First generation :-Immorality, depravity, alcoholic excess, and moral degradation, in the great-grandfather, who was killed in a tavern brawl. transmitted to the next generation, and, if the hands. He grasps what he brings to his mouth pillars very much of the same colour-perhaps of unfavourable conditions continue, is aggravated with an apish hold. His thumbs are but additional a uniform green or brown. Instead of this, we in it; and thus a morbid variety of the human fingers. He has a leaping walk. He has heavy have sometimes displayed as much beauty as in kind, which is incapable of being a link in the line eyebrows, and short hair on his cheek or face. of progress of humanity. Nature puts it under He is muscular, active, and not dwarfish. He sits the perfect insect-iu some cases more—while the ban of sterility, and thus prevents the perma- on the floor in ape fashion, with his genitals al- there are very few caterpillars indeed that are of ent degradation of the race. Morel has traced, ways exposed. He has filthy habits of all kinds. a uniform colour. It is singular, though, that in through four generations, the family history of a He may be called an idiot of the lowest order; very few cases is there any resemblance between youth who was admitted into the asylum at Rouen yet there is a mischievous, brute-like intelligence the markings exhibited by the caterpillar and in a state of stupidity and semi-idiocy; the sum-in his eye. His head is not very small, its greatest those which adorn the wings of the imago promary of which may fitly illustrate the natural circumference being twenty inches and a half, but duced therefrom. Discernment is sadly at fault course of degeneracy when it goes on through in shape it strongly exhibits the ape-form of here amongst those non-entomologists who, from generations. abnormality." the circumstance that they work in gardens or Pinel has recorded the case of an idiot who was fields, come into contact with many different something like a sheep, both in respect of her kinds of caterpillars. As a rule, they notice no tastes, her mode of life, and the form of her head. differences amongst them, but class them all toShe had an aversion to meat, and ate fruit and gether as "green varmint" or 'blight," and vegetables greedily, and drank nothing but water. regard them as things to be squashed out of existHer demonstrations of sensibility, joy, or trouble, tence as speedily as possible. So that of many a were confined to the repetition of the ill-articulated gardener we might say, parodying the poet's words bé, ma, bah. She alternately bent and lines, that all he notices israised her head, and rubbed herself against the belly of the girl who attended her. If she wanted Fourth generation:-Defective intelligence. to resist or express her discontent, she tried to First attack of mania at sixteen; stupidity, and butt with the crown of her head; she was very transition to complete idiocy. Furthermore, passionate. Her back, her loins, and shoulders probable extinction of the family; for the gene- were covered with flexible and blackish hairs, one rative functions were as little developed as those or two inches long. She never could be made to of a child of twelve years of age. He had two sit on a chair or bench, even when at meals; as sisters who were both defective physically and soon as she was placed in a sitting posture, she morally, and were classed as imbeciles. To com-glided on the floor. She slept on the floor in the plete the proof of heredity in this case, Morel posture of animals. adds that the mother had a child while the father was confined in the asylum, and that this adulterous child showed no signs of degeneracy. Second generation :-Hereditary drunkenness, maniacal attacks, ending in general paralysis, in the grandfather. Third generation :-Sobriety, but hypochondriacal tendencies, delusions of persecutions, and homicidal tendencies, in the father. When epilepsy in young children leads to idiocy, as it often does, we must generally look for the deep root of mischief in the family neurosis. No one can well dispute that in the case of such an extreme morbid variety as a congenital idiot is, we have to do with a defective nervous organi-head, and thin and scanty hair, so that the crown sation. We are still, however, without more than a very few exact descriptions of the brains of idiots. Mr. Marshall has recently examined and described the brains of two idiots of European descent. He found the convolutions to be fewer in number, individually less complex, broader, and smoother than in the apes; " in this respect," he says, "the idiots' brains are even more simple than that of the gibbon, and approach that of the baboon." The condition was the result neither of atropy nor of mere arrest of growth, but consisted essentially in an imperfect evolution of the cerebral hemispheres or their parts, dependent on an arrest of development. The proportion of the weight of brain to that of body was extraordinarily diminished. We learn, then, that when nan is born with a brain no higher-indeed lower-than of an ape, he may have the convolutions fewer in number, and individually less complex, than they are in the brain of a chimpanzee and an orang; the human brain may revert to, or fall below, that type of development from which, if the theory of Darwin be true, it has gradually ascended by evolution through the ages. With the defect of organ there is a corresponding defect of function. But there is sometimes more than a simple defect. A curious and interesting fact, which has by no means yet received the consideration which it deserves, is that, with the appearance of this animal type of brain in idiocy, there do sometimes appear or reappear remarkable animal traits and instincts. There is a class of idiots which may justly be designated theroid, so like brutes are the members of it. The stories of so-called wild men, such as Peter the wild boy, and the young savage of Aveyron, who ran wild in the woods, and lived on acorns, and whatever else they could pick up there, were certainly exaggerated at the time. These degraded beings were evidently idiots, who exhibited a somewhat striking aptitude and capacity for a wild animal life. Dr. Carpenter, however, quotes the case of an idiot girl, who was seduced by some miscreant, and who, when she was delivered, lower animals do. Dr. Crichton Browne has now under care in the West Riding Asylum, a deformed idiotic girl, who in general appearance and habits has points of resemblance to a goose; so much so, that the nurses who received her describes her as just like a plucked goose." Her father died in the asylum, and her mother's sister was also a patient in it at one time. She is 4ft. 2in. in height, has a small of the head is partially bald. The eyes are large, round, prominent, and restless, and are frequently covered by the eyelids, as if by a slow forcible effort at winking. The lower jaw is large, projecting more than one inch beyond the contracted upper jaw, and possesses an extraordinary range of anteroposterior, as well as lateral, movement; the whole configuration of the lower part of the face having a somewhat bill-like appearance. The neck is unusually long and flexible, and is capable of being bent backwards so as actually to touch the back between the scapula. The cutis anserina is generally over the body, but is most marked on the back and dorsal aspects of the limbs, where it looks exactly as if it had been just deprived of feathers. The inferior angles of the scapulæ stands prominently out, and, moving freely with the movements of the arms, have precisely the appearance of rudimentary wings. The girl utters no articulate sounds, but expresses pleasure by cackling like a goose, and displeasure by hissing or screeching like a goose, or perhaps like a macaw. When angry, she flaps her arms against her sides, and beats her feet upon the floor. She knows her own name, and understands one or two short sentences, such as "Come here," and "Put out your hand." She recognises the persons who attend upon her and feed her, and is much agitated if touched by a stranger. She cannot feed herself, but swallows voraciously all that is put into her mouth, showing no preference for one article of diet over another. She is dirty in her habits, and no amount of attention has improved her in this respect. She is very fond of her bath, cackling when she is put in, and screeching when she is taken out of it. (To be continued.) CHAPTERS ON CURIOUS CATER- BY J. R. S. CLIFFORD. gnawed through the umbilical cord as some of the THE thoughtful observer of Caterpillar life says, amongst these creatures, even if we confine our A blight upon the shrubs or trees, Some common blight, 'tis all he sees- Well, in these times, the schoolmaster is abroad A host of caterpillars is feeding in June, especially in the early part of the month; towards the close, however, a good part will have become pupa, and await the change to the imago, or perfect state. There is some difference in each year, according to the weather and the state of the vegetation; this present year (1870) has as yet retarded insect life, and many species are a fortnight or three weeks behindhand. In some of our woods, more particularly in the south of England, the caterpillar of that handsome and remarkably agile butterfly known as the Silverwashed Fritillary, may be detected by a very careful search in its food plant, the violet. This caterpillar, besides feeding on the species of violet, is also said sometimes to be found on the wild raspberry, but this is extremely doubtful. As such lowgrowing plants cannot be "beaten," the best plan is to crouch down and turn over the leaves, disregarding the stiffness in the back thereby produced, and keeping in view the fact that the caterpillar has the trick of falling off the plant at a very slight touch, doubling itself up partly. The parent butterflies deposit their eggs in July or August, and as these hatch shortly after, and the caterpillars are not adult until the beginning of June, they thus pass about nine months in this state. The ground colour is black; down the back are two yellowish stripes, with a black stripe between them; along the sides in a triple series are delicate lines of a rust colour. On each segment are six spires, which give off fine bristles ; on the second segment there are two out of the six, which project over the head of the caterpillar, and have black tips. (See Fig. 1.) Suspending itself against some twig or stem, when it has ceased to eat, the caterpillar's skin is cast off and the chrysalis state assumed, and in this case the name is really correct, for the shell of the chrysalis is decorated with spots and dashes of gold. In the early part of the present century, the singularly-formed Comma Butterfly (Vanessa C. Album) was taken pretty freely near the metropolis; it has now disappeared, nor does it apparently occur in the southern and eastern counties of England. In Herefordshire, Mr. Newman reports it as still occurring, and in the Lake District, and a few other localities, individuals are seen on the wing most seasons. During 1864, an entomologist obtained the caterpillar of this species, and it is one of some singularity, feeding, as far as observed, only upon the hop-vine. As it is sluggish in its movements, and a day-feeder, it might probably be obtained by beating this climber. It is also supposed to feed on the currant and on nettles. Like the preceding, it has two the caterpillar of the Comma they actually spring processes projecting in front of the head, but in from the head, and are of a horny nature; these are black, as is the head and the next segment of the body, though the general colour of the remainder is grey, chequered with fulvous; from the seventh to the twelfth segment there is a white stripe down the back; on the sides and back are seven rows of branched spines; the eyes, as may be observed by a magnifier, are crowded to FIG. 1. The caterpillar of the Small The Author stated that when, in 1828, the Chocolate Tip (Clostera Reclusa), late Mr. J. B. Neilson (M. Inst. C.E.) intromay be beaten off dwarf sallows duced the plan of heating the air employed as in many places throughout England blast, by means of iron placed in or near a fire, in this mouth. It is slightly hairy, the increase of temperature was at first only marked with grey and yellow, the from 60 deg. to 100 deg. Fahr. Subsequently, under surface, legs, and claspers Mr. Neilson obtained a temperature of 600 deg. being smoke-coloured, and the head or 650 deg., and the pipe stoves had since been black. The cocoon is spun amongst urged up to 900 deg., and in a few cases to the leaves, and the moth flies forth 1000 deg. The wear and tear, however, with in August, giving birth to another such temperatures of blast were considerable. brood of caterpillars in September. there was great loss of heat by conduction, and A much handsomer caterpillar than the pipe stoves were, as a rule, worked in a leaky that of Reclusa is its congener, the condition, necessitating the expenditure of engine Scarce Chocolate Tip. (C. ana- power for blowing air uselessly. choreta), which, however, no ento- The improvements described in the paper were mologist is very likely to find at based upon Mr. Siemens' regenerative furnace. large, as it is of exceeding Each stove of a pair consisted of a wrought-iron scarcity. Nevertheless, specimens cylindrical casing, lined with fire-brick, and proof the moth are common enough vided with a central shaft or flue, which extended in collections, nearly all of which to within a few feet of the brick dome forming are the descendants of some caterpil- the top. Around this shaft there were a number gether. The chrysalis is suspended, head down- lars found at Folkestone, a few years since. It is a of compartments, or boxes, formed of bricks so wards, from some leaf-stalk, and has a few silver species which will breed in confinement, and by placed that those in one course were not exactly blotches, on an umber ground; it is also marked this means an abundance of the caterpillars have coincident in position with those in the courses with fine black lines. The butterfly emerges in been got year after year. The general hue of the either above or below, though a passage was August and September; it is also found in the body is velvety black, mottled with smoky-grey; left open from the bottom to the top of the mass spring of the year, and individuals then on the a stripe of dingy white runs down the back, and of brickwork. This wrought iron casing was wing have possibly lived through the winter. when the caterpillar is crawling, we can perceive provided with several valves, three being for the Common in most parts of Britain, and occur- that this apparent stripe is composed of square admission of cold blast, of gas, and of air for ing also in Ireland, is the moth known as the markings, which are connected by lines running combustion, and two being for the exit of the Beaded Chestnut. (Anchocelis Pistacina.) The between the segments; a double series of similar hot blast and of the products of combustion. caterpillars emerge in the spring from eggs laid markings runs along the sides, one row above the When a stove had been at work heating blast, and the previous autumn, and as they feed on the spiracles, the other below them; there is a hump it was wanted to re-heat it, the first thing to be buttercup and other meadow plants growing of chestnut-brown on the fifth and twelfth seg done was to put another stove in operation, then amongst the grass; they may be conveniently ments; that on the fifth is surrounded by a white to shut the hot and the cold blast valves, allowtaken by sweeping the grass which is growing patch; in addition there are smaller prominences ing the air in the stove to be blown out at a small for the hay crop, but not during the middle of on three other segments; the head is black, and valve to reduce it to atmospheric pressure. The the day. They fall into the net rolled up closely, also the legs; the claspers of a smoky hue. gas, air, and chimney valves were next opened, but soon relax and march off briskly, and present, Towards the end of June, or early in July, this and the gas, igniting as it entered, gave a large as they move, an odd appearance, for, at the in-caterpillar (at least, when in captivity) has volume of flame right up the central shaft and terstice of each segment is a fold of skin of a yellow over and into the regenerator, thus heating the colour, and these folds appear and disappear, top course of brickwork considerably, the next looking like yellow rings. The body is velvety course rather less, and so on, the products of and cylindrical, apple-green in tint, with an excombustion passing away to the chimney at a tremely slender white stripe down the back, and temperature of about 300 deg. In the course of a few hours, a large amount of caloric was stored up in the bricks forming the regenerator, a good red heat penetrating nearly to the bottom, when the stove was again ready to heat the blast to a temperature of 1400 deg. or 1500 deg. In these stoves the cost of dust catchers was avoided, and the expense of producing gas was also saved, as the gas was used direct from the top of the blast furnace, and the stoves could be cleaned ont with the greatest facility. The construction of the regenerator in compartments or boxes, connected together vertically but not horizontally gave the power of applying the blast with efficiency (inasmuch as the whole force of the blast was confined to the one passage that was being blown at the time), and admitted of a brush being passed up or down the boxes to remove the dust. The form and proportion of the passages had been found, after numerous experiments to produce an excellent effect in mixing the air, thereby ensuring a rapid and perfect conduction of heat from the brick to the air, or vice versa, from the products of combustion to the bricks. EGGER CATERPILLAR.- Described in No. 266. reached its full size; and spins itself a cocoon A truly ferocious caterpillar is that from which rather of a rose-coloured hue generally, though A not very common moth is known as the broader one along the sides; there are also a Lilac Beauty (Pericallia Syringaria), and it few dots sprinkled along the back. Early in June, deserves the name it bears, for the wings, which these caterpillars enter the earth, and beneath it are of a lustrous grey, are tinged with red and form compact cocoons of grains intermingled yellow, mingled with white and brownish markwith silk. It has been noticed by Mr. Newman ings. The caterpillar feeds on lilac and other that they remain some weeks unchanged, but ulti- shrubs in this month; when of full size, it is mately become chrysalides, which produce moths in September and October. An instance how certain species simulate the appearance of the plants on which they feed is furnished by the caterpillar of the Mallow Moth. (Eubolia Cervinaria.) When the Common Mallow is shaken, and there are any of these caterpillars feeding upon it, they roll themselves into rings, the legs, head, and claspers being hidden, and resemble the seed of the plant, well-known to all country children as cheeses;" also when not disturbed they extend themselves along the stalks, to which they assimilate in colour, and thus again escape notice. The whole body is covered with minute warts, each tipped with a tiny bristle; these are white, REGENERATIVE HOT BLAST FURNACES. while the general colour is dull green; down the back is a darker line, showing the course of the alimentary canal; the legs are curious, being very Dale and nearly transparent. These caterpillars e full grown in June. A The results obtained by Messrs. Cochrane from the adoption of these stoves at Ormesby, as regarded the quality of iron, the increased make, and the saving of coke in the blast furnace, had been most satisfactory. Thus there was a saving of 4 cwt. of coke per ton of iron produced, by the use of the regenerative stoves for heating the blast, when compared with good cast-iron pipe stoves, and the saving was still more ordinary pipe stoves. With a large furnace, producing 475 tons & week, the first cost of these stoves was somewhat less than the cost of pipe stoves, while the expense of working was less, so that the profit, taking every thing into account was estimated to amount to about £416? year. BARNACLES. over BARNACLES. a the legs and claws grow out of the swimming apparatus. Some of the barnacles that live on coral reefs are very beautiful, and their shells are ornamented in imitation of the flower-like polypes of the stony madre pores. The accompanying illustration will give the reader a good idea of the appearance which a family of barnacles presents, clinging to the under surface of a floating log.-Scientific American. NOTES ON RECENT DISCOVERIES IN POISONOUS PROPERTIES OF NEW DYES. A FURTHER step has been made in the ins vestigation of the reputedly poisonous properties of some of the new dyes. There can be no doubt that cases have occurred in which intensely irritating effects have been produced by a few of these colours, but they have been rare relatively to the frequent use of articles, such as stockings, dyed with them. The researches of M. Guyot go to show that these dyes are poisonous or not according as they are pure or impure. Thus, it is said that azuline, the blue, is poisonous if it contains an excess of aniline. The same colour also produces irritation of the skin when prepared with coraline containing excess of phenol. The coraline red, as we have mentioned before, is the colour which in most cases produced the effects which caused the alarm on the subject. It is not necessary to say more on the matter, for, as the manufacture of the dyes improve, the effects now seen but rarely will never be observed. ELECTROLYSIS OF NITRIC ACID. When a very dilute acid is operated upon, hydrogen only is evolved at the negative pole, and no secondary product is found in the liquid contained in the negative compartment. With a less dilute acid, that is, an acid with about 125 equivalents of water, hydrogen is first given off, then a little nitrogen, and the liquid is found to contain traces of ammonia. In the case of a stronger acid with only 15 equivalents of water, while oxygen is freely given off at the positive pole, no hydrogen for some time escapes at the negative, all that gas re-acting on and combining with the acid in the compartment, the liquid assuming a distinctly blue colour. After some time, however, hydrogen mixed with some nitrogen comes off, but soon gives place to an evolution of binoxide of nitrogen, which in its turn ceases, and hydrogen again appears. In the end a good deal of ammonia is found in the negative liquid, and also much nitrious acid. Nitric acid with two equivalents of water gives off at first only binoxide of nitrogen, then hydrogen. Thus we see that the reducing action of hydrogen on nitric acid, according to the strength of that acid, produces nitrous acid, binoxide of nitrogen, nitrogen, and ammonia. LOGWOOD IN WINE. TENSION OF LIQUIDS. A very easy way of detecting logwood colour in wine has been published in France, which, if good for anything, will be useful in discovering the includes the crabs, shrimps, and lobsters. If a eyes, and swims about most vigorously. It ap-acetate of copper, and dip it into the suspected barnacle belongs to the same class of animals that legs close to its head, and a large tail; it has adulteration of port. We have only to moisten a strip of paper with a strong solution of neutral piece of rock is put into a large glass full of sea pears to be constantly in movement, and although vinous fluid, which, if it contains logwood, will water, many things may be seen on it which are actively employed in swimming, and in crawling, of a white colour, and whose shape is something it does not care to seek for food. After a while give a blue colour to the paper. If, however, the like that of a thimble with the top battered in. If the young free-swimming creature rests upon a colour of the wine be the natural product of the they are examined it becomes evident that the piece of rock, or wood, or even on the back of a grape the paper changes to a grey shade. conical outside is formed of several little bits of fish, and then a wonderful alteration takes place, hard shell joined together very carefully, and The long legs and feelers near the head grasp the An observation has been made which has rethat the top has a valve in it. When the water is substance on which the creature is to live for the sulted in the discovery of a new mode of estimatquite clear and quiet, a small flapper is forked out future, and a gummy substance comes from a through the valve, and is moved to and fro with gland which has been growing for some time close ing the strength of alcohol. M. Ducaux has been experimenting on the superficial tension of liquids motion like that of opening and shutting the fin- to the head. The gum sticks the legs and the with an apparatus which exhibits the variations of gers. The flapper has some long bristles attached feelers to the substance, the eyes diminish in size it in a very remarkable way. A dropping tube, to it, and they are beautiful, feathery-looking and are no longer seen, the tail and the hind legs for instance, is arranged to let fall in air 100 drops things when examined under a microscope. The grow into the feathery flappers already noticed a minute. If, now, the experiment be repeated movement goes on for hours, and ceases upon the and the shell of many pieces encloses all. The in air saturated with vapour of alcohol, instead of least alarm. Then the flappers are withdrawn, barnacle is then fixed for life, head downwards, 100 drops, 110 will fall in the minute. This is the valve closes, and the barnacle-for such is the and it loses its organs of sight, and receives a caused by the solution of some alcohol in th creature-looks again like a conical piece of stone mouth and stomach, which it had not before, when water, by which the superficial tension of th The flappers are the lungs as well as the hands of in the free-swimming state. All barnacles do not liquid is diminished. Further experiments led t the barnacle, and minute living creatures are en- undergo this change, for the males of some kinds the discovery that the strength of alcohol could tangled by them and passed by a current of water live inside the conical house which holds the be exactly determined by ascertaining how many into the mouth, which is within the shell. When female, and never have houses of their own, for drops would fall in a minute from a given orifice. the barnacle produces its eggs, it ejects them with they remain in the free-swimming state. All the a stream of water, and they float about in the sea, animals of the crab class have to undergo a change being very minute things. They soon become of form before arriving at maturity, and the comhatched, and then it is that the reason becomes mon shore crab, when it is first hatched, is a long clear why barnacles and crabs are placed by thing with a great head, and legs fitted for swimzoologists in the same class. The young barnacle ming, and not for crawling. As it grows the body is just like a shrimp, with a glong body, many long shortens by curling the tail end underneath, and TO DYE LINEN WITH ANILINE BLACK. * From the Mechanics' Magazine. TO DETECT THE ADULTERATION OF RICE out blackening, remaining brilliant to the last. A MODIFICATION OF SMEE'S GALVANIC line. The goods are first immersed in a bath con- A USEFUL CEMENT. We mentioned a year or two ago that an excellent cement for fixing iron or stone was made by mixing together commercial glycerine and ground litharge. To-day we read of many other applications of this compound, which seems to be extremely useful. As a cement for joining chemical apparatus, it offers many advantages, for it is unaffected by chlorine, hydrochloric acid, sulphur vapour, sulphurous acid, nitric acid, and, indeed, resists most corrosive vapours. Further than this, it withstands the solvent action of alcohol, ether, sulphide of carbon, and all hydrocarbon vapours. It hardens in from ten to thirty minutes if mixed of the consistence of ON STAR-GROUPING, STAR-DRIFT, AND a thick dough, and sets under water as quickly as in air. Moreover, it will stand a very much higher STAR-MIST.* EARLY a century has passed since the temperature than any oil cement. The composition NE ACTION OF HEAT ON DIAMONDS. A jeweller at Marseilles had a couple of diamond shirt studs sent to him for the purpose of lectively the diffused light which forms the Milky Way. Sir John Herschel, applying a similar series of researches to the southern heavens, was led to a very similar conclusion, His view of the sidereal system differs chiefly in this respect from his father's, that he considered the stars within certain limits of distance from the sun to be spread less richly through space than those whose united lustre produces the milky light of the galaxy. Now it is clear that if the supposition on which these views are based is just, the three following results are to be looked for. In the first place the stars visible to the naked eye would be distributed with a certain general uniformity over the celestial sphere; so that if on the contrary we find certain extensive regions over which such stars are strewn much more richly than over the rest of the heavens, we must abandon Sir Wm. Herschel's fundamental hypothesis, and all the conclusions which have been based upon it. In the second place, we ought to find no signs of the aggregation of lucid stars into streams or clustering groups. If we should find such associated groups we must abandon the hypothesis of uniform distribution, and all the conclusions founded on it. Thirdly, and most obviously of all, the lucid stars ought not to be associated in a marked manner with the figure of the Milky Way. To take an illustrative instance. When we look through a glass window at a distant landscape, we do not find that the specks in the substance of the glass seem to follow the outline of valleys, hills, trees, or whatever features the landscape may present. In like manner, regarding the sphere of the lucid stars as in a sense the window through which we view the Milky Way, we ought not to find these stars, which are so near to ns, associated with the figure of the Milky Way, whose light comes from distances so enormously exceeding those which separate us from the lucid stars. Here again, then, if there should appear signs of such associa tion, we must abandon the theory that the sidereal system is constituted as Sir Wm. Herschel supposed. It should further be remarked that the three arguments derived from these relations are independent of each other. They are not as three links of a chain, any one of which being broken the chain is broken. They are as three strands of triple cord. If one strand holde, the cord holds. It may be shown that all three are to be trusted. a It is not to be expected, however, that the stars since far the larger number are but faintly as actually seen should exhibit these relations, visible; so that the eye would look in vain for the signs of law among them, even though law may be there. What is necessary is that maps sbould be constructed on a uniform and intelligible plan, and that in these maps the faint known the Newton of observational astronomy, as he has justly been called by Arago-conceived the daring thought that he would gange the celestial depths. And because in his day, as indeed in our own, very little was certainly known respecting the distribution of the stars, he was forced to found his researches upon a guess. Hə supposed that the stars, not only those visible to the naked eye, but all that are seen in the most powerful telescopes, are suns, distributed with a certain general uniformity throughout space. able to remove easily the stones from the setting Wm. Herschel was himself led to suspect during he determined to leave them. Not having any the progress of his researches this guess was a been devised for this purpose amongst others. The maps exhibited during this discourse have charcoal, moreover, he heated his muffle furnace mistaken one; that but a small proportion of the with coal. When the studs were taken from the stars can be regarded as real suns; and that in There are twelve of them, but they overlap, so muffle he found that the enamel was perfect, but to his surprise the diamonds were black. Vain place of the uniformity of distribution conceived were his endeavours to restore the brilliancy of by Sir Wm. Herschel, the chief characteristic of the stones. Rubbing only made them shine like the sidereal system is infinite variety. It having the gold setting enamelled. Not being is my purpose to attempt to prove that-as Sir stars should be made bright, and the bright stars brighter. that in effect each covers a tenth part of the heavens, There is first a north-polar map, then five maps symmetrically placed around it; again, there is a south-polar map, and five maps symclosure of the whole sphere. In effect every map so fit in with the first five as to complete the enof the twelve has five maps symmetrically placed around it and overlapping it.* black lead. The stone of the lapidary, however, views are based may be clearly apprehended, it metrically placed round that map; and these five In order that the arguments on which these cut away the black layer, and then it was found that the weight of the stone had not been dimi nished. This curious result induced M. Morren to make some experiments on the behaviour of diamonds exposed to heat under different conditions. First, he heated one to a white heat in a current of coal gas, and obtained exactly the same result as the jeweller. The stone appeared to be covered with a layer of plumbago, which could not be removed by friction, and the stones were found to have increased in weight. M. Morren succeeded in burping the black deposit away by simply heating the stone to redness in the air, after which it was as brilliant as before. Heated in hydrogen the diamond remains completely unaffected, even at the temperature at which platinum melts. In carbonic acid, however, it loses brilliancy and also weight if the exposure to heat is prolonged. M. Morren tells us that it is often difficult to burn diamonds, which is a matter of little consequence, since it is what people seldom wish to do. If anyone. however, desires to indulge in the expensive amusement he may be glad to know that in most cases it is sufficient to make the stone white hot on platinum, and plunge into oxygen, when it is quietly consumed with Since the whole heavens contain but 5932 stars But in will be necessary to recall the main results of Sir nearest to us. Sir Wm. Herschel was led by this process of B.A., at the Royal Institution on May 6. To show the influence of these rich regions, it is only necessary to exhibit the numerical relations presented by the maps. The north-polar map, in which the largest part of the northern rich regions fall, contains no less within the half corresponding to the rich region. than 693 lucid stars, of which upwards of 400 fall It will be understood that the description here, and all which immediately follows, replaces portions of the discourse which would only be intelligible when illustrated by means of the diagrams and illuminated maps actually employed. Of the adjacent maps, two contain upwards of 500 | variety of structure, and special laws of distribu-motion among the stars, but he did not interpret It is noteworthy, too, that the greater Magel lanic cloud falls in the heart of the southern rich For example, we have in this process the means region. Were there not other signs that this of settling the question whether the apparent wonderful object is really associated with the brightness of a star is indeed a test of relative sidereal system it might be rash to recognise this nearness. According to accepted theories the relation as indicating the existence of a physical sixth-magnitude stars are ten or twelve times as connection between the Nubecula Major and the far off as those of the first magnitude. Hence southern region rich in stars. Astronomers have their motions should, on the average, be correindeed so long regarded the Nubeculae as belong-spondingly small. Now, to make assurance ing neither to the sidereal nor to the nebular doubly sure, I divided the stars into two sets, the systems, that they are not likely to recognise very first including the stars of the 1st, 2nd, and 3rd, readily the existence of any such connection. Yet the second including those of the 4th, 5th, and how strangely perverse is the reasoning which 6th magnitude. According to accepted views, the has led astronomers so to regard these amazing average proper motion for the first set should be objects. Presented fairly, that evidence amounts about five times as great as that of the second. I simply to this :-The Magellanic clouds contain was prepared to find it about as three times as stars and they contain nebula; therefore they are great; that is, not so much greater as the accepted neither nebular nor stellar. Can perversity of theories require, but still considerably greater. To reasoning be pushed farther? Is not the obvious my surprise I found that the average proper conclusion this, that since nebula and stars are motion of the brighter orders of stars is barely seen to be intermixed in the Nubeculæ, the equal to that of the three lower orders. nebular and stellar systems form in reality but one complex system. As to the existence of star-streams and clustering aggregations, we have also evidence of a decisive character.* There is a well-marked stream of stars running from near Capella towards Monoceros. Beyond this lies a long dark rift altogether bare of lucid orbs, beyond which again lies an extensive range of stars, covering Gemini, Cancer, and the southern parts of Leo. This vast system of stars resembles a gigantic sidereal billow flowing towards the Milky Way as towards some mighty shore-line. Nor is this description altogether fanciful; since one of the most marked instances of star-drift presently to be adduced refers to this very region. These associated stars are urging their way towards the galaxy, and that at a rate which, though seemingly slow when viewed from beyond so enormous a gap as separates us from this system, must in reality be estimated by millions of uniles in every year. Other streams and clustering aggregations there are which need not here be specially described. But it is worth noticing that all the well-marked streams recognised by the ancients seem closely associated with the southern rich region already referred to. This is true of the stars forming the River Eridanus, the serpent Hydra, and the streams from the water-can of Aquarius. It is also noteworthy that in each instance a portion of the stream lies outside the rich region, the rest within it; while all the streams which lie on the same side of the galaxy tend towards the two Magellanic clouds. Most intimate signs of association between lucid stars and the galaxy can be recognised,(i) in the part extending from Cygnus to Aquila; (ii) in the part from Perseus to Monoceros (iii.) over the ship Argo; and (iv.) near Crux and the feet of Centaurus. ; Before proceeding to the subject of Star-drift, three broad facts may be stated. They are, I believe, now recognised for the first time, and seem decisive of the existence of special laws of distribution among the stars: First, the rich southern region, though covering but a sixth part of the heavens, contains one-third of all the lucid stars, leaving only two-thirds for the remaining five-sixths of the heavens. This proves beyond all possibility of question that by far the greater number of the fainter orders of stars (I refer here throughout to lucid stars) owe their faintness not to vastness of distance, but to real relative minuteness. To pass over a number of other modes of research, the actual mapping of the stellar motions, and the discovery of the peculiarity to which I have given the name of star-drift, remains to be considered. In catalogues it is not easy to recognise any instances of community of motion which may exist among the stars, owing to the method in which the stars are arranged. What is wanted in this case (as in many others which yet remain to be dealt with) is the adoption of a plan by which such relations may be rendered obvious to the eye. The plan I adopted was to attach to each star in my maps a small arrow, indicating the amount and direction of that star's apparent motion in 36,000 years (the time-interval being purposely lengthened, as otherwise most of the arrows would have been too small to be recognised). When this was done, several well-marked instances of community of motion could immediately be recognised. Perhaps the most remarkable instance of stardrift is that observed in the constellations Gemini and Cancer. Here the stars seem to set bodily towards the neighbouring part of the Milky Way. The general drift in that direction is too marked, and affects too many stars, to be regarded as by any possibility referable to accidental coincidence. It is worthy of note that if the community of star-drift should be recognised (or I prefer to say, when it is recognised), astronomers will have the means of determining the relative distances of the stars of a drifting system. For differences in the apparent direction and amount of motion can be due but to differences of distance and position, and the determination of these differences becomes merely a question of perspective.* Before long it is likely that the theory of stardrift will be subjected to a crucial test, since spectroscopic analysis affords the means of determining the stellar motions of recess or approach. The task is a very difficult one, but astronomers have full confidence that in the able hands of Mr. Huggins it will be successfully accomplished. I await the result with full confidence that it will confirm my views. (To be concluded next week.) MECHANICAL MOVEMENTS. It is necessary to premise, however, that before 119 Compensation balance, this the the experiment was tried, there were reasons for screws for regulation at the ends. t and tare two compound bars, of which the outside is brass and the inside steel, carrying weights bb. As heat increases, these bars are bent inward by the greater expansion of the brass, and the weights are thus drawn inward, diminishing the inertia of the balance. As the heat diminishes, an opposite effect is produced. This balance compensates both for its own expansion and contraction, and that of the balance-spring. This was found to be the case, indeed, in several instances. Thus the stars in the constellation Ursa Major, and neighbouring stars in Draco, 120. Endless chain, maintaining power on exhibit two well-marked directions of drift. The going-barrel, to keep a clock going while winding, stars B, y, d, e, and of the Great Bear, besides during which operation the action of the weight two companions of the last-named star, are tra- or main-spring is taken off the barrel. The wheel velling in one direction, with equal velocity, and to the right is the "going-wheel," and that to the clearly form one system. The remaining stars in left the striking-wheel." P is a pulley fixed to the neighbourhood are travelling in a direction the great wheel of the going part, and ronghened, almost exactly the reverse. But even this relation, to prevent a rope or chain hung over it from thus recognised in a region of diverse motions, is slipping. A similar pulley rides on another arbor full of interest. Byron Madler, the celebrated p which may be the arbor of the great wheel German astronomer, recognising the community of the striking part, and attached by a ratchet of motion between Ursa and its companions, and click to that wheel, or to clock-frame, if there calculated the cyclic revolution of the system to be certainly not less than 7000 years. But when the complete system of stars showing this motion is considered, we get a cyclic period so enormous, that not only the life of man, but the life of the Thirdly, the southern hemisphere contains one human race, the existence of our earth, nay, even thousand more lucid stars than the northern, a the existence of the solar system, must be regarded fact which cannot but be regarded as most as a mere day in comparison with that amazing striking when it is remembered that the total cycle. number of lucid stars in both hemispheres falls Then there are other instances of star-drift short of 6000. where, though two directions of motion are not Two or three years ago, the idea suggested it- intermixed, the drift character of the motion is self to me that if the proper motions of the stars not at once recognised, because of the various were examined, they would be found to convey distances at which the associated stars lie from the clear information respecting the existence of Secondly, if the two rich regions and the Milky Way be considered as one part of the heavens, the rest as another, then the former part is three times as richly strewn with lucid stars as the second. Here, again, without the illustrative maps the argument is necessarily rendered imperfect. eye. is no striking part. The weights are hung, as may be seen, the small one being only large enough to keep the rope or chain on the pulleys. If the part of the rope or chain is pulled down, the ratchet pulley runs under the click, and the great weight is pulled up by e without taking its pressure off the going-wheel at all. 121. Harrison's "going-barrel." Larger ratchet-wheel, to which the click R is attached, is connected with the great wheel G by a spring S S'. While the clock is going, the weight acts upon the great wheel G through the spring; but as soon as the weight is taken off by winding, the Here no account is taken of the motions of the stars A case of this kind is to be met with in the with the conimon motion of the system. within the system; such motions must be minute compared stars forming the constellation Taurus. It was here that Mädler recognised a community of Editor of the American Artisan. + Extracted from a compilation by Mr. H. T. Brown |