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Daniel, Professor of Physics at the Central School of Arts. It is generally admitted that the current of the pile moves in the interpolar circuit from the positive to the negative pole. The existence of a mechanical action exerted in this direction is confirmed by the movement produced in the carbon by the voltaic arc. It is evident also from the difference of level which takes place under the influence of a current, in a vessel divided into two compartments by a porous diaphragm, and enclosing a liquid of weak conductivity, which at the commencement of the experiment presents two surfaces of equal height at each side of the separation. The movement of the liquid, by the current discovered by Porret, has been examined by Messrs. De la Rive, Becquerel, and latterly by Windemann, who has determined its laws under certain conditions. It is possible to place in evidence this action of electricity, and to show the direction by an experiment more simple than the preceding. M. Daniel fills. with slightly acidulated water, a glass tube of any length, and of a diameter from ten to fifteen millimetres, bent at a right angle at its two extremities. He introduces into the liquid column a globule of mercury two or three centimetres long, and immerses the electrodes of a more or less powerful pile into the two vertical portions. By means of the globule of mercury the instrument is easily levelled. As soon as the current passes the globule becomes elongated and begins to move; going from the positive to the negative pole. If by means of a commutator interposed in the circuit, the direction of the current be changed, the globule stops and immediately takes an opposite direction, always from the positive to the negative pole. By properly moving the commutator, we can make the mercury take an indefinite alternating motion. The ends of the globule under the influence of the current do not present the same appearance. It is brilliant towards the negative electrode, and dull towards the positive one. This is owing to its possessing positive tension in front and negative tension behind. The oxide of mercury formed during the experiment is collected at the negative end, and is reduced, at least in part, by the hydrogen produced at the same time. If the liquid contain too much acid, a salt is formed which affects the transparency of the liquid, and bubbles of hydrogen are disengaged.

When the direction of the current is altered, a sort of veil which covers one of the extremities of the globule is seen to fly to the other extremity. Four Bunsen elements suffice for this experiment, if we employ a tube 0-40 m. to 0·50 m. long. With twentyfour elements we can operate upon a tube a metre long. The current of fifty elements gives too great a velocity to the mercury, and breaks it up into globules which travel in the same direction. When the tube is inclined the mercury can still move from the lower to the upper end. Thus the weight of the mercury being

known, we can form a very clear idea of the work performed by the portion of the current which traverses the globule. If the inclination be progressively augmented, a moment arrives at which equilibrium is established between the force of the current which tends to make the mercury ascend and the action of the weight which causes it to descend, the globule resting stationary, but elongated. It is subject to a very apparent interior movement, and takes a rotatory motion, first in one direction, then in another. The same experiment can be made by means of a Ruhmkorff's coil. As the currents furnished by this apparatus are alternately in contrary directions, a commutator is necessary to suppress the inverse current. It is important to remark that the conductivity of the transported material is one of the necessary conditions of the movement; a globule of bisulphide of carbon introduced into the tube is insensible to the passage of the current. These experiments have a close similarity with those which Mr. Gore, F.R.S., described before the Royal Society some years ago.

The Abbé Moigno has brought forward a claim to be the first to make known the nature and application of the mysterious agent, ozone. In 1845, on the first news of the curious observations of M. Schönbein, he says he proceeded to Basle and visited this celebrated chemist. The abbé then wrote to the Epoque' a letter, inserted on December 31, in which the following very important passage occurs:-"It is necessary to return immediately to the ideas of Ampère, and consider the atoms of bodies as having two states-first, with the essential primitive electricity or in a nascent state; second, with their electricity more or less disseminated, or their atmosphere of electricity in a neutral state. The ozone of M. Schönbein is, in our eyes, only a molecule of oxygen in a nascent state, with only negative electricity in its atmosphere. I am, I think, able to rigorously prove and account for the wonderful properties of this agent that we cannot lay hold of, and of which so much has been said." The abbé says that he asks all chemists of that time, and Dr. Thomas Andrews, of Belfast, in particular, whether at that period any one had so clearly defined the essential nature of ozone: so much talked about, written upon, and discussed without any decided conclusion being arrived at. Two years afterwards the same reverend author asserted in the Nouvelle Revue Encyclopédique' of M. Didot, for July, 1847, the following more explicit statement:-"Sufficient attention has not been yet paid to the important fact that oxygen disengaged by plants is not in a neutral state. We are perfectly convinced that this nascent oxygen, without its positive atmosphere, is the ozone discovered by M. Schönbein, with an odour sui generis, and possessing, in the highest degree, all the properties of electro-negative substances. The bleaching of linen stuffs, ivory, wax, &c., in the open air, on

VOL. IV.

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grass, the formation of nitric acid and saltpetre, also many other phenomena, are only caused by the powerful action of oxygen in a nascent state, or with its negative electricity developed."

From 1845 to 1867 thousands of contradictory opinions have been written on the subject of ozone, but men of science are now returning to the idea clearly pointed out above. The Abbé Moigno has so often pleaded the cause and defended the interests of English scientific men, that we consider it a duty to lend our influence to establish his claim to this forecast of a great discovery.

11. ZOOLOGY (ANIMAL MORPHOLOGY AND
PHYSIOLOGY).

(Including the Proceedings of the Zoological Society.)

MORPHOLOGY.

A new Gland in the Human Body.-Von Luschka of Tübingen drew the attention of Human anatomists lately to the presence of an undescribed gland situated at the terminal extremity of the human backbone, which he called the Coccygeal gland, comparing it with the pineal gland. Krause has since found the same body more largely developed in Macacus cynomolgus—and Meyer has examined the tails of the dog, rat, and mouse for a similar structure, but without success. In the cat, however, a similar structure was found. Meyer is inclined to regard this very remarkable body as similar to the caudal hearts or retia mirabilia, which are appendages of the arterial system in many animals.

Cervical Ribs in Man.-A case of a woman is recorded by Dr. Stieda of Dorpat, in which a pair of cervical ribs sprang from the seventh cervical vertebra. The ribs appear to have been wellmarked fully formed pleurapophyses, and were attached by cartilage below to the sternum. The other vertebræ in the body were normal.

Professor Humphry on the Chimpanzee. Two specimens of the Troglodytes niger have been dissected lately by the Professor of Anatomy at Cambridge, and he gives some account of his observations in the Journal of Anatomy and Physiology,' the second number of which has just been published. Professor Humphry makes some excellent remarks on the joints of the limbs, and points out the way in which structure is here concurrent with habit. He dwells on the differences between man and the ape, and discusses the use of the word Quadrumanous. If we are to regard that extremity of a limb which is adapted for grasping as a hand, then assuredly the ape's hind-limb-extremity is as much a hand as

man's fore-limb-extremity; each differing in an exactly comparable manner from the feet (fore and hind) of the bear or dog. If, however, man's hand is to be the anatomical standard of comparison, Professor Humphry admits that there is a wide structural difference between the ape's foot and a hand. He seems inclined to favour the adoption of the term Chiropoda as a substitute for Quadrumana, a term which comes to us from Professor Halford in Australia, who has taken up this question as a strong Owenite, and has written a pamphlet on the monkey's foot.

Dentition of Marsupials.-Mr. Flower, the Conservator of the Museum of the Royal College of Surgeons, has quite recently communicated an interesting discovery to the Royal Society relative to the teeth of the Marsupial Mammalia. The lower forms of Monodelphous Mammals (e.g. Bruta) differ in their dentition from the higher, in having, as à rule, but one set of teeth, which lasts them for life, whilst the higher forms have a temporary set of teeth when quite young, whose place is afterwards taken by the permanent teeth-incisors, canines, and "premolars." From the examination of the jaws of adult marsupials, it appeared highly probable that they, although so low in the scale of mammalian life, resembled the higher members of the class in having a large milk or temporary dentition. Mr. Flower has succeeded in showing that this resemblance, like many others exhibited by the marsupials in relation to monodelphous mammals, is merely superficial. No marsupial, Mr. Flower finds, has ever more than four temporary teeth, and apparently all agree in having these four-one in the molar series of each half of each jaw. This tooth is succeeded by what is to be regarded as a premolar, and is chiefly remarkable for this, that it corresponds to that premolar (viz. the most posterior) in man and all the higher mammals, whose milk-predecessor is the first to develop, which appears earliest itself, and which in the various modifications of the dental series in the Mammalian class is the largest and most constant.

Sowerby's Whale.-The Ziphius Sowerbiensis, a rare whale of which there are only two or three specimens in the museums of Europe, is chiefly interesting as being one of the few living representatives of a very considerable group of dolphins, with long, firm, cylindrical snouts, called Rhynchoceti by Eschricht, and having teeth only in the lower jaw, and there but two or four of large size, almost like tusks. One of the known specimens of Sowerby's whale was cast ashore sixty years since in Elginshire, and its skull is now at Oxford. Another male specimen has lately been cast ashore on the coast of Kerry, and the head and teeth were procured in a perfect condition by Mr. Andrews, of the Royal Dublin Society. At a recent meeting of the Microscopical Society of London, Mr. Ray Lankester read a paper on the teeth of the Oxford specimen, in

which he showed that they presented a very low type of structure (resembling foetal teeth), corresponding to the degradation of their function from prehension or mastication to mere incidental "sexual marks." The structure of the recent teeth also threw some light on the nature and condition of fossil cetacean teeth in the Red Crag, called Balaenodon by Professor Owen.

Dentition of the Mole.-The teeth of the common mole have also recently received attention from Mr. Spence Bate, who is well known for his writings on teeth as well as for his more numerous observations on Crustacea. The dental formulæ in Insectivorous mammals is often a matter of extreme doubtfulness, and is one which can only be properly settled by the study of their development. Fred. Čuvier, Bell, De Blainville, Owen, and Blasius have each assigned a different dental formula to the mole. Mr. Bate has examined the jaws of young moles from the period when they have no hair on the body, and has satisfactorily shown what is the origin and what the antecedents of the permanent teeth. He considers that his observations confirm the formula given by Owen, viz. :

i cpmm × 2 = 44.

Mr. Bate's paper was communicated to the Odontological Society, and is published in abstract with a plate in the Annals' for June.

Ray Society.-Nitzsch's Pterylography' is the title of the last volume issued by the Ray Society, having been translated by Mr. W. S. Dallas from the German. Pterylography is the study of the distribution of feathers, and their arrangement in "feather tracts," or "pteryla," on the bodies of birds. Nitzsch was one of the most single-minded and persevering naturalists of his time-he devoted nearly the whole of his life to accumulating material for the present work, and one or two other matters relating to birds, to which class he entirely gave himself up. He died, however, before he could make up his mind to bring together his results. His friend, H. Burmeister, who succeeded him at the University of Halle, made it his first duty to do what he could with Nitzsch's material; and the German edition of 1840 was the result. The present translation is admirably performed, and the ten original plates of small folio size are well rendered. Before Nitzsch wrote, no one had made a philosophical attempt to discriminate the dermal appendages of any of the Vertebrata, beyond the rough division into Scales, Hairs, Bristles, and Feathers. He, however, has shown in a most masterly way, that there are definite regions marked out on the bodies of birds, which carry different sorts of feathers, and that these regions or pterylæ (feather-forests) can be compared and identified in different genera and species of birds, and that they furnish a means of classifying birds in a very natural way, limiting groups which are otherwise doubtful, and exhibiting their value and importance in other ways.

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