-The summer course in entomology and general invertebrate zoölogy, of Cornell university, will begin Monday, June 21, next, and continue ten weeks. After completing an elementary course in either general zoology or entomology, the student may select some subject in systematic zoölogy, economic entomology, or insect anatomy, for special investigation. It is planned to have the work of each student, as far as possible, an original investigation. Members of this class will have free use of the library, and all other privileges of students of the university. Those desiring to join the class should make application to Prof. J. H. Comstock, Ithaca, N.Y., before June 10.

From the returns of the German quinquennial census, in December last, it was found that Prussia has a population of 27,279,111, an increase of 3.79 per cent; Bavaria, 5,284,778, an increase of 2.49 per cent; Saxony, 2,972,805, an increase of 6.94 per cent, the largest of any of the states, the returns of which are so far available. In only a few provinces has there been a decrease; Pomerania, with 2.22, being the most important.

The cold weather during the past winter in Florida, has, Dr. Riley finds, destroyed the injurious orange scale insects wherever it was severe enough to cause the shedding of the leaves. The eggs, however, were uninjured.

- The journal of the Society for psychical research for April contains a second instalment of Mr. Myers's Notes on the unconscious self,' which is principally devoted to answering the criticisms of Hon. Roden Noel on Mr. Myers's previous papers. Some interesting anecdotes on the general subject of mesmerism are given by C. Kegan Paul, the well-known publisher, and his sister. At a general meeting of the society, announced for the evening of May 3, Mrs. Henry Sidgwick was to read a paper on spiritualism, which was looked forward to with great interest.

In tables just published by the U. S. geological survey, Mr. J. D. Weeks gives the total production of manganese ores in the United States during 1885 at 23,258 tons, with over seven thousand additional tons of manganiferous iron and argentiferous manganese ores. For the year 1884 there were 10,180, for 1882 only 4,532 tons. This includes only those ores containing over 44 per cent of metallic manganese.

-The small island Juan Fernandez, where Alexander Selkirk passed his four years of solitude, has been leased by the Chilian government to a Swiss named Rodt, who has established there

a flourishing colony. M. Rodt exercises the powers of a viceroy, and has the fullest administrative authority. The chief occupation of the inhabitants is agriculture, but some branches of manufacturing industry are also practised. M. Rodt encourages immigration, and among the new Crusoes are to be found Austrians, Englishmen, Frenchmen, North and South Americans, South Germans, Swiss, and Spaniards. There are no Prussians, the governor having a rooted antipathy to Prussia.

- The tenth anniversary of Johns Hopkins university was celebrated April 26. The statistics show that the whole number of students admitted since its foundation is 923, of whom 19 have died. Addresses were made by Profs. W. H. Welch, and H. A. Rowland, and others.

- The Smithsonian has received the first evidence of the successful introduction of salmon in the head waters of the Potomac. Last week Mr. R. A. Golden, a fish-dealer in the Washington market, presented a fine specimen of the Sebago salmon to the institution, measuring over one foot in length. It was caught in a trap-net at Ragety Point; and the presence of this wellgrown specimen in the Potomac waters is an earnest of what may be looked for in the future. The introduction of land-locked salmon in this river marks an important era in the progress of fish-culture and the success of the U. S. fish commission.

The proposition to establish a national military and naval museum in Washington appears to be regarded with general favor. The plan proposed is to erect a building on the Smithsonian grounds for this purpose, the museum to be under the supervision of the Smithsonian. This plan would doubtless commend itself to congress more forcibly than would the proposition to erect a large separate building in another part of the city. The army and navy museum would be quite distinct from the other departments of the national museum, and would be placed under the control of representatives of the two services upon which it must depend for growth and development.

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The vessels belonging to the U. S. coast survey were assigned to duty last week. The Palinurus, Lieut. D. D. V. Stuart commanding, is stationed in Long Island Sound; the Eagre, Lieut. C. P. Perkins, in company with the Daisy, will proceed in a few days to the North River, to complete the work begun last year by the Palinurus. This work will take until the middle of July, when the Daisy will be employed along the shores of Staten Island. The Eagre will then begin operations in the East River at a point midway

between Hell Gate and Blackwell's Island, working by degrees through the sound until meeting with the Palinurus coming west.

- Some estimate of the signal service as a promoter of original research may be gathered from the fact that two of the three gold medals awarded by the Royal geographical society were secured by Lieutenant Greely and Sergeant Brainard, for geographical discoveries. Professor Langley was awarded the Draper medal by the National academy, for discoveries at Mount Whitney; and the Royal society of science, letters, and arts, has made Lieutenant Finley a member with its highest honors, for his original work on the subject of tornadoes, all of which was under the direction of the signal service in its legitimate duties.

The secretary of state has forwarded to the house of representatives a letter from the American minister at Paris, enclosing an invitation to the United States to be represented at the convention of the Philomathical society of Bordeaux, France, to be held Sept. 1. The purpose of the convention is to consider all questions relating to commercial and industrial education. A letter from commissioner of labor, Wright, suggests the following gentlemen as delegates: Prof. C. M. Woodward of the St. Louis manual training school, Prof. W. P. Atkinson of the Massachusetts institute of technology, and professors from the Columbia school of mines and Stevens institute.

Reymond communicates some interesting notes as to the geology of the region of the great African lakes, especially of the south-east part of the Tanganyika and Nyassa basins, from specimens collected by Giraud. The region appears almost exclusively composed of primitive rocks. The only sedimentary rocks collected were from south of Tanganyika, at Yendivé station, and from Mpasa, two or three days' march from the northern end of Lake Nyassa to the north-west, on the route between the two lakes. These rocks are of a schistose character, contain Cyrena and remains of Lepidosteus, and are referred by Reymond to the upper cretaceous or lowest tertiary age. This agrees with what is known of the geology of Africa in general, where the cenomanian and nummulitic strata alone are found resting on a vast denuded plateau. The beds of brown iron ore, which cover a very large extent of country, and are worked by the natives, are supposed to have been leached out, as it were, from the crystalline rocks, by the action of the water and car

bonic acid held in the vast bogs and spongy marshes of the region. One of the chief characteristics of central Africa is the absence of calcareous formations. The metallic wealth of the country, except for iron, is little known; but Giraud reports copper rather abundant between Bangweols and Luapula. In South Africa the sedimentary beds are of greater extent, and contain a considerable amount of coal of inferior quality. The collection of fresh-water and land shells made by Giraud comprises, according to Bourguignat, ninety-three species and several new forms.

What appears to be a justifiable complaint against the delay in printing scientific reports is made by Commissioner Colman to the senators and representatives. Of the forty-five thousand copies of the first annual report of the bureau of animal industry, ordered nearly two years ago. scarcely a twentieth part have been so far delivered by the printer. Another work, Riley's report on the cotton and boll worm, long since ordered, and in the printer's hands, has not yet been delivered, though stereotyped for nearly a

It seems to the writer that almost every one connected with Cornell misconstrues the fundamental law. President Adams says, "It includes not simply agriculture and the mechanic arts, but, etc. President White speaks of the efforts of the trustees being "devoted to agriculture and the mechanic arts alone." When, some years ago, a committee of the legislature was appointed to investigate Cornell, and report as to the way in which the provisions of the law and the charter were being carried out, that committee was shown the machine-shops and farm. and the work of the professor of agriculture and of the professor of mechanic arts, as though these departments comprised the whole of the provision made at Cornell for fulfilling the requirements of the law. The law says, to teach such branches of learning as relate to agriculture and the mechanic arts. Does that mean that boys shall be taught to hoe corn, or plant potatoes, or shove a jack-plane, or swing a hammer? What are those branches of learning that relate to agriculture'?

Mathematics, the physical and natural sciences, drawing, mechanics, and the characteristic studies of mechanical and civil engineering, all these 'relate to agriculture, or the mechanic arts, or both. The law requires that the leading object of the institution founded under it shall be to give instruction in such branches. Will this be the leading object' if, as suggested by President Adams, only six hundred thousand dollars of the endowment should be devoted to this purpose? To the writer nothing can be plainer than that, to fulfil the law, whatever other endowment is accepted, whatever other branches are taught, the institutions founded upon the landgrant must make "such branches of learning as relate to agriculture and mechanic arts" (not agriculture and mechanic arts themselves) the leading object of instruction.

President Adams says the instruction contemplated by the law includes not simply agriculture and the mechanic arts, but other scientific and classical studies, military tactics, and the several pursuits and professions of life. This last is made to appear by quoting the last paragraph of the much-quoted passage first.

The meaning of that whole passage seems so plain, that it is strange that such diverse interpretations should be put upon it. It requires the founding of an institution whose branches of learning relating to agriculture and the mechanic arts shall be the leading object of instruction, and where other sciences and the classics may have a place, in order that the industrial classes in the several pursuits and professions of life may there receive a 'liberal and practical education.'

Can any thing be plainer than that the institution contemplated by the land-grant act should have for its leading object, whatever else it does, to provide for the instruction of the industrial class in such branches of learning as they most need in their pursuits?

Now, have the branches of learning that relate to agriculture and the mechanic arts been so well provided for that it is time to reduce expenditures in those directions for the purpose of establishing law and medical schools and what not? Large additions have been made to the material equipment of some of the departments; but not one of them can be considered fully equipped, and some have suffered in usefulness the last year from the cutting-off of ap

propriations. Some important branches are suffering for want of instructing-force. This is notably the case in chemistry and physics, where the number of instructors is less than for the same branches at some of the classical colleges, and much less than at some of the technical schools.

The proposition to multiply departments at Cornell seems to the writer most unwise. It is far better to take the highest rank in a few departments, if those are in the direction of the object contemplated in the foundation, than to take a lower rank in a wider field; and it is certain that the income of Cornell will need to be much larger than at present before she can take first rank in all the departments now established. A. W.

Phylloxera.

The following answers were suggested by the questions relating to the phylloxera, asked by A. M. D.' in the issue of Science for April 2, 1886.

1. Was it known as a pest in this country before its introduction abroad? The gall-type of the phylloxera was first known and described by the state entomologist of New York in 1856, seven years before the same form was known in any European country. Unmistakable evidences of its existence reach much farther back, even to 1843. In later years more or less injury was done, but the true cause of the trouble was not known until the discovery of the root type in 1868.

2. When and how did it reach Europe? The effect of the pest was first noticed in France, by M. Pinarum, in 1863; the gall-type was described by Westwood, in England, in the same year; and the first statement of the disease in Germany followed two years later; but it remained for Prof. J. E. Plouchon to first announce, in 1868, the discovery of the roottype, and to give to it the name it now bears. During the same year the winged form was discovered, and the following year the root-type was asserted to be of the same species as the gall-type of the United States. The vineyards were noticeably diseased some time before, particularly those near some American vines which were a part of a heavy importation made in 1860, - the probable time of the introduction of the pest. Undoubtedly the pest reached France through these cuttings or stocks. The fact of transporting by cuttings is further evidenced by later experience in Germany, Switzerland, and other countries where infection began among American stocks.

3. Why is it more injurious in Europe than in its native habitat? Four reasons may be given: 1. Insects indigenous to a country are frequently kept in subjection by its enemies. Such is the case to a great extent in the Mississippi valley, where the galls of the phylloxera are often cleared of its inhabitants by depredating enemies. This restriction is removed in the new country, and the pest has full chance for development. 2. The predominating varieties of vines of Europe, and also of California, are of the kind most attractive to the root louse, while Mississippi valley produces largely gall-bearing varieties of vines, which to a greater or less extent resist the attacks of the root-louse. 3. The predominance in Europe of the most destructive type, the root-louse, against the gall-louse in the Mississippi valley, — the one attacking the roots, and affecting the vine permanently; the other attacking the foliage, and pro

ducing only a transient effect. 4. Probably the chief cause of a comparative greater destruction can be found in the difference in soil, and more especially in the climate; that is, when European countries are compared with districts, like California, cultivating a similar variety of vine. It has been a notable feature in California experience that the spread is usually very slow, and only showing noticeable rapidity in exceptional cases. In our observations (see Report of college of agriculture, 1886') we have shown that a peculiar growth of roots, induced by late rains, or again by surface manuring, will produce the winged form in great abundance. But the general climate of California is extremely dry during this growing period, and therefore no such roots are apt to be formed; while in the portions of Europe where the spread has been most rapid, their type of vine being similar to that of our own, a growth of fine surface rootlets is undoubtedly induced by the summer rains, and myriads of the winged-form insects developed and spread to adjoining vineyards. The effect of fertilizing on the production of similar rootlets is doubtless greater than is usually supposed.

4. Is there any reason to suppose that the pest will be mitigated by natural causes as time goes on? As yet there seems to be no evidence in favor of such a supposition. This case should be analogous to that of other insect pests, which have been overcome only by insect enemies. This insect has been with us many years; and yet no enemy which can destroy all the forms has appeared, although the gall-type, accessible above ground, has undoubtedly been decreased in numbers by such enemies as the thrips, tyroglyphus, and others. No enemy with the needed multiplicity of forms, enabling it to traverse the vine and at the same time all parts of the roots, is known. Until such does appear, there is little doubt that the loss caused by any local disturbance will soon be replaced by the other types, and thus the species will be continued. F. W. MORSE.

Berkeley, Cal., April 22.

Topographical models or relief-maps.

I hope you will find space in your paper for the following description of a new method of making topographical models from contour maps. I compleced it a few weeks ago, and have made several models of complicated surfaces.

Make a careful tracing of the contour lines on waxed or oiled tracing-paper. Linen must not be used, as it will distort the lines when wetted. Paste the tracing on a clear piece of white holly veneer an eighth of an inch in thickness, and cut or have cut, with a fine fret-saw, the lines of contour, leaving spaces now and then, should the lines so run that the intervening wood would drop out. Fasten the veneer to a board, being sure that the surface is flat. Fasten veneer by the edges, and not through the spaces between contour lines. Cut or have cut strips of thin brass, each strip being as wide as the height of each contour line, and insert the strip into the corresponding saw-cut in the veneer. They must be pressed down until they touch the board below the veneer. When all the contours are in place, paint the whole surface over with heated wax, which will prevent the moisture of the clay from distorting the wood. When all is coated, fill in the spaces between the strips with clay until only the edges of the brass

show. Where spaces are left, the strips are cut with a slanting end long enough to span the space uncut, and the line of contour is thus unbroken.

By this method nothing is left to the eye, and perfect accuracy is gained. I have made some models for Prof. N. S. Shaler, and it was at his request that I send this description to your paper. HENRY BROOKS. Boston, April 26.

Poison rings.

Appreciating your kindness in inserting my previous letter, containing a number of questions as to what we know of the past of the pest phylloxera, and what we may expect for its future, answers to which would certainly interest many laymen like myself, and not discouraged by the lack of response from your readers, I venture to send you this.

In the recently published volume (xx.) of the 'Encyclopaedia Britannica,' under the head of 'Ring,' it is stated that "Pliny records, that, after Crassus had stolen the gold treasure from under the throne of Capitoline Jupiter, the guardian of the shrine, to escape torture, broke the gem of his ring in his mouth, and died immediately." Hannibal is also recorded as having killed himself with his ring; and the writer further says, the "anello della morte, supposed to be a Venetian invention, was actually used as an easy method of murder."

Can any of your readers inform me whether any of these ancient rings are still in existence, and, if they are, how they are made, and with what poison they were filled? A. M. D.

New York, May 3.

It has just come to my knowledge that the 'tramp' geologist who has been wandering up and down the earth' for the last three years, the man of many accomplishments and aliases, is now in the vicinity of St. Cloud, Minn., posing as 'Capt.' I. C. White of the West Virginia university.

I would say, in my own defence, that the title of 'captain' is not worn by me, and that in this case I can establish an alibi, with the help of my friends.

Cannot something be done to throttle this nuisance before he scandalizes every geologist in the country? Probably a committee from those whom he has swindled and misrepresented would hunt him down most successfully, and I am sure such a committee could be trusted to squelch him effectually. I. C. WHITE. West Virginia university, April 29.

Pompous prolixity of the French.

One reads with amused surprise, on p. 403 of the last issue of Science, that the literary style of French scientific writers is characterized by 'pompous prolixity.' We all understand that "that which is not clear is not good French." We had supposed that the genius of that sententious language was as much opposed to pomposity and prolixity as to obscurity. A. G.

Recent Proceedings of Societies.

Engineers' club, Philadelphia.

April 17.- Mr. H. W. Sanborn made some remarks on recent stream-gauging for the future water-supply of Philadelphia. The streams gauged were the Perkiomen Creek and tributaries in Montgomery county, the Neshaminy and tributaries and the Tohickon in Bucks county. The original intention was to gauge the minimum flow only, and for that purpose weirs were constructed on eight different streams. They were very substantially built, as they had to withstand the run of ice in the spring of the year. Heavy bed-logs were placed at the level of the bed of the stream, and the superstructure built on that. They were made water-tight either by sheeting placed below the bed-log, to rock-bottom, or a cement mortar wall. The crests of the weirs were generally about two feet above the beds of the streams, and were made of two inch oak-plank. Gauge-boards were placed about five feet above and below the weirs, and connected, by levels, with the same. The one above indicated the depth of the water on the crest. The one below was used only in case the weir was submerged by high water. The weirs varied in length from fifteen to seventy feet, according to the width of the stream. Stream-gauge stations were established near the weirs. Readings were taken there at the same time that they were at the weirs. When a sufficient number of readings, at various heights, were made, a 'curve of flow' was plotted by a comparison of the two. Then, when the crests of the weirs were removed for the winter, the flow was found by referring the stream-gauge readings to the curve of flow.' The great fluctuation in the flow of the streams, caused by the great number of mills on them, necessitated a great many observations at the weirs to get a correct gauging. This difficulty was overcome by the use of automatic gauges. They were run by clock-work, and drew a line on a roll of paper, corresponding to the rise and fall of the stream. The minimum flows were found to be so small that the larger flows had to be determined. These had to be found by other methods, for the weirs would only carry, at the most, two feet in depth, while the water in the streams sometimes raised as high as sixteen feet. The measurements of the large flows were made mostly by the use of electric-current meters. The measurements had to be made from bridges, and, where none existed, in proper places, small suspension-bridges were put up. One was built over the Perkiomen, at Frederick, of 120-feet span, and one over the Neshaminy, at Rush Valley, of 133-feet span. By means of the meter, the velocity of water was taken at a great number of places in a line across the stream, and a close estimate of the velocity of the whole cross-section determined. Stream-gauges were placed near the meter-stations, to be read when measurements were made, answering the same purpose as those connected with the weirs. In some cases, large flows were measured by getting the velocity of the stream, by means of pole-floats. When used, care was taken to have the length of them as near the depth of the water as possible, and they were run at as many stations across the stream as was necessitated by the changes in the even flow of the stream. The rise and fall of the water during freshets was so sudden, and the stations, eleven in number, were so scat

tered, the water-sheds covering five hundred square miles, that it was impossible to get to, and make measurements of, more than one or two streams during a freshet. Then, many times, the freshets would come in the night, and nothing could be done but the taking of continuous readings of the streamgauges. To overcome these difficulties with our small force, and get at least fair measurements of all the streams at the high point of a freshet, 'maximum stream-gauges' were set up on most of the streams. A place was chosen where the bed of the stream was uniform in width and slope, and two similar gauges set up. They were usually from two hundred to five hundred feet apart. They were made in the form of a box from eight to twelve feet long, and six inches square inside. One side opened as a door. They were placed on end and shielded and supported by heavy timbers, embedded in the soil or bolted to the rock bottom. Vertically through the centre of the box ran a brass rod, which was graduated. A metallic float ran on the rod in such a manner that it would rise with the water, but would remain fixed on the rod, at the highest point the water reached, after it had fallen. The two gauges were connected by levels, and from the gauge-readings the slope of the water was determined. From this the velocity of the stream was found by the Kutter formula. The daily flows of all the streams have been tabulated, from the commencement of the gauging in July, 1883, to January 1, 1886, and the field is still being continued. The daily flows have also been shown graphically on sheets, with the rainfall on the watershed and the temperature annexed. The connection between the three is well shown. Rain-gauge stations were established over all the watersheds; and the data obtained from them, combined with that from previously existing gauges, which was kindly furnished us by the observers, have also been plotted graphically, showing plainly the variations of the rainfall over large areas. Three automatic rain-gauges were used to show the intensity of the storms. Mr. E. V. d'Invilliers spoke upon the geological position, characteristic features, and method of mining the ore at the Cornwall ironmines, Lebanon county, Penn. The ore-deposit occurs in three hills, five miles south of Lebanon. The extreme length of this magnetic ore-deposit is 4,400 feet in a general east and west line, and its area is about 63 acres. The ore is surrounded on three sides by a steeply sloping wall of dolerite (trap) rock 100 feet thick, the mesozoic sandstone abutting against the south-west dipping-ore on the south side of the deposit. The ore was referred to the lime-shale layers between the Siluro-Cambrian limestone and the Hudson River slates, is magnetic, practically free from phosphorus, but contains considerable sulphur and some copper; and, except in the soft surface ore, all requires roasting before it is worked in the furnace. There are three commercial grades of ore; but the bulk of the output is the No. 3'select ore,' mostly lump, with about 48 per cent of iron and 2.5 to 3 per cent sulphur. Mining at present is carried on entirely above water-level, though the records of several bore-holes have established the great depth of this deposit beneath the waterplane; one bore-hole being down 325' below the surface, without any trap or other foot vein being struck. The ore is mined in successive terraces and stopes, as in huge open quarries, and, by means of six compressed-air drills, large quantities can be