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examination showed it to be a far more energetic chlorine carrier than iodine, since (1) it acts more readily and quickly, (2) it carries the process more uniformly from one stage to the next, and (3) it can be more readily removed from the products. If to 500 grams anhydrous benzol, 5 grams MoCl, be added, and a stream of chlorine be passed through it, heat being applied by a water-bath and a return-cooler being used, after three days the liquid solidifies on cooling to an intermixed crystal mass, consisting of nearly pure para-dichlor-benzol, which after purification is equal in weight to the benzol taken. By acting on toluol in this way, the author in conjunction with DIETRICH, has obtained several new chlorine derivatives of this hydrocarbon.-Ber. Berl. Chem. Ges., viii, 1400, Nov., 1875.

G. F. B. 4. On the Effect of Mass on the Chemical action of Water.Ostwald has made, in the laboratory of the Dorpat University, a research upon the action of water in mass upon chemical action. A concentrated solution of bismuth chloride in hydrochloric acid was divided into 25 equal portions. To the first, water was added till a permanent turbidity appeared, and quantities of water gradually increasing from this were added to the other portions, the last receiving enough to precipitate all the bismuth. After standing six weeks, the various liquids were separately analyzed, the chlorine, bismuth, hydrogen and water being determined. These results are given in a table. To compare them a second table is given in which the chlorine and bismuth are calculated for 100 parts of water. If froin these figures a curve be constructed with those for bismuth as abscissas and chlorine as ordinates, the form of the curve for two-thirds of its length is a hyperbola. The first third is nearly a straight line, differing from this no more than is allowed by experimental errors. Hence either Berthollet's law is true and the action is exactly proportional to the mass, the curve being due to foreign influences, or the law of the action of mass is a function of a higher order, and Berthollet's law only a special case of it, where the higher powers are neglected. The author inclines to the former view; since he has detected one such disturbing cause in the fact that considerably more of the bismuthyl chloride remains suspended in the diluter than in the more concentrated liquids.-J. pr. Ch., II, xii, 264, Nov., 1875.

• G. F. B. 5. Formation of Alizarin by Reduction of Rufigallic Acid.WIDMAN has observed that when rufigallic acid is reduced by sodium amalgam, a violet solution is obtained. On precipitating this by hydrochloric acid and dissolving the precipitate in potassa, barium chloride throws down a second precipitate, which when treated with HCl leaves a residue. This dissolved in methyl alcohol or acetic acid, is left on evaporation. Heated to 250°, it sublimes in brilliant orange-red peedles, having all the reactions of alizarin. Hence rufigallic acid is hexa-oxyanthraquinone C, H, H and the production of alizarin in the vegetable kingdom, is explained.-Bull. Soc. Ch., II, xxiv, 359, Nov. 1875. G. F. B.

6. On the Separation of Mixed Liquids. Duclaux bas made a careful study of the conditions under which a homogeneous mixture of two liquids will separate into two entirely distinct layers, and has arrived at some very curious results. He finds, for instance, that a mixture of 15 cubic centimeters of amyl alcohol, 20 cubic centimeters of ordinary alcohol and 32.9 cubic centimeters of water, gives at the temperature of 20° C., a molecularly unstable grouping, so that the least diminution of temperature causes it to separate into two nearly equal layers : He states that under these conditions the composition of the two layers is invariably the same whatever the composition of the initial liquid, the layers varying only in amount. The same fact is also true of three as of two liquids; though in this case the third liquid takes no part in the separation, and remains the same in each of the two layers as in the original liquid. Hence it is always possible to start with a given liquid such that by depression of the temperature, two layers of the same volume are produced. The range of variation of temperature necessary to effect this separation is extremely minute, being much less than a tenth of one degree Centigrade! Moreover, the introduction of mere traces of certain substances, as sodium and calcium chlorides and other soluble salts, and the vapor of chloroform produce the same effect as a lowering of temperature. So also a drop of water or one of amyl alcohol will cause the separation. The author has applied this phenomenon to the construction of an ingenious minimum thermometer. By varying the amount of water present in the above mixture for example, the temperature at which separation ensues may be varied. The solutions may be readily prepared by taking the necessary quantities of amyl and ethyl alcohol, maintaining them at the exact temperature required and adding water drop by drop, until a slight turbidity appears, which should dissolve upon the slightest heating. The mixture is then placed in a tube and this is hermetically sealed. Ordinarily the liquid is clear but it becomes turbid as soon as the temperature falls below that at which it was prepared. A few drops of carmine in ammonia makes the separation mure distinct, since the lower layer only is colored. If ten parts of ether be mixed with six of commercial methyl alcohol, and water be carefully added as above, a liquid will be obtained acting as a maximum thermometer, since it becomes turbid and separates when the temperature rises above that at which it was made. This is colored with a little blue ink. Several tubes of each kind would evidently be exceedingly useful in maintaining a given temperature constant for any purpose, since they could be graduated to any interval. – C. R., lxxxi, 815, Nov., 1875.

G. F. B. 7. Stationary Liguid Waves. Professor GUTHRIE has recently communicated to the London Physical Society the results of his observations on wave motion. If water in a cylindrical vessel, not less than nine inches in diameter, be agitated by depressing and elevating a flat circular-disk on its surface at the center, a form of oscillation is set up which the author terms binodal. He finds that these fundamental undulations in an infinitely deep circular vessel are isochronous with those of a pendulum whose length is equal to the radius of the vessel, and that the pendulum and water keep together throughout their entire paths. This was shown experimentally by a short pendulum with a heavy adjustable bob, having a card-board sector attached to its upper end. A silk thread attached to the edge of this sector carries a small paraffin disk, which rests at the center of the surface of the water contained in the cylindrical vessel. The length of the pendulum is altered until the motion of the disk is isochronous with that of the water. Two other forms of motion may also be produced by alternately compressing and extending opposite diameters, as in a bell, and by rocking the vessel. Each has its own period, the last being the slowest. They may be superposed and a rotation of the water, however great, does not interfere with their formation.

In rectangular troughs binodal and mononodal waves may be formed, the former by raising and lowering a wooden lath at the middle of the surface, and the latter by tilting the vessel. Experiments of binodal motion show that they are isochronous with à pendulum whose length is 2 divided by a times that of the trough. The principal questions still to be considered are: (1) Why are the motions pendular? (2) How is it that in circular binodal motion the times are identical with that of a pendulum of given length ? and (3) What is the mathematical connection between the individual motion of each particle and that of the mass ?- Nature, xiii, 99.

E. C. P. 8. Waves in Elastic Tubes ; M. MAREY has studied the laws of the circulation of the blood by a mechanical representation in which a liquid wave is made to traverse an elastic tube. The changes in the shape of the tube are measured at six points by small elastic reserroirs connected with a chronograph so that the form of the wave and its time of transit past each point, are represented graphically. The wave is generated by forcing water by a pump into the tube. Positive waves are thus formed which follow the general laws of undulatory motion. The velocity is proportional to the elasticity of the tube and inversely as the density of the liquid. It diminishes gradually as the wave progresses and increases with the rapidity with which the liquid is added. With a sudden addition of liquid, secondary waves are formed of continually diminishing amplitude. When the tube is closed or parrow at the end, reflected waves are formed. If the walls of the tube are not very extensible, harmonic vibrations are formed superposed on the primary waves. In branching tubes a very complicated combination of waves is formed passing from tube to tube. But in the case of the blood the aorta does not permit the waves to pass from one artery to another. Its own waves are transmitted to the arteries where they are gradually lost, but like an elastic reservoir it absorbs and extinguishes the reflected waves. Journ. de Phys., iv, 25.

E. C. P. AM. JOUR. 8c1.—THIRD SERIES, Vol. XI, No. 62.- FEB., 1876.

9. Transparency of Flame and of the Air.-M. E. ALLARD has presented to the French Academy several memoirs on the absorption of the light of lighthouse lamps. The first memoir relates to the transparency of flame. From one to six concentric wicks are

cms. A comparison of the luminous intensity of the flames shows that the brightness increases a little less rapidly than the consumption of the oil ; comparing the intensity with the dimensions of the flame, it appears that the brightness per square centimeter increases, but that per cubic centimeter diminishes with the size of the flame. This difference may be accounted for by assuming that the flame is not perfectly transparent. Three methods were adopted for measuring the absorption, by comparing the light of the edge and side of a flat flame, by reflecting the light a second time through the flame by a mirror, and by viewing the electric light through a large flame. The results lead to the coefficient of •80 for the absorption per centimeter in thickness.

After having established the theoretical formulas which give the effective brightness of the flame as a function of its volume and coefficient of absorption, it appears that to satisfy the observations we must assume that the specific brightness increases a little with the diameter. Multiplying then the specific brightness by the volume, it appears that the total quantity of light increases much more rapidly than the weight of oil burned; but as the quantity of light absorbed increases still more rapidly, the light increases a little less rapidly than the oil consumed, as experiment shows.

The second memoir relates to the nocturnal transparency of the atmosphere. Observations are made three times every night by the lighthouse-keepers, as to which of the adjacent lights are visible. Combining the results for several years gives the percentage of nights on which each light is seen. The equation of the range of visibility and a graphical construction serve to show for each light in all cases what degree of transparency of the air is needed to render the light visible. A curve may then be constructed with the transparency of the air and the visibility of the lights as coördinates. From this it appears that during half the year the coefficient of transparency per kilometer exceeds .91 in the Atlantic and .932 in the Mediterranean. Similar curves give the transparency at different points along the coast, and during the four seasons.

The third memoir treats of the apparent brightness of a light caused by revolving the system of lenses employed with greater or less rapidity. With a certain velocity, à flickering effect is produced, but with an increased speed the light becomes steady with an intensity one or two tenths less than would be obtained by distributing the light uniformly around the horizon.--Comptes Rendus, lxxxi, 1096.

E. C. P. 10. Étheric Force of Edison.-Prof. E. J. Houston, in an article in the January number of the Journal of the Franklin Institute, concludes from his experiments—as many physicists may have concluded from the published account of the supposed new force" that all the phenomena noticed by Mr. Edison are explainable by the presence of inverse electrical currents of considerable quantity, but comparatively small intensity, instantaneously produced at the making or breaking of the battery circuit.”

II. GEOLOGY AND MINERALOGY. 1. U. S. Geological and Geographical Survey of the Territories, F. V. HAYDEN in charge. Department of the Interior. Bulletin No. 5, Second series. Washington, Jan. 6, 1876.—This new Bulletin contains the following important papers: A review of the fossil flora of North America, by L. LESQUEREIX; New fossil plants of the Lignitic formations, and from the Dakota group of the Cretaceous, by L. LESQUEREUX; Notes on the Lignitic group of Eastern Colorado and Wyoming, by F. V. HAYDEN; Geology of localities near Cañon city, by S. G. WILLIAMS; On Zapus Iudsonius, and on the breeding habits, nest and eggs of Lagopus leucurus (the white-tailed Ptarmigan), by Dr. ELLIOTT Cotes, U. S. A.; List of Hemiptera of the region west of the Mississippi, including those collected during the explorations of 1873, by P. R. L'HLER; On the supposed ancient outlet of Great Salt Lake, by A. S. PACKARD, Jr.

The question as to the age of the Lignitic beds is here discussed anew by Prof. Lesquereux with the presentation of some additional facts. His conclusions remain unchanged. They are as follows.—Above the Lower Cretaceous beds or those of the Dakota group, in the Rocky Mountain region, the first fossil plants met with are the species of the Lignitic formation. This formation is divided into (1) the Lower Lignitic, marked by the presence of a profusion of Palms, especially species of Sabal (showing a warm, moist climate, like that of Florida, while the Cretaceous plants of the Dakota group indicate one like the present of Ohio) along with species o Ficus, Cinnamomum, Magnolia, Myrica, Quercus, Platanus, Diospyros, Mamnus, Viburnum, etc. (and as yet no Acer), and referable to the Eocene ; (2) the Evanston group, “ considered Upper Eocene or Lower Miocene ;” (3) the Carbon Group (more to the eastward, about long. 1061o W.) “or Middle Miocene,” above which comes (4) the Green River Group, or Upper Miocene. The flora of No. 2 includes thus far 90 species, of which a third are known from No: 1: fruits have been found that have been referred to the Palms, but no leaves; there are also in it dentate and serrate leaves of Salix, Betula, Alnus and Acer. The flora of the Carbon Group is “positively Miocene;" 18 species, or nearly a third of all, are identical with European Miocene plants, and 1:3 with Arctic Miocene, while a few occur also in the Lower Lignitic (No. 1.)

Among 23 species from the Point of Rocks, referred to No. 1, or the Lower Lignitic, two occur also in beds to the north of the

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