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side. In this specimen the pyrite which replaced the chitinous remains of the animal has decomposed, and the dorsal crust weathered away, exposing below the stems of the exopodites, with their fringes extending over the entire pleural areas on both sides. A pygidium, with three attached thoracic segments, from another entire specimen (figures 5 and 6), preserves the details of the appendages in the most perfect and satisfactory manner. As both halves showed essentially the same extent and disposition of the fringes on the dorsal side, the specimen was cut in two along the center of the axis, and the left side was then imbedded in paraffine. By careful preparation the appendages were exposed from the ventral side.

The cephala of the three specimens described are considerably compressed, and from them a very imperfect knowledge of the mouth parts could be obtained, so that this information must be left to future discovery.

Endopodites.—The three posterior thoracic endopodites are very similar, and in a general way closely resemble those of Triarthrus from the same region of the thorax. They are, however, comparatively shorter and stouter, and could not be extended beyond the ends of the pleura. The two distal joints are cylindrical, with well-marked articular surfaces and ridges. The joints preceding these proximally become much wider, flattened, and produced into transverse extensions which carry large tufts of setæ at the end, as also does the end of the last joint of the limb (dactylopodite).

The endopodites on the pygidium offer no conspicuous differences from those just described, except that a gradual change in form is manifest as the terminal limbs are reached. The separate endites become more and more transversely cylindrical, until the whole limb appears to be made up of cylindrical segments transverse to its length. A similar condition was observed in the young of Triarthrus.*

Exopodites.These seem to be composed of slender joints, the distal exites being long and slightly curved outwards. They carry very long, close set, overlapping, lamellose fringes, which evidently had a branchial function. Some of the lamellæ are spiniferous. The exopodites become shorter on the pygidium, and apparently are represented near the end of the series of limbs by the oval plates indicated at c, figure 6. If this interpretation is correct, the posterior exopodites are simple flabella attached to the limbs, as in Apus.

Both Professors A. E. Verrill and S. I. Smith agree that the characters of the appendages in Trinucleus indicate an animal of burrowing habit, which probably lived in the soft

* This Journal, vol. xlvii, Pl. VII, fig. 3, April, 1894.

mud of the sea bottom, much after the fashion of the modern Limulus. In addition to its limuloid form, the absence of eyes seems to favor this assumption. So does the fact that many specimens have been found preserving the cast of the alimentary canal, showing that the animal gorged itself with mud like many other sea-bottom animals.

Yale Museum, New Haven, Conn , March 15th, 1895.

EXPLANATION OF PLATE III.

Trinucleus concentricus Eaton. Figure 1.-Cephalon of young individual without genal spines; showing ocular

ridges and two rows of perforations around anterior and lateral

borders. x 40. FIGURE 2.-Cephalon of younger individual before the growth of the perforate

border; showing distinctly the clavate ocular ridges, a, a. * 40. FIGURE 3.–Pygidium of young individual; showing the indistinct limitation of

axis and the elevated transverse ridges of the pleura and axis. * 40. FIGURE 4.-Thorax and pygidium of an entire specimen from which the dorsal

test has been removed by weathering, exposing below the fringes of the exopodites, which entirely cover the pleural portions. The stronger lines ascending from the axis are the main stems of the exopodites. The black dots along the axis are the fulcra for the

attachment of the limbs. * 4. FIGURE 5.-One-half the pygidium with three attached thoracic segments, from

an entire specimen, with a portion of the test removed ; showing the

highly developed, lamellose fringes of the exopodites. x11. FIGURE 6.—The same; lower side; showing the short, stout, phyllopodiform

endopodites, a, and the long, slender, exopodites, b, bearing the lamellose branchial fringes. In the lower third of the figure the ends of the joints of the separate endopodites are shown by the oblique ascending rows of setiferous nodes. The small ovate organs (c) along the side are provisionally correlated with the exopodites. A narrow striated doublure margins the pygidium and the ends of the thoracic pleura. xll.

Utica slate. Near Rome, N. Y.

SCIENTIFIC INTELLIGENCE.

. I. CHEMISTRY AND PHYSICS. 1. On the Inorganic Preparation of IIydrazine.-Hitherto the preparation of hydrazine has been possible only from complex organic compounds. DUDEN however has now succeeded in effecting its synthesis from inorganic materials. For this purpose he makes use of a compound originally discovered by Davy, produced by the action of sulphurous acid upon potassium nitrite, and which has the composition K, SO,. ,0,. And he finds that this substance, upon careful reduction with sodium amalgam or with zinc dust and ammonia or soda, at a low temperature, gives a solution having very strong reducing properties and which yields

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after acidification, the salt of bydrazine corresponding to the acid employed. In practice the recently prepared compound of nitrogen dioxide and potassium sulphite is suspended in water cooled by ice, the whole is placed in a freezing mixture and sodium amalgam is gradually added until the liquid is found to reduce Fehling's solution strongly and to yield, after being acidified and heated to expel the sulphur dioxide a precipitate of benzalazine on the addition of benzaldehyde. The benzalazine thus obtained is identical with that described by Curtius, fusing at 93° and bav. ing the formula (CH.CHN),. This substance treated with sulphuric acid yields hydrazine sulphate (N, H.),. H.SO,, of melting point 256°, and otherwise identical with the product obtained from organic sources. The reaction appears to take place in two stages. In the first

ADO, SN.NO+H. = "SO: N.NH,+H.0+ KOH Then a subsequent reaction takes place between the alkali and the sulphite compound thus

KSO,

PAN. NH, + KOH =K+HN. NII, - Ber. Berl. Chem. Ges., xxvii, 3498, January, 1895. G. F. B.

2. On the Production of Carbon chlorides at ordinary Temperatures.— The production of C,cl, and C,CI, by the dissociation of carbon tetrachloride at a red heat, with the setting free of chlorine is well known. Victor MEYER has now called attention to the fact that during the preparation of carbon tetrachloride by the chlorination of carbon disulphide at ordinary temperatures, these two chlorides are produced. At these works of Müller and Dubois, near Mannheim, this process is operated on the large scale, at temperatures between 20° and 40°. After some days, the liquid becomes deeply colored owing to the production of sulphur dichloride S,CI,. The tetrachloride is then distilled off leaving the chloride of sulphur. On rectification of the tetrachloride an oily liquid having a higher boiling point, is obtained. Upon fractioning this the author finds that it separates into three constituents, CCI, C,CI, and C,C1,, the last being a solid, and being thus obtained in crystals, practically pure. Since the carbon disulphide also was practically pure, the author considers that the chlorides C,C1, and C, C1, are produced by direct synthesis, as follows:

(CS,), +C1,0 = C,C1, +(S,CI,),

(CS,), + Cl. = C,C1, + (S,C1,), -Ber. Berl. Chem. Ges., xxvii, 3160, November, 1894. G. F. B.

3. On the Atomic masses of Nickel and Cobalt.- In the earlier determivations of the atomic masses of nickel and cobalt, made by WINKLER, he obtained the values 58.90 for the former metal and 59•67 for the latter; the results being secured by analysis of the chlorides prepared from electrolytically deposited metals. He now finds that a small error was introduced in the case of cobalt, due to the fact that the metal deposited on the platinum electrode contained a minute quantity of the hydrate Co,0,. (1,0),. No such result however occurs with nickel. Moreover he finds that a solution of iodine in potassium iodide of decinormal strength is capable of dissolving the deposited metal from the platinum terminal at once, without attacking the latter. In the case of nickel the platinum is left perfectly clean, while aster the removal of the cobalt a stain remains due to about one half per cent of oxide. To remove this oxide, the electrodeposited cobalt was reduced by hydrogen before use; and then it proved to be pure on solution in iodine. The determination was made by titrating with sodium thiosulphate the excess of iodine left after the pure metals were dissolved. As a result of two complete and concordant series of analyses the final values obtained are 58.72 for nickel and 59:37 for cobalt, H being 1 and I 126.53; the atomic mass of cobalt being apparently about one-balf a unit higher than that of nickel.-Zeit. anorg. Chem., viii, i, December, 1894.

G. F. B. 4. On the Atomic Mass of Bismuth.-More than forty years ago SchneIDER fixed the mass of the bismuth atom as 208, relative to that of hydrogen. A few years subsequently, i. e. in 1859, Dumas made atomic mass determinations of a number of elements, among which was bismuth; giving to this metal the value 210. This figure continued to be accepted down to 1883 when Marignac undertook his well known investigations upon atomic mass and by a series of determinatious which were carried out with great thoroughness concluded upon 208:16 as the atomic mass of bismuth ; thus corroborating the work of Schneider. In consequence of the slightly higher result 208.9, obtained by Classen by an electrolytic method, Schneider has now repeated and extended his work in this direction. The method adopted by him in this new series of determinations is based upon a compari. son of the equivalent relation of metallic bismuth to the trioxide of bismuth ; with a view of testing certain suggestions made by Classen concerning possible errors in his former estimations. The result finally obtained, for ( = 16, is 208.05; the greatest divergence from this mean among the values obtained in all the experiments being only 0.21. This result not only confirms the value originally obtained by Schneider himself, and also that of Marignac, but it is specially important as tending to show that bismuth belongs to the increasing class of elements whose atomic masses are represented by whole numbers.-J. prakt. Ch., II, 1, 461, November, 1894.

G. F. B. 5. On the Use of Dihydroxytartaric acid as a Reagent for Sodium.-By oxidizing tartaric acid in presence of iron, FENTON observed the production of a new crystallized acid, which by oxidation is converted into dihydroxytartaric acid. To effect this oxidation, the crystallized acid is covered with glacial acetic acid and a solution of bromine in this glacial acid is added drop by

Am. JOUR. Sci.-T9IRD SERIES, VOL. XLIX, No. 292.- APRIL, 1895.

drop with constant shaking, until a faint permanent yellow color appears. On neutralizing with sodium carbonate, a heavy white crystalline precipitate is produced, which after washing and drying, finally in vacuo over sulphuric acid, proved to be sodium dihydroxytartrate. From this salt, by covering it with anhydrous ether and passing dry bydrogen chloride into the mixture, dihydroxytartaric was obtained on evaporation. Owing to the ease with which this acid can now be procured, the author suggests the use of it as a reagent for the detection of sodium. For this purpose, a few crystals of the acid are dissolved in a drop of water on a watch-glass, the solution to be examined is added and if necessary tbe liquid is neutralized with a drop of ammonia. On stirring with a rod, a white crystalline precipitate of the sodium salt appears, generally in lines as in the detection of potassium by tartaric acid. The test is fairly delicate, a one per cent solution of sodium chloride giving the reaction almost immediately. Neither potassium nor ammonium interferes with the reaction.J. Chem. Soc., Ixvii, 48, January, 1895.

G. F. B. 6. On the Commercial Synthesis of Acetylene.The produce tion of the carbides of barium, strontium and calcium, by Moissan in bis electric furnace,* seems likely to become of considerable commercial utility. In a paper by LEWES, read before the Society of Arts, he bas called attention to the production of acetylene by the action of water upon these carbides as the starting point of important practical developments. Although Wöbler had made calcium carbide by susing an alloy of zinc and calcium with carbon, and bad obtained acetylene from it by the action of water; and although in 1892 Macquenne had made barium carbide by heating together barium carbonate, magnesium powder and charcoal, and still later Travers had made calcium carbide by the action of a high temperature upon a mixture of calcium chloride, carbon and sodium, yet no commercial importance was attached to these processes on account of their expense. But when working with the electric furnace, in the attempt to form alloys of calcium, Willson observed that a mixture of lime and pulverized anthracite, exposed to the high temperature of the arc, fused to a semi-metallic mass, which when thrown into water, effervesced strongly and evolved acetylene, the process became of practical value. The calcium carbide thus produced is a dark gray substance, having a density of 2.262. When pure a pound of it yields 5.5 cubic feet of gas, containing 98 per cent of acetylene. This gas is colorless, with a penetrating odor resembling garlic. It is poisonous, and is soluble in a little less than its own volume of water, and in one-sixth of its volume of alcohol. It has a density of 0:91. It burns with a highly luminous and smoky flame, and liquefies at 0° C. under a pressure of 21:5 atmospheres. When sprayed into the air the liquid evaporates rapidly, absorbing so much beat that a portion of it is converted into a snow. white solid. For illuminating purposes it can be burned only in

* See this Journal, III, xlviii, 506, December, 1894.

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