Popular Science Monthly/Volume 17/August 1880/Popular Miscellany

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The Catskill Mountains.—Professor A. Guyot gives, in the "American Journal of Science" for June, the results and a map of the first scientific survey of the Catskill Mountains, which he has undertaken, and with the aid of interested assistants has so far successfully carried out. These mountains, though situated in the most populous and civilized part of the United States, and visited every year by thousands, are among the least known in our country. Yet several features of the group are well calculated to excite the curiosity of the scientific investigator, and to call for a thorough study of its plastic forms. Though a part of the Appalachian system, the range appears in it as an anomaly; for, while the other Appalachian ranges trend from the southwest to the northeast, the Catskills run at right angles to them, or from the southeast to the northwest. The Catskills also surpass all the neighboring ranges of mountains by two thousand feet of height. Professor Guyot has devoted the summer vacations of seventeen years to their examination. His map represents a surface of about four thousand square miles, of which the mountainous part proper occupies somewhat more than one half, or about twenty-four hundred square miles. The distances and bearings are computed from the points of the triangulation of the Coast Survey along the Hudson River as a base. The mountain region is divided by the Esopus Creek into two groups, differing considerably in their physical structure, the northern, or Catskills proper, and the southern Catskills or Shandaken Mountains. "The northern group, or Catskills proper, between the Esopus and Catskill Creeks, form a massive plateau having the shape of an irregular parallelogram, extending from southeast to northwest, and shut up between two high border chains, ten or fifteen miles distant from each other, running about in the same direction. The southwest border is formed by what may be called the central chain of all the Catskills, the other by the northeast border chain. The south-east end is closed by the short chain of the High Peak; the northwestern by the high swell of plateaus which divide the head-waters of the Delaware and Susquehanna from those of the Schoharie Creek and the Hudson. Inside of this highland, three secondary ranges, starting from the northeast border chain and running nearly west, almost to the foot of the central chain, fill the inner space, inclosing deep valleys in which flow the waters of the Schoharie Creek and its tributaries. ... A striking peculiarity of the plastic forms of the northern Catskill group is, that while its western end is, as it were, buried in the general plateaus of western New York, its mountains rising but moderately above their surrounding base, its eastern end stands isolated on three sides by deep and broadly open valleys, projecting, in all its height, as a mighty promontory, to within ten miles of tide-water in the Hudson River." The very base of its mountains rarely exceeds six hundred feet above tide. "No wonder, then," says Professor Guyot, "that the aspect of the Catskills is nowhere more imposing than from the Hudson River and the surrounding lowlands, from which their whole height is seized at a glance, and that it has been thus far believed that the highest points were found among the mountains of the eastern end." The panorama of the mountains, as seen from Catskill village, is not a view of a single chain, but takes the eastern end of the border chains and the short range bearing the High Peak, which rises between the two. The Catskills do not present prominent examples of anticlinal and synclinal folds or arches, or fragments of arches, as in ordinary mountain-chains, but are masses of piled-up strata, seldom deviating notably from their original horizontal position. On account of this disposition of the strata, and their tendency to break at right angles to the planes of stratification, they are marked by the frequent abrupt ledges which are peculiar to them. For the same reason, the tops of the mountains are not pointed peaks, but are mostly flat surfaces, often of considerable extent. The central chain is the longest and most massive of the series, and is the backbone of the whole Catskill region. From Overlook Mountain to the Utsyantha, near Stamford, it is a little more than thirty-five miles long, and is divided into four almost equal parts by three deep gorges or cloves. The heights increase regularly from the Overlook to Hunter Mountain, one quarter of the way back, which, 4,038 feet high, is the highest point of the northern Catskills, overtopping High Peak, which has borne that name, by nearly four hundred feet. From this point the heights diminish to the Utsyantha, at the western end of the chain, whose height, 3,205 feet, is not greatly different from that of Overlook, 3,150 feet. The High Peak range, which is sandwiched between this range and the northern range, is only six miles long, and is distinguished by its High Peak, 3,664 feet high. The northeast border chain begins at South Mountain, near the Catskill Mountain House, which is 2,497 feet high, culminates at Black Dome, 4,003 feet high, and ends at Leonard Hill, 2,649 feet high, showing a similar rapid rise for a quarter of the distance, and a gradual fall toward the western end with the central range. The highland between these two chains, an irregular parallelogram twenty-seven miles long and from six to fifteen miles wide, is filled by three ranges, which are separated by valleys in which flow the tributaries of Schoharie Creek. This stream and its tributaries furnish the entire drainage for the interior highlands of the Catskills proper. The streams that run directly to the Hudson draw no water from the interior, but belong properly to the outside slopes. This drainage, which sends the waters of the Catskills all the way around to the Mohawk to come back by the Hudson, after a course of one hundred and seventy-five miles, to within ten miles of their starting-point, is certainly remarkable, and betokens a very peculiar physical structure. This is made more striking by the fact that on both sides of these highlands the waters of the valleys of the Catskill and Esopus Creeks flow, as we might have expected, from the western plateaus directly to the Hudson River. The nearly horizontal position of the strata, which is common to the mountains and the surrounding plateau, and the peculiar features of the drainage, lead to the inference that the plastic forms of the Catskill region are the work of erosive forces, and are not due to the ordinary dynamic process which has folded and shaped the other parts of the Appalachian system. "We may, therefore, conceive the original form of the Catskills to have been that of a high plateau, a mass of elevations forming a part of the Appalachian plateau region which extends west of the Alleghanies from south Virginia, and fills nearly all the western portion of the State of New York south of Lake Ontario and the Mohawk River. The lowest altitude of the primitive plateau is marked by the ideal plane which would pass through the mountain-tops, and its superior elevation on the east would account for the flow of the waters, the gradual scooping out and the sloping of the valleys in the direction they now have." The southern Catskills have not the regular features which characterize the northern group; the boundaries are not well defined, except along the Esopus Valley; and, instead of their having an interior plateau inclosed by high border chains, the massive central chain, which bears the highest summit, is accessible from all the surrounding valleys without crossing any high pass. Their general direction is about the same as that of the northern Catskills, but several important ridges run at right angles to this direction, and impart considerable physical irregularity to their structure. The Slide Mountain, the culminating point of this group, is the highest of all the Catskills, measuring 4,205 feet, and is the hydrographic center of the region, whence the waters run to the northwest by the Esopus, to the northeast by Woodland Creek, to the south by the Rondout to the Hudson, and to the southwest by the Nevisink to the Delaware. The geological structure of the group is similar to that of the northern Catskills. Professor James Hall has announced that, after four years of observation, he has detected the existence of four lines of anticlinals, nearly parallel to each other, and running from southwest to northeast, in conformity with the ordinary trend of the Appalachian range. Professor Guyot is willing to acknowledge the fact, but calls attention to the other fact that these axes cross the chains and valleys almost at right angles, "and were probably posterior to the scooping out of the valleys and mountain-chains, on the conformation of which they had so little effect. . . . A hypsometric feature, which may refer to this order of facts, is that the three maxima of altitudes above four thousand feet, the Slide Mountain, Hunter Mountain, and Black Dome, are situated in a straight line, trending from southwest to northeast."

Silicified Forests of the Yellowstone Park.—In Bulletin No. 1 of Vol. V. of the "Geological and Geographical Survey of the Territories," Mr. W. H. Holmes gives an account of a most wonderful geological formation, which attains its greatest development in the valley of the east fork of the Yellowstone River. It occurs in horizontal layers, having an aggregate thickness of fifty-five hundred feet, that is, the whole formation at this point is a little more than a mile in depth. This is filled throughout with the silicified remains of a multitude of forests, many of the trunks of trees that are still to be seen being of very large size. Some of them are prostrate, and from fifty to sixty feet long; others are upright where they grew, and some of the stumps measure from five to six feet in diameter. One gigantic trunk is described that stands twelve feet above the eroded strata about it, and is ten feet in diameter. This trunk is hollow, but the woody structure of what remains is well preserved, the rings of growth being clearly defined. The bark on this stump is four inches thick, and on its outer surface deeply lined. Scattered through the formations among the trunks is a great variety of vegetable remains, consisting of branches, rootlets, fruit, and leaves. Specimens submitted to Professor Leo Lesquereaux have been identified as follows: Aralia Whitneyi, Magnolia lanceolata, Laurus Canariensis, also new species of Fraxinus, Cornus Alnus, Tilia, Diospyros, Pteris, and Fern. The wood is in many cases completely agatized, and cavities which existed in the decayed trunks are filled with crystals of calcite and quartz. The formations are of the "Volcanic Tertiary," and composed of fragmentary volcanic products, breccias, conglomerates, and sandstones, the two former consisting chiefly of basalt. Many are of great size, and are cemented together in enormous masses or heavy beds by tufaceous and other fine grained material. These beds or layers represent successive formations, arising from the subsidence of the land, during the intermissions of which the forests grew. The beds have evidently been changed by the action of water; and the conclusion is that the formation represents the shore or margin of a great Tertiary lake. It is believed that the beds cover or have covered an area of over ten thousand square miles.

Germs of Disease in Water.—Professor Huxley, in a recent discussion of a paper by Dr. Tidy on water for dietetic purposes, said that diseases caused by what people not wisely call germs are produced invariably by bodies of the nature of bacteria. These bodies could be cultivated through twenty or thirty generations, and then, when given under the requisite conditions, would invariably cause their characteristic disease. Bacteria are plants, and we know under what conditions they can live and what they will do. They can be sown and will thrive in Pasteur's solution, just as cress or mustard in the soil; and, if a drop of this solution were placed in a gallon of water, Professor Roscoe thinks it doubtful if there is any known method by which its constituents could be estimated. Every cubic inch of such water would contain fifty thousand to one hundred thousand bacteria, and one drop of it would be capable of exciting a putrefactive fermentation in any substance capable of undergoing that fermentation. The human body may be considered as such a substance, and we may conceive of a water containing such organisms which may be as pure as can be as regards chemical analysis, and yet be, as regards the human body, as deadly as prussic acid. This is a terrible conclusion, but it is true; and, if the public are guided by percentages alone, they may often be led astray. The real value of a determination of the quantity of organic impurity in a water is that by it a shrewd notion can be obtained as to what has had access to that water. If it be proved that sewage has been mixed with it, there is a very great chance that the excreta of some diseased person may be there also. On the other hand, water may be chemically gross, and yet do harm to no one, the great danger being in the disease-germs.

Man in America.—Professor Flower, in a recent lecture on the "Anatomy of Man," before the Royal College of Surgeons, London, discussed at some-length the question of his origin on the American Continent. Till recently, opinions on the early peopling of America had been divided between the views that the inhabitants of this continent were a distinct indigenous people, and therefore not related to those of any other land; and that they were descended from an Asiatic people who, in comparatively recent times, passed into America by the way of Behring Strait, and thence spread gradually over the whole Continent. These theories have had to undergo considerable modifications in consequence of the discovery of the great antiquity of the human race in America, as well as in the Old World. The proof of this antiquity rests upon the high and independent state of civilization which had been attained by the Mexicans and Peruvians at the time of the Spanish conquest, and the evidence that that civilization had been preceded by several other stages of culture, following in succession through a great stretch of time. The antiquity of this quasi-historical period is, however, entirely thrown into the shade by the evidence now accumulating from various parts of North and South America, that man existed on the Western Continent, and under much the same conditions of life, using precisely similar weapons and tools, as in Europe during the Pleistocene or Quaternary period, and perhaps even farther back in time. Recent paleontological investigations show that an immense number of forms of terrestrial animals, that were formerly supposed to be peculiar to the Old World, are abundant in the New. Taking all circumstances into consideration, it is quite as likely that Asiatic man may have been derived from America as the reverse, or both may have had their source in a common center, in some region of the earth now covered with sea.

Illusions and Apparitions.—All illusive visions and apparitions are susceptible of a scientific explanation. They originate in some derangement of the brain and nervous system, and are for that reason most likely to occur to persons who are out of health. The apparent reality of some of these illusions is often wonderful, and might well prompt those who are not acquainted with nervous physiology, or who have not devoted careful attention to the subject, to refer them to something out of the common. Even while we are in perfect possession of our faculties, we imagine that we see objects before us as clearly as though they were actually present, or hear, with equal distinctness, sounds which have no real existence outside of ourselves. The explanation may be found in a simple study of the physiology of the nervous system, and shows that the illusions have a material basis. Our sensations are transmitted from the organ that receives them to the brain, and it is the brain, not the organ, that experiences them and is their seat. In the case of sight, it is the function of the eye to receive and adjust the rays of light coming from the object that we see, so that they shall produce an impression on the brain. The eye represents the lenses of the photographer's camera; but the brain corresponds to the sensitive plate which receives the image, and on which all subsequent alterations of the image are effected. Similar relative parts are played by the organs and the brain in the case of the other senses. Now, if a similar impression to that which is transmitted to the brain from the organ of sense is produced upon it by any other cause, the same kind of a sensation will result. This may happen when the brain is in an excitable or irritable state from ill health or any other cause, and is enough to explain all the phenomena under consideration. The visions most often correspond to our previous experiences, and therefore represent objects we know. Sometimes, however, the images are unfamiliar, and they are then referred to objects that we have seen, but have ceased to remember in our natural condition. The apparitions are thus explained as the creatures of our imagination, which, through some brain-disturbance, is enabled to project its visions forward on the seats of sense, just as the ringing in the ears, with which we are all familiar, is produced by some irritation of the hearing center of the brain.

Soils as Filters.—Dr. Victor C. Vaughan, of the University of Michigan, has described in "The Sanitarian" some experiments which he has made to determine the power of soils to prevent the filtration of organic matter in solution. They had reference to the questions, To what extent are organic substances removed from solution by filtration through the soil; and do different soils differ in their capability of thus removing organic matter? Urea was selected as the substance with which the experiments should be tried, and urine as the fluid with which filtration should be performed. The ordinary gravel soil of Michigan was found to produce but little effect in detaining the urea, while it soon became saturated; and the conclusion was drawn that the secretions from a family of six persons each day would be sufficient, when properly dissolved, to saturate more than seven cubic feet of this soil, and that only a few weeks or months would suffice, with a proper amount of rainfall, to saturate every cubic foot of soil to the depth of five or ten feet in a small yard. Gravel, however, is the poorest of filters, for the spaces between the particles allow the liquid to run through freely at certain points. Sand and loam exhibited a more satisfactory action, the loam more so than the sand, both these substances receiving a perceptibly larger quantity of urea before they were saturated. This is probably owing partly to their greater uniformity of constitution, in consequence of which water can not run as fast through them as through gravel, and partly to their greater porosity, by means of which matter passing through them is more closely exposed to the action of oxygen, the most efficient agent for the destruction of organic impurities.

Freezing of a Lake by Radiation.—A remarkable instance of the freezing of water in consequence of the radiation of heat was remarked in the Lake of Morat, Switzerland, after the cold weather of March last. The lake, of which three fifths of the surface had been covered with ice, was clear on the 8th of March, and the weather had become warm. During the night of the 10th of March, the thermometer did not descend to the freezing-point; yet on the morning of the 11th the lake was covered over with a thin sheet of ice. The Lakes of Neufchâtel and Constance were similarly covered. The freezing is accounted for by supposing it to have been occasioned by the rapid and great radiation of heat which took place on a perfectly clear night. An intense degree of cold had been necessary to cause the lakes to freeze during the cloudy weather of the previous cold spell, and the freezing was then very irregular and unequal.

Effects of Diseased Meat.—Mr. Julius Hardwicke, F. R. C. S., an English local medical officer of health, recently read a paper at a sanitary meeting on "Meat as Food for Man," in which he considered the effects of diseased meat on the human system. The evidence on this subject is of the most conflicting character. According to Dr. Letheby, enormous numbers of animals that died of rinderpest in 1863, and more recently of pleuro-pneumonia, have been sent to the London market and eaten without having produced any tangible effects; the Scotch eat "braxy" mutton with impunity, and, some say, even prefer it to sound mutton; and the people of Paris must have eaten much diseased meat during the siege, though we have no account of their having suffered from the effects of it. The symptoms or complaints of those supposed to be suffering from having eaten diseased meat are very similar to those occasioned by the use of putrid meat. Parasitic disease is quite different. Dr. Parkes names as the diseases of cattle that should be watched for: Pleuro-pneumonia, foot and-mouth disease; cattle-plague, or rinderpest; anthrax, or malignant pustule; simple inflammatory affections of the lungs; dropsical affections from kidney or heart disease; indigestion with apoplectic symptoms. The first three are described as contagious, and the last three as sporadic diseases, in a work by Professor Williams, of Edinburgh. To this list Mr. Hardwicke adds, as contagious, glanders and farcy (which may be communicated to consumers of horse-meat), puerperal apoplexy, and variola. He also adds a list of epizoötic diseases, meaning diseases occasioned by parasites, including measles in the pig; rot, or fluke disease, in sheep; gid, turn-sick, or staggers, in sheep; phthisis, or hoore, in cows, pigs, and poultry (gapes). The diseases of sheep are similar to those of cattle. They are subject to small-pox, malignant pustule, a parasitic chronic lung affection, and braxy or splenic apoplexy. Pigs are subject to anthrax, typhoid, and hog cholera. The contagious diseases are communicable by contact, by inoculation, and by infection. Hence it is not safe to let any of these classes of diseased meat go forth to the public as fit for consumption. To the opinion that cooking will destroy the contagious property and render the food fit for use, Mr. Hardwicke replies that there is no proof of it. Meat subjected to a temperature of 160°, which it is thought will thoroughly cook it, may still be productive of disease by inoculation. We are yet ignorant of the nature of the contagious property, and, if it be a living germ, what proof have we that, even if we succeed in destroying this germ and the entozoön of parasitic disease, a possible potent matter produced by the germ or ova of entozoon may not still exist and possess infective qualities?

The Milky Sea.—The peculiar coloration which has given the name of the milky sea to certain regions of the ocean has been remarked by many sailors, but a diversity of opinion has been expressed as to the cause of the phenomenon. Some have attributed it to electric action taking place during the hours preceding a storm; others to chemical combinations resulting from the decomposition of the bodies of marine animals and plants, and producing phosphorescence; others to spawn deposited on the surface of the water, which is supposed to be made to shine by the moving of masses of fish through it. None of these hypotheses have been confirmed, but they have all been contradicted by positive evidence that the milky sea is produced by a prodigious accumulation of animalcules, capable of becoming phosphorescent spontaneously, or of being made so by friction. The most recent and decisive evidence in this direction was observed on board the French ironclad Armida, on her recent voyage from Japan, while crossing from Point-de-Galle to Aden. At about half-past twelve in the morning of the 10th of February, 1880, the sky being clear, with no moon, the western part of the horizon, toward which the ship was going, became so bright as to attract the attention of the officer of the quarter. He at first thought the light was occasioned by the numerous bright stars which were about setting, but the increase of the light caused him to change his opinion, and he concluded that it was from a ship on fire. A half hour afterward a layer of whitish foam appeared covering the water for a considerable extent. The whole sea, shining with a milky luster as brightly as the usual phosphorescence which a ship produces in its passage through the water, resembled a field of snow in a clear night. It shone enough to efface all traces of the undulations of the swell; the waves could not be distinguished; and the sea seemed as flat and even as in a calm. The wake of the ship (which is generally visible for two or three miles back), and the disturbance of the water by the screw were hardly marked on the still surface. These facts proved that the luminous coating was not merely superficial, but that it had a considerable thickness. The phenomenon became more marked and intense, and one observing it might have believed he was locked in a sea of ice, had there been no movement of the ship to undeceive him. By daylight all had disappeared. On looking closely at the water as it rippled along the ship, there were noticed a great quantity of luminous particles pressed closely one upon another, the most brilliant ones being those which had been in contact with the bottom. The water when taken up in a bucket appeared to be full of phosphorescent bodies, from a half to three quarters of an inch long, which sparkled when they were brushed about by the hand. Nearly four hundred of them were counted in a bucket holding ten quarts. When taken from the water and examined by the light of a lamp, they were seen to be formed of a gelatinous substance which dried up quickly in the air and disappeared, leaving a dark globule a millimetre in diameter (see figure), which could be made lively again, and capable of becoming luminous, by putting a drop of water upon it. When rubbed in the hand, the bodies left a bright train which soon went out, leaving no odor. The globules under the compound microscope were transparent, filled with eggs of an ovoid shape, and were continually agitating their fins and tentacles. The organism is ellipsoidal

PSM V17 D590 Phosphorescent animalcule of the milky sea.jpg
A Phosphorescent Animalcule of the Milky Sea (natural size). A the dark globule Been in the center of a magnified.

and full of eggs, which are contained in an internal sac; the internal tentacles, t, always in motion, keep the eggs in circulation. The exterior tentacles, b, have a motion like that which we make in stretching out the arms, drawing them back and bending the elbows. The object marked n is a comb shaped fin, with twelve or fifteen bones. The epidermis is striated in the direction of the major axis of the ellipse. When kept till daylight and examined in a dark room, the water gave no light; it was of no use to shake or stir it, the bodies had lost their phosphorescent property. Fresh water, drawn up in the daytime and stirred in the dark, likewise showed no phosphorescence, although the color of the waters, a dirty-blue bordering upon gray, indicated that the ship was still close to the milky sea. On the next evening the milky tint came on again, all at once, at about seven o'clock, an hour and twenty minutes after sunset and an hour after dark. The beautiful appearances of the preceding night were again observed, but the whitish reflection in the horizon more resembled a fog which obscured it and made it seem nearer. Drops of water examined by themselves in the microscope revealed filaments of marine plants and numerous proliferous vegetable cells. The animalcules were the same as before, and were the only luminous objects. The nights of the 9th, 10th, 12th, and 13th of February were thus adorned with the splendor of the milky sea; during this time the ship had passed through six hundred and sixty miles, or two hundred and twenty marine leagues, in a mean latitude of 12° north, between the sixty-first and fifty-first meridians of east longitude. The atmosphere was in its normal condition, as was also the sea; the moon was new, the sky was clear, the barometer and thermometer were steady. No storm was near; no change was observed in the hydrometric condition of the air; the monsoon had been blowing a light breeze from the northeast for a considerable period. Several officers on board had previously witnessed this interesting spectacle in different places, as the Gulf of Aden, the Bay of Bengal, the Sea of Java, in hot latitudes, and during the months of January and February, but none of them had observed it when it was so bright, or had noticed it for so long a time.—La Nature.

The Health-Cure as a Remedy for Adversity.—The "Lancet" suggests that more account ought to be taken than is taken of the condition of health in estimating the causes of success or failure in life. The habit of failing is formed in some families, and seems to be transmitted by inheritance; the same is the case with constitutional peculiarities, and often with certain morbid conditions. It would be an interesting and profitable study to examine how far what is called ill luck or bad fortune is induced by such peculiarities. Accepting this view, "so far from its being strange that failure or success should 'run in families,' it would be inexplicable, and contrary to every natural law and precedent, if it did not do so. The force of character, strength of will, clearness of mental vision, and qualities of vigor, patience, and perseverance, which constitute the secrets of success in life, are the several properties of the physical organism, compounded as it is of body and mind." A new cure is suggested, then, the "health-cure," as a remedy for adversity, which would be first personal, then hereditary in its aim, aspects, and bearing. The subject is worthy the attention of medical men and social philosophers.

Carrying a French Meridian into Africa.—Colonel Perrier furnishes a description to "La Nature" of the manner in which the French system of triangulations and the meridian lines have been extended into Algeria under his direction. The idea of establishing a geodesic connection across the Mediterranean had been entertained for more than seventy years, but it was considered doubtful, on account of the great distance from each other of the points that would have to be used in the observations, whether a correct measurement was practicable. Preparations for making the observations were begun in 1873. Four points were chosen (Mulhacen and Tetica in Spain, 11,537 feet and 676 feet above the sea, Filhaoussen and McSahiba in Algeria, 3,760 feet and 1,876 feet above the sea), which formed a quadrilateral the angles of which were all visible from each other. It was necessary, from considerations of climate and locality, to make all the observations in the latter part of the summer and the early fall. Solar reflections were to be used in the day, and the electric light at night, as signals. The solar reflections were never seen at any of the distant points, and proved a complete failure. After about twenty days of effort, the electric light was made visible at all the points, and was used successfully from the 10th of September till the 1st of October, when the first series of observations was satisfactorily completed. The calculations showed that, notwithstanding the extraordinary distances apart of the points of observation (one hundred and seventy miles), the solutions were as exact as in cases involving only a few miles. In making the astronomical projections of the points, a system of rhythmic signals, or of stated alternate flashes and eclipses of the electric light, was employed from the 5th of October to the 16th of November. It was found that these signals were susceptible of great precision, but that the personal equation could not be disregarded in observing them. This equation operated in a double sense, as related to the observation of the stars and of the signals, in each observer, and had to be ascertained by a series of special experiments instituted in the case of each person at the observatories at Paris. Practically, it was a matter of indifference to the observers whether they directed their attention to the flashes or to the eclipses of the light, but they considered the observations of the eclipses likely to be more exact. The most convenient rhythm of signals was found to be one of about two seconds, allowing one second for the flash and one second for the eclipse. The constancy of the personal equation as it related to the luminous signals was remarked, and the error to be allowed for was estimated at less than one hundredth of a second.

Mr. Fleuss's New Diving-Process.—We noticed in the March number of the "Monthly" the invention by Mr. Fleuss of a process for breathing under water, which dispenses for the most part with the cumbrous apparatus that divers have hitherto had to employ. A fuller account of the new method has been published since, in the English papers, and those features of it which were then kept secret have been disclosed. The power of breathing depends on means which are provided within the helmet worn by the diver. These means are designed to furnish a continuous supply of oxygen, and to dispose of the carbonic acid which the breather exhales. No provision is made for the nitrogen which enters into the composition of ordinary air, for this merely serves as a diluent, and is not changed or diminished in quantity by breathing; hence the nitrogen which is naturally present in the diver's lungs and in his dress when he puts it on can be used over and over again, and is amply sufficient for its purpose. The oxygen is stored in the helmet in a compressed state, and the supply is regulated by a valve which is under the control of the diver. A solution of caustic soda, distributed through the pores of a mass of spongy India-rubber and confined in a close case, is provided for the disposition of the carbonic acid. A proper arrangement of tubing causes the whole of the exhaled air to pass through this case and its soda. A single charging with soda answers for a week of daily use of the apparatus. Mr. Fleuss exhibited his confidence in his apparatus by putting it on and going under water for the first time in his life, and remaining there for more than an hour.