Archives des Sciences Physiques et Naturelles, August 15.-On the rotatory polarisation of quartz (second part), by L. Soret and E. Sarasin.-Some new aromatic ketones obtained by molecular condensation, by A. Claparède.-On the quantity of hail that fell during the thunderstorms of August 21, 1881, and of July 13, 1788, and some words on the history of hail-preventers, by P. Dufour.

Gegenbaur's Morphologisches Jahrbuch, 8 Bd. Heft 1, 1882, contains:-Contributions to the morphology of the oral glands in vertebrates, by P. Reichel (plate 1) —On Rhodope veranii, Koll = Sidonia elegans, M. Schultze, by Prof. Dr. L. v. Graff (plate 2). This little animal, found on Úlva, at Trieste, belongs not to the Gastropods, as Kolliker thought, but to a section of the Rhabdocoela.-Notes on the calcareous skeleton in the Madrepores, by G. v. Koch (plate 3).-Contributions to the anatomy of the organs of vision in fish, by Dr. E. Berger (plates 4 and 5). Contains an account of researches made on one Cyclostomous nine Selachoid and nine Teleosteous fishes, and is accompanied by an account of the literature of the subject.

Niederländisches Archiv für Zoologie, Supplement Band 1, Lief. 3, 1882, contains a report on the sponges dredged up in the Arctic Sea by the Willem Barents, in the years 1878 and 1879, by Dr. G. C. J. Vosmaer, with four plates. Vosmaer differs from Sollas, though apparently without the same amount of material to judge from, regarding Thenea muricata, Bwk., as the same species as Th. wallichi. This very excellent memoir is written in good English, but as the sheets were not corrected for press by the author, several very perplexing mistakes occur, which are corrected in the appendix.-Report on the Echinoderms of the same expedition, by Dr. C. K. Hoffman, with one plate.-On the Nemertians of the expedition, by Dr. A. A. W. Hubrecht.-On the Gephyrea, by Dr. R. Horst, second portion, with two plates. Stephanostoma barentsii is described as a new species.-A catalogue of the Polyzoa, by D. W. J. Vigelius, with one plate.-On the Crustacea, by Dr. P. P. Č. Hoek, with three plates.-List of the Mollusca, by Th. W. Van Lidth de Jeude; and list of the Birds, by Dr. H. Schlegel.

SOCIETIES AND ACADEMIES
LONDON

Entomological Society, October 4.-Mr. H. T. Stainton, president, in the chair.-Two new Members were elected.-Mr. R. McLachlan exhibited nymph-skins of Hagenius brevistylus, Selys (a dragon-fly occurring in Texas).-Mr. C. O. Waterhouse stated that the beetle exhibited at the August meeting as destructive to beer-casks at Rangoon was not Xylborus Saxesenii, Ratz., but Bostrichus perforans, Woll. A discussion followed as to whether wood-feeding beetles attack healthy as well as unhealthy trees.-Papers read Prof. J. O. Westwood, Further descriptions of insects infesting figs.--Mr. G. C. Lewis, A supplementary note on the specific modfications of Japanese Carabi, and some observations on the mechanical action of sun-rays in relation to colour during the evolution of species.

PARIS

Academy of Sciences, October 9.-M. Blanchard in the chair. M. Dumas communicated the results of the labours of the International Committee of Weights and Measures for 1882. The comparison of a new metre and kilogramme of iridised platinum with the old French standards of platinum proved very satisfactory (showing close similarity).-On a new theory of the sun, by Dr. C. W. Siemens, by M. Faye. He urges that gas rarefied to would be, for the astronomer, a dense medium, presenting much greater resistance than is observed, to celestial movements. Moreover, the hypothesis adds 100000 times the mass of the sun, to those masses which celestial mechanics has hitherto reckoned so minutely.-On the shock of two spheres, having regard to their degree of elasticity, and to the friction developed on contact, by M. Ledien. These chiefly apply to the prevalent notion of electromotive forces, (total or partial) and of currents.-Observations of the great comet (Cruls) at Marseilles Observatory, by M. Borrelly.-Theorems on the functions of an analytical point, by M. Appell.-On Fuchsian functions, by M. Poincaré.-On a series for developing the functions of a variable, by M. Halphen.-On the gravity-barometer, by M. Mascart. He made a rough trial of his in-trument in a journey to the north of Norway. He finds that it is easily transportable, and that its precision is apparently not less than that obtained with the pendulum. One has merely to observe the mercury-level and the temperature,

and the installation may be done in less than an hour in a hotelroom.-Transmission of work a great distance, on an ordinary telegraph-line, by M. Deprez. Between Miesbach and Munich (57 km.) he used two telegraph wires of galvanised iron 45 mm. thick. The total resistance of the circuit, including the two quite similar Gramme machines (each 470 ohms) was about 1900 ohms. In a first experiment, a work of 38 kgm. per second (or a horse-power) was got directly at Munich with a velocity of 1500 turns a minute (the Miesbach machine giving 2200 turns). More than 60 per cent. of the work expended was recovered. Heavy rain fell all the time of the experiments. The receiving machine fed a cascade through a centrifugal pump. The heating after two hours was hardly appreciable.-Thermoscopie method for determination of the ohm, by M. Lippmann. This differs from Mr. Joule's calorimetric method in not requiring measurement of the quantities of heat, nor a knowledge of the mechanical equivalent of heat. After measuring the heat from passage of a current of known intensity through a wire in a calorimetric vessel, equal heat is developed by friction in the vessel, and from the work expended, and the intensity of the current, the electric resistance may be deduced.-On the rotatory polarisation of quartz, by MM. Soret and Sarasin. A new method is described, which yields results closely agreeing with those got before.-On experiments made to determine the compressibility of nitrogen gas, by M. Amagat. He notes important points of difference between M. Cailletet's method and his own (which some have affirmed to be quite similar), shows that the curves obtained are quite different, and contends for the greater accuracy of his own results.-On some combinations of bisulphide and biselenide of tin, by M. Ditte.-On the fermentation of nitrates, by MM. Gayon and Dupetit. Their experiments confirm the hypothesis that the reduction of nitrates, as well as nitrification, is a physiological phenomenon. Thus, in sewage water containing a little nitrate of potash, with some altered urine, the nitrate disappears gradually, and the liquid is filled with microscopic organisms. Chicken broth does better sary.) Carbolic acid and salicylic acid in antiseptic, or even than sewage-water. (The presence of organic matters is neceshigher doses, not only do not hinder the life of the reducing microbe, but themselves disappear completely with the nitrate.— Note on the transformation of amides into amines, by M. Baubigny. On the decomposition of the tertiary acetate of amy] by hear, by M. Menschutkin.-Observation of the aurora borealis of October 2, 1882, by M. Renou. Accounts of the phenomenon were received from the Park of Saint Maur, from Nantes, Evreux, and Cherbourg.-M. Maumené said that black phosphorus appears nearly always in the first drops of phosphorus which distil in a current of hydrogen (prepared from zinc and sulphuric acid). The following drops are colourless and destroy the colour of the first by liquefying them and mixing with them. CO, does not give the phenomenon.

J'

THURSDAY, OCTOBER 26, 1882

SCIENTIFIC WORTHIES

XX.-JAMES PRESCOTT JOULE

AMES PRESCOTT JOULE was born at Salford on Christmas-Eve of the year 1818. His father and his grandfather before him were brewers, and the business, in due course, descended to Mr. Joule and his elder brother, and by them was carried on with success till it was sold in 1854. Mr. Joule's grandfather came from Elton, in Derbyshire, settled near Manchester, where he founded the business, and died at the age of fifty-four in 1799. His father, one of a numerous family, married a daughter of John Prescott of Wigan. They had five children, of whom James Prescott Joule was the second, and of whom three were sons-Benjamin, the eldest, James, and John, and two daughters-Alice and Mary. Mr. Mr. Joule's mother died in 1836 at the age of forty-eight; and his father, who was an invalid for many years before his death, died at the age of seventy-four in the year 1858.

Young Joule was a delicate child, and was not sent to school. His early education was commenced by his mother's half-sister, and was carried on at his father's house, Broomhill, Pendlebury, by tutors, till he was about fifteen years of age. At fifteen he commenced working in the brewery, which, as his father's health declined, fell entirely into the hands of his brother Benjamin and himself.

Mr. Joule obtained his first instruction in physical science from Dalton, to whom his father sent the two brothers to learn chemistry. Dalton, one of the most distinguished chemists of any age or country, was then president of the Manchester Literary and Philosophical Society, and lived and received pupils in the rooms of the Society's House. Many of his most important memoirs were communicated to the Society, whose Transactions are likewise enriched by a large number of communications from his distinguished pupil. Dalton's instruc tion to the two young men commenced with arithmetic, algebra, and geometry. He then taught them natural philosophy out of Cavallo's text-book, and afterwards, but only for a short time before his health gave way in 1837, chemistry from his own "New System of Chemical Philosophy." Profound, patient, intuitive," his teaching must have had great influence on his pupils. We find Mr. Joule early at work on the molecular constitution of gases, following in the footsteps of his illustrious master, whose own investigations on the constitution of mixed gases, and on the behaviour of vapours and gases under heat, were among the most important of his day, and whose brilliant discovery of the Atomic Theory revolutionised the science of Chemistry and placed him at the head of the philosophical chemists of Europe.

66

Under Dalton, Mr. Joule first became acquainted with physical apparatus; and the interest excited in his mind very soon began to produce fruit. Almost immediately he commenced experimenting on his own account. Obtaining a room in his father's house for the purpose, he began by constructing a cylinder electric machine in a very primitive way. A glass tube served for the cylinder; VOL. XXVI.-No. 678

a poker hung up by silk threads, as in the very oldest forms of electric machine, was the prime conductor; and for a Leyden jar he went back to the old historical jar of Cunæus, and used a bottle half filled with water, standing in an outer vessel, which contained water also.

Enlarging his stock of apparatus, chiefly by the work of his own hands, he soon entered the ranks as an investigator, and original papers followed each other in quick succession. The Royal Society List now contains the titles of ninety-seven papers due to Joule, exclusive of over twenty very important papers detailing researchesundertaken by him, conjointly with Thomson, with Lyon Playfair, and with Scoresby.

Mr. Joule's first investigations were in the field of magnetism. In 1838, at the age of nineteen, he constructed an electro-magnetic engine, which he described in Sturgeon's "Annals of Electricity" for January of that year. In the same year and in the three years following he constructed other electro-magnetic machines and electro-magnets of novel forms; and experimenting with the new apparatus, he obtained results of great importance in the theory of electro-magnetism. In 1840 he discovered, and determined the value of the limit to the magnetisation communicable to soft iron by the electric current; showing for the case of an electromagnet supporting weight, that when the exciting current is made stronger and stronger, the sustaining power tends to a certain definite limit, which, according to his esti mate, amounts to about 140 lbs. per square inch of either of the attracting surfaces. He investigated the relative values of solid iron cores for the electro-magnetic machine as compared with bundles of iron wire; and, applying the principles which he had discovered, he proceeded to the construction of electro-magnets of much greater lifting power than any previously made, while he studied also the methods of modifying the distribution of the force in the magnetic field.

In commencing these investigations he was met at the very outset, as he tells us, with "the difficulty, if not impossibility, of understanding experiments and comparing them with one another which arises in general from incomplete descriptions of apparatus, and from the arbitrary and vague numbers which are used to characterise electric currents. Such a practice," he says, "might be tolerated in the infancy of science; but in its present state of advancement greater precision and propriety are imperatively demanded. I have therefore determined," he continues, "for my own part to abandon my old quantity numbers, and to express my results on the basis of a unit which shall be at once scientific and convenient."

The discovery by Faraday of the law of electrochemical equivalents had induced him to propose the voltameter as a measurer of electric currents; but the system proposed had not been used in the researches of any electrician, not excepting those of Faraday himself. Joule, realising for the first time the importance of having a system of electric measurement which would make experimental results obtained at different times and under various circumstances comparable among themselves, and perceiving at the same time the advantages of a system of electric measurement, dependent on, or at any rate comparable with the chemical action producing the electric current, adopted

DD

MM. HAUTEFEUILLE AND CHAPPUIS have obtained what appears to be pure liquid ozone, by compressing a mixture of oxygen and ozone at 125 atmospheres, and cooling the end of the capillary tube by a jet of liquid ethylene: on suddenly releasing the pressure, a drop of a very deep indigo-blue liquid remained in the end of the tube. The gas above this liquid was colourless, but as the last traces of liquid evaporated, the gas was seen to have a blue colour (Compt. rend. xciv. 1249).

It is well known that sulphuretted hydrogen produces little or no precipitate in an aqueous solution of arsenious oxide: according to the experiments of Messrs. H. Schulze (Fournal für pract. Chemie, 2, xxv. 431), such a liquid contains a colloidal form of arsenious sulphide. This colloid may be completely separated from dissolved arsenious oxide by prolonged dialysis; the solution, if dilute, is scarcely changed by long-continued boiling; the presence of free acids or of such soluble salts as chloride of potassium, iron, or chromium induces a change of the colloidal into an insoluble form of arsenious sulphide.

By strongly compressing phosphoretted hydrogen in presence of water, and then suddenly decreasing the pressure, M. Cailletet has obtained a crystalline hydrate of this compound, the existence of which is conditioned by the temperature and pressure ; the critical point, i.e. the temperature above which the substance cannot exist, whatever be the pressure, is 28°. Hydrates of sulphuretted hydrogen and of ammonia have also been obtained by this method (Compt. rend., xcv. 58).

By a somewhat similar process, M. Wroblewski has obtained a solid crystalline hydrate of carbon dioxide, CO2. 8H.O: the experimental results of this author seem to show that at the pressure required to cause the absorption of carbon dioxide by water in the proportion indicated by the formula CO,. H2O, the water would be entirely frozen, and therefore that this hydrate cannot be obtained by this method (Compt rend., xciv, 1355).

"WHEN Solution of two salts, capable of mutual action, are mixed, the solution contains four salts": it has hitherto been difficult to give a direct experimental proof of this generalisation made half a century ago by Berthelot. In the last number of the Berichte of the German Chemical Society (15, 1840) Herr Brügelmann describes the following experiments designed to prove the justness of Berthelot's statement :-Equal volumes of cold saturated solutions of cobalt chloride and nickel sulphate are mixed and allowed to deposit crystals by evaporation at ordinary temperatures; the crystals contain cobalt and nickel, but combined with sulphuric acid only. A mixture of solution of cobalt chloride and copper sulphate, prepared similarly to the preceding, deposits sulphate of the two metals almost free from chlorides. Copper sulphate and potassium dichromate solutions when mixed deposit crystals consisting almost entirely of sulphates of copper and potassium, the second crop of crystals contain a little chromate of the two metals, and the final crop is nearly free from sulphates.

THE "Compagnie Generale des Cyanures et Produits Chimiques" of Paris have issued a small pamphlet explanatory of the various technical applications of the salts known as sulphocyanates, which can be now readily manufactured in a state of purity. Sulphocyanate of aluminium is used as a mordant in

alizarine dyeing; sulphocyanate of copper in the preparation of aniline black, and also, along with potassium chlorate and antimony sulphide, in the preparation of matches; sulphocyanate of potassium may be employed as a refrigerating material, as during the solution of 130 parts of this salt in 100 parts of water, temperature is lowered through 34°; sulpho-cyanate of ammonium is more effectual, weight for weight, as an antichlor, than hyposulphite of soda.

INVESTIGATIONS conducted at the Baden Aniline and Soda Works show that the change of orthonitrophenyl propiolic acid into indigo, which (as already explained in this journal) has been for the most part effected by grapes or with sugar, can also be produced by the agency of sulphides, sulphydrates, polysulphides, thiocarbonates, and especially the alkaline xanthates (Chemisches Centralblatt, 1882, 366).

NEWS has been received from the expedition of Dr. Emil Riebeck, dated July 7 last. It will be remembered that Dr. Riebeck, together with Dr. Schweinfurth made a thorough investigation of the island of Socotra, which was of high scientific importance. After this task was accomplished, the travellers separated, and Dr. Riebeck crossed to Bombay, travelled through large tracts of the Himalaya Mountains, remained for some time in Cashmere, then passed through the Ganges land, investigated Ceylon, and eventually undertook a special and detailed examination of the coast district of Aracan. He ascended the Karnasuli River from Tschittagong as far as the Hill tribes, to which Prof. Bastian has drawn special attention. He made many measurements, took numerous photographs and plaster casts of this highly interesting tribe, which is still living in a most primitive natural state. The climate, however, and particularly the frequent fording of rivers, soon told upon Dr. Riebeck's health. He contracted a fever, and had to be taken to Singapore. His valuable collections of zoological, anthropological, and ethnological specimens duly attracted the attention of geographers, and were frequently referred to at the recent Geographentag." Since then Dr. Riebeck has continued his journey. Starting from Singapore, he is to follow the eastern coast of the Asiatic continent, then to cross over to Australia and New Zealand, and finally to return to Europe next summer by way of San Francisco and Panama.

To the Berlin Geographical Society the other evening, Major von Mechow gave some account of his explorations during the last year or two in the region of the Coango. Leaving Berlin in September, 1878, accompanied by a ship's carpenter and a gardener, Major von Mechow arrived at Dundo on the Coanza in the following January; but, owing to various difficulties, it was the beginning of 1880 before he could start northwards into the interior at the head of 115 native carriers. Crossing and re-crossing the Cambo, and passing through various powerful and hospitable tribes, the German traveller, after a thirty-seven days' march, at last reached the Coango on July 19, 1880, and, under the guidance of the great chief Tembo Aluma, visited the magnificent Succambɔndu waterfall, which he named after the Emperor William. After canoeing it on the Coango for twentyfive days, Major von Mechow made a detour to pay his respects to the great Muene Putu Kassongo, by whom he was received in great state, and returning on September 19 to the river, he followed it to longitude 5 deg. 5 min., from which point the fear of his followers of the neighbouring cannibals compelled him to return. In forty-five days he again reached the abode of Kassongo, where he stayed some time, and at last arrived on February 20, 1881, at Malange, where he met his returning countryman, Dr. Buchner, as well as Herr Pogge and Lieut. Wissmann, who were both starting on a similar tour of exploration.

A GERMAN edition of Amici's "Morocco" has been published by Hartleben of Vienna. Herr von Schweiger-Lerchenfeld is the editor, and has to a considerable extent remodelled the work, adding interesting ethnographical and historical notes, and omitting passages and references which in the original work can only interest Italian readers, on account of their purely private and local character. Its scientific value is also considerably increased. Two new chapters have been added, one on Southern Morocco, the other on the war between Spain and Morocco in 1860, and these are not the least attractive ones in the book, quite apart from the geological interest attaching to