Rowland, after Maxwell's determinations, equal to 28,800 millions. W. Weber's value would be 31,074 millions. I give below under M. the results calculated with the former value, under W. those calculated with the latter.

The following is the result of the calculation of only three series of experiments conducted under favorable circumstances:(1) Ten experiments with alternately opposite rotation. In each, three readings, of which the middle one was made with the electrification of the disk opposite to that of the first and third.

Mean difference of the position of equilibrium, in scale-divisions

Spark-length

Electro-dynamic force acting on the astatic pair-observed

6.735 0.2845

0-00000327

The accordance may be looked upon as satisfactory in the measurement of a force which amounts to only 5000 of the force of the earth's magnetism, since in two of the series the observed values fall between those corresponding to the different measured values of Weber's constant.

As regards the signification of these experiments for the theory of electro-dynamics, they correspond to the hypotheses of the theory of W. Weber; but they can also be referred to Maxwell's, or to the potential-theory which takes account of the di-electric polarization of the insulators. The volume-elements of the stratum of air situated between the resting and the moved plates suffer continual displacements in the direction of a rotation round radially directed rotation-axes. The existing di-electric polarization of these elements will therefore in each material element continually change, while retaining in space the same direction normal to the surface of the electrified disks. The arising and disappearing components of this polarization would constitute the current which is indicated by the astatic pair of needles.—Monatsbericht der kön. preuss. Akademie der Wissenschaften zu Berlin, 1876, pp. 211-216; Phil. Mag., Sept. 1876.

II. GEOLOGY AND MINERALOGY.

1. Note on specimen of Metadiabase from Connecticut Lake, collected and sliced by G. W. Hawes.-The fragments, apparently organic, in this slice agree with that figured by Mr. Hawes in the August number of the American Journal of Science, Plate v, fig. 5. They consist of a transparent brownish substance, traversed by parallel bars or ribs of greater transparency. In places the bars are interrupted abruptly, and crossed by similar bars nearly at right angles to the others. Between the longitudinal bars are irregular transverse and oblique lines; but these are not properly structural, and appear to be cracks, some of which are open and transparent, but the greater part closed and of a black color. From the irregular shape of the fragments, and the manner in which the ends project in shreds, it is to be inferred that the substance, if organic, was not hard or stony like a coral, but tough and soft, and in an advanced stage of decay. Fragments of the horny investment of Hydroids or Bryozoans might present such appearances, and in this case the planes where the bars are interrupted may represent the mouths of cells. Again, the chitinous crust of some Entomostracans, as for example, species of Dithyrocaris, shows bands not very dissimilar from those in the fragments, which, however, present no trace of the cellular structure usual in such crusts. Again, the Devonian plants of the genus Dictyophyton show a rectangular areolation which, though much coarser, reminds one of these specimens. Lastly, Gumbel has figured from the Laurentian of Bavaria certain films with rectangular meshes, much finer than those of Mr. Hawes' specimens, but not unlike them in appearance, and which he regards as organic. On the whole, though these objects are unlike any purely mineral substance with which I am acquainted, and are probably fragments of some organic body, I do not think it possible at present to indicate with any certainty their probable affinities. Sept. 7, 1876.

J. W. DAWSON.

2. On Streams of Water beneath Glaciers. Mr. CHARLES KNIGHT, in the Philosophical Magazine for June, states that, according to Professor Wm. Thomson's experiments, the freezing point of water is lowered 0°23 F. for each additional atmospheric pressure; and that, hence, if a glacier have a thickness of 3,000 feet, the pressure would be about 80 atmospheres, and under this pressure the temperature at the base should not exceed 13° F. to retain the solid form. The statement needs a correction, since Professor Wm. Thomson's experiment made the lowering of the freezing point of water 0°-23 F. for sixteen atmospheres of pressure. This would give for 80 atmospheres, supposing the increase by arithmetical ratio, only 10-15 F.

3. Quinto Apendice al reino mineral de Chile i de las Republicas vecinas publicado en la segunda edicion de la Mineralojia de don IGNACIO DOмEYKо. 79 pp. 8vo. Santiago, 1876.-The fifth

Appendix by Domeyko to his Mineralogy of Chili follows the fourth after an interval of two years. It contains much valuable and interesting matter, including the description of the following new minerals:

2

Daubreite.-Amorphous. In structure earthy and compact, in parts fibrous. H.-2.5. G.-6.4-6.5. Color yellowish to grayish-white. Opaque. An analysis gave Bi2O, 89.60, Cl 7.50, H2O 3-84(?), Fe, 0, 0.72, which corresponds to the formula (BigO3)4, BigCl. This formula places the mineral in the series with the two artificial compounds (BiO3)2, Bi, Cl, and (Bi203), Bi, Cl. It is easily soluble in hydrochloric acid, without residue. Locality, Constancia Mine, Cerro de Tazna, Bolivia.

Krönkite.-In irregular crystalline masses with coarse fibrous structure; probably triclinic. Cleavage distinct parallel to an edge of the prism. Color azure-blue, changing somewhat on exposure to the air. Luster vitreous; translucent. Composition CuSO4+Na2SO4+2H2O, which requires CuSO, 47-23, Ña2SO 42.09, H2O 10-68-100. Perfectly soluble in water. Found in the copper mines near Calama, on the road from Cabija to Potosi, Bolivia.

Phillipite.-Forms small irregular masses and bands in the same argillacous ochre in which the copper pyrites occurs, by the decomposition of which it has been formed. Structure fibrous, sometimes compact; never prismatic like Krönkite. Color azureblue. Luster vitreous; translucent. Soluble in water, but unaf fected by exposure to the air. Composition CuSO4 + FeS3012+ n aq. Analysis gave SO, 28.96, FeO, 9.80, CuO 14 39, MgO 0-85, H2O 43.72 AIO, tr=100.00. Found at the copper mines in the Cordilleras of Condes, Province of Santiago, Chili.

3

3

3

Huantajayite.-Isometric. Crystallizes in cubes like the chlorides of sodium and silver. H. 2. Transparent. Color white, not altered by exposure to the air. Fragile, easily reduced to a powder, not sectile like cerargyrite. Composition 20NaCl+ AgCl; an analysis gave NaCl 89, AgCl 11-100. B.B. decrepitates and fuses easily, losing its transparency; with soda yields metallic silver. Found at the mine of San Simon, in the Cerro de Huanjayita.

The descriptions of the following new minerals in the Appendix are given by Sr. Raimondi.

2

bands intimately H.=3; G.=3·90. Cu2O 50:45, CaO

Cuprocalcite.-Occurs in small masses, and in mixed with a ferruginous carbonate of calcium. Color bright vermillion-red. The analysis gave 2016, CO2 24.00, H2O 3.20, FeO, 0·60, AlО, 0·20, MgO 0·97, SiO, 0-30-99-88. This leads to the formula (Cu2O)2 CO2+ 2CaCO3+H2O, which requires Cu2O 52-2, CaO 204, CO2 24°1, H2O 33-100. Soluble in hydrochloric acid with effervescence. The solution, formed with exclusion of the air, has a strong deoxydizing power, precipitating metallic gold from solutions of gold salts. Found at the mines of Canza, near the city of Ica, in Peru.

Werthemanite.-Occurs in powder, or in masses easily reduced to powder. Color white. Gives an argillaceous odor, and adheres

3

3

3

to the tongue. G.-2.80. Soluble only in sulphuric acid. An analysis gave SO, 34-50, A10, 4500, FeO, 125, H2O 19-25=100. This affords the formula AISO+3H2O; or like aluminite except in the smaller amount of water. Found near the city of Chachapoyas.

6

Malinowskite.-A variety of tetrahedrite. An analysis of the mineral from the district of Rocuay gave S 24-27, Sb 24-74, As 0.56, Pb 13'08, Cu 14:37, Ag 1192, Fe 9-12, Zn 192=100. Other analyses of the same mineral from the mine of Carpa agree closely with this. It occurs massive, and has a gray color and metallic luster.

III. BOTANY.

E. S. D.

1. Flora of British India; by J. D. HOOKER, C.B., &c. Part IV. pp. 240. Date of issue not given.-This commences the second volume and contains the orders Sabiacea, Anacardiacea, and Connareece, by Dr. Hooker, and the Leguminosæ down to the genus Derris (two thirds of the 132 genera), by Mr. Baker. The model of the British Colonial Floras is followed. It is curious to find our Clitoria Mariana as an Indian species. A. G.

2. Composite Indica descriptæ et secus Genera Benthamii ordinatæ, a A. B. CLARKE. Calcutta, Thacker, Spink & Co. 1876. pp. 347, xlv, Svo, 1876.-This important side-contribution to the Indian flora is in Latin, but otherwise on nearly the plan of the Flora of British India, except that the generic characters are wholly given in the conspectus; and it is supplemented by copious tables of geographical distribution. The whole appears to be very well done, and, being published at the author's own expense, the cordial thanks of botanists are justly due. A. G.

3. Proceedings of the American Association for the Advancement of Science, 24th meeting, 1875. Botanical Articles.-These are few, occupying only 20 pages of the thick volume, and are not of high importance. The longest is that in which Mr. Meehan asks the question "Are Insects [of] any material aid in fertilization" of flowers? He answers the question in the negative, but not to our satisfaction. Some of the facts are open to question, or would take in other hands a different interpretation; and several of the illustrations of supposed self-fertilization are from flowers in which other observers, with opposite prepossessions, see exquisite adaptation to crossing. As we may not ourselves rightly appreciate Mr. Meehan's ingenious argumentation (our own observations all pointing to an opposite conclusion) we state that he claims to have proved:

"First, that the great bulk of colored-flowering plants are selffertilizers.

Secondly, that only to a limited extent do insects aid fertilization.*

* Apropos to Mr. Meehan's suggestion, that, although the alpine plants of the Colorado Rocky Mountains are mostly highly colored, insects are there so rare that they can be of no material aid to fertilization, and therefore these plants must self-fertilize, it may not be amiss to introduce testimony. An entomologist now

'Thirdly, that self-fertilizers are every way as healthy and vigorous, and immensely more productive than those dependent on insect aid.

6.

Fourthly, that where plants are so dependent, they are the worse fitted to engage in the struggle for life."

It is not easy to perceive how the last two very comprehensive propositions are or can be demonstrated.

The next article, on Carnivorous Plants, by Professor Beal, of Michigan, is short and sketchy, recapitulating some facts wellknown in the science, though novel to a popular assemblage; and finally, referring to Martynia and the vast number of small insects which are caught by its sticky glands, he suggests that "it is a true insectivorous plant." That may well be; but the observations and experiments recorded were not carried to the point of proving it, although this might not have been very difficult.

Inequilateral Leaves, by the same author, is a brief article, detailing a good number of cases, and ending abruptly with the remark: "Why these leaves have unequal lobes I cannot see; and I have no theory to offer as a probable explanation."

The Venation of a few odd Leaves, also by Professor Beal, is a short note, in which the main point is a curious suggestion as to the morphology of the odd leaf of the Ginkgo tree.

Some Observations on the structure and habits of Utricularia vulgaris, by T. B. COMSTOCK, is an abstract merely, describing the apparatus and apparent action of the bladders."The value of this paper is slight, except as confirmatory, in a measure, of the discoveries of others, and as an illustration of the great ease of conducting similar observations, now much needed.”

Lastly, Periodicity in Vegetation, by JAMES HYATT, of Dutchess Co., N. Y., is a longer article, noting how certain plants appear and disappear in different years, in certain places, Silene antirrhing, for instance, abounding in 1864, 1869, and 1874, "while not a single plant has shown itself, neither in 1875, nor in any other year than those specified since 1864;" from which it would appear that "the seeds lie dormant through the intermediate period." The article concludes with some noteworthy suggestions and plans for the convenient keeping of a useful botanical diary, especially for the recording of periodical phenomena.

A. G.

at my side, who has passed four summers among these mountains and made frequent visits to the alpine regions, informs me that he has "always found insects of all orders quite abundant in the Rocky Mountains, and especially so wherever flowers occur in most variety, as in the immediate vicinity of the timber-line, 10,000 to 12,000 feet," etc. Also that "insects are much more abundant everywhere in the mountains than on the plains." He has "frequently noticed the congregation of butterflies, in considerable numbers, about the bleak and barren summits of rocky peaks far above the timber-line, whither they had probably been drifted by the wind. Bees and other Hymenoptera occur in considerable variety and abundance at the timber-line. In fact, one of the best places for collecting them is among the vast fields of flowers which there occur." Finally he remarks that "although, as a rule, insects, as well as other animals, are not so plentiful in all the Rocky Mountains as in many other parts of the country, yet, comparing the alpine regions with the plains, I have always found insects very much more abundant in the former than in the latter."

A. G.