on, proceeding hopelessly to certain death. The direction of the march is dependent on the valleys, and the exodus may "radiate in quite opposite directions from one and the same mountain plateau. * * * * Thus during migratory years the southern ramifications of the Lang Fjeld will emit swarms which may advance eastward as far as the Christiania Fjord; southward, down to the coastal regions of Christiania Stift; and westward, to the fjords in the counties of Stavanger and Söndre Bergenhus. *** During the entire course of the summer and autumn, they continue to pour forth from the mountains. * * * * In the valleys they invariably meet with lakes or rivers, and large numbers constantly endeavor to cross them. If the mountains are high on both sides, the valley will, as a rule, receive contributions from each slope, and individuals may be observed crossing the river in both directions."

"During the migrations they do not allow themselves to be stopped by rivers, or even by the arms of a fjord, but trust themselves, without hesitation, to the mercy of the waves, in order to reach the opposite shore. It would almost seem as if no stretch of water were too wide for them to cross if they but see land on the other side. During the great migration in the district of Trondhjem in 1868, which has previously been mentioned, a steamer on the Trondhjem Fjord steamed into a crowd of swimming Lemmings of such vast extent that she took over a quarter of an hour to pass through it, and as far as one could see from the vessel down the fjord its waters were covered everywhere with these animals. During the great migratory years similar accounts are received from all the great lakes (Mjösen, Randstjord, Kröderen, etc., etc.)."

Great havoc is wrought in meadows and grain fields by the hungry hordes, particularly in mountain pastures and farms situated on the higher slopes.

It is stated that no rule can be laid down concerning the frequency of the migratory years. The greatest migrations, which extend down to the most distant lowlands, take place but seldom and rarely occur in the southern districts oftener than once in ten years. The number Dr. Collett has collected data for is surprising. He gives the dates and areas invaded for seven great migrations from 1739 to 1790, and for no less than 24 in the present century.

As to the extent of the areas invaded, Dr. Collett says: "On the whole it may be assumed that scarcely any accessible point of Norway (except the outermost islets) has not been invaded by their hordes during one or other prolific year."

"It has hardly ever happened that a prolific year (and the consequent migration) has simultaneously embraced the entire land. The rule is that the increase takes place in great or small districts independent of each other, but the area which may be involved thereby may be of very considerable extent. Occasionally the increase will take place simultaneously in two separate districts, divided from each other by an area of greater or lesser extent, in which the production is normal. the production is normal. In Norway there may be recognized, on the whole, at least five great groups of mountains within which most of the migrations have their radiating centre. One migration may embrace either the entire group or small portions of it."

The regular enemies of the Lemming are numerous and many of them increase with the Lemmings; as the birds of prey, the large gulls and skuas, and weasels and foxes. In prolific years certain birds which follow the Lemmings change their breeding grounds and nest in localities where they are never seen at other times. To these may be added certain irregular enemies; for Dr. Collett tells us that reindeer (both wild and domesticated), cows, goats and pigs kill and eat them in great numbers.

But the destruction of the Lemmings after reaching the lowlands is only in small part due to these enemies. "The most active factor in their extermination," says Dr. Collett, "appears to be infectious diseases, which invariably occur whenever a species of animal has multiplied in excess of its natural numbers."

"To

Not only do the Lemmings themselves die of disease; but they are believed to cause serious disease among the human population. This belief has been current in Norway from time immemorial and was published by Ziegler more than 350 years ago. Dr. Collett states that during Lemming years all running water is contaminated by the decaying excrement. this may be added the dead animals, which will be found lying scattered about in great numbers, and which, during hot summers, become quickly decomposed. The rain carries the putrid matter on to the nearest watercourse, whence it makes its way to wells, and becomes mixed with the drinking water of the inhabitants.

"During some great prolific years, definite forms of sickness have appeared in certain of the overrun districts, and the people have given these the name of 'Lemming Fever,' as they presumed that they were connected with the appearance of these animals."

After citing medical testimony and describing the disease, Dr. Collett concludes: "Lemming fever is thus a disease which, in its phenomena, is related to scarlet fever. Its origin is regarded, both by medical men and the populace, as having a certain connection with the appearance of the swarms of Lemmings and the pollution of water by their putrifying carcasses and dung during dry summers.”

Dr. Collett's treatise on the Habits and Migrations of the Lemming in Norway is replete with interest from beginning to end and must long remain the standard authority on the subject. C. H. M.

NOTES AND NEWS.

ASTRONOMY.

THE London Times gives the following accounts of recent lectures before the Royal Institution and of the last meeting of the British Astronomical Association :

Dr. W. Huggins, F. R. S., gave the second of his course of lectures on the instruments and methods of spectroscopic astronomy, at the Royal Institution, on May 30th. He dealt with the more complex instrument which is placed at the eye-end of the telescope so that the images of the stars fall upon its slit. The important question of its efficiency was connected, the lecturer said, with its power to break up the spectrum into as many parts as possible. This power of separation was fixed by certain conditions-the linear length of the spectrum, its dispersion, and the resolving power of the prism. The latter, which was independent of dispensive power, was governed by the size of the prism, hence larger prisms have greater resolving power. But the use of larger prisms in astronomical work entailed certain disadvantages, such as increased weight and cost, and difficulty of obtaining glass of uniform quality. It was therefore fortunately possible to get the results of large prisms by passing the beam through several smaller ones, though the loss of light by absorption and reflection from the faces of the prisms was very serious. An alternative way of obtaining a spectrum was to use a diffraction grating, which we owed to the experiments Fraunhofer made to discover whether the lines of the spectrum were due to interference of light. His original gratings were made by winding wire in a screw-thread round a piece of glass; ultimately he adopted the plan of ruling the lines on glass with a diamond point. Great advances were made by Rutherfurd, whose machine cut lines to the number of 17,000 to an inch, and by Rowland. There is, however, but little to choose

between a prism and a grating with 14,000 lines to the inch.

THE Friday evening discourse at the Royal Institution on May 31st was given by the Earl of Rosse, who took as his subject the 'Radiant Heat from the Moon during the progress of an Eclipse.' Sir Frederick Abel was in the chair, and among those present were Lord Kelvin, Sir James Crichton-Browne, Sir Frederick Bramwell, Professor Dewar, Mr. C. V. Boys, Dr. Frankland, Mr. Ludwig Mond and Mr. Crookes. Lord Rosse began by showing the results of his observations on the variations in the amount of heat radiation from the moon during the lunar month. Speaking of the heat given off during an eclipse, he said that in the total eclipse of January, 1888, he had found there was a great decrease in its amount some time before the first contact. During the total phase the heat radiated was a mere trifle, and it had not regained more than 80 per cent. at full moon

-an hour and a half after the last contact. Lord Rosse then described the apparatus he had used, and also the apparatus and some of the results of other investigators.

THE usual monthly meeting of the British Astronomical Association was held at University College on May 28th, Mr. E. W. Maunder, the president, being in the chair. A paper was read from Professor H. H. Turner, Savilian Professor of Astronomy at Oxford, on Simple Apparatus for Measuring Stellar Photographs.' Mr. Holmes read a paper on on The Reproductions of Astronomical Drawings,' etc., in which the value of photographic processes was commented on as being more accurate. He also read a paper on the apparent roundness of small spot markings on planets. A paper from Mr. Monck on the 'Spectra and Colours of Stars' was read. The report of the Lunar Section, by Mr. T. Gwyn Elger, F. R. A. S., the director, was read, and at

tention was called to the progress made recently in lunar photography.

GENERAL.

PROFESSOR C. LLOYD MORGAN, author of Animal Life and Intelligence and other works upon comparative psychology, is coming to this country next winter to deliver one of the Lowell Institute courses in Boston. He will also deliver four lectures upon Instinct in the Columbia Biological Course.

FIELD exploration in vertebrate palæontology is increasing very rapidly, and this summer a large number of parties will be in the field. The American Museum expedition to the Uinta Basin entered the field in March, accompanied by Mr. J. B. Hatcher, representing the Princeton Mus

eum. On June 1st Dr. J. L. Wortman takes charge of the American Museum party, which will include four collectors. The University of Kansas will send three parties into the fossil beds of Kansas, Dakota and Wyoming. The University of Nebraska will also send a party under the direction of Prof. Barbour. Prof. Baur, of the University of Chicago, announces a field expedition as a regular part of the University curriculum.

THE Royal Academy of Sciences of the Institute of Bologna offers a gold medal of the value of 1,000 francs for a memoir which either from the chemical, physical or mechanical point of view will indicate a practical system or new apparatus for the prevention or extinction of fire. The essays may be written in Italian, French or Latin. Those in other languages must be accompanied by an Italian translation. The essays are to be signed with a nom de plume and to be accompanied by an envelope containing the author's real name. All essays must be in before May 29, 1896, and should be addressed: "Al Segretario della R. Academia delle Scienze dell' Instituto di Bologna."

THE Trustees of the British Museum have issued a Catalogue of Additions to the Manuscripts in the years 1888-1893. The catalogue is provided with a serviceable index. They have also published a translation of the Papyrus of Ani which contains the most complete text of the famous Egyptian Book of the Dead. The translation, which is accompanied by a valuable introduction, is from the pen of Mr. E. A. Wallis Budge.

ANOTHER Egyptian publication of importance is from the press of Brill, at Leiden, and contains fac similes and descriptions of a papyrus (F. T. 71 So-am-tra) devoted to mortuary customs.

MR. M. A. MACKENZIE, of Trinity University, Toronto, has been appointed professor of mathematics in place of the Rev. Dr. Jones, who has accepted the position of bursar in the same institution.

PROFESSOR FRANKLAND has been elected a foreign associate of the Académie des Sciences. The vacancy was caused by the death of M. van Beneden.

APPLICATIONS for the position of lecturer in Chemistry in the university of Toronto should be sent to the Canadian Minister of Education before August 15th. The initial salary will be $1,000, increasing by annual increments of $100 until it reaches $1,800. The duties of the lecturer will be to assist the demonstrator in the superintendence of the laboratories under the direction of the professor of chemistry, and also to deliver such lectures on physiological, organic and inorganic chemistry as may be assigned to him by the professor.

The Lancet announces the following foreign medical appointments: At ErlangenDr. G. Hauser has been promoted to the chair of general and anatomical pathology, vacant by the retirement of Dr. von Zenker. At Gratz-Drs. Drasch and Jarisch have been promoted to professorships

of histology and dermatology, respectively. At Oporto-Dr. I. do Valle, Professor of General Pathology, has been appointed to succeed Dr. Carlos Lopez in the chair of materia medica, Dr. Maximiano de Lemos taking the chair of general pathology.

AT Berlin, Dr. Ferdinand Karsch and Dr. Anton Reichenow have been made professors in the Zoological Museum, Dr. Victor Kremser in the Meteorological Institute, and Dr. A. Börsch in the Geodetic Institute.

Ar the anniversary meeting of the Royal Geographical Society of London, Mr. Clements R. Markham was elected President for 1895-6. Mr. W. T. Blanford, the Hon. G. C. Brodrick, the Hon. George Curzon, Sir George Taubman Goldie, General R. Strachy and Rear-Admiral W. J. L. Wharton were elected Vice-Presidents.

DANIEL KIRKWOOD, professor of mathematics in Indiana State University, died at Riverside, Cal., on June 11th, at the age of eighty-one. He retired from the active duties of the professorship in 1856.

THE chair of physics in the University of California, recently filled by the late Professor Harold Whiting, has been offered to Mr. Exum Percival Lewis, Ph. D., of Johns Hopkins University.

AT a meeting of the Royal Botanical Society on May 31st Professor George Henslow delivered a lecture on A Century of Progress in Floriculture.' He exibited specimens of the original wild plants from which some of our most admired garden flowers have been developed, illustrating with numerous diagrams the various stages in the way of cultivation and hybridization through which they passed before reaching the perfection of to-day.

FLOOD & VINCENT (Chautauqua Press), of Meadville, Penna., announce the appearance of Thinking, Feeling, Doing,' a popular exposition of experimental psychology

by E. W. Scripture, of Yale University. The book contains one colored plate and over 200 illustrations; it has a voluminous index.

ACCORDING to the Evening Post Professor Fabian Franklin has resigned his Professorship of Mathematics in Johns Hopkins University in order to become editor of the Baltimore Evening News.

THE American Medical College Association in Baltimore has decided by a vote of of 29 to 5 that a four years' course of study

shall be demanded of all students henceforth matriculating in institutions belonging to this organization.

AT the graduating exercises of Johns Hopkins University on June 13th the degree of Ph. D. was conferred on 46 candidates, distributed among the different departments as follows: History and economics 12, chemistry 12, geology 3, German 2, English 3, physics 4, Romance 3, Latin and Greek 5, biology, mathematics and astronomy, each 1.

BARNARD COLLEGE has purchased for $160,000 a site on Cathedral Heights, adjacent to that of Columbia College. The sum of $200,000 has been subscribed towards the new buildings.

ON January 18th the great seismometrograph at the Osservatorio del Collegio Romano at Rome registered five complete pulsations of slow period characteristic of earthquakes originating at a great distance. They commenced at 4h. 37m. 30s. p. m. (Greenwich mean time), and lasted 1m. 22s., giving an average duration of 16.4 seconds for each pulsation. On the same day a severe earthquake was felt along the east coast of Japan, and was recorded at Tokio at 3h. 48m. 24s. The distance between this place and Rome being about 9,500 km., the pulsations must have traveled with an average velocity of 3.2 km. per second (see Nature, vol. 1, pp. 450-51; vol.

li., p. 462). At Nicolaiew and Charkow, in the south of Russia, the horizontal pendulums were disturbed for nearly an hour, the epoch of maximum amplitude occurring a few minutes earlier than at Rome.Nature.

MESSRS. MACMILLAN & Co. will shortly publish an Introduction to the Study of Seaweeds, with illustrations, by Mr. George Murray, the newly appointed Keeper of Botany in the Natural History Department of the British Museum.

It is announced that Professor Albert S. Bickmore, of the Museum of Natural History, New York, will deliver the address at the laying of the corner-stone of Butterfield Museum, Dartmouth College. It is hoped that the museum, which will cost about $60,000, will be ready for occupancy in the latter part of 1896.

ARRANGEMENTS for an accurate map of Africa will be made at the International Geographical Congress which is about to meet in London. It is expected that Great Britian, France, Germany, Belgium, Italy and Portugal, being the powers chiefly interested, will divide the expenses of the map.

THE Naturalists' Directory published by S. E. Cassino, Boston, for 1895, contains the names of 5,747 naturalists of the United States and Canada arranged in alphabetical order, giving under each name the specialty studied and the address. The names are also arranged by subjects and geographically by States. The directory contains 382 pages, and is neatly bound in cloth. The price is $2.50.

THE following appointments have been made in Cornell University: Virgil Snyder Ph. D. (Göttingen) has been appointed instructer in mathematics; Darwin A. Mortant, assistant in chemistry; W. K. Hatt (assistant professor at Purdue University) and John Hayfold, instructors in civil engineering; Elias J. Durand, assistant in