end of the tube, and the mirror, being half-way between these, is at a loop. Hence it tends to set itself at right angles to the vibratory motion. This tendency is opposed by the magnetic forces; but the image on the scale shifts its position through a distance proportional to the intensity of the action. The instrument reveals an enormous disproportion between sounds which, when heard consecutively, appear to be of the same order of magnitude. (Phil. mag., Sept., 1882.) c. B. C.

Optics.

[4

Absorption spectra of ozone and pernitric acid. The places of eleven absorption bands due to ozone are catalogued by M. J. Chappuis according to wave-length. Of these, by far the most intense are those having the limits 2 = € 609.3 to 593.5 and 2 577.0 to 560.0, which are Nos. 2 and 3 of the table; next in intensity is 2 = 535.0 to 527.0, which is No. 5 of the table. These bands were observed in light which had traversed a tube 4.5 m. long, containing ozonized oxygen prepared at the atmospheric pressure and a temperature of 15° C. Variations of length of tube and pressure of gas were accompanied by a variation in the intensity of the absorption bands, such that the effect produced seemed proportional to the quantity of ozone traversed by the light. lowering of temperature, however, produced, independently of change in density, an increased intensity of the bands. M. Chappuis succeeded also in observing the absorption spectrum of the blue liquid which is obtained by compressing a mixture of carbon dioxide and ozone, in which he found the two characteristic bands Nos. 2 and 3 near D; the absence of the others being attributed to the small quantity of the liquid used.

A

If the smallest quantity of nitrogen were present in the tube, other bands of a greater intensity appeared, which M. Hautefeuille and the author were led to attribute to an oxygen compound of nitrogen richer in oxygen than nitric acid, and to which they gave the name pernitric acid. The stronger of the bands were readily seen in a tube no longer than 0.1 m. The eight bands attributable to this substance are tabulated and described.

In the second part of his paper, the author gives a discussion of the bearing of his discoveries on the telluric lines of the solar spectrum, with the conviction that the lines 2, 3, and 5 of the ozone spectrum are present in the spectrum of the sun when at the horizon. That a part of the cause of the blue color of the sky is the presence of ozone, is also indicated. · (Journ. de phys., Nov., 1882.) C. S. H. Reflection of 'actinic' rays. — M. de Chardonnet finds that silver alone, of a large number of solid and liquid bodies, exerts an elective absorption on light of short wave-length. Polishing a body does not alter its action. — (Journ. de phys., Dec., 1882.)

C. S. II.

[5

[6

is directly proportional to the square of the aperture of the observing telescope, may lead to sensible errors. The paper contains a table of differences of magnitudes, as determined by himself, compared with the same quantities derived from the Harvard observatory. ·(Month. not. roy. astr. soc., Nov., 1882.) [8

C. S. H.

Photometric measurements of the sun, moon, and electric light. According to the measurements of Pouillet, the sun is radiating 7,000 horsepower per square foot of its surface, or 50 horse-power per square inch. Sir William Thomson states that the normal current through a Swan lamp giving 20 candle-power is 1.4 amperes, with a potential of 40 to 45 volts. Hence the actual work is 61.6 ampere-volts, or watts (so-called). Dividing by 746, we find .085 horse-power for the electric activity in a Swan lamp. The filament is 3.5 inches long, and .01 inch in diameter: hence the area of the surface is .11 of a square inch, and the activity at the rate of .75 horsepower per square inch. Therefore the activity of the sun's radiation is about 67 times greater than that of a Swan lamp for an equal area.

An experiment on sunlight compared with an observation on moonlight made by our author, has led him to conclude that the surface of the moon radiates something not enormously different from onethird of the light incident upon it. The moonlight at the time and place of the observation (York, early in September, 1881, about midnight, near the time of full moon) was found to be equal to that of a candle at a distance of 230 centimetres. The luminous intensity of a cloudy sky was found, about 10 A.M. in York, during the meeting of the British association, to be such that light from it through an aperture of one inch area is equal to about one candle.

An experiment on sunlight last December showed, at one o'clock, the sunlight reaching the author's house to be of such brilliancy, that the amount coming through a pinhole in a piece of paper .09 of a centimetre diameter produced an illumination equal to that of 126 candles. The area of the candle-flame was 2.7 square centimetres, or 420 times the area of the pinhole, and therefore the intensity of the sun's light was equal to 126 × 420, or about 53,000 that of a candle-flame. — (Electr. review, Dec. 23, 1882.) Sir W. Thomson's first calculation showing that a Swan lamp giving out 20 candle-power uses up only

the amount of energy of the sun for the same unit of surface is interesting; but, if we include the question of the light obtained, quite a different result will be reached. The total area of the carbon filament, as we have seen, is .11 of an inch; but only half of this, or .055 inch (equal to .36 centimetre), can be seen at once; and this gives out 20 candlepower. The area of the pinhole in the last observation was .0063 square centimetre, and gave out 126 candle-power. Hence × 120 = 359,- the intrinsic brilliancy of the sun in terms of the Swan light. The sun therefore radiates 67 times the energy, but 359 times the light, of the Swan lamp, or 5.4 times the light for every horse-power expended.

36 .0063

In May, 1879, the writer conducted some observations on this subject (Proc. Amer. acad., 1880, xv. 236), by which it was found on one occasion that the total brilliancy of the sun, when at an altitude of 25°, was 64,700 candle-power at one metre's distance; and another time, when at an altitude of 40°, 82,000 candle-power. The apparent area of the sun's disc at this distance would be .68 centimetres; and assuming that the area of the candle flame in this instance was 2.7 centimetres, which could not be very

.68

far out of the way, we have the intensity of the light from the sun's disc in the two instances, 2:1 × 64,700257,000, and 326,000 instead of 53,000, times that of the candle.

In our author's observation the altitude of the sun could not have been far from 12°; which, together with the greater clearness of the American skies, may have produced the large discrepancies in our results. But assuming my results to be correct, even at an altitude of 40° the sun gives out 33 times the light of a Swan lamp for the same amount of power expended. W. H. P. [9

(Photography)

Green fog. A possible explanation of this difficulty is offered by Mr. E. Dunmore, who thinks it is due to the action on carbolic acid by ammonia, converting it into aniline. Both substances are generally present in an emulsion prepared with ammonia; and, with regard to an acid-boiled emulsion, the gelatine may of itself contain them, the ammonia from incipient decomposition, and the carbolic acid from what has been used to preserve it from putrefaction during manufacture. ·(Brit. journ. phot., Dec. 1, 1882.) W. H. P.

[10

A modified gelatine emulsion. Mr. W. K. Burton employs a process by which, in the results obtained, the density of the negative will increase nearly proportionally to the amount of light received. By the ammonia process the density increases too rapidly at first, while in the long boiled emulsion the increase is too slow. But the great advantage which he claims lies in the fact that the gelatine which has gone through the ordeal of the operation necessary to obtain sensitiveness is eliminated. It is this gelatine which he thinks gives rise to many of the evil phenomena which gelatine plates exhibit, especially when ammonia is used. — (Brit. journ. phot., Dec. 15, 1882.) W. H. P. [12

CHEMISTRY.

(General, physical, and inorganic.) Lecture experiments. — Dr. A. W. Hoffmann has devised a series of lecture experiments similar in principle to those described in his Einleitung in die moderne chemie. The electrolysis and formation of hydrochloric acid are illustrated in a simple manner, and several improvements are introduced into experiments illustrating the phenomena of combustion. Some experiments on the volumetric relations of gases are suggested, and the analysis of ammonia gas is made less tedious in its details. A new form of apparatus is described, which is intended to give an experimental illustration of the law of Dulong and Petit.(Berichte deutsch. chem. gesellsch., xv. 2656.) C. F. M.

[13

Lecture experiments with zinc-dust and sulphur. In the experiment which is usually performed to illustrate chemical combination, instead of heating sulphur with copper or iron filings, Schwarz makes an intimate mixture of sulphur and zinc-dust, and ignites it with a match. It burns like gunpowder, with a bright greenish flame, leaving a residue of zinc sulphide. When heated in a retort with carbonic disulphide, zinc-dust is converted into the sulphide, and carbon separates in the form of soot. Many complex organic compounds containing sul

phur are decomposed when heated with zinc-dust with the formation of zinc sulphide and carbon compounds of a simpler order. (Berichte deutsch. chem. gesellsch., xv. 2505.) C. F. M. [14

Preparation of oxygen at ordinary temperatures. When potassium permanganate is mixed with concentrated nitric acid, M. Guyard finds that oxygen is liberated from the permanganic acid with great regularity, and the action continues until two and a half equivalents are set free. If the apparatus is then immersed in boiling water, the disengagement of gas is kept up until altogether three equivalents of oxygen are obtained from the permanganic acid. -(Bull. soc. chem., xxxviii. 383.) C. F. M. [15

The double haloid salts of mercury. - For the purpose of obtaining a more definite knowledge of reactions which take place in the formation of double salts, M. Berthelot has determined the heat of formation of certain double salts of mercury. It appears that the quantity of heat liberated in the formation of the anhydrous salt is smaller than when the hydrous salt is formed: Hg Cl. K Cl = +1eal. 9; Hg Cl2. K Cl. H2O=+2cal. 7. The acid salt Hg I. 2 III. sets free the same amount of heat as the salt Hg I. 2 K I. While the heat of formation of the three haloid salts of potassium is nearly the same, it is very different in the corresponding salts of mercury: Hg Cl=11cal.; Hg Br2 15 cal. 4; Hg I

=

21cal. 7. This inequality, as the author proposes to show, is the determining cause of double decompositions. — (Bull. soc. chim., xxxviii, 369.) C. F. M. [16

Fine gold from chlorination. - Gold produced from the mines of the Canada consolidated gold mining company by Mear's chlorination process is reported to be the finest ever received by the U. S. mint. (Eng. min. journ., Nov. 18, 1882.) R. H. R. [18

Improvements at Batopilas in silver amalgamation. The losses of 50 oz. per ton in the tails by the old arrastras have been reduced to 8 oz. per ton. The improvements consist of pan amalgamation for the first and second class ore, concentration folThe lowed by pan amalgamation for third-class ore. loss in mercury has been reduced at the same time from 27 per cent, as incurred by the arrastra, to 24 per cent with the pan. (Eng. min. journ., Nov. 18, 1882.) R. H. R. [19

GEOLOGY. Lithology.

4. Silicates and meteoric iron forming a granular mixture. Mesosiderite.

5. Meteoric iron porphyritically enclosing crystals of silicates. Pallasite.

6. Meteoric iron. (Abhandl. gesellsch. Isis, 1882.) [22 M. E. W. The Pallas iron.- Dr. Stanislas Meunier has made a recent study of a specimen of the celebrated iron olivine meteorite found by Fallas at Krasnjarsk, Siberia. He regards the structure of this meteorite as a vein-form similar to the terrestrial veins commonly known as filons en cocardes. The pyrrhotite in this he seems to regard as derived from the nickeliferous iron by the action of sulphuretted hydrogen. On account of this derivation, he claims that this meteorite should be separated from the others enclosed under the pallasites by Gustav Rose. (Comptes rendus, xcv. 938.) M. E. W. [23 Fusion-structures in meteorites. In this abstract Mr. F. G. Weichmann holds that the supposed organic forms described by Dr. Otto Hahn from meteorites are fusion structures,' that is, formed by the cooling of the meteorite from a state of fusion. This view was taken by Prof. Kengott in 1868,

The hurricane of Oct. 20, 1882.—The observatory of Manila has published a small monograph containing a detailed account of this disastrous storm. It is rare that a storm of this nature passes so near an observatory equipped with self-recording instruments, as in this instance. The centre of the storm moved almost exactly over Manila, which gives this report peculiar value. It contains a chart of the records of the several meteorological instruments, and diagrams illustrating the progress of the hurricane. The observations recorded as the centre of the depression was passing are especially noteworthy. The pressure experienced a rapid fall of 24 millimetres in 3 hours, and a correspondingly rapid rise; the temperature rose from 25° to 31° C. in forty-five minutes, and fell with equal rapidity; while the relative humidity dropped from 100 to 53 per cent in the same short time, and rose again. The velocity of the wind, which was 54 metres per second (about 120 miles per hour) immediately before and after the passage of the centre, was 0 for two minutes only before the change of its direction. The diameter of the vortex was about 15 miles, and its velocity of translation 19 miles an hour. — W. U. [25 [An abstract of the Jesuit observations with fuller details and diagrams is given in another part of this week's issue.]

Exposure of thermometers. - Experiments made by Dr. Gill at the Cape of Good Hope, with the Stevenson shelter, Glaisher stand, and a window screen, show large differences in the records of maximum and minimum temperature. An extreme difference of 9.2° is found in the annual value for 1881 of the range between the maximum and minimum readings. Experiments made by Rev. F. W. Stow, with the Stevenson and metallic shelters, favor the latter; but care was not taken to have the shelters of the same size, and the instruments similarly placed within them. There is much need of attention to the subject of uniformity of thermometer exposure, especially in this country. (Quart. journ. meteor. soc., July, 1882.) w. U. [26

PHYSICAL GEOGRAPHY. Terraces and beaches about Lake Ontario.J. W. Spencer continues his studies in Canada in the region of the former connection of Lakes Erie and Ontario, and finds evidence of post-glacial lake-submergence 1,700 feet above present sea-level: the Great Lakes must then have been confluent, and connected with the sea by several outlets, St. Lawrence, Mohawk, southward from Cayuga and Seneca Lakes, and by several paths southward across Ohio. The beaches corresponding to the level of these old outlets are believed to be the most conspicuous and widespread. The 'Artemesia gravel' is regarded as a shore deposit of the subsiding lake. Shore-ice is considered an important agent in building the beaches. —(Amer. journ. sc., Dec., 1882.)

W. M. D.

[28

Explorations in Alaska. - Drs. Arthur and Aurel Krause of the geographical society of Bremen, who undertook, under the auspices of the society, in 1881, to make explorations in Alaska and the neighborhood of Bering Strait, have returned, and made their preliminary report to the society. In the spring of 1881 they took passage on a small schooner for Bering Strait, and were landed near St. Lawrence Bay on the shores of the Chukchi Peninsula. Here they spent the summer in exploration, returning to San Francisco in autumn, and thence proceeded to Alaska. The winter was spent at a trading-post on Chilkoot Inlet at the head of Lynn Canal, in lat. 59° N., and long. 135° W. Last summer Dr. Aurel Krause returned to Germany, via Panama; and in October his brother followed him by way of the line of the Northern Pacific railway. They brought very extensive collections. A catalogue of the ethnologica has just been issued by the society. The natural-history material has been assigned for study by the director of the Bremen museum as follows: crania, to Prof. Welcker; echinoderms, to Prof. H. Ludwig; fish, to Dr. F. Heincke; decapod crustaceans, to Dr. F. Richters; hydroids and polyzoa, to Herr Kirschenpauer, in Hamburg; reptiles, to Dr. J. G. Fischer; Prof. Metzger takes the amphipods and isopods; Poppe, the copepods; Dr. P. C. Hoek of Leiden, the cirripeds and pycnogonida; Dr. Marenzeller, the annelids; Prof. C. Heller, the tunicates; Dr. F. Karsch, the spiders and myriapods; Dr. W. Peters, the mammals; Director Spängel, the amphibians and zephyreans; Dr. Hartlaub, the birds; Drs. Krause and von Martens, the mollusks; Dr. Aurel Krause, the fossils; while the botanical collections are divided among Drs. F. Kurtz, C. Müller of Halle, Gottsche, and Hagena. Charts of part of the west shore of Bering Strait, of the water-shed between the head of Lynn Canal and the sources of the Yukon, of the East Cape of Asia, and various harbors, have already been issued from plans by the explorers, in the Deutsche geographische blätter. On Nov. 4, Dr. Aurel Krause lectured before the Gesellschaft für erdkunde, Berlin, on the T'linkit Indians of Alaska. The preparation of the final reports will naturally take some time; but the society is to be congratulated on its successful foray in a region so difficult of access, and so distant from the base of operations. - (Deutsche geogr. blatt., v. 4, 1882.) W. H. D.

.

[32

Arctic whalefishery in 1882. — The catch' of

the Dundee whaling-fleet, eight steamers, amounts to seventy-nine whales, affording about nine tons of blubber each, equivalent to about 5,000 bbls. oil and 100,000 lbs. baleen. Last year, a much more 'open' season, only forty-seven whales were obtained. In the Bering-strait region, the San Francisco fleet obtained a fair reward for their exertions in the form of 21,054 bbls. oil, 313,100 lbs. baleen, and 16,600 lbs. walrus-tusks. The fleet numbers about thirty sail, and the value of the catch' reported is about $960,000. The species pursued in these seas are Balaena mysticetus L. (bowhead of the Pacific whalemen, and right whale of the North-Atlantic whalers), and B. Sieboldii Gray (known as the Pacific right whale). The whalers resort to walrusing' in Bering Strait in default of whales; but in good seasons little walrusoil is taken, and most of the tusks are purchased by barter from the natives of the region.-w. H. D. [33 (Africa.)

German exploration in Africa. - In the past nine years, the German African association has sent six expeditions to the Kongo region, at a total cost of £22,000. The first, under Güssfeldt (1873-76), went to the Loango coast, north of the Kongo. Although not penetrating far into the interior, this trip alone cost £10,500. All the other expeditions entered at S. Paolo de Loanda. Pogge (1875) advanced 700 miles eastward to Kawenda, the chief town of a region as large as Germany, ruled by the Muata Yanvo (king) named Shanama. Mohr died at Malandje, the most advanced Portuguese trading-station, 200 miles from the coast. Schütt (1877-79) reached the Chikapa River, 500 miles inland. Buchner (1879-80) went also as far as Kawenda, staying there six months; and on returning early in 1881, met at Malandje the latest expedition, still in the field, under Pogge and Wissmann. Finding the road to the Muato Yanvo's town (Kawenda) closed on account of his difficulties with the neighboring and aggressive Kioko, Pogge and Wissmann turned north-east, and were last heard from among the Tushilange people, at the towns Mukenge and Kingenge, on the river Ruru (Lulua). They intended going on past Lake Mukamba to Nyangwe, on the Lualawa (Lualaba), lat. 44° S., long. 264° E., whence Wissmann was to proceed to the east coast if possible, and Pogge would return westward. [Wissman arrived at Zanzibar last November.]

The region consists of three physical divisions: the littoral slope, barren and dry, with short rivers running westward; the mountain belt; and the southern part of the Kongo basin, of undulating or hilly surface, well wooded or grassy, cut by very numerous rivers generally running northward, and nearly all with the syllable Lu, Ru, or Ku in their names. This district has a rainy season from September to April, with a temperature from 63° to 81° F. The dry season is occasionally as cool as 45°. The hippopotamus is the only large animal seen; other large game is very scarce. ·(Proc. geogr. soc. Lond., Nov., 1882, map.) W. M. D.

[34

Upper Senegal and Niger.- Commandant Galieni was charged by the Governor of Senegal, in 1880, with a mission of exploration in western Soudan, and with powers of treaty to induce the Sultan Ahmadou of Segu to place the Niger within his dominions under French protection. The expedition left St. Louis, Jan. 30, 1880, and began its work of exploration beyond Bafulabe, where the Senegal branches, on March 30 following. Ascending the Ba-khoy branch, the village chiefs accepted French protection; and by Mount Kita a fort was built to serve as an advanced outpost. Here the party divided; Lieut.