Two experiments were tried. In the first, the yellow light remained stationary, and the blue one was moved towards the screen till equality of the shadows was obtained. In the second experiment, the blue light was left in its first position, and the yellow one moved away from the screen till the shadows were equal. On comparing the results obtained, it was found that they differed materially from one another. In another experiment the two shadows were cast so that when the eye was in a certain position they appeared of equal brilliancy. On approaching the screen, the blue shadow was found to appear more brightly lighted than the other; and, on going away from the screen, the reverse effect was observed. To further investigate these results, two methods of measurement were employed: 1. The intensity of the light corresponding to the different wave-lengths of the spectrum was determined by means of a Rumford photometer, as above described; 2. A small figure consisting of three short, broad, black lines, drawn on a white surface, was placed in different portions of the spectrum, and the intensity of the light increased or diminished until its outlines were just distinguishable.

It was found that the results obtained by the two methods agreed almost exactly for the less refrangible portion of the spectrum, as far as wave-length 517; but beyond that point the differences suddenly became very marked; and it was shown that a blue light had to be many times brighter than a yellow one in order to distinguish the same details by its aid; also, that the brighter the lights were, the more marked did this difference become.

Now, for purposes of artificial lighting, whether public or private, the end desired is less to produce a luminous sensation upon the eyes than to enable us to distinguish the objects around us. It is therefore concluded, that, for lights of equal brilliancy, the superiority of yellow sources (such as gas-flames and incandescent electric lamps) to sources richer in the blue rays, as the arc light, is beyond question. (Journ. phys., Feb.) W. H. P.

-

Electricity,

[696

Transmission of power. - Experiments relating to the electrical transmission of power were made on the 4th of March last, in Paris, at the Chemin de fer du Nord, before a commission of the French institute, composed of MM. Bertrand, Cornu, Tresca, de Lesseps, and de Freycinet. The resistance of the line was 160 ohms, a resistance equivalent to that offered by a copper wire 106 kilometres in length, and 4 mm. in cross-section. The power applied to the generating-machine was equivalent to 4.4 horsepower; and the rotation of the generating armature was varied from 380 to 1,024 revolutions per minute in order to ascertain the effect of speed of rotation upon the mechanical return at the other end of the line. As the general result of the experiments, 'La Lumière électrique' announces that the available power transmitted was 47.5% of that which actuated the generating-machine. - (La Lum. électr., March 17.) A. G. B. [697

ENGINEERING.

Steel for structures.- Mr. Ewing Matheson discusses at considerable length the important question of the modern use of steel for engineering-works. The author commences by stating the following propositions: 1. Rolled plates and bars of the various forms required for structures are now made of steel with as much certainty, in regard to quality, as iron of the first class; 2. Advantages in regard to size

and weight of pieces can be obtained in steel, which in iron are either impossible, or can only be had at very great expense; 3. Steel has a superiority in strength, ranging from once and a half to twice that of iron, and at the same time a more than proportionate superiority in ductility and elasticity; 4. Steel can be bent, straightened, cut, punched, planed, and drilled with the same tools and processes that are used for iron, and, for the most part, without extra force; 5. Protection against rust is of more importance for steel than for iron, but, if treated in the same way as is usual with iron, steel is less liable to waste by rust; 6. Owing to the above advantages, structures of steel are superior to those of iron, but economically it is only in some cases in regard to ships, and in still fewer cases in regard to bridges, that there is at present any pecuniary advantage in using steel; 7. This limit to the application of steel is due partly to official rules, which restrict the working-strains on steel, and partly to exigencies of design, which hinder the reduction in size and weight of members to the extent which its superior strength might otherwise allow; 8. Although, for the above reasons, steel structures may cost more than iron without any immediate compensation, yet, if measured by actual units of strength and durability, steel is cheaper as well as better for all but very small structures; 9. The employment of steel may be encouraged and extended by a fuller knowledge, among those who use it, of its qualities, by facilities for verifying these qualities by exercising a wider choice of the kind of steel suited to the purpose in view, and by such a liberal alteration of the present official rules as will allow fuller advantage to be taken of steel than is usual or permitted at present. The simplicity of manufacture, as compared with that of rolled iron, renders almost certain a nearer approximation in cost, if, by a wider permission, the demand for steel should increase. Each of the above points is taken up in detail and carefully considered, the admiralty specifications for steel plates for ships are given, the question of steel riveting is examined, the important matter of rust is discussed, and an extended comparison is made between the weight and cost of iron and steel for bridges. The whole paper is of great value, and well worth careful study.-(Proc. inst. civ. eng.) [698

G. L. V.

Recent hydraulic experiments.- At a meeting of the Institution of civil engineers held in London Nov. 14, 1882, Major Allan Cunningham gave an account of an extensive course of experiments on the flow of water in the Ganges canal, extending over four years (1874-1879), the principal object being to find a good mode of discharge measurement for large canals, and to test existing formulae. Not less than fifty thousand measurements for velocity were made, and six hundred for surface slope, while five hundred and eighty-one cubic discharges were measured under very varied conditions. Forty measurements of evaporation from the canal surface were made in a floating pan, during twenty-five months. The results showed the movement of water in such a canal to be in many respects quite different from those before reported. — (Engineering, Nov. 17, 1882.) G. L. V. [699

The type of modern marine engines. - Constructing-engineer Albrecht, of the Austrian navy, discusses the various forms of engines and boilers which have been proposed or used, gives data and indicator-diagrams for various ships, shows that the compound engine effects a saving of fifty-seven per cent over the simple, and pronounces the threecylinder compound engine the most economical and best. (Mitth. gebiete seew., x. 9.) C. E. M. [701

Torpedo-nets. - Lieut. Sleeman, R.N., proposes to render torpedo-nettings useless as a protection for ships by sending one Lay torpedo after another, in the same path, at short intervals. The first breaches the net; the second passes the breach, and explodes against the ship.—(Journ. de la flotte, Feb. 18.)

C. E. M.

[702

Pendulum-chronograph. — Capt. Caspersen, of the Danish army, has devised a chronograph for ballistic purposes, which consists of a pendulum prolonged above its point of suspension so that it can be arrested at its extremities at will by levers connected with electro-magnets. A horizontal wire is fastened at the point of suspension, with its ends bent so as to dip in cups of mercury; and thus, when the pendulum is oscillating, the contact is made alternately on the two sides, and registered automatically on a dial. The instrument measures with precision the hundredth of a second. — (Mitth. gebiete seew., x. 9.) [703

C. F. M.

C. E. M. CHEMISTRY.

(General, physical, and inorganic.) Conduct of moist phosphorus and air towards carbonic oxide. In repeating the experiments of Leeds and of Baumann, Prof. Ira Remsen and E. H. Kaiser observed a copious precipitate on passing the mixed gases through barium hydrate. When, however, all contact of the gases with corks and connectors was prevented, there was no formation of barium carbonate. — (Amer. chem. journ., iv. 454.) [704 White phosphorus. A modification of phosphorus, quite different in its properties from the variety hitherto known as white phosphorus, was obtained by Remsen and Kaiser in the distillation of ordinary stick phosphorus. The distillation was conducted in an atmosphere of hydrogen, and the distillate collected in a receiver partly filled with water and ice. At the end of the distillation a thin white cake was found floating on the surface of the water. It dissolved readily in carbonic disulphide, melted at the same temperature as the common form, and, on melting, was transformed into the latter. It withstood the action of sunlight longer than ordinary phosphorus. (Amer. chem. journ., iv. 459.) [705

C. F. M.

mixture of zinc filings and arsenic in powder was subjected to a pressure of 6,500 atmospheres, W. Spring observed the formation of an arsenide (ZnAs). Corresponding arsenides of lead (Pb3As2), cadmium (Cd3 As2), and of copper (Cu3As), were also prepared. Varying the proportions of copper, Cu, As and Cu, As were formed. Tin gave Sn3 As, and silver AgAs and Ag As, the latter a brittle mass of metallic lustre and gray color. — (Berichte deutsch. chem. gesellsch., xvi. 324.) C. F. M. [707

Production of apatites and wagnerites containing calcium bromide. - When sodium bromide is heated to a temperature just above fusion, and calcium phosphate is added to it, A. Ditte states that welldeveloped hexagonal pyramids separate on cooling, which have the composition Ca Br. 3 (Ca3(PO4)2). On heating calcium bromide and calcium phosphate together, a compound (Ca Br2. Ca ̧ (P O1)2) corresponding to wagnerite crystallizes in long needles. If calcium arseniate is used, instead of the phosphate, in the preceding experiments, in the first case the compound Ca Br2. 3 (Ca (As O4)2) crystallizes in hexagonal pyramids, and, in the second case, Ca Br, Ca (As O1) is formed. When vanadic acid is fused with sodium bromide and calcium bromide, the chief product is a bromo-vanadate, Ca Br. . 3(Ca,(V O4)2). The corresponding wagnerite (Ca Br. Ca (V O4)2) results when the acid is fused with pure calcium bromide. Analogous compounds may be formed in which calcium is replaced by other metallic elements. — (Comptes rendus, xcvi. 575.) C. F. M.

[708

The atomic weight of lanthanum. — Since the atomic weight of lanthanum was reduced by the results of Brauner to 138.28 from 139.15, the value formerly obtained by Cleve, the latter sought to verify or disprove Brauner's result by a more careful preparation of the material from which the atomic weight was determined. From 1.5 kilos. of the mixed oxides of cerium, thorium, lanthanum, and didymium, the first two elements were removed by treating the partially decomposed nitrates with water, and didymium by fractional precipitation with ammonium hydrate. The seventh fraction was converted into the sulphate, and submitted to fractional crystallization. The last mother-liquor contained 10 grms. of the sulphate, which, on analysis, gave 138.69 as the atomic weight. Since a trace of didymium could still be detected by the spectroscope, the fractional crystallization was continued until analysis showed a constant percentage of lanthanum. The mean of several determinations gave 138.22 as the atomic weight. Cleve seeks to explain the difference between his results and those of Brauner by the different methods employed to obtain pure material. He thinks, that, since Brauner depended upon a fractional crystallization of the oxalates, his product may have contained a trace of yttrium. (Bull. soc. chim., xxxix. 151.) C. F. M. [709

METALLURGY.

Ac

Silver-milling at Charleston, Arizona. cording to Mr. W. Lawrence Austin, the ore, as the mine was developed, gradually changed, and was found to carry wulfenite (molybdate of lead). The bullion resulting from milling this changed ore ran down to from 200 to 300 fine. The fineness was again restored to 970 by stamping much finer, and giving up altogether the grinding in the pans; departing from the usual custom of stamping, 35 mesh to the inch, and grinding, and also by the use of lime in cleaning the amalgam. Cerussite and galenite did not cause the same trouble as wulfenite. — (Eng. min. journ., Jan. 27.) R. H. R. [710

Refractory bricks. The waste liquors from manufacturing potash salts at Stassfurt and Leopoldshall, containing 27 to 30% of chloride of magnesium, are now saved. The evaporated salt is treated, at an elevated temperature, with highly superheated steam in an oxidizing flame; and nearly chemically pure magnesia and hydrochloric acid of 21° Baumè, are obtained. This magnesia is well adapted, not only for making the cement of oxychloride of magnesia, but also for making magnesia firebricks, now so much used. ·(Eng. min. journ., Feb. 24.) R. H. K.

[711

Proposed modification in copper-smelting. Paul Johnsson proposes to heat the 35 to 40% copper matte, derived from cupola or other furnace smelting, in a Siemens furnace, and to direct a blast of air upon the surface of the molten metal, in order to oxidize the impurities, and to bring the matte forward to blister copper in one operation of 12 hours. He estimates that 20 tons of matte could be treated in one furnace, with the labor of 10 men, in 24 hours; while, by the old method, 8 calciners, 4 reverberatory furnaces, and 40 men, would be required to do the same work.-(Eng. min. journ., March 3.) R. H. R. [712 Bessemerizing matte in a reverberatory furnace.-H. M. Howe refers to the article of Paul Johnsson (Eng. min journ., March 3), and claims that the credit of the process belongs to the Orford nickel and copper company, and not to Paul Johnsson. -(Eng. min. journ., March 17.) R. H. R.

GEOLOGY. Lithology.

[713

Lithology of the Eisengebirge. The rocks of the Eisengebirge of Bohemia are divided by Helmhacker into three groups, -crystalline schistose rocks, crystalline massive rocks, and clastic (fragmental) rocks. Under the first are described rocks classed as amphibole gneiss, gneissoid granulite, porphyroid, mica schist, and phyllite; under the second group are placed red granite, gray granite, gneissoid granite, syenite, granite porphyry, quartz porphyry, felsite porphyry, diorite, diorite aphanite, diabase, gabbro, uratite diorite, corsite, and troktolite; and of the last, a diorite-tuff-conglomerate only is described.

Under the name 'porphyroid,' a term well known in the early part of this century and previously, Helmhacker places rocks which resemble quartz and felsite porphyry, but have a schistose structure. They possess a felsitic groundmass and crystals arranged in more or less parallel layers. Phyllite is divided into staurolite, andalusite, and ottrelite phyllite, and fruchtschiefer and lydite. In the thin section, the first is seen to possess a groundmass composed of sericite plates, between which biotite scales and magnetite grains were lying. The staurolite lies porphyretically enclosed in this groundmass, and shows aggregate polarization. In the second, the groundmass is principally composed of biotite scales and magnetite or anthracite grains. The andalusite in the thicker sections is of a pale rose tint; in the thinner, colorless. The ottrelite schist or phyllite was formed by the contact metamorphosis of black argillite with granite. This formation of ottrelite schist, by the action of intrusive rocks, agrees with the present writer's observations on Lake Superior (Bull. mus. comp. zool., vii. 45). The ottrelite or chlorotoid plates are surrounded by a very fine, granular, scaly groundmass, formed principally of a muscovite-like mineral, which polarizes brilliantly. The irregular polygonal ottrelite plates have a pale grayish-green color, and are plainly dichroic. They are homogene

ous, and, excepting some dust-like grains of magnetite, are free from inclusions.

The term 'troktolite' is the equivalent of the more common one forellenstein'; and the diabase-tuff-conglomerate belongs to that class of rocks which the present writer named in a briefer way, in 1879, porodite (1. c., v. 280). Our space forbids an adequate idea of an extended paper filled with details. — (Arch. natur. landesdurchf. Böhmen, 1882, v. 87.) M. E. W. [714

METEOROLOGY.

Winds on sea and on land. - Mr. Alexander Buchan has recently discussed the observations of the wind made by the Challenger during its cruise of three years and a half, ending with May, 1876. Observations of the force and direction of the wind were made on 1,202 days, at least 12 times each day. Of these, 650 were on the open sea, and 552 near land. The seas were the North and South Atlantic, North and South Pacific, and the Southern Ocean.

This he

Mr. Buchan finds the diurnal range of the windvelocity on the open sea very small, not varying more than 1 mile, on either side of 17.5 miles per hour, during the 24; while near land the range was very marked, being nearly 15 miles per hour at 2 P.M., and only a little over 11 from 9 P.M. to 8 A.M. explains from the fact that the daily range of surfacetemperature, for example, on the North Atlantic, is only .7°; and hence over the ocean the atmosphere rests on a floor the temperature of which is all but constant day and night. On approaching the land, however, the daily range of the temperature of the air over the sea becomes materially augmented, and amounts to 4.3°; and we know, from all observations, that on the land the range is still greater. This shows that the phenomena of the daily range of windvelocity is intimately associated with that of the surface-temperature. Mr. Buchan writes, "So far as concerns any direct influence on the air itself, considered apart from the floor or surface on which it rests, solar and terrestrial radiation do not exercise any influence in causing the diurnal increase of the wind-velocity with the increase of temperature." On nearing land, the wind is everywhere greatly reduced in force, the retardation being due chiefly to friction. The winds were found lightest over the North Pacific (14.5 miles per hour), and strongest over the Southern Ocean (23.5 miles per hour). —(Nature, March 1.)

Rainfall of New South Wales. - A valuable map by H. C. Russell, for 1881, shows a fall of forty to sixty inches at several points along the coast north and south of Sydney, and diminishing to twenty or even ten inches on the plains of the Darling River, some five hundred miles inland. - (Journ. roy. soc. N. S. Wales, xv.) W. M. D.

[716 Weather-predictions in Australia. All the Australian colonies being now connected by telegraph, it is proposed to issue daily, at Melbourne, a weatherchart, showing atmospheric conditions at nine A.M., and attempting predictions for the following day, especially when cyclone disturbances show themselves within the vicinity of the coast. Most of these storms come from the southern Indian Ocean, and move east or north-east, sometimes running ashore, sometimes passing south of Tasmania. As the barometer falls on their approach, warm north winds come down with increasing strength from the heated interior country. Rain is generally heaviest with these winds, but sometimes falls to a considerable amount after the storm-centre has passed, the wind veering through the north-west, as a rule, but some

times backing through the east when the centre passes inland. Australia sends storm-warnings by cable to New Zealand. Nearly every barometric depression observed in the former region reaches the latter, requiring two or three days for the intermediate oceanpassage.-(Trans. roy. soc. Victoria, xviii.) w. M. D. [717

PHYSICAL GEOGRAPHY.

Hawaiian Islands. - Preparatory to his studies of the Cascade range, Capt. Dutton, of the U. S. geological survey, visited the Hawaiian Islands last year. He regards Kilauea formed independently of Mauna Loa, and describes its lava-lake. The colossal eruptions of Mauna Loa were especially remarkable: that of 1855 would have built Vesuvius. The mountain has no cinder-cones; and when in eruption there is no roar of vapors or cloud of steam, but a huge river of fiery lava wells forth like water from a radial fissure on the mountain flank, sometimes beginning as a great fountain several hundred feet high, then swiftly flowing down toward the sea. The lava being very liquid, the volcano is abnormally flat, and, as yet, it has no streams or ravines upon it; but there are many long tunnels in the lava, which lead the drainage underground. Mauna Kea has numerous cinder-cones, which form striking features on its slopes. The difference between the erosion on its windward and leeward sides is very marked. The other islands were also examined. Haleakala, on Maui, presents grand scenery in its deep valleys; Oahu and Kaui are also deeply eroded, implying a cessation of their activity earlier than that of Hawaii, but not necessarily an earlier beginning. — (Amer. journ. sc. 1883, 219.) W. M. D.

GEOGRAPHY.

(Arctic.)

[718

Norwegian arctic fishery in 1882.-The fisheries from Tromsö and Hammerfest employed 575 persons, in 67 vessels of 2,654 tons total burden, and produced, in 1882, 148 walrus, 5,839 seal of all species, 117 beluga, 49 polar-bears, 211 reindeer, 332 kilos eider-down, 65 hectolitres whale-blubber, 261,400 haddock, 369 hectolitres of haddock-livers, and 2,430 of other fish-livers, having a total value of some 210-, 000 kronor, or about $60,000. — (Deutsch. geogr. bl., vi. i. 1883.) W. H. D. [719 Commerce of the White Sea. In curious contrast with prevalent notions about the arctic regions, are the statistics of trade between the four ports of Norwegian Finmark and the Russian ports of the White Sea, especially Archangel. In 1881 four hundred and seventy vessels, employing over two thousand men, visited the Finmark ports; and in 1882 a still larger number, bringing goods, chiefly the product of the rich fisheries of the White Sea, to the amount of more than $700,000, and receiving cargoes for Russia of nearly equal value. (Deutsch. geogr. bl., vi. i., 1883.) W. H. D.

(Asia.)

[720

Persia. Stack's 'Six months in Persia' (2 v., New York, Putnam, 1882) is an entertaining narrative of an overland journey by one well fitted for it from his knowledge of the language of the country. His descriptions seldom have an especially geographical turn, as most of his route had been fully described before; but one would like to hear more of the burial of the old town of Askizar in drifting sands (ii. 4), of the depth to which the rivers have cut in the alluvial

slope at the foot of the mountains, so as to be out of reach for irrigation, and of the ascent of Demavend (ii. 179). The characteristic Persian landscape is desert plains bordered by rugged mountains, with villages along the lower slopes where they can get a supply of water. The accounts of the people's dissatisfaction under Persian misgovernment; of their apparent desire for external control, and their wonder whether it will come from Russia or England, of which they have very indistinct notions; and of the polyglot society in the larger towns,- are all of interest. A chapter is given on the outfit necessary for travelling in comfort; and a number of route-maps illustrate the several parts of the journey from Bushir to Karmán, Ispahan, Tehran, and the Caspian.-W. M. D. [721

Southern Persia. - Persian exploration seems to be attracting much attention in England; and the March number of the Royal geographical society's proceedings is almost entirely occupied with the accounts of recent travellers there, and the discussions their narratives excited. Col. Champain points out the small amount of trade carried on with Persia by British merchants, and shows that Russian wares are superseding British in the Persian markets. This

he ascribes to the wretched condition of the roads from the southern coast of the country and in Turkish Arabia, and advocates an attempt to improve them, as well as to build a railroad from Baghdad to Khanakin (100 m.), and to improve the channel of the Karún River where obstructed by rocks at Ahwaz. G. S. Mackenzie, of the house of Gray, Paul, & Co., at Bushir, on the Persian Gulf, described his experience on inland journeys, made some years ago, as far as Ispahan; and, while he considered it too soon to project railroads there, he thought much could be done by improving the rivers and roads. Capt. H. L. Wells gives detailed narrative and surveys of several routes across the mountainous country from Bushir, inland to Ispahan, and from Lake Niris, near Shiraz on the south-east, as far as the Karún River, 300 miles to the north-west. Although far better than the deserts of central Persia, the towns are generally forlorn and dirty, and the roads are very rough. Lake Niris is also quite unlike the flat swamps of the desert regions farther east, as its shore-line is very irregular, its banks are often precipitous, and numerous rocky islands rise from its blue waters. It was found to have a large extension to the east from its north-western end, not previously explored, known as Tasht or Nargis, joining the main lake by a narrow passage. The lake has no outlet, and its waters are bad but drinkable. Ruins and cuneiform inscriptions were found at several points. w. M. D. [722

Yesso. This northern Japanese island is described by Dr. Brauns of Halle as even more picturesque than Dai Nippon. Its surface is sharply broken by mountain and valley, and the volcanic peaks and leaping streams give it a most attractive landscape. Volcano Bay, north of Hakodate, with numerous cones rising to six thousand feet around it, is named as one of the most beautiful places in the world. The central part of the island contains a bold and high range of old crystalline rocks, bordered by the heavy miocene lignite formation, and the fossiliferous pliocene strata. The volcanic rocks belong with the latter, and consist of the true eruptive masses (Lyman's old volcanic formation') and the later stratified tuffs, which often cover extensive areas. No glacial action is recognized in the quaternary deposits. Brief notes are added on the fauna and flora. (Verh. erdk. Berl., 1883, 43.) W. M. D. [723

BOTANY. Cryptogams.

Action of light on Algae. — Berthold has made a minute study of the action of light on seaweeds, especially Florideae, and gives the results of his observations on species growing near Naples, and of his cultures made at the zoological station in that city. Under the influence of feeble illumination, the species studied turned towards the light; but, when stronger light was used, they turned from it. He considers, in detail, the effect of light in modifying the growth and branching of different species. Many seaweeds are, at some seasons of the year, covered with colorless hairs, whose function has hitherto been supposed to be connected with absorption of nutritive material. Berthold denies this supposed office of the hairs, and maintains that they act as a protection against too bright light, and states that exposure to light is followed by an increase in the growth of hairs. He also gives an explanation of the iridescence of certain species, which is produced by the formation of small plates on the outer part of the cells, as in Chylocladia, or by globular or irregular bodies in the cells, as in Chondria and Cystoseira. He denies the existence of any true fluorescence in such cases, which he considers to be merely instances of iridescence, and asserts that the plates and globules act as shields against too strong light. He also attributes a similar function to the calcareous incrustation found in Chara and seaweeds like Acetabularia and Corallina. - (Pringsheim's jahrb.) W. G. F. [724 Fertilization of red seaweeds. - Professor Fr. Schmitz has published some general observations on red seaweeds, in which he advances the view that the thallus in this group of Algae is always of a filamentous origin, no matter what the cellular character of the mature frond may be, and secondary celldivisions never include the axis of the primary cells. He considers, in detail, the fertilization and the formation of the carpospores, and is of the opinion that there is no indirect impulse transferred from one cell to another at a distance, even in genera like Dudresnaya and Polyides, but that there is always a direct transfer of cell-contents. The abstract question of the nature of the sexuality in Florideae, as compared with that of other orders, as Ascomycetes and Collemaceae, is treated at length; and he unites the Bangiaceae with Chlorophyceae, rather than with Florideae, as has recently been done by Berthold. (Bericht, akad, wiss. Berlin.) [725

Phenogams.

W. G. F.

Influence of sunny and shaded localities on the development of foliage-leaves. - Stahl of Jena has given considerable attention for several years to the effect which light has in the development of the assimilative tissues. It has been held by some that the degree of exposure of a leaf unfolding from the bud can have no influence upon the character of its cells, except so far as etiolation or blanching might produce it. Upon reviewing all the evidence in the light of his recent researches, Stahl thinks that in shaded places the leaves have a less well-marked palisade system, whereas in full sunlight they develop a better palisade system and a less well-characterized spongy parenchyma. The author is convinced that these facts in regard to the partial adaptation of leaves to their surroundings should be borne in mind in the selection of the amount of light in our greenhouses. The paper is well illustrated. — (Zeitschr. naturwissensch., xvi.; N. 8., ix. 1, 2.) 1726

G. L. G.

The largest flower. - Dr. Thurber gives an account of the pollination of Rafflesia, written in an interesting way for young readers. The immense mottled flowers, with an expanse of three feet and a weight of fifteen pounds each, are dioecious. They are fertilized by flesh-flies, attracted by their carrion odor. (Amer. agric., April.) W. T. [727

ZOÖLOGY.

Coelenterates.

Structure and development of nematophores. - As the result of his study of the nematophores of Aglaophenia, Antennularia, and Plumularia, Merejkowsky concludes that we must abandon the old view that a nematophore is an amoeboid mass of sarcode, since the use of reagents shows that it is made up of distinct nucleated cells. These cells are derived from both layers of the body; the endoderm forming the central axis, and the ectoderm the outer layer. The nematophore is usually divided into two parts, of which one shows no power of motion, and contains a battery of very large lasso-cells; while the second portion is very movable, and exhibits amoeboid changes of form. The active portion is composed entirely of ectoderm, while the immovable portion contains an endodermal axis. The active portion presents a peculiar type of histological structure, since its cells are embedded in and surrounded by a structureless layer of contractile protoplasm, which has in itself the power of active change, and to the contractile power of which the amoeboid movements are due. This protoplasmic layer seems to correspond to that which unites together the cells of labyrinthula; and something similar is found in sponges.

Merejkowsky's investigations of the development of nematophores have led him to believe that these structures are neither organs which have been acquired for a special purpose, nor specialized polymorphic hydranths, but simply degenerated hydranths.

In support of this view, he says, that, when a colony of Plumularia halicioides was kept over night without a supply of running water, the tentacles and oral orifice disappeared, the whole body became reduced in size, and the hydranth thus became converted into something which bore a very close resemblance to a nematophore. The ectoderm gave rise to long pseudopodia, and changed its form continually, exhibiting amoeboid movements which were almost exactly like those of a true nematophore. (Arch. zool. exp. gén., 1882, 4.) W. K. B. [728

Worms.

Haplobranchus, a new serpulid. A. G. Bourne describes Haplobranchus aestuarinus, a new species of serpulid, belonging, apparently, to the Sabellidae, but differing from all known forms. A description, including a few anatomical notes, is given. The worm was found on both the Irish and English coasts.— (Quart. journ. micr. sc., 1883, 168.) C. S. M. [729

The species of branchiobdella on cray-fish. Oustroumoff has found a species near Kasan on the gills of Astacus leptodactylus, but which is nearer to B. parasita than to B. astaci, and for which he proposes the name B. astaci leptodactyli. (Zool. anz., vi. 76.) C. s. M.

[730

The teeth and synonymy of Dochmius. — Megnin discusses the synonymy of the genera Dochmius, Strongylus, and Ankylostoma. Dujardin separated Dochmius as toothless forms: but Megnin finds teeth in the Dochmius of the dog; and, believing that they will be found in the other members of the genus, he maintains that the name ought to be re