The meeting closed with some remarks by Mr. W. Lindgren, U. S. Geological Survey, on the Boise Folio (No. 45, of the Geol. Surv.), recently published.

WM. F. MORSELL.

DISCUSSION AND CORRESPONDENCE.

ON THE MAKING OF SOLUTIONS.

***

TO THE EDITOR OF SCIENCE: A remark in a recent paper by Professor Macloskie calls my attention afresh to a curious error which, so far as I know, is universally current in our zoological laboratories. Professor Macloskie remarks (SCIENCE, Vol. IX., p. 206) "a 1% solution of cane *** that is 342 sugar in water, grams, dissolved in 34,200 grams of water." In other words, a 1% solution is made by mixing 1 part of the substance to be dissolved with 100 parts of the solvent. In this conception the zoologists appear to be at one. It is sufficient to refer to any of the well-known text-books: Marshall and Hurst, Practical Zoology,' 4th ed., p. 464; Gage, 'The Microscope,' 6th ed., p. 179; Dodge, Elementary Practical Biology,' p. 391. Like many other text-books, Huxley and Martin's 'Practical Biology' (revised ed., p. 496), does not directly commit itself to the error, but gives directions to make the 'normal saline solution' by mixing 7.5 grams of salt with a liter of water. That the normal saline solution is a % solution is directly stated by Whitman ('Methods of Research,' etc., edition of 1885, p. 207), and Lee (The Microtomist's Vade-mecum, 4th ed., p. 263.),

These citations abundantly prove that Professor Macloskie's conception of a 1% solution corresponds with that of other zoologists. If, however, we ask a chemist how such a solution is made, the reply will be: "Dissolve one part of salt, sugar, or whatever the substance may be, in ninety-nine parts of the solvent." And that this is logically correct becomes selfevident upon a moment's thought. A 1% solution of HCl, as all will agree, consists of one part of the acid to ninety-nine parts of water. Why should the fact that in one case we deal with a solid, in the other with a liquid, alter the case?

It would seem that unless, or until the zoologists come into agreement with the chemists,

every investigator in publishing his researches should make a point of preventing ambiguity by stating whether his 1%, 5%, 20% solutions of solids are compounded on the logical or the zoological plan. M. A. WILLCOX.

WELLESLEY COLLEGE, March 6, 1899.

THE ORIGIN OF NIGHTMARE.

OVER and over again when a child I was for years the victim at night of a certain form of mild nightmare, so that it came to be to my fearful imagination no insignificant part of my unpleasant experiences. This nightmare always took the form of a great wave of something gradually rolling towards me and finally engulfing and oppressing me to a painful extent. It would roll up a huge shapeless mass of no particular material, but always irresistibly towards me helpless and overwhelmed. Most often it finally appeared to be a huge soft pillow or even formless feather bed, but without color or other qualities save that of engulfing and terrifying. At its worst on various occasions this mass as it rolled up became a huge fat boar, defined as such, however, only subconsciously, but always dreadful in its power to overwhelm me. All this was years ago.

One night recently, as I was falling asleep in bed in a lighted room, I became gradually aware of that sensation which compression of a nerve produces, a vague and quite indefinite sense of discomfort localized only in the region about my head and arms, but in my state of somnolence only a growing sensation of discomfort pressing on my consciousness. Increasing steadily, it finally began to awaken me, and I then became distinctly conscious of the well-remembered nightmare of my childhood beginning to approach. With the noise in the room I was now sufficiently awake to be interested in this familiar visitor, and I lay still deliberately. Gradually the mass rolled up towards me exactly as of yore, with no terror in its coming now, until finally it was upon me and all about me oppressively. I very slightly moved my arm (upon which my head was lying), and the nightmare was for the moment lost sight of in the sensations now localized there. I opened my eyes and instantly the whole experience vanished, closed them and it instantly returned

in all its force and peculiarities. Over and over again this little experiment was performed without variation in its results, until, finally, satisfied, I moved my head off my arm and stretched my arm out of its cramped position, and felt no more this bête noir of earlier days, now again returned, bringing with it emphatic and unmistakable explanation of its cause.

G. V. D.

ASTRONOMICAL NOTES.

A NEW SATELLITE OF SATURN.

A NEW Satellite of the planet Saturn has been discovered by Professor William H. Pickering at the Harvard College Observatory. This satellite is three and a half times as distant from Saturn as Iapetus, the outermost satellite hitherto known. The period is about seventeen months, and the magnitude fifteen and a half. The satellite appears upon four plates taken at the Arequipa Station with the Bruce Photographic Telescope. The last discovery among the satellites of Saturn was made half a century ago, in September, 1848, by Professor George P. Bond, at that time Director of the Harvard College Observatory.

EDWARD C. PICKERING.

HARVARD COLLEGE OBSERVATORY,
CAMBRIDGE, MASS., March 17, 1899.

NOTES ON PHYSICS.

THE NERNST LAMP.

THE electric lamp recently invented by Nernst, as has been stated in this JOURNAL, consists of a small rod of magnesia which is heated to brilliant incandescence by an electric current which is pushed through it by an electromotive force of several hundreds of volts. The rod must be heated nearly to a red heat by a blowpipe or other independent means before it passes sufficient current to operate.

A number of these lamps have been made in the Physical Laboratory at Bethlehem, Pa. It has been found that a rod of pure magnesia can scarcely be started even with 1,000 volts and a good blow pipe. The surrounding air becomes electrically too weak to withstand the high electromotive force at a temperature lower than

that required to make the rod a sufficiently good conductor. This is true even when the rod has been heated to softness beforehand in a temporary mounting.

The conductivity of the rod may be completely controlled by mixing with the magnesia varying amounts of silica and of fusible silicates. A satisfactory lamp is made as follows: Pure calcined magnesia (heavy) is thoroughly mixed with two or three per cent. of powdered silica, one or two per cent. of magnesium sulphate, and one per cent. or less of sodium or potassium silicate (water glass). The mixture is dried until it is just moist enough to pack under pressure. A small piece of brass tubing is lined with a roll of several thicknesses of stiff writing paper, and the mixture is tamped into this tube. The tube is then baked until the paper is burned, when the rod of magnesia may be removed. This rod is then laid upon a bed of magnesia (powdered lime would, perhaps, answer) and by means of carbon terminals an alternating current is passed through the rod, heating it first to redness by a blow pipe. With some care a very hard and compact rod of magnesia is thus formed which is then ground to a thin rod with large grooved ends. Platinum wire is wound on these grooved ends and, if desired, cement made of water glass and powdered magnesia may be used to cover the platinum. The two platinum wire terminals may then be bound to the sides of a small glass tube as a support. A lamp made in this way may be started easily, although its resistance rises slowly with continued use, owing, perhaps, to the volatilization of the potassium or sodium silicate. Calcium silicate would, perhaps, be more satis. factory in this respect.

A very striking experiment may be performed with a piece of glass tubing several inches long wound with copper terminals at its ends. The tube begins to pass considerable current at a low red heat, with a few hundreds of volts, and is quickly melted by the current. A thin-walled tube half an inch or more in diameter is best, and it should be heated along one side only so that the cool portion of the tube may for a short time serve as a support for the hot conductive portion.

W. S. F.

PYROELECTRICITY AND PIEZOELECTRICITY.

W. VOIGT (Wiedemann's Annalen, No. 13, 1898) shows that the electrification of certain crystals by heating (pyroelectricity) and the electrification by deformation (piezoelectricity) are in general one and the same phenomenon, and that it is only in such a crystal as tourmalin, which has a single axis distinguished from all other axes by characteristic physical properties, that pyroelectricity is not due wholly to the deformation accompanying a rise of temperature. Professor Voigt also points out that a plate of tourmalin can be used to generate accurately known electric charges by subjecting it to measured compression, and he gives the results of a determination of an electrostatic capacity based upon the known charge generated by a tourmalin plate and the known e. m. f. of a standard cell. W. S. F.

THE ROTARY CONVERTER.

IN two short articles in the Electrical World, for December 17th and 24th, Mr. C. P. Steinmetz gives a quite complete discussion of the theory and action of the rotary converter, a machine used to convert alternating current into direct current, mainly in connection with long distance transmission. Mr. Steinmetz's papers are, almost without exception, very difficult to read for the reason, chiefly, that he always gives a great deal of precise information about difficult subjects not generally understood. The present paper cannot, of course, be abstracted, but it is mentioned for the reason that Mr. Steinmetz deserves to be more generally known as one of the foremost electricians of our time; that he is a scientific electrician is a matter of course. W. S. F.

THE TELESCOPE-MIRROR-SCALE METHOD.* PROFESSOR S. W. HOLMAN has given in the Technology Quarterly, for September, 1898, a most complete and usable discussion of the telescope-mirror-scale method for measuring angular deflections. Almost at the very beginning of the paper a list of the fourteen instrumental errors is given, together with directions for making the adjustments which are necessary *Published separately by John Wiley & Sons, New York. Price, 75 cents.

to reduce each error to a prescribed value. Following this is a general discussion of each error of adjustment and a derivation of the error in angle due to each. Most physicists have, of course, looked into the detailed theory of the telescope-mirror-scale method in spite of the fact that the literature on the subject is not generally accessible, but the habitual use of the method for rough measurements makes one lose sight of a dozen or more of the adjustments and precautions which are necessary in accurate work, and, therefore, almost every physicist will find this pamphlet of Professor Holman's a useful reminder when the need arises to use the method with all the precision it is capable of. W. S. F.

NOTES ON INORGANIC CHEMISTRY. SOME time ago a committee was appointed by the German Chemical Society to formulate an atomic-weight table which should serve as a basis for practical use in analytical calculations. This committee consisted of Professors Landolt, Ostwald and Seubert, and has recently brought in a report which has been widely published. With three exceptions, the decimals in the atomic weights are given only as far as the last figure is practically correct. The weights as far as given agree in general with those published by Professer F. W. Clarke. The most interesting point in connection with the table is that the basis used is the atomic weight of oxygen = 16. It is now a number of years since Dr. F. P. Venable and others in this country and abroad uttered strong protests against the use of hydrogen 1 as a standard, especially since the atomic weights with few exceptions are determined with reference to oxygen, and at that time the ratio between hydrogen and oxygen was uncertain. Now that this ratio has been, thanks to Professor Morley, rendered almost certain to three decimal places, it is still unnecessary and unscientific to bring in even this little uncertainty, which in the elements of high atomic weight amounts to quite an appreciable quantity. Professor Seubert has been one of the strongest advocates of the basis H = 1, and it is noteworthy that he has agreed to the committee report. In the report Seubert says that, while H = 1 is in

principle the most correct and natural, he agrees to the report chiefly because with O = 16 many of the weights most frequently used in calculations are represented by whole numbers, and hence these numbers are most conveniently used. Landolt adds that he hopes this report will lead to an international agreement as to the figures used.

IN a recent paper in the Journal für praktische Chemie, W. Eidmann describes the action of metallic magnesium upon compounds containing nitrogen, especially upon the cyanids. At a red heat almost all compounds, inorganic and organic, which contain nitrogen are decomposed, generally with the formation of magnesium nitrid, Mg,N2. The cyanids of the alkalies and alkaline earths are decomposed without explosion, the carbid of the metal being formed. This, Eidmann says, shows that the ordinarily accepted C=N formula of the cyanids, e. g., Ba is C = N correct. In the case of those cyanids which decompose at a red heat, as those of zinc, nickel, lead, copper, etc., the reaction with magnesium is more violent and decomposition into magnesium nitrid, carbon and the metal ensues. In the case of those cyanids, as those of silver and mercury, which decompose below a red heat the liberated cyanogen reacts with magnesium with explosive violence.

A SERIES of analyses of waters from wells near the sea-shore are published by P. Guichard in the Bulletin Société Chimique. The water in these wells rises and falls with the tide, while the composition of the water leads to the conclusion that there is no direct connection between the wells and the sea, and, hence, it follows, according to the author, that subterranean waters must be affected by the moon, even as the ocean. This conclusion will, doubtless, find

many to dissent from it.

2 volts. Water and carbon dioxid are carefully added as the electrolysis proceeds. With care as to the strength of the electrolyte, a purity of whitelead is obtained not hitherto reached. The hygienic regulations of the factory are worthy of mention. Every operative receives daily one liter of fresh milk, and at the conclusion of his daily work must clean very thoroughly his hands, finger nails, etc. In addition he receives Glauber's salts, and every fortnight must take a complete warm bath in water which contains a certain amount of liver of sulfur. By these precautions all cases of saturnine poisoning have been avoided for several years.

ALTHOUGH not under the head of inorganic chemistry, mention may be permitted of a description of the manufacture of artificial silk in a recent number of the Zeitschrift für Angewandte Chemie from the pen of H. Wyss-Naef. The first practical use of the process was in 1889. The raw material is carded cotton which is first converted into nitrocellulose by a bath of strong nitric and sulfuric acids. After washing and drying it is dissolved in a mixture of alcohol and ether. This collodion is then spun through openings .08 mm. diameter. The alcohol and ether evaporate almost instantly on spinning and the material is carefully dried. It is then treated by a secret process to reduce the nitro groups, ammonium sulfid being probably the reducing agent used. The silk is then bleached with chlorin and is ready for the market.

J. L. H.

CURRENT NOTES ON METEOROLOGY. THE THEORY OF CYCLONES AND ANTICYCLONES. A PUBLICATION of unusual interest, containing conclusions of the greatest importance in meteorology, has been issued as Bulletin No. 1 (1899), of the Blue Hill Meteorological Observatory ('Studies of Cyclonic and Anticyclonic Phenomena with Kites,' by H. Helm Clayton). This is a study of the results obtained during the kite flights of September 21st-24th and of November 24th-25th last, and it will aid materially towards once more strengthening belief in the older Ferrel, or convectional theory of cyclones and anticyclones, as opposed to the newer Hann, or driven theory. Lack of space

The

prevents mention of many of the striking facts set forth in this Bulletin. The flights of September 21st-24th brought down records from altitudes of 2,000 to 3,400 meters, in a wellmarked anticyclone, and in a succeeding cyclone which followed the same track. temperature near the center of the anticyclone was the same at 2,100 meters as at 1,200 meters, and the humidity at the greater altitudes was excessively low. These results agree with those previously found in similar conditions. The axis of the anticyclone was inclined backwards, the high pressure occurring later at high than at low levels. Up to 3,000 meters the temperature of the air was higher on the day of the cyclone than on the day of the anticyclone-a normal condition at Blue Hill, as previous kite ascents have shown. A further notable discovery is that cyclonic and anticyclonic circulations observed at the earth's surface in this latitude do not seem to embrace any air movement at greater altitudes than 2,000 meters, except in front of cyclones. Above 2,000 meters there seem to be other poorly developed cyclones and anticyclones, with their centers at entirely different places from those on the earth's surface, and with different wind circulations.

On November 24th-25th the kite meteorograph was sent up near the center of a cyclone and in a succeeding anticyclone. From sealevel to 2,300 meters the temperature was 13°-24° F. higher on the day of the cyclone (November 24th) than on the following day. The results of the observations on November 24th-25th also go to show that when the cold in the rear of a surface cyclone is exceptionally severe, the axis of the cyclone is inclined backward so sharply that the circulation breaks into two or more systems. Thus there come to exist a surface cyclone, a mid-air cyclone and an upper-air cyclone. On November 25th, at 3,000 meters, there existed a cold-center cyclone, in which the air had a descending component of motion, as indicated by the low humidity.

The results of the careful study made by Mr. Clayton lead him to the view that the convectional theory of cyclones is the true one. This Bulletin again bears evidence to the admirable work which is being done by the staff of the

Blue Hill Observatory, and to the important contributions which Mr. Clayton and his assistants, with Mr. Rotch's liberal support, have made to meteorology.

CARBONIC ACID IN DEATH GULCH.

THE amount of carbonic acid in the atmosphere, which, under ordinary conditions, averages about 0.03%, may, in exceptional circumstances, attain a considerably higher percentage. In certain volcanic districts the amount of carbonic acid may be large enough to cause the death of animals which stray into the hollows where, owing to its density, the gas collects. The Grotto del Cane, near Naples, is a region of this sort. Another is Death Gulch, in the Yellowstone National Park. In an account of a recent trip in the Park, in Appleton's Popular Science Monthly for February, Jaggar reports his discovery, in Death Gulch, of the carcasses of eight bears, all of which had doubtless been asphyxiated by the excessive amount of carbonic acid in the air.

HARVARD UNIVERSITY.

R. DEC. WARD.

ZOOLOGICAL NOTES.

NEOMYLODON LISTAI.

DR. EINAR LÖNNBERG describes at length * some portions of skin found in a cave at Eberhardt, near Last Hope Inlet, 51° 35′ S., 72° 38' W., in the Territorio de Magallanes, Chile, and obtained by the Swedish expedition which visited Tierra del Fuego in 1896. The cave, located a few kilometers from the coast and about 500 feet above sea-level, was about 600 feet deep and 150 feet wide at the entrance. It was discovered by some farm laborers, who promptly destroyed the human skeletons found in the cave, although they fortunately preserved some pieces of thick, strange-looking skin, and the sheath of a claw found partly imbedded in the stalagmitic deposit of the floor. The claw and two pieces of skin were secured by Nordenskjold; the smaller piece measured about 7× 15 cm.; the larger, irregular in shape, 50 X 76 cm., is believed to be from the left fore leg. The small

* Reprint from Wissenschaftl. Ergebnisse Schwedischen Expedition nach den Magellansländern unter leitung von Otto Nordenskjold.