matites des Environs d'Antsirabe à Madagascar. (Geneva, Kündig, 1910.) -Describes with many illustrations the gem deposits of Madagascar. HARKER, A.-"Some Aspects of Modern Petrography." Address of the President of the Geological Section, British Assoc. Advancement of Science, 1911.

uni

his paper, "The Nature of Volcanic Action." Daly's main theses, however, are of quite another nature. He regards volcanic action as primarily a deep-seated phenomenon, due to mechanical intrusion from a versal substratum of basaltic magma through a higher, acidic (granitic) earth shell; and he regards the gases (whatever be their nature) as of vast importance as heat carriers during the eruption, by a process of what he calls "two-phase convection," or the formation of strong currents in the magma through the formation and rising of bubbles of gas in the magma. Like Brun, Daly regards water in its relation to volcanic eruptions as largely an unimportant surface agent, and considers that it will be possible, and necessary, to distinguish between true magmatic eruptions and those due to steam explosions, to which he applies Suess's term of phreatic eruptions.

8.

9.

ogy. (Ann Arbor, Mich., Wahr, 1911.) Describes the more important minerals. Interleaved for note

taking.

and HUNT, W. F.-Tables for the Determination of Minerals. (New York, McGraw-Hill Book Co., 1911.) -Tables for physical determination of minerals.

TUTTON, A. E.-Crystallography and Practical Crystal Measurement. (London, Macmillan & Co., 1911.)-Complete description of methods of measuring all crystallographic properties.

EARTHQUAKES AND VOLCANOES

HARRY FIELDING REID

serious

The

A

Earthquakes.-The most earthquake of the year in America was that which occurred in Mexico in the early morning of June 7. The center of the disturbance was in the neighborhood of Mt. Colima, not far from the Pacific Coast. shock came at 4:26 in the morning; it caused great damage and killed many persons within a distance of perhaps 100 miles of its center. second shock the next day about 5 p. m., though much less severe, added to the damage already done. It is quite probable that the seat of the disturbance extended further toward the east, as the city of Mexico, 300 miles distant, was severely shaken, a number of houses were overthrown, cracks formed in the National Palace and several of the churches, and over 60 people killed. Mexico is built on an old lake bottom and the incoherent character of the foundation is probably the cause of the great damage in that city. Fissures were reported in the streets and the tracks in one place sufficiently to disturb of the street railways were twisted, traffic for some time. The accounts of the shock are meagre, but there can be no doubt that the earthquake

l'Exha

laison Volcanique. (Geneva, Kündig, 1911.) Notes on the rôle of gas in eruptions, analyses of gas contained in rocks and gaseous exhalations, and many illustrations.

3. DALY, R. A.-"The Nature of Volcanic Action." (Proc. Am. Acad. Arts and Sci., 47, 3, 1911.)—Describes a theory of the mechanism of volcanic eruption, with many observations supporting it from the volcanoes of Ha

waii.

"Magmatic Differentiation in Hawaii." (Jour. of Geol., 19, 1911.) — Describes the nature of the Hawaiian lavas and offers a theory as to how the different phases are related.

As

was one of very great violence. noted later, the volcano Colima became violently active.

A few seconds after 2 o'clock in the afternoon of July 1 a large part of central California was shaken by a fairly strong earthquake. No very serious damage was done, but the memory of the earthquake of 1906 made the people timid and they were greatly frightened. The center of the shock was not far from Mt. Hamilton, at which place cracks were formed in some of the brick buildings and the pier of the great telescope was shifted three-fourths of an inch on its base, but fortunately was not injured. Furniture was displaced a foot or more. At Coyote, in the Santa Clara valley, a few miles to the southwest, the shock seems to have been about equally strong; water-tanks were overthrown and many windows were broken, etc. In the neighboring towns the disturbance was not so strong, but nevertheless it produced quite a panic, especially in San Francisco. The shock was felt as far as Redding in the north, a distance of about 240 miles, and was also reported at Los Angeles, to the southeast, a distance of 300 miles, but in the latter case it was extremely slight. It was felt at Stillwater, Nevada (240 miles). In all probability the shock was distinctly felt over a land area of 100,000 sq. miles. The distribution of the intensity was somewhat like that of the great earthquake of 1906, i. e., the intensities were stronger on the great alluvial valleys of California than on the mountain ranges. In the central Sacramento and San Joaquin valleys the shock was quite strong, whereas in the Sierra mountains it was extremely slight; several places in the mountains reported not having felt it at all. Still further east, at Carson City, Nev., it was fairly strong, but was distinctly weaker at Virginia City and Reno. The delicate earthquake instruments at Mount Hamilton, at Santa Clara College near San José, and at Berkeley were thrown out of adjustment by the shock, so that their records were very defective. The times of beginning, however, at these stations point to a center not

far from Mt. Hamilton. Slight local shocks had been felt at Mt. Hamilton on Dec. 12, 15, 19 and 31, 1910. During the two months following the earthquake, 65 after-shocks were felt, or recorded, at Mt. Hamilton. A smaller number are also reported from Santa Clara.

Moderate shocks were felt at Nome, Alaska, Nov. 20, 1910, and at Fairbanks, Jan. 7, 1911; a slight shock was also reported from Yakutat early in Sept. On Sept. 21, a severe earthquake was felt at Valdez and the surrounding country. The military cable was broken very near Valdez.

Moderate shocks were felt at Imperial Valley, southern California, on Dec. 27, 1910; at San Miguel Island on March 28, 1911; at Oxnard and Los Angeles on May 10; in western Riverside County, Cal., on Aug. 11 and 21; at Ellensburg, Wash., July 4, and at Bellingham, Wash., on Sept. 28.

During the month of November, 1910, twelve shocks were felt in Esmeralda County, Nev., five being on the 21st. A few of these were fairly strong shocks. A later shock came on the night of Dec. 21-22. A fairly strong shock occurred in southeastern Arkansas on March 31, 1911. It was felt over an area of about 18,000 sq. miles in the states of Arkansas, Louisiana, Mississippi and Tennessee.

On June 2 the James River Valley, in the southeastern part of South Dakota, was visited by a moderate earthquake which was felt apparently over an area of about 40,000 sq. miles, but did no damage. Slight shocks were felt in the neighborhood of Ogdensburg, N. Y., Jan. 29, and near Cæsar's Head, N. C., April 21.

A shock, in the neighborhood of Mazatlan, on the west coast of Mexico, April 7, caused some damage to property. Slight shocks were felt near Lake Ilopango, San Salvador, Dec. 17, 1910; and very strong shocks in the western part of the Republic of Panama, Dec. 21-22; but they were slight in the Canal Zone.

In the latter part of 1910, a violent shock was felt at sea south of Jamaica, Oct. 31, but was not noticed on land. Moderate shocks were felt in St. Vincent, Nov. 6; in

Fort de France, Martinique, Nov. 18; and in Santiago, Cuba, Dec. 9. A number of houses were destroyed and several people injured, by an earthquake in St. George, Granada, on May 31, 1911. A shock, felt in the western part of Hayti and in Turk's Island to the north, on Oct. 6, 1911, threw the people of Portau-Prince into a panic, but did little damage. A severe earthquake in the middle of Sept., 1911, caused the death of many people in the northern part of Chile. Three heavy shocks were felt at Guayaquil, Ecuador, a few days later.

Many minor shocks in the Philippine Islands are reported by the Philippine Weather Bureau; but no important shock has been felt during the past year. Many shocks took place at the time of the eruption of Mt. Taal.

Volcanoes.--About 40 miles south of Manila, in the Island of Luzon, lies Lake Bombon, about 15 miles long and 9 miles wide. In the middle of this lake the volcano of Taal rises as an island. The island itself and the shores of the lake are inhabited by natives engaged in agriculture. Taal has had a number of violent eruptions since the early Spanish occupation of the Philippines, but none of them apparently was more violent than the short eruption of Jan. 30, 1911. On the evening of Jan. 27 great masses of black cloud poured from the crater, accompanied by subterranean noises and frequent light earthquakes. This condition continued with more or less variation until the night of Jan. 29-30. About one o'clock, on that night, the explosions became very violent, and shortly after 2 o'clock the greatest explosion occurred, the noise of which is reported to have been heard at a distance of 300 miles. Immense quantities of black ashes were shot up from the crater, forming a cloud, in which there occurred many brilliant electrical discharges. This seems to have exhausted the eruptive force of the volcano and it quieted down; in two days it was simply emitting puffs of white steam; a week later it had resumed its ordinary condition. As in former eruptions no

lava was poured out of the volcano, all the material ejected being in the form of dust and stones thrown into the air. The quantity of dust thrown out was enormous, the greater part being carried to the west, where it attained a thickness of 31 in. as far as six miles from the crater. It was noticeable on roofs and plants at a distance of 25 miles. The suddenness of the explosion and the great number of people living on, or close, to the volcano resulted in the death of over 1,300 persons and the destruction of much property. Everything over an area of 90 square miles was laid waste. Large waves, raised on the lake, invaded the surrounding shores and completed the destruction begun by the volcano, so that many of the smaller villages were entirely annihilated. The volcano itself and the surrounding country seem to have been depressed from three to six feet by the eruption. During the activity of the volcano many earthquakes occurred, some of which were felt at Manila, 40 miles distant. The seismograph in the Weather Bureau, . at Manila, recorded 197 shocks on Jan. 28; 113 on Jan. 29; 96 on Jan. 30; 199 on Jan. 31, and 127 on Feb. 1. After this the daily number rapidly decreased, so that by the middle of February only one slight shock per day was recorded. It is rather remarkable that on Jan. 29 and 30 the number of shocks recorded was only a little more than one-half the number recorded on Jan. 28 and 31, and that at the time of the most violent explosion of the volcano no shock was recorded.

On Jan. 7, at the time of the great earthquake in Mexico, Mount Colima, near the coast, 300 miles west of Mexico City, became violently active; great quantities of ashes were thrown into the air, and lava poured out from the side of the mountain. Much damage was done to the surrounding country and many people were killed, though it is uncertain whether the deaths are to be ascribed to the earthquake or to the volcanic eruption. The volcano soon grew quiet, but on June 17 it threw out enough dust and ashes to be strongly noticeable in Mexico City;

and again on July 12 there was renewed activity. This is the most serious eruption of Colima since 1869. Mt. Bacalar, in Yucatan, which has not heretofore shown any signs of life, was reported in activity at this period, but the accuracy of the report is doubtful.

On May 1 the volcano Ometepe, in Lake Nicaragua, became active, but did no damage.

On Sept. 2 Capt. Petersen, of the schooner Elvira, witnessed a violent

eruption in the Bogoslof Islands, Alaska. It began about 4 a. m. and continued until the evening. The islands seemed to be enveloped in flames and smoke, and many violent explosions were heard. The next morning several small new islands were seen to have been added to the archipelago and many changes had taken place in the group. A few weeks later the volcanoes Shishaldin and Pavlof were reported in moderate eruption.

METEOROLOGY

Aeronautic Charts.-America is not to be behind Europe in putting the results of her meteorological knowledge in such form that they will be available for the use of aviators and aeronauts. From Blue Hill Observatory (Mass.), a center of meteorological research of the highest scientific standing, comes a publication, the first of its kind, which is significant of the practical turn which is being given to meteorological investigation. Professor A. Lawrence Rotch, Director of the Observatory, and Andrew H. Palmer, Research Assistant, have prepared a set of charts intended primarily for those who "navigate the ocean of air." These charts embody the results of observations made at Blue Hill during the past 25 years, as well as those obtained from the trade-wind region of the Atlantic Ocean on several expeditions in which Professor Rotch coöperated. While the charts relate only to portions of the United States and of the Atlantic, they are highly important as pioneer work of a thoroughly and immediately practical kind."7

Studies of Wind Velocity and Direction. Another contribution, along similar lines, is A. H. Palmer's study of the wind velocity and direction in the free air as shown by kite and cloud observations at Blue Hill, and by ballons-sondes observations secured during 1904-07 from St. Louis. This investigation brings out (1)

the general increase in wind velocity with height; (2) the rare occurrence of gusts of wind below low heights; (3) the frequent clockwise and occasional counter-clockwise change of direction with height; (4) the shallow character of easterly winds; and (5) the relative frequency of ascending as compared with descending currents."

Cloud Formation. Much light on the formation of clouds is obtained from H. H. Clayton's study of the data obtained by means of kites sent up from Blue Hill. Here again the practical use of such data is clearly brought out; for it is by means of just such studies as these, which show the conditions leading to cloud formations of various kinds, that weather changes may some day be predicted.*

Free Air.-The free air data obtained by means of 896 kite and 117 captive-balloon ascensions from Mt. Weather Observatory in the three years July 1, 1907,-June 30, 1910, have been summarized by Dr. William R. Blair, in tabular and graphic form, in "Summary of the Free Air Data at Mount Weather Observatory for the Three Years, July 1, 1907, to June 30, 1910" (Bull. Mt. Weather Obsy., Vol. IV, Part 2, 1911, pp. 25-63). Diagrams of temperature gradients are given and charts show wind directions at different altitudes. Prof. Alfred J. Henry has studied the temperatures and pressures at certain summit and base stations in the Rocky Moun