Popular Science Monthly/Volume 28/November 1885/Popular Miscellany
The New Star.—Astronomers have been surprised by the fact, which was first announced by Dr, Hartwig on the 29th of August, that a star of about the eighth magnitude had suddenly appeared in the middle of the great nebula of Andromeda. This nebula, the most conspicuous of all the phenomena of the kind, has long been regarded as a stellar nebula, since Mr. Huggins showed that its spectrum possessed the characteristics of stellar spectra, but it has never been resolved. The appearance of the new star within it, if it belong to it, which is not yet ascertained, may mark some important movement going on within it. The star was seen, within a few days of Dr. Hartwig's observation, by several other observers, and has now become an object of interest and attention to every one who possesses a telescope. The first observation of it appears to have been by Mr. Isaac W. Ward, of Dunecht, on August 19th. It was not visible at Brussels at the beginning of August; and the Rev. S. H. Saxby, carefully observing the nebula on the 6th, 9th, and 10th of the month at Davos Platz, saw no sign of a stellar nucleus. The telescope at Dunecht on the 5th of September showed it as a star of the 71 magnitude, with a continuous spectrum. At the Greenwich Observatory, on the 4th of September, its spectrum was shown to be of precisely the same character as that of the nebula, or perfectly continuous, with no lines, either bright or dark, visible, and the red end wanting. It therefore presents no evidence of an outburst of heated gas, such as was the case with the "temporary" stars T. Corona in 1866 and "Nova" Cygni in 1876. The appearance of new or temporary stars, though an event that must always excite remark, is not really unusual. One appeared in May, 1859, in the nebula or cluster 80 Mersier, and shone with a magnitude diminishing from the 7th till the 10th of June, when it vanished, and has never been seen since. A similar star was discovered in a nebula in the Unicom in 1861, and is now ranked as a variable star, R. Monoccrotis. The star Eta Argus, in the "key-hole nebula" in Argo, is also a variable star, whose appearance at its brighter stages might suggest to superficial observation the idea of a new or temporary star. It remains to be ascertained whether the present star really belongs to the nebula or is an outsider passing over the line of vision between us and it. Spectroscopic and photometric observations, so far as they have gone, indicate a constitution identical with that of the nebula, but they are not complete. If it does belong to the nebula, a fact mentioned by Mr. R. A. Proctor becomes very important. Mr. Spencer has pointed out that no nebula which could be resolved into stars could possibly lie outside the limits of the galaxy or of the great system of which our solar system is a member; for the outer edges of that system are so far irresolvable. It was generally agreed that, if any nebula lay outside of the system, it was this one in Andromeda. Now, if a star is distinguished in this body, it is clear also that it too must lie within our system.
Shall we raise Silk at a Loss?—In the discussion of a paper by Dr. Riley, in the American Association, advocating tariff "encouragement" of silk-culture in the United States, Mr. Edward Atkinson remarked that the project is not desirable. There is no lack of employment for labor in the United States, as the high rate of wages shows; and the fact that the making of reeled silk has been unprofitable shows that capital can be better employed. Silk-culture is a handicraft simply, and has been carried on by the poorest and most inefficient peoples, who, as they rise in the scale, abandon it, as is now coming to be the case in Southern France. The argument that we shall save the $20,000,000 which we now pay for imported silk is fallacious. When we exchange articles produced by labor costing one dollar per day, for the silk of China or Japan raised by labor costing five or ten cents a day we gain and not lose. We can not afford to do for ourselves what pauper laborers will do for us cheaper.
Chemistry at the American Association.—The Chemical Section of the Association was opened with an address by Professor W. R. Nichols, of the Massachusetts Institute of Technology, on "Chemistry in the Service of Public Health." The author showed that chemistry has an educational office to fill in the service of sanitary science, in teaching the public what its capabilities and limitations are, and correcting the erroneous ideas that are entertained as to the nature of certain processes in preparing food-substances, and the effect in them of the application of particular reagents. Respecting two subjects now much talked of in sanitary circles. Professor Nichols said: "Microbes may well be left to the biologists, and possibly sewer-gas as well, since chemists have failed to discover any substances in the gas which could produce the well-known ill effects. . . . It is asserted by some that the day of chemical examinations is passing away, and that the wholesomeness of water will be determined by the biologist, not by the chemist. Without detracting from the present value of biological methods, we can not believe that they can replace chemical examination for a long time yet; it must first become certain that all the evil effects of impure water arc due to the organisms now so eagerly studied. When the biological examination of water has been placed on a firm basis, it will then be necessary to carry out the work begun by Professor Mallet, of discovering the chemical characteristics which belong to waters which a biological examination condemn.", and of making the characteristics the basis of future chemical analysis. In the matter of the pollution of streams by sewage, there is much chemical work to be done." Chemistry may be made of service to public health by investigating the actual state of existing evils; in suggesting practical remedies for them; and in the examination of foods and drinks. The education of those who propose to follow these lines of work requires a thorough knowledge of general and analytical chemistry, and of physics. "There is room in the community for a class of persons knowing a little engineering, a little chemistry, a little biology, and a little of other things, an occupation legitimate and honorable, but one which does not justify our calling a person so posted a sanitary engineer or chemist."
Professor Prescott gave the results of experiments in fixing the limits of recovery of certain poisons when mixed with organic matter.
Professor F. P. Dunnington described a method of fixing crayon-drawings, by saturating them with a preparation composed of one part of Damar varnish and twenty-five parts of turpentine. The drawings arc made on unsized manila paper. When dried after treatment, they are ready for use.
Professor Mabery, and the Messrs. Cowles, of Cleveland, Ohio, presented a paper on a new electric furnace and the reduction of aluminum and other metals rare in the metallic state, and the formation of a number of new useful alloys by its aid. Experiments were made in the inquiry for the best means of obtaining a continuous high temperature on an extensive scale. It was found that by introducing coarsely pulverized carbon, mixed with the oxide to be reduced, and applying the electric current, reduction was effected and the temperature was raised to such an extent that the whole interior of the retort fused completely. In other experiments lumps of lime, sand, and corundum were fused, with indications of a reduction of the corresponding metal; on cooling, the lime formed large, well-defined crystals, and the corundum beautiful red, green, and blue octahedral crystals. Following up these experiments, Professor Mabery found that the intense heat thus produced could be utilized for the reduction of oxides in large quantities; and it has already been found that aluminum, silicon, boron, magnesium, manganese, sodium, and potassium, can be obtained from their oxides with ease. Good commercial results have been derived from the application of the process, in the manufacture of aluminum-bronze of various grades, and possessing superior qualities of one kind or another according to the grade; of silicon-bronze, which promises to afford the best material for electric wires; and of boron-bronze, in which boron appears to have almost the same effect when added to copper as carbon when added to iron in the manufacture of steel.
The question, "What is the best initiatory work for students entering upon laboratory practice?" was discussed. Professor H. W. Wiley insisted on the importance of training the novitiates in habits of accuracy—that they should understand at once that chemical science is no guess-work, but a science of definite proportions. Professor R. B. Warder thought it was better to begin with metals than with gases, and Professor F. P. Dunnington suggested a course of metallurgy and assaying. Mr. Thomas Antisell remarked that much depended on the object of instruction—whether it was given only as a part of a liberal education, or with the view of making chemistry a profession. Professor Prescott thought that students should, in analytical work, practice first on known bodies before beginning on unknown; and that too much reliance should not be placed on laboratory work alone, which should be associated with rigid class work in the lecture and recitation rooms. Professor Mabery would have young people begin with common phenomena, master the principles of stoichometry, and work, as far as possible, quantitatively.
Physics at the American Association.—In the Section of Physics, Professor S. P. Langley read a paper on the sources of invisible radiations and on the recognition of hitherto unmeasured wave-lengths. The object of the researches he described was to ascertain whether there arc other wavelengths than those found in the sun's heat, 60 that we may perhaps explain how it is that the surface heat of our planet is maintained in spite of the ready radiation of extreme solar heat through the atmosphere. We have in the infra-red portion of the solar spectrum the greater part of the heat which sustains organic life on this planet, and the questions arise. Does the planet radiate heat of the wave-lengths that it receives from the sun? and how is its temperature maintained, probably several hundred degrees above the temperature of space, when our observations show that the direct radiations of heat from the sun can only raise it about fifty degrees above the surrounding temperature? Experiments at Allegheny show that the dark solar heat is transmitted by our atmosphere with less difficulty than the light; and, if the radiations of the soil are of this wave-length, our planet should actually be cooler on account of its atmosphere than if it had none. Professor Langley has for two years past made measurements of the radiations from bodies of the temperature of the earth, using for his experiments prisms and lenses of rock salt. From the results of these researches, he says that we have every reason to believe that heat radiated by the soil has a wavelength twenty times that of the lowest visible line of the solar spectrum. His experiments thus tend to show that this heat is of a totally different quality from that received from the sun. Among the other papers read in this section were those of Professor H. S. Carhart on surface transmission of electrical discharges, in revision of work by Professor Henry; of Professor E. L. Nichols, on the chemical behavior of magnetic iron; of Major H. E. Alvord, on the results of telemetric observation at Houghton Farm; and of Commander Theodore F. Jewell, on the apparent resistance of a body of air to a change of shape. In the experiments on this subject, a disk of gun-cotton was exploded on a metal plate. Each of the disks had the letters "U. S. N" and the year of manufacture stamped upon it. After explosion upon the iron, similar Indentations were found upon the plate, as if the air in the indented letters had been driven into it. Professor E. L. Nichols stated that from comparisons he had made of the spectrum of the unclouded sky with that of the sunlight reflected by magnesium carbonate, he had deduced the conclusion that the spectrum of the sky is of the same character as that of white light. The blue color of the sky and of other opalescent media is, according to these and other correlative experiments, not due to an excess of the more refrangible rays in the light reflected by them, but is of a subjective character. These results disagree with those obtained by Professor Langley in his experiments. Mr. H. Helm Clayton, of Ann Arbor, presented evidence favoring the supposition that there arc at times slow progressive movements of barometric change, and of temperature from west to east, and attempted to show that the weather of the United States during the last year had been marked by certain periodicity of character.
Plants growing at Strange Heights.—Many anomalies have been observed in the distribution of plants by altitude, which M. F, Krasan has endeavored to account for, in Engler's "Annuaire botanique," by supposing changes to have taken place during the recent period in the height of the mountains on which the vegetation is found. Thus, in several valleys of the Alps, oaks are growing at unusual altitudes, and live under climatic conditions that seem to exclude them elsewhere. They do not, however, appear to be reproducing themselves, and are probably destined to be crowded out by the beeches. On the Humberg, in Southern Styria, at a height of between 750 and 1,360 feet, are found growing in the midst of vines and associated with southern plants masses of purely Alpestrine species; and in the mountain-region north of Cilli, the highest altitude of which is less than 3,000 feet, are not less than fifty-one species that occur normally in the region of pines. The Humberg is more than twenty miles from the nearest Alpine summit, yet the plants appropriate to such a situation are represented, not by individuals, but by a large mass of plants that appear to be perfectly acclimated. The mystery is heightened by the fact that in a neighboring mountain district of considerable higher altitude, which borders on a really Alpine region, only a small number of Alpine plants are found. Similar anomalies have been remarked in the Pyrenees. Many Alpine plants can and doubtless do live and thrive in lower situations than their habitual ones, and their general absence from such places is probably rather due to their being crowded out, and the ground possessed by the species more peculiarly fitted to the locality than to any positive unfitness of their own. But if a mountain is suddenly raised up or depressed, the entire vegetation growing upon it is transported to a new region. It will then offer a long and sturdy to the rival species that may come in to dispute with it for occupancy; and this resistance may in the end last long enough for the species to become acclimated to the new conditions, when they will reproduce themselves, and the phenomena under consideration will be manifested.
Metal-Working Art in Cashmere.—Herr Carl von Ujfalvy, who has been exploring in the western Himalayas, asserts that the Cashmereans must be regarded as the noblest of the Indian races. "At least," he says, "it must be admitted that a people that prepares its food in handsome kettles of beaten and carved copper, adorned with tasteful engravings, drinks its tea and coffee from elegantly shaped pots, and uses showily decorated pitchers and cups, and beaten and enameled dishes, vases, pipes, candlesticks, lamps, tea-vessels, and plates, and engraved spittoons, must have a peculiar artistic gift. What is more remarkable is that objects of such character are in daily use, not only in the mansions of the rich, but also in the peasants' huts; and any one who takes this fact into consideration must say that we have to do with a particularly endowed race of Aryans, who, too small in numbers and too weak to contend with the barbarians, have found satisfaction in devoting themselves to art. When we reflect," adds Herr von Ujfalvy, "that all the household utensils in High Asia, Persia, and India, and the innumerable idols in the latter country are made of beaten or cast metal, we may be able to form an approximate idea of the importance and extension of this industry in all those countries." Copper is the basis of these industries, either pure, in hammered, beaten, and carved forms, or alloyed or set off with gold, silver, steel, tin, lead, or zinc. In Turkistan a yellow, in Kashgar a red, in Cashmere an ornamented red metal is worked. Yellow metal is here of very ancient origin. The metal industry is most extensively developed and most flourishing in Cashmere and there no difference is recognized between art-work and mechanical work, and it is therefore not strange that we should so frequently meet with real masterpieces of art.
Blind Men's Dreams.—How do the blind dream? is discussed by Mr. B. G. Jones, in the (English) "National Review." In nearly all ordinary dreams we imagine we see something—persons or things, or both. This can not happen with the blind, who have no conception of things that are seen; or, if they were not born blind, of things that they had not seen before they lost their sight. The blind man may recall a person or a place, but his recollection can only be commensurate with what he has obtained by the senses of touch, hearing, or smell. A blind boy dreamed of his brother who was dead. He knew him by his voice, and he also knew he was in the fields with him, for he felt himself treading upon the grass and smelling the fresh air. His idea of a field could not possibly roach much beyond this. Another person dreamed he was in his workshop; he knew this by sitting on a box, and by the tools which were in it. A blind tramp paid when he dreamed it was just the same as when he was awake—he dreamed of hearing and touching. A blind man is mentioned who dreamed of a ghost, and this is the way he told his story: "I heard n voice at the door, and I said, 'Bless me, if that ain't John!' and I took him by the sleeve; it was his shirt-sleeve I felt; and I was half-afeared of him, and surprised he was out weeks before his time. Then (In my dream) I dreamt that he tried to frighten me, and make believe he was a ghost, by pushing me down sideways, etc. After that I waked and heard no more." We fancy ghosts as impalpable beings, clothed ill white. Blind men can hardly have as distinct an imagination of their appearance.
A Workmen's Scientific Class.—How knowledge may be disseminated by means of local lectures to working-men is illustrated in a story told by Mr. Roberts, of Cambridge. Two miners, at Buckworth, England, walked four or five miles and back m the evening, after work, to attend the course at Cramlington. Finding others in their village wanting to know something of chemistry, but not able to attend the course, they took to repeating to a class of seven on the next evening the lectures they had heard, and, having supplied themselves with chemicals, repeated the experiments. Mr. Roberts attended one of the meetings of this class at the end of the term, examined the members, and found that they had acquired a sound enough knowledge of the subject to pass the regular university examination. The class were this summer to carry on in the same manner a course in physiology, in aid of which they were endeavoring to procure a microscope.
Mechanical Science at the American Association—The vice-presidential address of Professor J. Burkitt Webb, in the Section of Mechanical Science, was on "The Second Law of Thermo-dynamics," but was too technical for abstract in these pages. Mr. L. S. Randolph gave an account of his experiments in seeking for an explanation of the peculiar manner in which the stay bolts between the fire-box and the boiler shell of steam-boilers had been found to break. He indicated a drawing and bending of the bolts occasioned by the shifting of the plates under changes of temperature as the cause, aided by the corrosive action of the water that might reach the bolts. Mr. Stephen S. Haight presented a paper on the use and value of accurate standards for surveyors' chains. He exhibited a specimen chain of flattened steel wire, with thermometer attached to record temperature, a spring-balance to weigh the tension, and a spirit-level. Professor Davis exhibited a tape which he had found accurate enough for general use in a large range of work in Michigan. Professor J. B. Webb read a paper on the lathe as an instrument of precision, in which he called attention to the desirability of greater accuracy in instruments of this class, and described some simple methods for making tests of the degree of error in any particular instrument. Professor Cooley explained a new smoke-burning device. A committee report was presented and a discussion had on the best methods of teaching mechanical engineering. The object of the instruction being admitted to be thorough preparation in theory and principle, Professor Thurston said that the training should be adapted to the work to be done, and that he therefore favored classification into manual training-schools, schools of mechanic arts, and schools of engineering. It I was asserted by other speakers in the course of the discussion that there are no manual I training-schools where a boy can learn a trade before entering the higher schools; and that the St. Louis and Chicago manual training-schools will not make workmen, and probably not five per cent of their students will ever become workmen.
Science In Common Schools.—The committee of the American Association on methods of science-teaching in the schools stated that much had been accomplished in the investigation, in which many associations, schools, and persons had interested themselves. The committee of conference with foreign associations in reference to an international convention of science associations had conducted an extensive correspondence, and the subject was to be brought before the British Association at Aberdeen. An endowment fund of twenty-five thousand dollars had been given to the scheme by Mrs. Elizabeth Thompson, of Stamford, Connecticut. The committee was continued as I the "Committee on International Scientific Congress." The committee on the encouragement of researches upon the health and diseases of plants reported that at its suggestion the Commissioner of Agriculture had appointed Mr. F. L. Scribner, of Girard College, Philadelphia, to take charge of a section in his department, devoted to work of that character.
The British Association.—The British Association met at Aberdeen, Scotland, September 9th, and was opened by the president for the year, Sir Lyon Playfair, with an address which we publish in the present number of the Monthly. Among the more noteworthy papers presented were the vice presidential addresses of Professor H. E. Armstrong, on more efficient methods of teaching chemistry; of Professor Judd, in the Geological Section, on some unsolved problems of Highland geology; of Mr. B. Baker, of the Mechanical Section, calling attention to deficiencies in bridge construction; of Mr. Galton, in the Anthropological Section, on "Types and their Inheritance"; and of Professor Sidgwick, of the Section of Economical Science and Statistics. In the last section Professor Leone Levi read an elaborate paper on "The Alleged Depression of Trade; its Causes and Remedies."
New Problems in Chemistry.—In his address as Vice-President of the Chemical Section of the British Association, Professor II. B. Armstrong criticised the way in which the science is taught in the schools, and insisted upon the importance of giving more prominence to research by the students, and of cultivating in them the spirit of original investigation. They must not merely be taught the principles and main facts of the science, but must be shown how the knowledge of those facts and principles has been gained, and must be so drilled as to have complete command of their knowledge. Chemistry was no longer a purely descriptive science. The study of carbon compounds and Mendelejeff's generalization had produced a complete revolution. The faults in the present system of teaching were precisely those which had characterized the teaching of geography and history, and which were now becoming 80 generally recognized and condemned. Both in teaching and examining two important changes ought to be made. The students ought at the very beginning of their career to become familiar with the use of the balance; and the imaginary distinction between so-called inorganic and organic compounds should be altogether abandoned. Touching on the progress that had been made in chemical theory, Professor Armstrong mentioned the change which had taken place in views concerning chemical action. Hitherto it appeared to have been commonly assumed and almost universally thought by chemists that action took place directly between A and B, producing A B, or between A B and C D, producing A C and B D. In studying the chemistry of carbon compounds, they became acquainted with a large number of instances in which a more or less minute quantity of a substance was capable of inducing change or changes in the body or bodies with which it was associated without apparently itself being altered; but so little had been done to ascertain the influence of the contact-substance, or catalyst, as he would term it, that its importance was not duly appreciated. Recent discoveries, however, must have given a rude shock, from which it could never recover, to the belief in the assumed simplicity of chemical change. Then, after considering briefly some questions of the relations of chemical and electrical action, Professor Armstrong went on: Complaints are not unfrequently made that a large proportion of published work is of little value, and that chemists arc devoting themselves too exclusively to the study of carbon compounds, and especially of synthetic chemistry; that investigation is running too much in a few grooves, and that we are gross worshipers of formulæ. But the attention paid to the study of carbon compounds may be more than justified, both by reference to the results obtained and to the nature of the work before us. "The inorganic kingdom refuses any longer to yield up her secrets—new elements—except after severe compulsion. The organic kingdom, both animal and vegetable, stands ever ready before us. Little wonder, then, if problems directly bearing upon life prove the more attractive to the living. The physiologist complains that probably ninety-five per cent of the solid matters of living structures are pure unknowns to us, and that the fundamental chemical changes which occur during life are entirely enshrouded in mystery. It is in order that this may no longer be the case that the study of carbon compounds is being so vigorously prosecuted. . . . As to the value of the work, I believe that every fact honestly recorded is of value." No unprejudiced reader can but be struck with the improvement in quality which is manifest in the majority of the investigations now published. The great outcome of the labors of carbon chemists has been the establishment of the doctrine of the structure. That doctrine has received the most powerful support from the investigation of physical properties, and it may almost, without exaggeration, be said to have been rendered visible in Abney and Festing's infra-red spectrum photographs.
Limits of Stress on Iron Bridges.—Addressing the Mechanical Science Section of the British Association, Mr. B. Baker spoke of the want of understanding among engineers regarding the admissible intensity of stress on iron and steel bridges, concerning which "at the present time absolute chaos prevails. The variance in the strength of existing bridges is such as to be apparent to the educated eye without any calculation. . . . It is an open secret that nearly all the large railway companies are strengthening their bridges, and necessarily so, for I could cite cases where the working stress on the iron has exceeded by two hundred and fifty per cent that considered admissible by leading American and German builders in similar cases. . . . In the present day engineers of all countries are in accord as to the principles of estimating the magnitude of the stresses on the different members of a structure, but not so in proportioning the members to resist those stresses. The practical result is, that a bridge which would be passed by the English Board of Trade would require to be strengthened five per cent in some parts and fifty per cent in others before it would be accepted by the German Government, or by any of the leading railway companies in America." This undesirable state of affairs arises from the fact that "many engineers still persistently ignore the fact that a bar of iron may be broken in two ways—namely, by the single application of a heavy stress, or by the repeated application of a comparatively light stress. An athlete's muscles have often been likened to a bar of iron, but, if fatigue be in question, the simile is very wide of the truth. Intermittent action—the alternative pull and thrust of the rower, or of the laborer turning a winch—is what the muscle likes and the bar of iron abhors. From tests made several years ago by royal commissioners, the deduction was made that "iron bars scarcely bear the reiterated application of one third the breaking weight without injury, hence the prudence of always making beams capable of bearing six times the greatest weight that could be laid upon them." Hundreds of existing railway bridges which carry twenty trains a day with perfect safety would break down quickly under twenty trains an hour. Although many more experiments are required before universally acceptable rules can be laid down, "I have thoroughly convinced myself that, when stresses of varying intensity occur, tension and compression members should be treated on an entirely different basis."
Some Aspects of Heredity.—Mr. Francis Galton spoke, in the Anthropological Section of the British Association, from his researches in family histories and records, on types and their inheritance. He discussed the conditions of the stability and instability of types, and urged the existence of a simple and far-reaching law governing the hereditary transmission. From experiments he had made several years before on the produce of seeds of different size but the same species, it appeared that the offspring did not tend to resemble their parent-seed in size, but to be always more mediocre than they—to be smaller than the parents if the parents were large, to be larger than the parents if the parents were very small. The special subject of this paper was hereditary stature, where a similar law seemed to prevail. His data consisted of the heights of nine hundred and thirty adult children and their parentages, two hundred and five in number. The child inherits partly from his parents, partly from his ancestry. Speaking generally, the further his genealogy goes back, the more numerous and varied will his ancestry become, until they cease to differ from any equally numerous sample taken at hap-hazard from the race at large. Their mean stature will then be the same as that of the race, or mediocre. The average regression of the offspring to a constant fraction of their mid-parental deviations, which was first observed on the diameters of seeds, and then confined by observations on human stature, is now shown to be a perfectly reasonable law, which might have been deductively foreseen. This law tells heavily against the full hereditary transmission of any rare and valuable gift, as only a few of many children would resemble their mid-parentage. The more exceptional the gift, the more exceptional will be the good fortune of the parent who has a son who equals, and still more if he has a son who overpasses him. This law is even-handed; it levies the same heavy possession tax on the transmission of badness as well as of goodness. If it discourages the extravagant expectations of gifted parents that their children will inherit all their powers, it no less discountenances extravagant fears that they will inherit all their weaknesses and diseases. The number of individuals in a population who differ little from mediocrity is so preponderant that it is more frequently the case that an exceptional man is the somewhat exceptional son of rather mediocre parents than the average eon of very exceptional parents.
Vision of the Honey-Bee.—According to the Rev. J. L. Zabriskie's observations, the honey-bee sees as through the woods. The ocelli arc situated on the top of the head, arranged as in an equilateral triangle, so that one is directed to the front, one to the right, and one to the left. "Long, branching hairs on the crown of the head stand thick, like a miniature forest, so that an ocellus is scarcely discernible except from a particular point of view"; and then the observer remarks an opening through the hairs—a cleared pathway, as it were, in such a forest—and notes that the ocellus, looking like a glittering globe half immersed in the substance of the head, lies at the inner end of the path. The opening connected with the front ocellus expands forward from it like a funnel with an angle of about fifteen degrees. The side ocelli have paths more narrow, but opening more vertically; so that the two together command a field which, though hedged in anteriorly and posteriorly, embraces, in a plane transverse, of course, to the axis of the insect h body, an arc of nearly one hundred and eighty degrees.