was repeated to him. . The moral of Wordsworth's Hart-leap well was not so much a principle as an instinct with him. I remember his once speaking to me of the subject of vivisection. He did not condemn its use, supposing the method could be shown to be fruitful, which at that time he doubted ; but ‘couldn't do it, you know,' he added, with a sensitive, wistful look, not easy to forget."

In his twenty-first year his poetical side and religious side found greater expression than before, and his great strength in mathematics made itself felt. It is related that he often shortened the long train of analysis of the tutor by giving a short geometrical solution; and, whenever the subject admitted, he had recourse to diagrams rather than to analysis. At the age of twenty-two, Maxwell was second wrangler, Routh being senior; and Routh and Maxwell were declared equal as Smith's prizemen. At this age we find him speculating upon electricity and magnetism, and engaged in researches on color.

At the age of twenty-five Maxwell was appointed professor of natural philosophy at Marischal college, Aberdeen. At this period of his life he began his paper on the structure of Saturn's rings. His letters at this period are extremely suggestive. The death of his father, and his engagement to Miss Dewar, daughter of Principal Dewar, gave a characteristic coloring to them. These great events in his life had a powerful influence upon his speculations. His devotional side found full expression; and the study of ethics and metaphysics seemed to be strongly controlled by that of science.

He writes after his engagement,

"My lines are so pleasant to me that I think that everybody ought to come to me to catch the infection of happiness. This college-work is what I and my father looked forward to for long; and I find we were both right, that it was the thing for me to do."

In the same letter he remarks,

"I have observed that the practical cultivators of science (e.g., Sir J. Herschel, Faraday, Ampère, Oersted, Newton, Young), although differing excessively in turn of mind, have all a distinctness and a freedom from the tyranny of words, in dealing with questions of order, law, etc., which pure speculators and literary men never attain."

The period of Maxwell's life extending from twenty-nine to forty was very rich in intellectual work. His calculations upon the character of Saturn's rings led him to speculate upon the molecular theory of gases.

In

1860 he presented a paper on Bernoulli's theory of gases to the British association; in 1862 we find him engaged with others in determining the electrical unit of resistance; he was also occupied upon an investigation of the ratio between the electromagnetic and electrostatic units of electricity; and his great work on electricity and magnetism was in progress. He speaks in his letters of wading through the works of German mathematical writers, and of the careful study of the results of Faraday. His intercourse with the latter was of the pleasantest character.

On one occasion he was wedged in a crowd attempting to escape from the lecture-theatre of the Royal institution, when he was perceived by Faraday, who, alluding to Maxwell's work among the molecules, accosted him in this wise:

"Ho, Maxwell, cannot you get out? If any man can find his way through a crowd, it should be you."

The influence of Faraday's intellectual methods of thought can be plainly traced in Maxwell's later writings upon electricity. No one can understand Maxwell's intellectual growth at this time who has not read his great treatise on electricity and magnetism. In this book are embodied the results of long and continued study of the observed phenomena, and of the best methods of interpreting them by mathematics. In this treatise one can find his electromagnetic theory of light, upon which he spent much thought during this busy period of his life.

In 1870 he was appointed director of the Cavendish physical laboratory at Cambrige by the consensus of eminent men whose advice had been asked in regard to the best man for the position. Lord Rayleigh, who succeeded Maxwell as director, wrote to him at this time,

Cambridge, Feb. 14, 1871. "When I came here last Friday, I found every one talking about the new professorship, and hoping that you would come What is wanted by most who know any thing about it, is not so much a lecturer as a mathematician who has actual experience in experimenting, and who might direct the energies of the younger fellows and bachelors into a proper channel I hope you may be induced to come: if not, I don't know who it is to be."

Maxwell, in a letter to the vice-chancellor of Cambridge, expressed the opinion that the "special researches connected with heat, which I think most deserving of our efforts at the present time, are those relating to the elasticity of bodies, and, in general, those which throw light on their molecular constitution; and the most important electrical research is the de

termination of the magnitude of certain electric quantities, and their relations to each other." The Cavendish physical laboratory was not opened until 1874. Maxwell died in 1879, five years later. In this short term of office he left the impress of his genius upon the scientific work of Cambridge. Sir William Thomson has said, "There is, indeed, nothing short of a revival of physical science at Cambridge within the last fifteen years, and this is largely due to Maxwell's influence." We have said that no one can thoroughly appreciate the genius of the man who has not read his treatises on

electricity, on heat, and his various essays, which are soon to be collected and published.

His life, with its great expressions of reverence for higher things and its respect for true scientific work, is one to ponder over; and his correspondence is rich in literary suggestions, and enlivened by the play of humor. It will always be a source of gratification to Americans to know that the American academy of arts and sciences and the American philosophical society were the first of the foreign scientific societies to elect Maxwell a foreign honorary member.

MATHEMATICS.

The polar quadrilateral. — Given a conic and a polar quadrangle: the five quadrilaterals got by taking the poles of its vertices, or the pole of one vertex and the lines joining the other three, are polar quadrilaterals such that conics circumscribing their diagonal triangles osculate the given conic in the same six points. S. Kantor gives a geometrical proof of this theorem by showing that the six points in which a conic inscribed in a quadrilateral can be made to touch the given conic are the same for the five quadrilaterals, and that any one of the triply infinite number of conics with respect to which a fixed quadrilateral is polar osculates other conics of the system in the same six points in which it is touched by conics inscribed in the quadrilateral. He points out an application of the latter property to the determination of the points of inflection of the unicursal quartic obtained by a quadric transformation of the conic. (Math. ann., xxi. 299.) c. L. F.

[754

Theory of functions. -The second part of a paper by Rausenberger treats of single valued functions with non-interchangeable periods. It is not convenient here to do more than refer to this paper, as a review of it can hardly be given without introducing a good deal of algebraical work. The paper, however, as introducing a certain number of new and interesting ideas, is decidedly worthy of consideration. (Math. annal., xxi.) T. c. [755

Impact of billiard-balls.-M. Resal has generalized some of the results obtained by Coriolis in his Théorie analytique des effets du jeu de billard. Coriolis has considered the two balls as being homogeneous, and possessing identical properties in every respect. M. Resal takes account of possible differences in the masses of the two balls, and in their moments of inertia with respect to a diameter, -two properties which might interfere very seriously with the play of even a skilful player. One of the principal results obtained by M. Resal is, that, during the instant of impact, the direction of the friction is not constant. The contrary was assumed by Coriolis. — (Comptes rendus, Oct. 16, 1882.) T. c.

PHYSICS.

Acoustics.

[756

Vibrations of membranes. A. Elsas has studied the vibrations of both square and circular membranes, exciting them by connecting the middle of

the membrane with a tuning-fork by means of thread, attaching the thread to the membrane with sealing-wax. The nodes and loops were determined in the usual manner by the use of sand and lycopodium powder. Thirty different forks were used, and a great variety of membranes. The sound-figures showed a gradual change from one mode of vibration to another as the pitch of the fork was changed, thus verifying the results of Savart. (Beibl. ann. phys. chem., No. 2, 1883.) C. R. C. [757

By

Photography of sound-vibrations.— Boltzmann has studied the vibrations of a plate actuated by the voice, using a method similar in many respects to that employed several years ago by Prof. Blake of Providence. A thin platinum plate was attached perpendicularly to the iron plate; and, by an application of the principle of the photophone, it was shown to vibrate in the same manner as the iron plate. means of a solar microscope, an image of the shadow of the platinum plate was thrown upon a screen, the straight bounding-line of the shadow being condensed by a cylindrical lens. The screen was then replaced by a sensitized plate, moved rapidly at right angles to the line of light produced by the cylindrical lens, while the iron plate was made to vibrate by the voice. The bounding-line between light and shadow on the plate formed a curve whose nature varied according to the sound uttered. The curves due to the vowels are simple; those due to consonants, much more complex. [758 (Phil. mag., Feb.) C. R. C.

Optics.

Conditions of sight which affect accurate shooting. Formerly the sight of a soldier as regards shooting was a matter of little consideration; but with the introduction of the Martini-Henry and other rifles, which are accurate at 1,500 yards, sound eyesight becomes an important element. Dr. Litton Forbes, surgeon-major in the Servian war, discusses the various changes taking place in the eye by which the sight is affected, and proposes to correct defective vision by means of a stenopaeic sight-adjuster. This consists of a disk of colored glass, perforated with a pin-hole aperture, having a correcting-lens of colorless glass cemented to its back. The whole is to be worn in a spectacle-frame. (Journ. roy. united service inst., no. 118, 1882.) C. E. M.

[759

A new optical phenomenon. - Axenfeld describes the conditions of an experiment in which straight lines, a little on the near or far side of the

distance for which the eye is focused, appear curved. The explanation of the phenomenon is essentially the same as that of 'Scheiner's experiment.' The author suggests that it may be employed in the construction of an optometer. (Pflüg. archiv, xxx. 288.) H. N. M. [760

Heat.

Thermometry. — In a recent communication Prof. Cleveland Abbé has reviewed the subject of the determination of the temperature of the air at a given locality, and described an original device. Beginning with the simple hanging of the thermometer in the open air, he proceeded to describe and point out the defects of the various methods of exposure of the past and present, the thermometer in the shade, the Glaisher screen, the Stevenson screen and doublelouvre screens in general, the double metallic cylinder shelters of Jelinck and Wild, the silver-thimble screen of Regnault, the whirling thermometer of Saussure and others, and Joule's method. The method devised by himself in 1865, and practised for a short time at Pulkova, consisted in constructing a very perfect louvre screen, within which were established black-bulb and bright- or silvered-bulb thermometers. One of these was greatly influenced by radiations from the surrounding screen, and the other very little; and the difference of their readings enabled the effect of radiation to be computed and eliminated. Provided the theory of the action of the bright and black bulbs is perfectly understood, they can be employed in conjunction by meteorologists and physicists without a screen, and even in sunlight.

The formula used for reduction at Pulkova was

tats + c(to - ts),

in which ta is the temperature of the air, ts and to are the readings of the bright-bulb and black-bulb thermometers, and c is a co-efficient to be determined experimentally for each pair of instruments. Quite recently Prof. William Ferrel has made a theoretic investigation of the co-efficient, showing that it is not strictly constant, but varies with the velocity of the air-current passing the bulbs. Representing by r, and r the radiating powers of the bright and black bulbs, by B, B', and B", certain constant co-efficients depending on the size, conductivity, and specific heat of the bulbs, and by v the velocity, he writes the full formula thus:

full in Ann. phys. chem., iv. —(Ann. phys. chem., iii.) J. T. 1762

Telephony. At a recent meeting of the Society of telegraph engineers and of electricians, J. Munro described some new forms of microphonic transmitters. Among them was one consisting of two pieces of wire gauze held together by a magnet. In another form the microphonic contact was between the links of a short stretched chain. No details of practical trials are given. Mr. Stroh described an experiment in which he showed, by the use of a mirror and screen, that, in the case of one carbon cylinder resting across another, the upper one was raised mm. during microscopic contact. (Electrician, March 17.) J. T. [763

2,000

C10H160+ NH,OH = H2O + C11 = NOH. This reaction is a strong indication of the ketone character of camphor. Hydroxylamine was without action upon borneol and menthol. With chloroform the following reaction took place: CC13 COH Chloroform.

+ 2 NH2OH = 2 HCl + H2O +

CIC NOH

H - C - NOI Monochlorglyoxime.

NH2OH NH,OH and one molecule by benzoin, CH; - CO CH-C CH-CHOH CH-CHOH On trial it was found that one molecule only of hydroxylamine entered into the reaction in either case. To make sure that hydroxylamine acts the same upon the group -CO-CO- as upon the group -CO-CH-, the reaction was tested with glyoxal, with the following results: NH2OH HC = NOH HC - NOH

HCO

+ 1

HCO

= 2 H2O +

NH2OH

(glyoxime).

Benzil cannot, therefore, be a substituted glyoxal. These investigations will be continued in different directions to determine which of several possible formulae represents its constitution. (Berichte deutsch. chem. gesellsch., xvi. 494, 500.) C. F. M. [766

Certain substituted acrylic and propionic acids. - Dr. C. F. Mabery described several acids belonging to these series, which he had obtained in various ways. By the addition of chlorine to B-dibromacrylic acid, a dichlordibrompropionic acid (C Br Cl- CHCI COOH) was formed, which will be designated as the y-acid, to distinguish it from the a- and B-dichlordibrompropionic acids previously investigated. A molecule of hydrobromic acid was removed from the y-acid by the action of aqueous baric hydrate, with the formation of a dichlorbromacrylic acid (C Br Cl = C Cl -COOH). In like manner, from the a- and B-acids, baric hydrate removed hydrobromic acid, giving the corresponding substituted acrylic acids, whose structure is yet to be determined. It was hoped that a chlorine addition-product of brompropiolic acid could be formed, since it would serve as a means of comparison; but on trial it was found that four chlorine atoms were taken up, instead of two, forming tetrachlorbrompropionic acid (C Br Cl2-C CI - COOH); melting-point, 225°. Chlorine was also absorbed by chlorbromacrylic acid. From the resulting trichlorbrompropionic acid (C Cl2Br - CHCI-COOH) baric hydrate eliminated hydrobromic acid, with the formation of trichloracrylic acid (C Cl2 = CCI-COOH). These substances will be submitted to further study. (Harvard chem. club; meeting April 24.)

AGRICULTURE.

[768

Rancid butter. According to Hagemann, the peculiar properties of rancid butter are due to the presence of free butyric acid, and other volatile fatty acids. These are set free from the glycerides of the butter by the action of the lactic acid arising from the fermentation of the small quantity of buttermilk retained by the butter. That the liberation of butyric acid itself is not due to a fermentative action, was shown by the fact that all attempts to render butter rancid by adding to it the butyric ferment failed, and also by the fact that rancid butter failed to infect fresh butter. That the explanation given above is an adequate one, was shown by mixing both lactic acid and other dilute acids with butter or with pure butter-fat, the fat speedily becoming rancid in all cases. The same effect was produced on artificial butyrin. To prevent butter from becoming rancid, the buttermilk should, in the first place, be removed as thoroughly as practicable. In the second place, any thing which will prevent the lactic fermentation will, of course, remove the cause of the evil. The author does not enter into a consideration of the most suitable means of doing this, further than to

point out that acids (such as salicylic acid) are not applicable, since they themselves are liable to act on the fat, and render it rancid. — (Landw. vers. stat., xxviii. 201.) H. P. A. [769

Ropy milk. -Schmidt finds that the ropiness of milk, which is sometimes observed, is caused by the action of a microscopic organism, which he describes, upon the milk-sugar. The same organism acts also upon cane and grape sugar and on mannite, converting them into a substance resembling vegetable mucilage in its properties. Small quantities of acid are produced, but no carbon dioxide. The fermentation appears to resemble, if not to be identical with, the mucilaginous fermentation of wine. The organism acts most energetically at 30°-40° C., and is destroyed by heating the fluid containing it to 60° C. or over. Freezing does not destroy it; and, if dry, it withstands a temperature of 100° C. Only comparatively large quantities of antiseptics prevent its action.-(Landw. vers. stat., xxviii. 91.) H. P. A.

GEOLOGY.

[770

Geology of Brazil. - Professor Edward D. Cope made a communication based upon a collection of vertebrate fossils from Brazil, recently placed in his hands for study. As his examination of the material was not yet completed, he could only allude to the leading points of interest in connection with the geology of the United States and western Europe. The localities in which the fossils in hand were found are all south of the Amazon River. The eastern and western ranges of mountains correspond to our Alleghany and Rocky Mountains, and are approximately of the same age. A cretaceous formation is found in the neighborhood of Pernambuco. There are bare fossiliferous deposits near Sergipe, while the beds near Bahia are evidently lacustrine. The fossils from Pernambuco include several genera of sharks, and a genus of crocodiles identical with Hyposaurus of New Jersey. There is found with these a fine genus of rays, the teeth of which were described. These genera indicate this cretaceous formation to be near the top of the series, corresponding to the Maestricht chalk, or our number 5. At Maroin was found a new species of fish of the genus Pycnodus. He believed it to belong to the order Isospondyli; although it is very different in general form from the herrings, salmons, and other recent fishes belonging to the order. The form of the basilar bone of the pectoral fin, which the speaker considered of first-rate importance as indicating the relationship of the genus, was observed, and indicated that the position assigned was the correct one. The region about Bahia furnishes many fishes and saurians, but no cretaceous mammalia have as yet been discovered. There are two species of herring, - a small one, six inches long; and a large one, two feet long, resembling Hyodon and Chirocentrus. Crocodiles and dinosaurs are abundant, the former indicating higher beds than those at Pernambuco. A gavial resembling Holops of the New-Jersey cretaceous No. 5 was also found in these beds, which may be said to represent the Laramie deposits of the western United States. A tertiary horizon in Bahia has so far produced but one fossil, a new species of Toxodon. The age is pampean. In San Paulo the beds seem to be Permian, and have yielded one batrachian form, which may, however, be carboniferous. The head bones of a large fish, the locality of which was not known, were also described. During the pliocene period the vertebrate fauna of Brazil was very distinct from that of North America; but the fossils now being studied

indicate a marked similarity in earlier periods. (Acad. nat. sc. Philad.; meeting April 10.) [771

Lacustrine formations of St. John, N. B.- As studied in the deposits of Lawlor's Lake, G. F. Matthew finds these to have begun about the middle of the terrace period, when the sea, which had previously submerged this portion of the coast to a depth of 200 feet, had so far shoaled as to bring up the land within 65 feet of its present level. During the interval between this epoch and the present time, a series of layers has been deposited, resting upon the marine Saxicava (or Macoma) sands below, and consisting, in succession, of lacustrine clays, lacustrine peat, peaty marl, and pure marl, to a depth of about 81 inches. From the character and relations of the deposits, together with the vegetable and animal remains which they contain, he finds it possible to trace out a number of successive phases in the lake-history of the region, accompanied, probably, by equally marked climatic differences. Among the plant-remains observed, the most interesting are those of the Characeae, of which particular descriptions, accompanied by figures, by Dr. T. F. Allen, are given. In addition to the spores of Chara, fragments of wood (some of them gnawed by the beaver), bark, cones of evergreen trees, bud-scales and leaves, and fruits of several species of land-plants, occur. A small fragment of charcoal was also found some distance below the surface, indicating, probably, the presence of man. The character of the plants is regarded as presenting a more northern facies than those dwelling in the same region to-day. The variations of the molluscan fauna attendant upon the changes in the condition of the lake are especially interesting, and have been made the subject of particular study by Prof. Hyatt. — (Bull. nat. hist. soc. N.B.) L. W. B.

Lithology.

(772

The Cheviot andesites and porphyrites. — The Cheviot district is composed largely of a series of quartzless eruptive rocks, to which the name 'porphyrite' is usually applied. They have a compact felsitic groundmass porphyritically enclosing numerous felspars. The color is generally dark purple or red. They are much altered; and amygdaloidal varieties are found. In addition to the ordinary porphyrites, there occur masses of volcanic ash and breccia, and also a rock known as pitchstone porphyrite. These porphyrites have been described by Teall under the name andesites,' regarding them as more or less altered andesites.

Mr. Teall describes the mineral constituents as felspar, pyroxene, magnetite or mennacanite (a glassy base containing various devitrification products), apatite, and hematite or biotite. The felspars contain numerous inclusions of the base, and are principally plagioclase. The pyroxene is in elongated, octagonal, and irregular crystals and grains. The crystals are sometimes twinned, and he regards them as augites. The inclusions in the augite are glass cavities and colorless microlites. The groundmass is described as a felted aggregation of microlites in a glassy base.' The present writer has preferred to denominate this as a 'felty base.' The microlites of the felty base Teall regards principally as felspar. The alteration products appear mainly to be siliceous. The age is stated to be post-silurian and pre-carboniferous.' Some specimens were later examined by Dr. H. Rosenbusch of Heidelberg, the leading European lithologist. He found that part of the pyroxenic constituent was orthorhombic, probably hypersthene, while the remainder is augite.

Northern notes. Later advices have been received from the British party at Fort Rae. After experiencing a miniature shipwreck on Great Slave Lake, they arrived at Fort Rae in the latter part of August. Sept. 1, meteorological, and, two days later, magnetic observations were begun. Winter set in Nov. 1. The minimum temperature of the air to Nov. 30 was 43° C. The latitude of Fort Rae was determined to be 64° N., a degree farther north than previously supposed. Corrections in the position and shape of Great Slave Lake also seem necessary. The party were well, and work progressing favorably. They expect to return in October, 1883.

The plans of Baron Nordenskiöld for the present summer in Greenland have been in part made public. South-west Greenland is to be visited, and a study of the inland ice from that direction is contemplated. Later in the season, when the usual lane of water forms between the pack-ice and the south-east shore north from Cape Farewell, the party will proceed in umiaks, or sealskin canoes, as far as circumstances will admit, with the view of reaching, at the head of some of the fiords, the highlands which exist in east Greenland, and which are believed to be partly free from glaciers. Traces of the ancient Norse colonies at Öst-bygd are among the things to be sought for, though the present weight of evidence is in favor of the theory that these colonies were on the south rather than on the east coast, and that they are represented by the well-known stone ruins of south Greenland. -W. H. D.

[774

Siberian notes. - Number four of the quarterly Isvestia of the imperial geographical society for 1882 (printed 1883) contains an article by N. S. Shtukin on Popular traditions of eastern Siberia,' which contains much interesting matter, and some amusing instances of ideas associated by the residents with certain ancient monuments. Another by the same author is, An explanation of certain picture-writings on the cliffs of the Yenisei River.' These are figured, but are not particularly remarkable, except as being the work of invaders from the far south, perhaps Persians. Camels and pheasants are among the animals represented. U. V. Arsenieff discusses the consequences of early publications on, and explorations of, the Amur River. Bussé continues his valuable (separately paged) bibliography of the literature of the Amur region. The first edition of this bibliography, containing 522 titles, appeared in 1874. The present edition is brought down to 1881, the fortyeight pages already published including 973 titles. The work, which will probably be completed in the next number, is announced to contain, in all, 1,416 titles, divided under appropriate subjective subheads, but catalogued by authors. Of the proposed bibliographies of Hoevert and of the academy of sciences, nothing has lately been heard, which makes the result of private enterprise so much the more welcome. Bussé's titles are condensed, but sufficiently full for reference, and a large proportion refer to articles in Russian periodicals. -W. H. D. [775