Let us see how this is brought about, not indeed inquiring into the processes by which at the Greenwich Observatory the elements of safety are obtained, but considering the method by which a seaman makes use of those elements.

In the measures heretofore considered, the captain of a ship in reality relies on terrestrial measurements. He reasons that, having been on such and such a day in a given place, and having in the interval sailed so many miles in such and such directions, he must at the moment be in such and such a place. This is called navigation. In the processes next to be considered, which constitute a part of the science of nautical astronomy, the seaman trusts to celestial observations independent of all terrestrial measurements.

The points to be determined by the voyager are his latitude and longitude. The latitude is the distance north or south of the equator, and is measured always from the equator in degrees, the distance from equator to pole being divided into ninety equal parts, each of which is a degree.* The longitude is the distance east or west of Greenwich (in English usage, and now most other nations employ the same starting-point for measuring longitudes from). Longitude is not measured in miles, but in degrees. The way of measuring is not very readily explained without a globe, but may be thus indicated:-Suppose a circle to run completely round the earth, through Greenwich and both the poles; now if this circle be supposed free to turn upon the polar axis, or on the poles as pivots, and the half which crosses Greenwich be carried (the nearest way round) till it crosses some other station, then the arc through which it is carried is called the longitude of the station, and the longitude is easterly or westerly according as this half-circle has to be shifted towards the east or west. A complete half-turn is 180 degrees, and by taking such a half-turn either eastwardly or westwardly, the whole surface of the earth is included. Points which are 180 degrees east of Greenwich are thus also 180 degrees west of Greenwich.

So much is premised in the way of explanation to make the present paper complete; but ten minutes' inspection of an ordinary terrestrial globe will show the true meaning of latitude and longitude more clearly (to those who happen to have forgotten what they learned at school on these points) than any verbal description.

Now it is sufficiently easy for a sea-captain in fine weather to determine his latitude. For places in different latitudes have different celestial scenery, if one may so describe the aspect of the stellar heavens by night and the apparent path of the sun by day. The height of the pole-star above the horizon, for instance, at once indicates the latitude very closely, and would indicate the latitude

travel farther north it will be lower; and thus its observed height shows just how far north of the equator any northerly station is; while if the traveller is in the southern hemisphere corresponding observations show how far to the south of the equator he is.

But commonly the seaman trusts to observation of the sun to give him his latitude. The observation is made at noon, when the sun is highest above the horizon. The actual height is determined by means of the instrument called the sextant. This instrument need not be here described; but thus much may be mentioned to explain that process of taking the sun's meridian altitude which no doubt every one has witnessed who has taken a long sea-journey. The sextant is so devised that the observer can see two objects at once, one directly and the other after reflection of its light; and the amount by which he has to move a certain bar carrying the reflecting arrangement, in order to bring the two objects into view in the same direction, shows him the real divergence of lines drawn from his eye to the two objects. To take the sun's altitude then with this instrument, the observer takes the sun as one object and the horizon directly below the sun as the other he brings them into view together, and then looking at the sextant to see how much he has had to move the swinging arm which carries the reflecting glasses, he learns how high the sun is. This being done at noon, with proper arrangements to ensure that the greatest height then reached by the sun is observed, at once indicates the latitude of the observer. Suppose, for example, he finds the sun to be forty degrees above the horizon, and the "Nautical Almanac" tells him that at the time the sun is ten degrees north of the celestial equator, then he knows that the celestial equator is thirty degrees above the southern horizon. The pole of the heavens is therefore sixty degrees above the northern horizon, and the voyager is in sixty degrees north latitude. Of course, in all ordinary cases the number of degrees is not exact, as I have here for simplicity supposed, and there are some niceties of observation which would have to be taken into account in real work. But the principle of the method is sufficiently indicated by what has been said, and no useful purpose could be served by considering minutiæ.

(To be continued.)

THOUGHT AND LANGUAGE.

BY ADA S. BALLIN.

XV.

at every place in a given latitude, a star rises to a given greatest height when due south; if we travel farther south the star will be higher when due south; if we with the utilitarian labours for which our national Observatory was founded.

Throughout this explanation all minuter details are neglected. In reality, in consequence of the flattening of the earth's globe, the degrees of latitude are not equal, being larger the farther we go from the equator. Moreover, strictly speaking, it is incorrect to speak of distances being divided into degrees, or to say that a degree of latitude or longitude contains so many miles; yet it is so exceedingly inconvenient to employ any other way of speaking in popular description that I trust astronomers or mathematicians who may read this article will forgive the solecism.

although the use of language is not wholly lost, the power of co-ordinating words or syllables is greatly impaired. Patients of this class sometimes pronounce words clearly, but misplace them, so that now and then, if the words are written down, they may be fitted together as in a puzzle, and the patient's idea understood. A case of this kind is mentioned by Winslow.* Dr. Bastian † con siders that, "roughly speaking, inability to recall names, or the miscalling of persons, places, or things, would be defects going with injuries to, or altered states of, perceptive centres, and might exist with comparatively slight impairment of intellectual activity; whilst, on the other hand, the extreme forms of amnesia, in which wholly

"Paralysis from Brain Disease." 1875. p. 189.
+"Brain as an Organ of Mind," pp. 637-8.

irrelevant propositions, or a mere jumble of words are uttered, are more likely to be associated with marked impairment of intellectual power-to be dependent, in short, upon injuries or altered states of parts of the brain more specially concerned with such modes of activity."

Winslow mentions the case of a man who, after an attack of paralysis, transposed the letters of words, saying tufle for flute, puc for cup, and gum for mug. Some letters may always be substituted for others; and the same with syllables. One of Trousseau's cases of aphasia during recovery uttered certain monosyllables to which he always tacked on tif; in words of two syllables he pronounced only the first, adding tif in the place of the second, as montif for monsieur, bontif for bonjour.* Mistakes in the pronunciation and use of words and letters occur occasionally in quite healthy persons, and may or may not be recognised by the speaker. When fatigued or inattentive to what I am saying, I have frequently made slips of the kind, such as asking for salt when I wanted sugar-a request to the absurdity of which I was made alive by a laugh going round the table.

The other morning I was attentively reading the newspaper when my brother made some comment on a daring case of robbery, to which I oracularly replied, "When the cheese is stolen, shut the chamber door!" A remark which, as may be imagined, was greeted with some merriment. In cases like this the fault may be found in lack of attention to the words spoken. Attention implies volition, and when the will is engaged in regulating one set of ideas it is not always immediately at liberty to turn to the consideration of another. Thus during what is called "a brown study," or a fit of abstraction, the thinker may be spoken to, and may not reply for some minutes, then he will answer as if he had only just heard the remark. The attention was retained on the first set of ideas until a natural break came in that train of thought, when it was turned to the other train started by the speaker; on the other hand, a reply may be given at random, as above, without the attention being distracted from the original train of ideas.

The exhaustion of fatigue is proportionately great according as the will is more or less exercised, and this, I think, accounts for the fact that words are misused more frequently during fatigue, for it is impossible to maintain attention beyond a certain point of nervous exhaustion; beyond this point sleep, unconsciousness, or delirium supervenes. Suspension of volition is the essential part of sleep, during which an accumulation of nervous force takes place. Hence, during deep sleep, impressions may be made on the senses without being communicated to the mind-i.e., without being attended to; but when the nervous exhaustion has been repaired, similar impressions will at the same time arouse the attention and the sleeper.

During the suspension of attention in sleep, words may be spoken at random and questions answered with more or less meaning, just as when the attention is otherwise engaged in waking moments.

A similar but more complete suspension of the will takes place during the effects of narcotics or anaesthetics. A typical case of this nature occurred recently in the practice of my friend, Mr. R. Fitzroy Benham. Before

I have met with a somewhat similar case in a little boy six years old, whose speech is defective, but who is, nevertheless, a very bright little fellow. He affixes the syllable na (vowel as in Italian) to every word he says, and pronounces only the first syllable of words of more than one syllable. Thus, he says Edena, when mentioning the gardener's name, Ede; Betna, for his cousin Bessie; and gardna for garden.

the performance of a serious operation an anesthetic was given to the patient, and while she inhaled it she was told to count ten slowly. She had counted as far as seven when she became unconscious. The operation then began, and lasted for nearly an hour. After this the effects of the anaesthetic began to wear off, and the patient was heard to say, "Eight, nine, ten." She then looked up for further instructions, never suspecting that her counting had for a moment been interrupted. In like manner, volition, and with it attention, may be paralysed by brain injury, and in cases of sudden wounds: for instance, when consciousness is suspended by some portion of the skull pressing on the brain beneath, the train of thought may be broken for weeks or months, but continued immediately on the removal of the pressure on the brain. In cases like this it is probable that impressions are made upon the senses, and are even frequently responded to by the lower nervous centres; but that they take no effect on the higher centres of the brain, owing to the impossibility of attending to them. In a naval battle a sailor was addressed by his superior officer as to the position of a certain vessel. Before he could reply, he was struck in the head by a bullet, and remained insensible for several months, until brought back to England and trephined. Hardly was the operation completed, when the patient uttered these words, "She's to starboard, sir!" in answer to that question put so long ago.

All these and similar cases of suspended attention hang together, the differences between them being only of degree, not of kind. The higher or intellectual centres of the brain being, as it were, paralysed, any action which may take place through the medium of the lower centres is unconscious or automatic.

Other cases apparently originate purely in the loss of memory for words. Such may occur in healthy persons, as people say: "The word is on the tip of my tongue, but I can't get it out."

A case of this kind, brought about by brain disease, is the following, recorded by Dr. Bastian.

CASE 8. The patient became suddenly paralysed in the right side of his body, and speech was almost lost on March 12, 1878, but sight and hearing were good. He improved slowly, and his condition on April 2 is thus described :- "He recognises common objects, but cannot name them; repudiates a false name and recognises the real one at once when he hears it. Can never remember his own name till it is suggested to him. On being asked to repeat it (Andrews), after a few trials, which vary each time, he pronounces it 'Anstruthers' or 'Anstrews'; his first name (Thomas) seems to come more readily, and he can often attempt this without prompting. But, either after it has been repeated to him or when he says it spontaneously, he pronounces it Towvers.' The letter 'L' is difficult for him to utter; sometimes he pronounces it like a 'D,' and at others like a 'V.' He has been taught to count, and can fairly pronounce the numerals from one till twelve; after twelve he is uncertain, the articulation and order becoming rapidly worse. He is conscious when he makes a mistake, but cannot correct himself, and ends in a hopeless muddle. In reading from a book, the words he pronounces have no relation to the print, either in length or sound. Neither does he seem to understand written characters, as he will not attempt to answer a question written on a slate, though he will at once endeavour to respond when the same question is put to him orally. He, however, recognizes numerals from one to nine when written, and is conscious when they are not placed in regular order. He cannot name any coins, but seems to have some idea of their

relative value. He indicated on his fingers that sixpence was worth six pennies, not being able from sight to utter its name." On May 10 he showed by his gestures that he understood a case in the police news which he was found reading, and could copy his own name with his left hand; but did not attempt to write any less familiar word from sound, even when he showed he quite understood it.*

The cases alluded to in this and the preceding article are strongly illustrative of the fact that those physical or mental characteristics which are the latest acquired in the life of the race or the individual, those which have had the least time to become engrained in it, are the first to be lost in the process of degeneration. Thus we find that in cases where the use of language is only impaired, it is always the most familiar words which are retained, the others being lost. It is the same in healthy people When the brain is suffering from as in my own case. exhaustion, recently-acquired facts and words are forgotten until the nervous system has been restored by rest. This, too, seems to explain the fact which is generally remarked on with surprise, that old people who have lost all memory for recent events can distinctly recall even trivial things which happened in their youth. In case 1, the patient used the more familiar word "potatoes" for the less familiar "pills." When urged to write, it was found that he could write his address fairly well, and wrote "My dear sir" correctly, but filled the sheet with meaningless writing, only the word "wife" being legible until his signature, which was as clear as ever, so that he was thus able to write the words which occurred most frequently in his correspondence when in health. Similarly, case 8 could not copy any word but his own name, although he apparently understood others; and as in this case, we find that in cases 6 and 7 the words retained were those most frequently used. We find also that in cases where the use of language is wholly lost, as in cases 2, 3, and 4, a perfect command over gestures is retained. In case 4 we find that the patient, although unable to speak himself, understood speech, and replied in gestures, just as the young child understands words long before it can use them, and just as we find some of the lower animals understanding certain words, a subject to which I shall revert hereafter. At the next stage we find case 2, who

FIRST STAR LESSONS.

BY RICHARD A. PROCTOR.

HE constellations included in the twenty-four maps

THE constellations incumbered throughout as follows

(the names being omitted on the maps, to clear these as far as possible from all that might render the stargrouping less distinct) :

1. Ursa Minor, the Little Bear (a, the Pole Star). 2. Draco, the Dragon (a, Thuan)

3. Cepheus, King Cepheus. 4. Cassiopeia, the Lady in the Chair.

5. Perseus, the Champion (B, Algol, famous variable). 6. Auriga, the Charioteer (a, Capella)

7. Ursa Major, the Greater Bear (a, ẞ, the Pointers). Canes Venatici, the Hunting Dogs (a, Cor Caroli). Berenices, Queen Berenice's Hair.

8. 9. Coma

10. Boötes, the Herdsman (a, Arcturus).

11. Corona Borealis, the Northern Crown.

12. Serpens, the Serpent. 13. Hercules, the Kneeler. 14. Lyra, the Lyre (a, Vega). 15. Cygnus, the Swan (a, Arided; B, Albires).

16. Pegasus, the Winged Horse. 17. Andromeda, the Chained Lady.

18. Triangula, the Triangles. 19. Aries, the Ram.

20. Taurus, the Bull (a, Aldeburan; n, Alcyone, chief Pleiad).

21. Gemini, the Twins (a, Castor; B, Pollux).

22. Cancer, the Crab (the

cluster is the Beehive). 23. Leo, the Lion (a, Regulus). 24. Virgo, the Virgin (a, Spica). 25. Libra, the Scales. the 26. Ophiuchus,

Holder.

Serpent 27. Aquila, the Eagle (a, Altair). 28. Delphinus, the Dolphin. 29. Aquarius, the Water Carrier. 30. Pisces. the Fishes.

31. Cetus, the Sea Monster (o, Mira, remarkable riable).

va

32. Eridanus, the River. 33. Orion, the Giant Hunter (a, Betelgeux; ẞ, Rigel). 34. Canis Minor, the Lesser Dog (a, Procyon).

35. Hydra, the Sea Serpent (a, Alphard).

36. Crater, the Cup (a, Alkes). 37. Corvus, the Crow.

38. Scorpio, the Scorpion (a, Antares).

39. Sagittarius, the Archer. 40. Capricornus, the Sea Goat. 41. Piscis Australis, the Southern Fish (a, Fomalhaut).

42. Lepus, the Hare. 43. Columba, the Dove. 44. Canis Major, the Greater Dog (a, Sirius). 45. Argo, the Ship.

THE PHILOSOPHY OF CLOTHING.
BY W. MATTIEU WILLIAMS.
XV.

SHOULD add, that only a small percentage of the

was readily made to understand gestures, and himself used gestures which were strikingly clear. On a still lower level stands case 5, who could only very slightly understand words, but understood gestures at once, although she could not always answer questions by gesture, and her own pantomime was lacking in clearness.

It appears to me that cases of the nature of those to which I have referred afford the very strongest circumstantial evidence in favour of the theory that gesture or imitative language was historically prior to verbal language as we know it, and further evidence in support of this will be forthcoming as we advance in our inquiries.

SPEAKING at Barnsley on Monday week, Mr. Thomas Burt, M.P., advocated in the case of colliery explosions that they should be the subject of special investigation by experienced men, such as was held when a great railway collision occurred. He impressed upon his hearers, who were mainly miners, the great danger of omitting to support the roof with props and stays. Taking the last thirty years, the number of deaths through insufficient timbering was nearly double the fatalities from explosions. Greater supervision was required in regard to timbering.

* "Brain as an Organ of Mind," pp. 642-3.

down are really stuffed with the down of the eider-duck. There are many substitutes-some very inferior, others slightly so. The nearest in quality is the down of the King Duck, an Arctic sea-bird of similar habits to the eider-duck. Goose-down is largely used, the best qualities being obtained from Arctic and marine species.

The necessity for an extra supply of air-holding—not oiled-under down in the clothing of such birds is illustrated by a fact not generally known, which came under my notice some years ago in the course of a cruise in a small schooner from Constantinople to London. We took on board an ample supply of live poultry-fowls and ducks. In the neighbourhood of Malta we had very dirty weather, and Jemmy Ducks failed to shelter the animals in his charge from the wash of the sea; the ducks were miserably wetted to the skin in spite of the supposed oiling of their feathers, they all had cramp, and were killed and eaten "to save their lives." The cocks and hens survived, though in the same quarters. This surprised me, but the captain told me that such is usually the case, and I now find that the faithful follower (referred to in my last) is more easily wetted than barn

feather clothing is misunderstood to a greater extent than I anticipated. Thus "G. A.," in KNOWLEDGE, Aug. 7, p. 122, still contends that the oil-glands of the duck are used for oiling the feathers by a painting action of the beak, head, and throat. As already stated, I do not question the structure of the uropigium, as described by "G. A.," and have no objection to calling it an oilgland. I regard it simply as an exaggerated pair of sebaceous glands resembling in secretion and function, though not in form, the sebaceous follicles described in my last, and the smaller and similar glands at the roots of the wing-feathers. I find the "two little heart-shaped glands," &c., in corresponding position near the root of the tails of cocks and hens, which, as Ray says, are pulveratrices. They powder their feathers with dust, which would become dirty adhesive paint if the secretion of the heart-shaped glands were used for oiling them. Besides this, I have examined the bill, head, neck, and back of a duck after it has nibbled and rubbed in the manner described by "G. A.," and positively deny that these parts are then or at any other time smeared with any such fat or oil as stated. The supposed paint-brushes are demonstrably less greasy than human skin, as may be seen by rubbing a clean piece of metal or glass upon the feathers of the head and neck of the duck, and a similar piece in like manner on one's own face and neck, and then comparing the smear. The ducks and swans in our London parks supply further proof. The white species remain white, instead of sharing the colour of London sheep, which they undoubtedly would if their feathers were greasy or oily like the wool, and exposed to the carbon flocculi which shower through our London atmosphere. The brushing action of the head and neck is not always preceded by a pinching of the oil-glands, nor usually so, as anybody may learn by watching the ducks in our parks. They clean their feathers, but do not smear them.

Upon this question of whether the water repulsion depends upon oiling of feathers or upon the adhesion of a film of air to them depends the verdict we must pass upon the desirability of using feathers for bedding and for clothing. At one time I joined with high sanitary authorities in denouncing feather-beds on the ground that, being organic animal matter, they should be liable to organic decomposition, and to saturation with condensed cutaneous exhalations. It is not very long ago since I wrote to my friend Dr. Richardson on the subject; but further investigation now induces me to recant, and the grounds of this recantation are the same as my repudiation of the supposed feather-oiling by ducks.

I find that feather fibres generally (I say "fibres" in order to exclude feather quills) are remarkably free from greasiness or humidity, more so than any other animal structure that I am acquainted with. I find also that they are exceptionally free from the vice of condensing sebaceous and other skin exhalations on their surface; that while cotton, linen, woollen, and silken fabrics become defiled by perspiration, feathers, similarly exposed, remain clean. The contents of a flock-bed after a few years of continuous use become matted and foul, while those of a goose-down bed after a similar or much longer period remain untainted; they are only dusty, the dust chiefly due to the fracture of feather filaments. I have examined feathers from a bed that has been half-a-century in continuous use, and find that, after a slight shake, the feathers are as clean as when they were new. Not so the enveloping fabric either inside or out, although it has been washed and renewed frequently during the lifetime of the feathers.

This, if am not altogether mistaken, depends upon the

fact that every filament of the down attaches to itself an obstinately-adherent film of air, which prevents the condensation of moisture on its solid surface. Thus we may lie on a feather-bed in a hollow formed by the pressure of our bodies, may perspire freely and moisten the coverings of the feathers, and yet the feathers themselves. shall remain dry and untainted, the vapour diffusing itself throughout their adherent atmospheres. advantage of this is obvious.

The

Down skirts are made and used, and must be far better than ordinary skirts of similar form, as the required amount of protection is obtained with far less weight. Whenever the merciless despotism of fashion may command its slavish victims to render themselves hideous by exaggerated nether expansions, either behind, or in front, or all round, the unfortunate creatures will suffer less by using light eider-down enlargements rather than metal cages or other heavy substrata. Let me not be misunderstood; I am not recommending such things on their own merits, but only as lesser evils in the meantime, until we can afford to erect lunatic asylums of sufficient capacity to stamp out the fundamental evil.

Feathers have been used as clothing materials by the most primitive of savages, usually by attaching the quill ends of the feathers to each other, and thus building up a mosaic fabric of highly ornamental as well as useful character. That from the South Sea Islands, exhibited by Lady Brassey at South Kensington last year, is a fine example, and said to be of great value. The labour expended on every square yard of such material must be immense; but whether it may be substituted by machinery I am unable to say. Another and a better mode of availing ourselves of the valuable clothing properties of feathers suggests itself, viz., that of carding and weaving the filaments of down, such as common duck and goose down, swans-down, &c. This appears to me to be quite a soluble problem, and I recommend it accordingly to the attention of ingenious mechanicians, believing firmly that such a fabric would, for ordinary clothing purposes, excel all others in lightness, warmth, and durability, with the additional excellence of allowing free passage of the perspiration and being waterproof without any oiling.

Vests and shirts of woven down would, I have no doubt, attain the nearest possible approach to perfection in underclothing for both winter and summer. They may, probably, be difficult to clean. Ordinary scrubbing with soap and water and soda is not likely to succeed. The laundress of the future in dealing with these will have to take lessons from the birds, probably from the pulveratrices above-named, and use cleansing powders applied with the aid of suitable brushes-feather brushes, like the duck's head.

OUR HOUSEHOLD INSECTS.
By E. A. BUTLER.
COLEOPTERA (continued).

NE of the finest, though at the same time most called Longicornia, or Longhorns. The beetles are many of them remarkably handsome and of considerable size, and are readily distinguished by the great length of their antennæ, which, in some cases, many times exceed even that of the body itself. These insects, in their larval condition, burrow into the solid wood of timber trees, where they live, often from three to five years, devouring