form the narrows which lead to the Nankan pass. They are intensely altered, and traversed by innumerable dykes of intrusive rocks. What Pumpelly describes as the Hwaingan beds, are probably the lower strata of this same great formation.

In Liao-tung, as in Shan-tung, the oolitic limestones carrying the trilobites, are overlain by a great thickness of limestone, which is immediately followed by the Coal-measures. In Liao-tung, I found no fossils in this limestone, excepting numerous Ammonites and Orthoceratites, which cannot be determined. They occur immediately below the coal-bearing strata, the conformable superposition of which on the limestone I observed in a number of places. There are localities, such as northwestern Shan-tung and southern Liao-tung, where there is an apparently uninterrupted series of sedimentary deposits, commencing with sandstones and shales thousands of feet lower than the oolitic limestone and ending with the Coal-measures. Every layer appears to be conformable to that which it overlies, but no such parallelism exists between the lower and upper portions of the series, a gradual change of inclination marking the former gradual changes of level. It is not improbable that in these localities the entire series of formations, from the Silurian to the Coal-measures, is represented. It is in these regions that the order of succession will have to be studied. There are, however, more numerous instances where the outbreaks first of granitic and then of porphyric rocks, which extended evidently over long periods, have created repeated disturbances. The vicinity of Peking has been among the theaters of the most intense eruptive action. But even here the Coal-measures are conformable to the underlying limestones, in all instances which came under my observation.

I am unable to pronounce at present an opinion on the relation of the northern Coal-measures to those of Shan-tung and the lower Yang-tse. The remains of plants which I collected in nearly every one of the northern coal-fields will probably help to elucidate this question. But, judging on mere stratigraphical grounds, I cannot help thinking, that the Coal-measures of Liao-tung and Liao-hsi, and the lower portion of those in the neighborhood of Peking, will not differ much in age, either among themselves, or as compared with the Coal-measures of Middle China, It is, however, a noteworthy fact, that the coal formation of Peking has an extraordinary development. I had only occasion to see those coal-bearing strata which lie immediately on the limestone. West of Peking, these strata, together with the limestone and a few thousand feet of superincumbent deposits, have undergone an intense metamorphism, the coal being converted into anthracite. It appears, from Mr. Pumpelly's description, that the Chaitung Coalmeasures (which I did not visit) occupy a, geologically, much higher level. Altogether it may be safe to conclude, that in China, as in other countries, the deposition of coal and intervening sediments continued during a considerable period, in which it shifted to different regions. Yet, I must confess, that comparison on stratigraphical grounds makes it difficult to believe that any portion of the Coal-measures of Northern China should be of so recent age as Dr. Newberry was inclined to conclude on the strength of the vegetable remains which he determined.

SCIENTIFIC INTELLIGENCE.

1. CHEMISTRY AND PHYSICS.

1. On the influence of electricity on air and oxygen as a means of producing ozone.-HOUZEAU has drawn the following conclusions from a great number of estimations of ozone obtained by means of Ruhmkorff's apparatus.

(1.) The production of ozone is greater in air renewed from time to time than in confined air.

(2.) It is greater at the negative than at the positive pole. (3.) The production of ozone increases only up to a certain point

with the duration of the electric action.

(4.) The ozone increases with the electric intensity.

(5.) The ozone diminishes when the distance which separates the electrodes increases.

(6.) The production of ozone varies with the length or surface of the electrodes.

(7.) Other conditions being equal, the production of ozone is greater by utilizing the effect of the two electrodes.

(8.) The production of ozone is equally manifested, out of direct contact with the air, with metallic electrodes, when these last are surrounded for their whole lengths with tubes of thin glass play