✓ . ■.Vi'-'-' •■V’; 1, . ’- .:.«'■ .•■.;-■■ : 'y. " . ■■ ■ " ■ i?t. '.r:^ •, A' ■ , 'iV*V' ■ 'V; ^ t. / r : -!ft.'?«ffe5'* ■-* ■. ^ ■ f' c:- ' :■ iuy- ■ ' /■ ;' iv "'3- .^' --V9' Ul... M ' ■ ■ 'V Is''' .N 2 ■ V P^ ■ i; '” «*a^'.«4< ‘■^< * ■ ■'' ■■' ■*■; •, -'i W^‘:v " A^' A')" " '. '•; , !■■ .- ^ 5S.S - • v« ^'"if r ‘*.1.»' . ' - ' : ■ T .■)' -if:. . ,-„>V''S- ■ ^ mm- vk,'"' :'.':V'W^*:€‘'’" THE POPULAR SCIENCE REVIEW. A QUAETERLY MISCELLANY OF ENTERTAINING AND INSTRUCTIVE ARTICLES ON SCIENTIFIC SUBJECTS. EDITED BY HENRY LAWSON, M.D. VOLUME VIII. LONDON: ROBERT HARDWICKE, 192 PICCADILLY"; AND ALL BOOKSELLEES. 1869. LOJTDO-\ : 1-lUNTliD LY fifOrriSWOODli and CO., NiiW-SXltEKT SQUARE AND rAUMAilENT STREET CONTENTS OE VOL. VIII PAGE FLYmG Machines. By Fred. W. Brearey, Hon. Sec. to the Aero- nautical Society of Great Britain. Illustrated ... ... ... 1 The Compound Ete oe Insects and Ckustacea. By Henry Fripp, M.D. Illustrated ... ... ... ... 12 Tkue and False Flint Weapons. By N. Whitley, C.E., Hon. Sec. to the Boyal Institution of Cornwall. Diagram ... ... 30 The Planet Mars in February 1869. By Eichard A. Proctor, B.A., F.R.A.S. Illustrated... ... ... ... ... ... 39 On the Molecular Origin oe Ineusoria. By J. Hughes Bennett, M.D., F.R.S.E. Diagrams 51 The CUTTLE-EISH. By St. George Mivart, F.Z.S. Illustrated ... Ill The Nature oe the Interior oe the Earth. By David Forbes, F.E.S. 121 On the Use and Choice oe Spectacles. By R. Brudenell Carter, F.R.C.S. Diagrams ... ... ... ... ... ... 131 The Use oe the Spectroscope in Astronomical Observation. By R. A. Proctor, B.A., F.R.A.S. Illustrated ... ... ... 141 The British Lion. By W. Boyd Dawkins, M.A., F.R.S. ... 150 Passion Flowers. By Maxwell T. Masters, M.D., F.L.S. Illus- trated ... ... ... ... ... ... ... 159 The Natural Development oe Bacteria in the Protolamic Parts oe Various Plants. By M. A. Bechamp 166 The Sertularian Zoophytes oe our Shores. By the Rev. T. Hincks, B.A. Illustrated ... ... ... ... 223 Hydrogenium. By Robert Hunt, F.R.S 233 The Structure and Aeeinities oe the Sea-squirts (Tunicata). By J. C. Galton, M.A., F.L.S. Illustrated 240 The Planet Saturn in July 1869. By R. A. Proctor, B.A., F.R.A.S 252 The Fertilisation oe Salvia and oe some other Flowers. By Wm. Ogle, M.D. Illustrated ... .. ... 261 In Articulo Mortis. By Benj. W. Richardson, M.D., F.R.S. ... 275 iv CONTENTS. PAGE Experimental Illustrations of the Modes of Determining the Composition of the Sun and other Heavenly Bodies by the Spectrum. By Wm. Allen Miller, M.D. ., D.C.L., V.P.R.S., Illustrated 335 What is Bathybius ? By Professor Williamson, F.K.S 350 Are there any Fixed Stars? By Kichard A. Proctor, B.A., F.R.A.S. Illustrated 358 Kfjjt’s Hole. By W. Boyd Dawkins, M.A., F.R.S. ... ... 369 The Lingering Admirers of Phrenology. By Professor Cle- land 378 The Anatomy of a Mushroom. By M. C. Cooke. Illustrated ... 389 The Chemistry of a Comet. By Edward Divers, M.D., F.C.S. ... 400 Reviews of Books Scientific Summary:— ... 67, 168, 284, 408 Astronomy ... 79, 178, 296, 418 Botany and Vegetable Physiology ... 83, 182, 300, 422 Chemistry ... 85, 186, 303, 427 Geology and Palaeontology ... 89, 190, 309, 430 Mechanical Science ... 93, 195, 313, 434 Medical Science ... 94, 197, 315,437 Metallurgy, Mineralogy, and Mining .. ... 97, 202, 318, 438 Meteorology 99, 205 Microscopy 206, 321, 439 Photography ... 100, 209, 323, 440 Physics ... 102,212,325, 440 Zoology and Comparative Anatomy ... ... 106,219,327, 445 Plate mVI. POPULAR SCIENCE REVIEW. FLYINa MACHINES. By FRED. W. BREAREY. Honokart Secretary to the Aeronautical Society of Great Britain. IN its normal state, the air is inapplicable as a power, but it is capable of becoming an overwhelming power, either by natural or artificial causes, as in the whirlwind and tornado or by rushing forcibly through it, as would be exemplified were the sails of a windmill rotated rapidly against it. Thus the bird may create for itself in a calm, by the agitation of its wing-surface, the power w’hich supports and prolongs its flight in a horizontal or ascending line ; but is also capable, in the calm of a sultry summer’s day, by the mere momentum of its own weight, of gliding for an immense distance upon an un- yielding plane, thus converting the inert air into a fulcrum or support. In- such a case, two only of the three requisites for successful flight are brought into action, viz. surface and weight, the third, force, being held in reserve for extraordinary occasions. This gliding motion, the writer has observed in a parachute which detached upon one occasion at no great height above his head on a calm evening sailed away down a gradually in- clined plane. It is upon bodies like these possessing extended surface, and brought under the influence of gravitation, that experiments are required. There can be no question in dispute, as to the possibility of so manipulating and inclining the surface or portions of the surface of a similarly descending bodjq so as to prolong the gliding motion, and convert it into one obedient in some degree to the will of the operator. When the two antagonistic 2 POPULAR SCIENCE REVIEW. forces, gravity and atmospheric resistance, are brought into operation, the result is a course, arrested and diverted in some direction, either by what we call accident, or design. Hitherto, as in the case of the parachute, accidental circum- stances have alone determined the deviation. It has been the great desire of man for ages to supply, either in his own person, or by the aid of apparatus, or by self-acting machinery, the third requirement for flight, viz. force, which may enable him to impel a plane surface at the proper angle of inclination against the air, and thus to nullify the effect of gravity. Necessarily, the relative proportion of sustaining surface to weight, and of power to uphold and propel that weight, have occupied much attention. Considerable misconception has existed upon these two points, and to this is mainly due the tardy progress of the science of aeronautics. In England, the subject has really never engaged the attention of scientific men, except under the form of aerostation, in the earlier years of its discovery. There have ever been persistent believers, and experimenters, and in the influential association which has been organised under the name of the Aeronautical Society of Great Britain, embracing amongst its supporters some of the first scientific men of the day, with the Duke of Argyll as President, the subject of aeronautics has been elevated into a science. The Papers ” read at the meetings of this Society, held at the Society of Arts, have contained much that is novel and sug- gestive, and evidence the fact, that scientific men have at length entered upon this wide field of discussion. In a paper by M. De Lucy of Paris, translated from the French by Dr. Cornelius Fox for the Aeronautical Society, there is detailed the result of actual experiments made by the author, with a view of de- termining the extent of wing surface to the weight to be sus- tained, and of the force requisite to raise and impel in horizontal flight. It will assist in rendering interesting the description of several designs lately exhibited at the Crystal Palace, if some of M. (le Lucy’s statements and deductions are more widely dissemi- nated. Iliis author asserts, that there is an unchangeable law, to which lie has never found any exception, amongst the consider- able number of liirds and insects, whose weight and measure- mentr lie has taken, viz. that the smaller and lighter the wingf-d animal is, the greater is the comparative surface. Thus in (emfiaring insects with one another: the gnat, which weighs •Uio times h-ss than the stag-beetle has 14 times greater relative surface. '1 he lady-bird wliich weighs 150 times less FLYING MACHINES. 3 than the stag-beetle, possesses 5 times more relative surface, &c. It is the same with birds. The sparrow which weighs about ten times less than the pigeon, has twice as much relative surface. The pigeon which weighs about eight times less than the stork, has twice as much relative surface. The sparrow which weighs 339 less than the Australian crane, possesses seven times more relative surface, &c. If we now compare the insects and the birds, the gradation will become even much more strik- ing. The gnat, for example, which weighs 97,000 times less than the pigeon, has 40 times more relative surface ; it weighs 3,000,000 times less than the crane of Australia, and possesses relatively 140 times more surface than this latter, which is the heaviest bird the author had weighed, and it was that which had the smallest amount of surface, the weight being 20 lbs. 15 oz. 2 J dr. avoirdupois, and the surface (referred to the kilogramme 2 lbs. 3*27 oz.) 139 square inches; yet of all travelling birds, they undertake the longest and most remote journeys, and, with the exception of the eagle, elevate themselves highest, and main- tain flight the longest. M. de Lucy remarks, that if the law of surface in inverse ratio to weight be regarded, the cause of all the errors which have been committed will be readily understood ; for a mathe- matician who should select as his type an excellent bird of flight such as the swallow, by ascertaining its weight and surface, will apportion nearly one mtee or 1,550 sq. in. to the kilo- gramme, and consequently 75 mtoes for a man of 75 kilo- grammes, that is to say, about 165 lbs. would require a surface of 116,250 sq. in. Should he select the pigeon, he will arrive at a result quite different, because the pigeon being heavier than the swallow has a surface relatively smaller. According to this type, he would arrive at the conclusion that only 20 m^res of surface or 31,000 sq. in. would be requisite for a man of the same weight. With regard to the crane of Australia, the weight of one of which was 20 lbs. 15 oz. 2i dr. avoir., possessing a surface of only 1,324 sq. in., this third example would give to a man of the before-named weight a surface of no more than 10,850 sq. in. Again, should he select a type amongst insects, for example the blue dragon-fly whose flight is so rapid, he would discover the weight to be rather more than J grain, and surface nearly f of a square inch, which referred to the selected standard of com- parison would give 9,416 sq. in. and for the man 705,800 sq. in. Were we to determine the amount of sustaining surface re- quisite for the man from some of the butterfly tribe, whose wings are so prodigiously expanded in comparison with their weight, we should arrive at results so much in excess of these B 2 4 POPULAR SCIENCE REVIEW. dimensions that the construction and manipulation of the appa- ratus would be impossible. The author next proceeds to state that The law of surface, in inverse ratio to weight, would naturally tend to lead us to this conclusion — viz., that the heaviest-winged animal, having the least surface, ought in return to possess the greatest force.” M. de Lucy then proceeds to disprove this assumption, by showing, that the muscular force of insects is much greater than that of birds, and he adduces various well-known instances in proof of his assertion. Upon the supposition that his facts, and the theory founded on them, are correct, it will be a fair hypothesis to assume that where large wing-surface is given to insects, the provision is accompanied by the relative power to control it, in compensation for absence of weight, which we have seen is during descent a power of itself, and is taken ad- vantage of by some birds, in gliding, or soaring against a breeze. For such purposes, weight is a necessity, and therefore we never see any similar method of flight in the winged insect tribe. Amidst the variety of contending theories, which have ever clothed the subject of aviation with mystery, it seemed most desirable to descend to the quieter field of practical effort, and to test the experience of those few and isolated workers, who, distributed about the civilised earth, had put their ideas into recognisable shape. It was desired to ascertain, as the foundation of future pro- ceedings, to what extent knowledge had been acquired, and applied, and at one collective glance, to review the whole question of aeronautics, as a 'point cVappui for further efforts. The limited publication of this intention, on behalf of the Aeronautical Society, produced a large correspondence from all parts of the world, and also a notification of many intended exhibitors, who had reduced their theories into practice, but, and in proof how much the study of aeronautics has been pursued by persons of limited means, many were deterred from taking part in the exhibition from considerations of pecuniary outlay. The Aeronautical Society itself partakes of this disadvantage, and labours hard against a tide which has been flowing for a long period, but which, owing to the Society's persistent efforts, and the practical character of its discussions, may be said to have reached its ebb, so that henceforward it may run with the stream of Lopular Science. The first recorded and scientifically based attempt to connect f»laiie surface, and weight, in relative proportion to one another, w;is that of wliidi all the world was cognizant in 1842, patented Ijy Henson. The plan resulted from conversation between li'Tison anrl Stringfellow at the residence of the latter-named gentleman in Chard, Somerset. Sliould any one reading Astra FLYING MACHINES. 5 Castra,” by Christopher Hatton Turner, a work devoted to the history of aeronautics, come to the conclusion, that Henson’s aerial macliine was ever constructed of the dimensions there stated, he would be in error. The passage alluded to, is ex- tracted from Newton’s ‘^Journal of Arts and Sciences,” and is as follows : “ The amount of canvas or oiled silk necessary for buoying up the machine, is stated to be equal to one square foot for each half pound weight, the whole apparatus weighing about 3,000 lbs., and the area of surface spread out to support it, 4,500 square feet in the two wings, and 1,505 in the tail, making altogether 6,000 square feet.” The fact is, that this machine was never constructed ; for after two abortive attempts to manufacture models, at the Adelaide Gralleiy, which should represent the dimensions before- named, he rejoined his friend at Chard, and the two together commenced their experiments under a variety of forms. Mr. Stringfellow frequently availed himself of the express train, taking with him an arrangement for testing the resistance of different angles against the air, at high speed, and he states that those experiments only tended to prove, that an}^ guess- work was better than the calculations hitherto made by writers on the subject. However, in 1844, they together commenced the construction of a model ; Henson attending chiefly to the wood or frame- work, and Stringfellow to the propulsive power, for which, after trial of other effects, he adopted steam. This model, completed in 1845, measured twenty feet from tip to tip of wing, by three and a half feet wide, giving seventy feet of sustaining surface in the wings, and about ten more in the tail. The weight of the entire machine was from twenty-five to twenty-eight pounds. As pictorial illustrations of this machine were widely pub- lished at the time, it is not thought necessary to reproduce them, especially as a succeeding attempt, hereafter depicted, bears a great resemblance to it ; the important difference existing in the improved method of construction. The principal feature was the very large sustaining surface in proportion to the weight, which, as we have seen in reference to M. de Lucy’s experi- ments, was far in excess of the requisite conditions. To sup- port tliis weight, it was necessary to propel the plane surface at an angle against the resisting air, and it is evident, that in pro- portion as the speed imparted was increased, so might the angle be decreased. It was necessary to provide initial force ; accordingly, an inclined plane was constructed, down which the machine was to glide, and it was so arranged that the power should be main- tained by a steam engine, working two four-bladed propellers, 6 POPULAR SCIENCE REVIEW. each three feet in diameter, at a rate of 300 revolutions per minute. A tent was erected on the Downs two miles from Chard, and for seven weeks the two experimenters continued their labours — not, however, without much annoyance from intruders. In the language of Mr. Stringfellow, “There stood our aerial protegee in all her purity — too delicate, too fragile, too beautiful for this rough world ; at least, those were my ideas at the time, but little did I think how soon it was to be realised. I soon found, before I had time to introduce the spark, a drooping in the wings, a flagging in all the parts. In less than ten minutes the machine was saturated with wet from a deposit of dew, so that anything like a trial was impossible by night. I did not consider we could get the silk tight and rigid enough. Indeed, the framework altogether was too weak. The steam engine was the best part. Our want of success was not for want of power or sustaining surface, but for want of proper adaptation of the means to the end of the various parts.” Many trials by day down inclined wide rails showed a faulty construction, and its lightness proved an obstacle to its success- fully contending with the ground currents. Shortly after this, ^Ir. Henson left England for America, and Mr. Stringfellow, far from discouraged, renewed alone his experiments. In 1846 he commenced a smaller model for in- door trial, and, although very imperfect, it was the most sue-* cessful of his attempts. The accompanying illustration (Plate XXXVI. fig. 1) is taken from a photograph. It will be observed that the sustaining planes were much like the wings of a bird. They were ten feet from tip to tip, feathered at the back edge, and curved a little on the under side. The plane was two feet across at its widest part ; sustaining surface, seventeen square feet ; and the propellers were sixteen inches in diameter, with four blades occupying three-fourths of the area of circumference, set at an angle of sixty degrees. The cylinder of the steam engine was three-fourths of an inch in diameter ; length of stroke, two inches ; bevel gear on crank shaft, giving three revolutions of the propellers to one stroke of the engine. The weight of the entire incKlel and engine was six pounds, and with water and fuel, it did not exceed six and a half pounds. The room wliich he had available for experiments did not mca‘>ure above twenty-two yards in length, and was rather con- tnicted in height, so that he was obliged to keep his starting wires very low. He found, Imwever, upon setting his engine in motion, that in one-third the length of its run upon the ex- tended wire, the machine w’as enabled to sustain itself; and up^ui its reaching the point of self-detachment, it gradually FLTINa MACHINES. 7 rose, until it reached the further end of the room, where there was canvas fixed to receive it. It frequently, during these experiments, rose after leaving the wire, as much as one in seven. At the request of the then proprietor of Cremorne, Mr. Ellis, who with two others went down to Chard to see the machine, Mr. Stringfellow repaired to those gardens with the two models, but it seems that not much better accommodation was afforded than he possessed at home. It was found that the larger model (Henson’s Patent) would run well upon the wire, but failed to support itself when liberated. Owing to unfulfilled engagements as to room, Mr. Stringfellow was preparing for departure, when a party of gentlemen, unconnected with the gardens, begged to see an experiment, and finding them able to appreciate his endeavours, he got up steam pretty high, and started the small model down the wire. When it arrived at the spot where it should leave the wire, it appeared to meet with some little obstruction, and threatened to come to the ground, but it soon recovered itself, and darted off in as fair a flight as it was possible to make, to a distance of about forty yards, further than which it could not proceed. Having now demonstrated the practicability of making a steam-engine fly, and finding nothing but a pecuniary loss, and little honour, this experimenter rested for a long time, satisfied with what he had effected. The subject, however, had to him its special charms, and he still contemplated the renewal of his experiments at some future day, but, he writes, ‘‘ it is doubtful if that day would ever have arrived, had not you (the writer) perse veringly called me into action.” The proposed exhibition of the Aeronautical Society, roused once more his old energies. In a paper read by Mr. F. H. Wenham, at the Society of Arts, on the occasion of a meeting of the Aeronautical Society, there occurred the following observation. Having remarked how thin a stratum of air is displaced beneath the wings of a bird in rapid flight, it follows, that in order to obtain the necessary length of plane for supporting heavy weights, the surfaces may be superposed, or placed in parallel rows, with an interval be- tween them. A dozen pelicans may fly one above the other, without mutual impediment, as if framed together ; and it is thus shown, how two hundredweight may be supported in a transverse distance of only ten feet.” Mr. Stria gfellow eagerly grasped this idea and set about con- structing the model which he exhibited at the Crystal Palace. The writer confesses to the feeling of disappointment which he experienced, upon his first introduction to this otherwise elegant little design. He had imagined, that the surest road to success, was that, by which a triumph had been previously achieved. 8 rorULAR SCIENCE REVIEW. Mr. Stringfellow bimself sa}\s, “Wit.li respect to the super- posed planes, I consider they are the most practical arrange- ments hitherto proposed, for machines on a large scale, but I had always my doubts if they would be effective in a small model on account of their nearness to each other.” Fig. 2 (Plate XXXVI.) is from a photograph of Stringfellow’s aerial machine which ran suspended from a wire in the nave of the Crystal Palace, June 1868. It contained in its three planes, a sustaining surface of twenty- eight square feet, besides the tail. Its weight, with engine, boiler, fuel, and water, was under twelve pounds. It possessed in its steam-engine one third of the power of a horse, and its weight was only that of a goose. It will be seen, therefore, that the sustaining surface was more than two feet to the pound, always supposing that the system of superposing the planes, was efficiently represented in so small a model, which may reasonably be doubted. This pro- portion of weight to surface is more than double that, which is generally allowed to be necessary. The necessity, however, for providing even for as little as one pound for every square foot, would not exist if a certain speed could be maintained. It was always ^Ir. Stringfellow’s intention to set this model off free in the air, when the requirements of the exhibition were satisfied, but it was found that the engine, which had endured much work, required repairs. It had been observed by several reporters for the press that the model showed a decided tendency to an upward course during its hundred yards run at the Crystal Palace, and anxious to see it afterwards liberated, the writer assisted to hold the canvas which should check its fall. The space at hand for the horizontal wire was small, and did not allow of sufficient speed being attained, before its liberation by a simple mechanical action. When freed from its support it descended an incline with apparent lightness, until caught in the canvas, but the general impression conveyed was this — that had there been sufficient fall, it would have recovered itself, and proceeded onwards. Subsequently, Mr. Stringfellow lengthened the propellers, and added nine feet to the central plane, which, with other alte- rations, decidedly deteriorated its aerial capabilities. He is now engaged in experimenting with a view of ultimately constructing a large machine that would be sufficient to carry a j>erson tr> guide; and conduct it. On this scale he would avoid many difficulties which are inseparable from small models. As Mr. Stringfellow gained the prize of 100^. for “the lightest steam-engine in proportion to its power,” and as the engine which propelled the model at the Crystal Palace differed from that but in dimensions, it will only be necessary to append FLYING MACHINES. 9 the following description of the steam engine, which was given in the Eeport upon the Exhibition published by the Aeronautical Society : ‘‘ The steam engine does not differ from an ordinary one, except in the precautions to ensure lightness. The two- inch cylinder is of very thin brass tube ; the covers, flanges, and glands are also as light as can be made, consistently with strength ; the ports and passages are in one separate piece, screwed on ; the piston-rod passes through each end of the cylinder, and by means of long connecting rods, works in op- posite directions two cranks, fitted to the axes of two four-bladed screws, three feet in diameter ; two light bars extend from the crank-shaft down each side of the cylinder : these sustain the thrust of the piston, and a framing is thus almost dispensed with. The boiler consists of a number of inverted cones, made of very thin sheet copper, with the joints soldered with silver solder. Each cone is closed wdth a hemispherical cap. The cones are placed in parallel rows ; the bottom ends, or apexes, of the series are all connected together by water-tubes ; and from the hemispherical tops a small steam pipe conveys the steam away to a cylindrical chamber above the system : this is set in the smoke-box, and serves as a super-heater, and the steam is quite dried therein. The cones are not liable to prime, as the water surface for the escape of the steam is extensive, and the steam rises clear from the generating surfaces. The fire space between the bases being large and free, this form of boiler is particularly well adapted for burning liquid fuels. The question may be asked. Is there not some hazard in em- ploying metal almost as thin as paper for sustaining pressures exceeding 100 lbs. per square inch ? But it is well known that in the so-termed ‘ tubulous ’ boilers, to which class this one belongs, if a rupture takes place in one of the elements, a gradual and harmless escape of water and steam is the only consequence ; this empties the boiler by degrees, and at the same time ends the danger by extinguishing the fire, thus differing in character to the explosion of a boiler, whose strength depends upon the external shell, the fracture of which causes instant destruction, both to itself and all within its vicinity.” The cylinder is two inches in diameter, stroke three inches, boiler pressure 100 lbs, per square inch. The engine makes 300 revolutions per minute. In three minutes after lighting the fuel, the pressure was 30 lbs. ; in five minutes, 50 lbs. ; and in seven minutes it attained its full working pressure of 100 lbs., driving two four-bladed screw propellers, three feet in diameter, at 300 revolutions per minute. In an article entitled Swimming or Flying,” contributed to the Times, and published April 9, 1868, signed The Apteryx,” the author comments upon the possibility of man’s sustaining 10 rOPULAll SCIENCE EEVIEW. himself by his own muscular exertion, and especially refers to Mr. Charles Spencer’s assertion that he could not only effect this feat, but that he could sustain flight for several yards. In opposition to this assertion, he says A gymnast who lifts weights, and who has supported his owh weight on his arms, on wide-set parallel bars, must conclude that the feat announced for June is simply impossible, for no acrobat could lift and sustain himself in the attitude of a spread eagle, by beating the air long enough to move the distance. If this aeronaut flaps at all, he will come to grief, like the sage in Easselas, and like all others who have tried flying with artificial wings.” ]\Ir. Spencer is acknowledged to be one of the best teachers of gymnastics in this country, and he is himself no mean per- former. His experience upon the trapeze induced in him the belief that it would not require so much proportion of plane surface to support a given weight as is generally supposed. He accordingly constructed an apparatus, and by its means he avers that he has proved, that 110 square feet properly dis- posed, is sufficient to sustain 158 lbs. weight. With such an apparatus, composed of plane and wings, he states, that running down a small incline in the open air, and jumping from the ground, lie has by the action of the wings, sustained flight to the extent of 1 20 feet. The framework of this apparatus, exhibited at the Crystal Palace, was a marvel of lightness and strength, composed of steel umbrella wires and wicker work. In attempting to im- prove upon a previously constructed design, the material with which he covered it, was found to be too fragile, but he states that on practising in the transept of the Crystal Palace — the apparatus being suspended from the roof by a rope — he was able to raise himself by the action of the wings. Fig. 3 is from a photograph of the apparatus. The tail is here denuded of its covering. Length of tail, 18 ft. ; width at the end, 8 ft. ; depth of keel at the end, 4 ft. ; weight of tail, 15 lbs. ; area of tail, 72 sq. ft. liCngth of wing, 7 ft. ; width at the widest part, • 4 feet; area, 15 sq. ft.; weight, 1^ lb.; weight of the whole tail, 15 lbs. ; wings, 3 lbs. = 18 lbs. ; weight of himself, 10 stone, and sustaining surface, 1 10 sq. ft. ; total weight of himself and appa- ratus, 158 lbs. ; making not quite 1^ lb. to the square foot. Owing to the wicker-work — which is made to fit tight round the body — causing pain, and otherwise obstructing his move- ments, he was un/ible to satisfy the curiosity of the public, and In* is now rerf»n.stnicting that portion, and substituting a stronger material for the; covering. O Arroriling to I)e Lucy’s theory of surface in inverse ratio to weight, the sustaining surface, instead of being 110 square feet, need (»nly have been about 31 sfjuare feet, always supposing - FLYING MACHINES. 11 that the surface was effectively disposed, which in Spencer’s apparatus may be very properly questioned. Want of space, however, precludes any attempt to pursue this question further. We come now to the description of another machine exhibited, the invention and construction of Wm. Gibson, a working man of Outram Street, West Hartlepool. Dissimilar to either of the former inventions, which respec- tively consisted of plane — and plane with wings — this was ex- pected to obey the action of the wings alone. The mechanical action at the command of the operator was intended to be controlled by the downward pressure of each leg alternately, assisted by the arms. The machine therefore consisted of a framework, to which were attached four wings, so that by pressure upon one treadle, two flew up feathered, and two descended with an impact upon the air, as in Fig. 4, where the two lower wings are in the act of ascending. In a previously constructed apparatus provided with two wings only, Gibson states that a man weighing 10^ stone re- peatedly raised himself from the ground from 12 to 18 inches, but that he could not sustain himself, because the wings being so heavy, he was not able to repeat the stroke. Each wing was 12 feet long, 1|- feet across at the wider part, and 1 foot at the narrower; surface of both wings 37 square^feet ; weight of each wing, 10 lbs. ; frame and rods, 21 lbs. ; weight of man, lOJ stone ; giving about 5 lbs. to each foot of sustaining surface, a condition which severely tests the theory of inverse proportion of surface to weight. The four-winged contrivance sent to the Crystal Palace was found to be too heavy for trial, but the inventor’s enthusiasm seems to be quite equal to the construction of another and lighter apparatus for further exhibition. It must be remarked as an interesting feature in Gibson’s apparatus, that the total weight of the man and apparatus, as compared with the surface, gives on De Lucy’s theory, about 38 square feet as the proper sustaining surface, or one foot more than it possesses — taking for our calculations, the Austra- lian crane, and the theory of inverse proportion with its margin of from eight to ten times. Experiments can alone determine the true path to success, and it is encouraging to find that these are now aiding in the de- termination of the question. It is possible that we may shortly witness some more advanced attempts, and should they prove to be failures in the practical solution of the problem, it will per- haps be remembered that previous failure having led to increased knowledge, so future success may result from their repetition. 12 THE COMPOUND EYE OF INSECTS AND CKUSTACEA. HE anatomy of the insect eye, as described in recent treatises and manuals enjoying a wide circulation, is little more than a repetition of observations made by Swammerdam,* Murcel de SerreSjt Strauss Durkeim,J Diiges,§ and Johann Muller. || For the most part, also, the accompanying illustrations consist of unaltered copies of figures drawn when microscopic anatomy was in its infancy. Consequently, text and illustrations date alike from a period when the nature of the terminal elements of the optic nerve fibres was entirely unknown, and the histology of the several component structures of the eye but very imper- fectly understood. From the dates given below, and from the recital of the same authorities, and the SJime meagre details of the anatomy of the compound eye, the reader might naturally conclude that no later discoveries had been made, or that no further examinations had been attempted. That this is far from being the actual state of things, we liope to be able to show in the following pages, wljerein the results of certain interesting researches, prosecuted by Professor Leydig in Tubingen and by other anatomists, will be recorded. Yet it must be admitted that our acquaintance with the structure of the insect eye, and with the true character • (ler Xntur” and ^‘General History of Insects,” 1GG3 (two cen- turies a;ro !). t Mic fragment of rock may reveal to us facts respecting the THE COMPOUND EYE OF INSECTS AND CRUSTACEA. 15 physical conditions of organic no after, and the physiological laws of animal sensation, which obtained on the surface of our globe at a time when no human eye had been formed ; and this with as much mathematical certainty as if we were drawing conclusions from the preparations of insect and crustacean eyes lying on our table, or studying diagrams from the latest work on physiological optics. The term compound,” as applied to the eyes of articulata, is at once significant of the most important modifications of structure met with in these animals, and of the most remark- able differences of opinion held by physiologists respecting the modus operandi of the organs in question. An entirely satisfactory definition of the compound eye is, therefore, scarcely possible, so long as its structure and function remain subject to dispute on all sides. As it is advisable to avoid entering into a controversy which still agitates the scientific world, and to limit our remarks as far as possible to the positive (i.e. the anatomical) side of our subject, we shall content ourselves with a very brief reference to the general doctrines which bear on the explanation of the several modes of vision. To place our readers properly en rapport with the doctrine at present held respecting the vision of animals possessing compound eyes, we must advert to the theory propounded by J. Muller, and still almost universally taught : namely, that the type of construction (and the optical principle on which it is based) differs radically from that of the eye of man and verte- brates generally. The vertebrate type is represented by a hollow globe formed by membranes commonly called tunics or coats of the eyeball. The interior of this globe is occupied by a large central mass of transparent substance (the vitreous humor), in front of which is placed a crystalline lens with a moveable diaphragm or iris. Light is admitted into the interior of the eye through the front transparent portion of its outer coat (cornea), and, passing through the crystalline lens, is con- verged to a focus near the centre of the eyeball ; but the rays cross at this point, and are transmitted through the vitreous humor in a diverging course coincident with the radii which fall upon the inner (concave) surface of the inner coat of the eye (choroid coat) from an imaginary centre, which closely corre- sponds with the focus of converging rays admitted through the cornea in front. At the back of the eye, where the inverted rays of light, after traversing the vitreous humor, fall on the inner coat, lies, interposed between the convex surface of the vitreous humor and the concave (inner) surface of the choroid coat, a membrane-like expansion of nerve fibres with associated elements composing the retina. This retina, therefore, is in direct contact with the rays of light that have traversed the 16 POPULAR SCIENCE REVIEW. interior of the eyeball. And it results from the action of the several curved surfaces of the cornea and lens, and from the specific power of refraction due to the density of their substance, that an inverted image of any illumined object in front of the eye must pass through the transparent retina, and be reflected back again from the inner surface of the choroid (which is darkened by pigment) upon the retinal elements in contact vdth it. An optical image is, therefore, received by the retina, and 'perceived as if it were the object itself. The action of the refractive media, by ^vhich this picture of external objects is formed on the inner spherical concave of the pigmented choroid coat, is commonly illustrated by likening the whole dioptric apparatus to a “ camera obscura,” where the images formed by the lenses fall on a prepared surface, or, as in a photograph camera, on a ground glass plate, or the chemically sensitive surface substituted for it when a photograph is taken. The type of construction of the compound eye is, on the contrary, not that of a globe filled with refractive media, nor is the retina of the compound eye spread out in membrane-like expansion over a vitreous humor. The optic nerve at the bottom of the eye swells into a large solid mass by addition of fresh nerve matter (granules, nuclei, and medullary sub- stance) together with pigment, connective tissue, blood vessels, tracheae, and even muscle fibrils. And this mass, known as “ optic ganglion,” fills the space at the bottom of the eye, pre- senting, as it is continued forwards to the centre of the eye, the form of a solid cone, widening towards the front. The peri- pheral surface of this optic ganglion is covered with a thick layer of pigment, which appears to intercept all passage of light from the front to the back of the eye. But, through this pig- ment layer, numerous nerve fibres (enclosed in sheaths of investing membrane) pass onwards in direct lines towards the cornea, but terminate in peculiar-shaped bodies situated im- mediately behind it (these will afterwards be more particularly described). Thus, there is neither a central vitreous humor nor a lens answering to the crystalline lens of the vertebrate eye ; nor is tliere apparently any retina interposed at the focal plane of a dio[>tric apparatus to receive and perceive images. And since it is impossible that, in an eye thus constructed, images could be formed by tlie passage of collective rays of light through its intf*rior, it was supposed that the sensation of light was produced by (lirr*ct contact of rays, which, falling on the cornea and pass- in j' through without refraction, met the nerve fibres behind . hut ih re hi ' ng no focal convergence^ no optical image 'was formed. Sufh an hypothesis, however, failed to show how external objects ‘•oubl ])e seen in definite form and with distinct detail. Ac- THE COMPOUND EYE OF INSECTS AND CRUSTACEA. 17 cordingly, another mode of vision was propounded to meet the seemingly anomalous conditions and deficient mechanism of the dioptric apparatus. This new theory was based on the fact, since proved to be erroneous, that the minute facets of the compound cornea presented perfectly flat surfaces, without and within, and that, although the general curve of the cornea rendered such eyes capable of a very wide field of vision, no collective image of objects was produced by lens action. Each separate facet was supposed, therefore, to admit only a central pencil of rays, which, penetrating in direct lines, reached the ends of nerve fibres from the optic ganglion, and produced separate impressions. That is to say, no optical image was per- ceived ; but as we see a pattern in mosaic composed of numerous inlaid pieces, so the image of an external object was supposed to be made up of the separate impressions caused by rays of light proceeding from the illumined points of the object seen. The concurrence and combination of these separate impressions into a picture, formed as it were by the mind’s eye, is there- fore a retinal or cerebral function rather than an optical pheno- menon brought to pass by physical means. To such a theory insurmountable objections present them- selves. Anatomical facts, as now interpreted, contradict it ; optical phenomena, long known but not sufficiently kept in view, disprove it ; physiological reasonings based on the study of the true analogies and homologies of the constituent parts of the eye compel us to reject it ; and, lastly, direct observation of the living organ indicates the closest possible approach to the same mode of vision in all eyes possessing a true retina. The hypothesis of a double type of construction and function of the simple and compound eye was, at the time of its pro- mulgation, supposed to be founded on anatomical facts. But these were, to say the least, veiy imperfect and too limited for so wide-reaching a generalisation. In so far as the word type ” may be meant to indicate the existence of important structural modifications (not, however, subversive of the law of unity of means and purpose), there may be said to be many types of eye structure. Strictly speaking, however, they are but variations of one fundamental scheme, and cannot be considered as distinc- tive characteristics of the respective provinces of vertebrate and invertebrate animals : for, in point of fact, the chief variations are found in the latter only. In comparing the ascending- series, a certain progressive complicity of the retinal structure is sufficiently remarkable, but its essential character is the same throughout. In respect to the dioptric apparatus, greater divergence of plan is apparent in the compound eye ; but this is strictly in accordance with the variation of retinal develop- ment. But the reason of such modifications is rather to be VOL. VIII. — NO. XXX. c 18 rOPULAR SCIENCE REVIEW. sought for ill the particular orgauisatiou and habits of the animal than in its place in the animal series. In the insect the com])oimd eye presents us with the solution of a truly wonderful problem : namely, the construction of an apparatus of vision surpassing in accuracy and perfection that of multi- tudes of creatures superior to it in other attributes, yet "with so little expenditure of material as not to burden its diminutive and buoyant body or interfere with its powers of flight. And when we remember tliat its most rapid motion is still guided by a sight so keen as to precede muscular action, we cannot avoid the conclusion that its faculty of seeing is adapted to its habits of life, without any reference to its position in our artificial classifications. If, then, it be admitted that our conception of a seeing faculty should be physiologically one and the same for all organs of siglit ; if, also, the variations of anatomical structure can be reduced to one fundamental scheme of construction, it follows that we shall best understand this by tracing the points of identit}* and similarity of parts and functions than by exag- gerating apparent differences, and finding in these a proof that Nature, in arranging an organ of sight, has departed from her usual singleness of aim and means. Now the fundamental principle maybe stated thus: the pro- duction by physical means of an optical image of external objects ; and the direct contact of percipient nerve elements with this image. And the problem which the anatomist has to solve, is to discover the constructive plan by which an optical image is produced and brought into contact with the percipient element. Whether the plane of contact be found at the back or front of the eye, the principle and the final result remain the same. The anatomical positions we take up are these. 1. The conipound eye of Articulata is the ground-type of visual organ in these animals. 2. The simple eye (found with the compound eye on the same animal, as in insects, spiders, &c.), is a variety of the compound eye, and not, as J. Muller believed, constructed on the so-called vertebrate type. 3. In neither kind of eye is the physiological signification of retinal or lens apparatus so essentially distinct as to justify the hypothesis of opposed principles of optical construction or visual function. In the iletails which follow we shall continue to employ the same (k^signations for homologous parts of the insect eye as are in common use in the description of the vertebrate eye. Thus the coats of the eye will still be called sclerotic, corneal, choroid f with its ap|»endage — iris). The dioptric structures (crystalline lens, vitreous humor), and the nerve structures (optic nerve trunk and fibres and retinal elements) will still receive the same flesignation wherever they are found, however modified. And first of tlie Cornea, THE COMPOUJ^D EYE OF INSECTS AND CHUSTACEA. 19 The general surface of the insect cornea is spherical and more or less complete according to the size of the eye. And the an- terior and posterior faces of the compound cornea are as a whole parallel (see Plate XXXVII. fig. 1, Plate XXXYIII. fig. 9). But in many insects (see figs. 3, 6, dragon-fly) the anterior surface is partitioned into a varying number of minute facets — four-sided in Crustacea, six-sided in insects (with unimportant exceptions). The number and shape of these are however of little signi- ficance, for four- and six-sided facets may be seen on the same cornea, whilst in beetles, butterflies and other insects a deposit of pigment at the angles formed by the sides leaves only a central circular clear space for transmission of light. A fact far more important is the convex lens shape of the anterior or posterior faces of the facetted cornea. This convexity is most strongly marked on the posterior faces. On the anterior face it is mostly slight (fig. 15, Hymenopterous insect, figs. 3, 6, dragon-fly, show it more distinctly). On the posterior surface corresponding to facets in front, the curve is often almost hemispherical (see figs. 13, 14, Coleopterous insects) ; but it is not so strong in Diptera (common fly) or in Hemiptera (notonecta). In beetles an an- terior and posterior curve is found. In certain Crustacea (Herbstia, fig. 12, Ilia, Lambrus) the posterior curve is strong, but in the cray-fish (fig. 9) it is flat. Without multiplying examples, it may be stated that the corneal facets of almost all insects present either an inner or outer curve, sometimes both. The optical significance of this fact is all-important; for it fol- lows that every corneule * of a compound cornea produces a dis- tinct focal convergence of rays, just as a plano-convex or double convex lens does. That is to say, an optical image is formed by each corneule, and on looking through a piece of compound cornea we see as many separate images as there are facets. Thus, an old writer remarks, on looking at a man through a piece of insect cornea we see an army of dwarfs ! Under such circumstances mosaic vision ” (see ante) is simply impossible. But how does the case stand with the simple insect eye ? J. Muller was led by his investigations to conclude that the simple insect eye closely resembled the eye of a fish. He describes the corneal surfaces as being plain, with their outer and inner faces parallel : behind this a globular crystalline lens, which however he expressly states to be adherent to the posterior surface of the cornea. Later researches have shown this description to be erroneous. The large globular ^Hens” of the simple eye is * This term is employed to denote each small segment of corneal substance corresponding to a facet and lying between the anterior and posterior boun- daries of its thickness. The corneule is at once understood by looking at the section of a cornea. 20 rOPULAR SCIENCE REVIEW. reall}" a projection of the inner corneal lamella?. : an excrescence, so to speak, of corneal substance : in fact, an exaggerated form of the inner curve of the corneule of the compound eye. M. Dujardin has well proved this in a memoir published in Annales des Sciences,” 1867 ; and Leydig has given figures showing it (figs. 7, 8). The cornea lenses therefore of the simple and compound eye are not exactly the same as the crystalline lens of the vertebrate eye. But they perform the same function and rank as analogous parts. The crystalline lens of the verte- brate e}"e is indeed developed from cuticular cells, and though a more perfectly differentiated structure, and separated from the cornea (which is also a cuticular mass metamorphosed into chitin in the insect eye, while in the vertebrate eye it retains traces of its cellular origin), is homologically almost idepitical with the corneal lenses of insects. Thus, one of the most striking differences between the two types is on closer examina- tion reduced to a variety of the same structural elements, the essential character of its functions being identical. The result of this variation in the disposition of corneal lenses is certainly remarkable : for in the compound eye a multiplica- tion of images is the consequence of its facetted arrangement, v.’hilst in the simple eye a single large corneal lens admits of the focal concentration of collective pencils of light upon the nerves behind it. AYhere, however, simple eyes (which are much smaller than the compound eye) are grouped together in one spot commanding the same held of vision, multiplication of images must occur so that the optical phenomena are similar. The reduction of multiple images into one mental picture is, however, a fact common to all animals, and not simply charac- teristic of the invertebrate eye. Single vision with two eyes is the most obvious and striking fact in our own experience. Bespecting the structure of the cornea little need be added. It is chitinised skin, or rather epidermis, its original cell elements being lost during the process of metamorphosis. The cornea shows nevertheless traces of a lamellar structure, as indi- cated by the hne horizontal lines running parallel with the surface (see figs. 3 and 6). Vertical lines more strongly marked (see same hgs.) divide the cornea into vertical segments, the anterior and posterior faces of which are bounded by the plane or curved facets, and each segment thus bounded is conveniently designated a corneule. Fig. 2 shows a surface view, and fig. 6 a section in which the curve of the exterior facet is well seen : tlie interior facet is in tliis instance a plane surface, and therefore the wliole i)osterior surface of the cornea forms a continuous Kinooth curve. In different insects the thickness of the cornea varies greatly. Figs. 13 and 14 sliow a thick cornea with flat front facet and convex inner facet (plano-convex lens). Figs. THE COMPOUND EYE OE INSECTS AND CEUSTACEA. 21 15 and 16 show a thin cornea with both faces slightly curved (double convex lens). Fig. 12 shows a thin cornea with flat front facet and half-round inner facet. Fig. 1 1 shows a thin cornea with flat outer and inner facets. All these varieties stand in close connection with the particular disposition of the parts lying under the cornea. Sometimes (but rarely) the two facets form a meniscus, the front facet curving outwards, and the back facet having a slighter curve directed the same way (i.e. it appears concave when seen in section). Before entering into the details of the underlying parts we must direct attention to their general disposition and relation. Fig. 1 is a section through the central plane of the dragon-fly’s eye. The double outline of the cornea sweeps in a regular curve continuous with the chitin skin (the figure is not suf- ficiently magnified to show the small facets). Immediately behind the cornea (already fully described) a dark shade repre- sents a mass of pigment, which causes the peculiar blackness of the eye when seen in front. No pupillary opening can be seen, as in the vertebrate eye, until a piece of cornea is placed under the microscope (with a high power objective). Then a clear opening in the very centre of each facet is observed, and the pigment around it corresponds with the iris pigment of the vertebrate eye. The colour of this pigment often corresponds with that of the insect’s skin : sometimes white or yellowish white, grey, yellow grey, and so on to the deepest purple or black; and it may even possess the same metallic brilliancy observed in the iris colours of the fish, amphibian and reptilian, eyes. Between the cornea and optic ganglion a series of radial lines (5) indicates what we have called the bacillar stratum, as we con- sider it the equivalent of that portion of the vertebrate retina known under the same name. A detailed description of this will be given below. The radial lines in our figure extend out- wardly to the cornea, inwardly to the peripheral surface of the optic ganglion (d). This latter occupies the centre and bottom of the eye, and is composed of nerve fibres and associated ele- ments corresponding with the retinal ganglionic layers of the vertebrate eye, though less perfectly developed. Sclerotic coat. — Continuous with the border of the cornea and where it joins the chitin skin, a membrane (indicated in the figure by a dark line marking the posterior boundary of the eye- ball) is seen, which completes the outer tunic. Even in the simple eye, small as it is, the neurilem or sheath of the optic nerve covers the optic ganglion, and is continued forwards as a delicate membrane which loses itself in the cornea. But in the compound eye of Libellula (see fig. 1) it is a stiff chitinised membrane on which muscles rest which are attached to its outer surface. At the equator oculi it conserves the globular form of 22 rorCLAR SCIENCE REVIEW. the eyeball, but at the bottom of the eye it curves iu (like the cup-shaped inversion of the bottom of a wine-bottle) and sepa- rates the eye from the general cavity of the head. In a physio- logical point of view the existence of a sclerotic coat or capsule is unimportant ; but anatomically the determination of its true homology possesses great interest, as it helps to prove the iden- tity of constructive plan which has been so much lost sight of in comparing the vertebrate and invertebrate eyes. Choroid and Iris, — In our figure a line of darker shading sweeping round the inner surface of the cornea and continued on the inside of the sclerotic coat and in front of the optic gang- lion represents a choroid coat. This is deeply pigmented, just as we see it in the vertebrate eye ; and where it lines the cornea a stroma of pigmented cells in irregular layers is very conspicu- ous after due preparation under the microscope. The same characteristic stroma is even more marked where the choroid lying on the periphery of the optic ganglion receives additions of pigment which line the nerve sheaths of the bacillar stratum. Thus the optic ganglion lies really outside the cavity of the eye- ball. In the eyes of higher mollusca (cephalopod and pulmo- gasteropod) this optic ganglion is seen much more distinctly se- parated from the eyeball proper, although covered by a reflection of the sclerotic capsule. In the vertebrate eye the separation of the optic nerve trunk into separate bundles of fibres occurs just as it passes through the choroid coat : and in the invertebrate eye the separation of isolated fibres from the ganglion mass occurs just in the same place and in a similar manner. But in the invertebrate eye the choroid pigment, besides lining the sides of the eye, is massed in quantity in the interior, both at the bottom of the eye and in bands which run through the optic ganglion and also invest the separate nerves. And the dense pigment layer covering the outer surface of the optic ganglion for a long time misled observers into the belief that rays of light could not reach the percipient elements of the retina ; whereas, as we now know, these percipient elements are situate in front of the optic ganglion, and in fact extend as far as the posterior sur- face of the cornea, their outer ends being in direct contact with the plane of images formed by the corneal lenses. On referring to fig. 5, which is that of a section across the bacilli (percipient elements), we see a number of clear circles, the sheaths of these bacilli, surrounded by dark lines representing the pigment on tlieir outside. Keferring again to fig. (), w^e see how the outer and inner ends of these sheaths are imbedded in the thick layers of pigment accumulated behind the cornea and in front of the optic ganglion. The portion of pigment in front wdiich sub- serves the office of iris covers the bulb-like or pear-shaped end of the bacillurn except at its point of contact with the cornea; so THE COMPOUND ETE OF INSECTS AND CRUSTACEA. 23 that light passing through each corneule falls upon this point and penetrates the clear refractive substance of the bacillum. The pigment surrounding the bacillum (or rather its sheath) isolates it complete!}^, and assists the internal refractions going on in the substance of the bacillum by reflecting the rays back on the nerve. The Bacillar stratum. — We now approach the most obscure point in the anatomy of the eye, and one which is most liable to misinterpretation, as it has proved also most fruitful of contro- versy. First in order, we may take the structure of the bacillar stratum as represented in our sketch of this apparatus in the dragon-fly. Looking at the section (fig. 6), we see stretched between the cornea and the optic ganglion a series of lines which represent the membranous sheaths of a number of bacilli, some of which are shown empty, whilst in others the nerve rod is figured within. The sheath is formed of clear membrane, but pigment strongly adheres to its outer surface. On its inner sur- face may sometimes be seen one or more small nuclei, and histo- logically the sheath membrane may be considered homologous with the connective tissue ” septa found in the retina of verte- brate eyes. At its outer extremity it is continuous with the stroma of pigment cells which lines the posterior surface of the cornea and is firmly attached to the corneal substance. A clear view of this connection can only be obtained by removing the pigment with the aid of solution of potash. In fig. 6 this con- nection is, however, well seen at the thin end of the section. Its inner extremity is in like manner continuous with the pigment- encrusted stroma of the choroid coat which covers the periphery of the optic ganglion. Thus then a framework of tubes fills the whole space between the cornea and optic ganglion; and the nerve fibres which spring from the optic ganglion, after piercing the pigment layer of the choroid, enter at the bottom of the tubes, and are continued forwards inside the tube (or sheath) to the cornea. But these nerve fibres are not like ordinary nerves. Their substance undergoes a remarkable metamorphosis, and their form an equally remarkable change. The nerve matter becomes highly refractive and crystalline in appearance, and the form of the nerve varies greatly in different eyes. Sometimes it swells into a club-shaped mass with ridges on four lines of its outer surface as soon as it enters its sheath : then in the middle of its course it runs to a fine thread, still preserving its quadran- gular shape (best seen in section) : again, as it approaches the cornea, it swells a second time into an oval or pear-shaped mass which entirely loses the character of nerve substance. In other instances the nerve has no bulbous swelling below, but as it ap- proaches the cornea swells into a four-lobed mass situate at its outer end. Some of the most characteristic forms are given in 24 POPULAR SCIENCE REVIEW. our figures. Thus fig. 9 shows the bacillar stratum enveloped in pigment, with the curiously varied form of the single bacilli, cross sections of which in fig. 10 exhibit the cruciform disposi- tion of its substance in different parts of its course. Fig. 1 1 shows the complete bacillum in detail : its club-shaped swelling below as it springs from the optic ganglion : its nerve-like thread in the middle, and its four-lobed mass (darkly pigmented) at its termination immediately beneath the cornea : also its enveloping sheath with nuclei on the inner wall. These three figures re- present the structure as seen in the eye of the cray-fish. In fig. 12 (Herbstia) a still more strongly marked change of form is seen. Below, the same club-shaped expansion ; then a dimi- nished rod-like portion, which soon swells into a very distinct four-lobed mass containing nuclei in each lobe ; then from the top of this a narrowed thread rises, which swells for the third time into a four-lobed highly refractive and delicate mass of transparent substance immediately under the corneal lens. The sheath closely invests this singularly shaped body, and is seen free only in the small space between its apex and the superja- cent corneal lens. In fig. 14 (eye of Procrustes) the nerve is seen springing from its optic ganglion, and swelling immediately into a spindle-shaped mass (cruciform in section) which is dis- tinctly striated : then a finer thread runs on and forms a second small four-lobed knot, from which again the nerve rises and swells a third time into a pyriform four-lobed mass which nearly touches with its apex the inner facet of the cornea. Its sheath is straight and invests the nerve loosely. Fine tracheae run up within this sheath ; and also (on the left hand) two muscle fibrillse (!) run up within the sheath, and are lost on the membrane investing the upper four-lobed swelling. (In all these prepara- tions the pigment is removed by solution of potash.) In fig. 13 (Dynastes) the nerve shows an elongated swelling, continued at the middle into a fine thread which ends in a small four-lobed knot, from the top of which the nerve again rises and soon ex- pands into a terminal pear-shaped mass touching and partially embracing the inner curved facet of the corneule above it. In fig. U) (Schizodactyla) the nerve undergoes little change of form until it approaches the cornea, where it swells into a pyra- midal l>o(ly. Tlie left-hand bacillum is figured with a crust of pigment ; that on the right hand is figured as it appears after the j>iginent is removed, by which the continuity of substance of the whole nerve structure is better shown. In fig. 4 Plate XXXVII. f I.ilielbda) two bacilli nearly resembling in form those repre- sented in tig. l.j (.Mantis) are seen. In both the simpler form of ( ‘-nieal swelling below and above clearly shows the anatomical continuity of the whole nerve. In fig. 18 (Acridium) the nerve ri;re« in the middle of the sheath accompanied by muscle fibrils THE COMPOUND EYE OF INSECTS AND CEUSTACEA. 25 which are studded with pigment : at the top of the nerve is the usual four-lobed terminal mass. In fig. 17 (Syrphus) the nerve is of nearly equal thickness in its whole extent up to the point where its ridged edges swell into a four-lobed knot embracing a trumpet-mouth shaped crystalline body at the top. Between the bacilli large tracheal tubes running from the optic ganglion up to the cornea are noticeable. Now, as may be expected, the interpretation of this curious structure has been variously given, and is still discussed ; for on the settlement of this question the explanation of vision in the compound eye rests. It is to be noted in the first place that the upper crystal-like oval or pyriform body was known and figured long before the peculiarities of form which the lower part exhibits were known. Whatever form the lower part takes, the crystal-like expansion above never fails ; and, from its delicate transparency and semi-fluidity of substance, as well as on account of its position close behind the cornea, it was never till recently suspected to be continuous with the nerve rod, or considered to be nervous matter. It was, there- fore, explained as an independent element, §.nd, in virtue of its position, shape, and refractive property, w^as supposed to be a lens and its function analogous with that of the vertebrate crystalline lens or vitreous humor. Thus, J. Muller, who first demonstrated its constant presence in all insect eyes, but who at the same time was unaware of the equally constant lens form of the inner corneal facets, looked upon this crystalline lens ” as the analogue of that of the vertebrate eye, and assigned as its office the transmission of the central ray of light penetrating through a corneal facet to the nerve behind it. Eudolph Wagner took a different view of the matter. Observing that this crystal-like body was composed of matter of different density — namely, an inner central portion more solid and refrac- tive, and an outer casing of softer matter — and believing that he had traced the nerve fibre behind it into the outer casing, he conceived that the inner central substance was a vitreous humor,” and the outer casing an expansion of nerve substance round it, just as the vitreous humor of the vertebrate eye is covered by the retinal expansion of nerve fibres. Accordingly, he interpreted the functions of the crystal-like body to be that of receiving rays of light from the cornea and forming an image of external objects upon its peripheral surface; that is, in direct contact with the retinal expansion of the nerve fibre. Wagner’s interpretation was obviously based on analogy of the vertebrate eye, but his anatomical research led him also to the discovery that a part at least of this crystal -like body was nerve sub- stance, a step in advance as compared with J. Muller’s views. The latter physiologist had indeed observed that the nerve 2(> rorULAR SCIENCE REVIEW. really reached the posterior surface of the crystal-like body; uor has any anatomist since his time doubted the nerve charac- ter of the fibre behind it. The various form of this fibre (as before described) was not, however, known or clearly demon- strated until Gottsche first, and after him Leydig, described the peculiar swellings, ridges, and knot-like expansions of the nerve so unlike anything hitherto observed in nerve structures. Nor was it until after long-continued and laborious investigations that Leydig finally expressed his opinion that the whole ap- paratus Avas nothing more than a peculiar modification of terminal nerve fibre, and, in fact, the homologue of the rod or cone in which the fibres of the vertebrate retina end. These cones or rods of the vertebrate retina are exceedingly minute in the mammalian eye, but in the lower vertebrates (e.g., frog, fish, &c.) are much larger and coarser. In the insect eye they are not only of a greater size and much more easy to prepare and examine, but they are also enclosed in separate sheaths, and have additions (such as muscle fibrils and tracheal tubes) which render them at first sight very unlike the rods and cones of the vertebrate ^retina. Nevertheless they agree in being terminal extremities of the nerve fibre, as also in the peculiar transformation of nerve substance into a highly refractive and transparent matter. They are, therefore, as much “ percipient elements ” as are the rods and cones of a vertebrate retina ; and they further agree in this, that they are placed just where the images formed by the corneal facets fall. In the first part of this article, we alluded to the fact that true optical images were formed by the corneal lenses, and that these images must ne- cessarily be produced in the plane immediately behind the cornea wliere the crystal-like expansions of the terminal nerves are situated. There is, therefore, no optical necessity for a second formation of images, but it is none the less certain that in this crystalline nerve end a series of refractions must occur. In the vertebrate eye, images formed by the lens are trans- ferred to tlie back of the globe, where the rod or cone ends of the retinal filn-es are disposed so as to meet the surface on whicli tlie image is formed. This disposition is similar in ]>oth kinds of eye ; the ends of the fibres are opposed to the ]>ictnre, and the direction of the bacilli or rods is radial to the centre of the eye. Hut, in the one case, tlie images and the “ j»ereif)ient bacilli ” are in the front of the eye — that is, vision is directly forwards — whilst in the other case the images and j>ercij)ient bacilli are at the back of the eye, and each nerve fibre entering the eyeball from behind turns back upon the inner surfat-e and looks towards the bottom of the eye; that is, visifuj is dirifctcd backwards. This inversion of sight is a special characteristic of the vertebrate eye. THE COMPOUND EYE OF INSECTS AND CRUSTACEA. 27 And further, notwithstanding the differences of size, form, and position of the bacilli of the insect eye as compared with those of the vertebrate eye, an important agreement in respect to the physical character and molecular arrangement of their substance has been recently noticed by Schultze. The sub- stance of the vertebrate retinal rod has been discovered to be composed of matter having different refractive power, which is so disposed that the length of the rod is made up of discs piled on each other. Under favourable circumstances, a faint stria- tion of cross lines may be seen when the retinal rod is examined under the microscope and is in perfectly fresh condition. In the club-shaped swelling, and indeed throughout the length of the nerve fibre of the insect compound eye, a similar striation is readily seen (the insect rod being larger and thicker) ; but on no other nerve structure, as far as is yet known, does this pecu- liarity exist. The cross markings are solely due to the different refractive power of the alternate elements or discs by the super- position of which the rod is formed. The fact is especially important, as it promises a further clue to the explanation of the physical conditions of vision. Hitherto the optical image has always been considered the final point to which physical investigation could conduct us. But in the newly discovered properties and composition of the retinal rod (which has been of late years universally acknowledged to be the percipient ele- ment), a step further towards the physical analysis of visual phenomena seems to be gained ; namely, the mode in which physical impressions of light may be transferred to the perci- pient element. Between the physical impression of light and the actual sensation or sense of sight there will always probably remain a chasm which no physiological enquiry can ever bridge over. But it is possible to conceive a differential process in the transmission of light impressions which may serve to render our ideas of what is perceived and how perceived more in- telligible. And perhaps the perception of colour, to an explana- tion of which these newly discovered facts apparently point, may receive a better elucidation. If such hopes be fulfilled, it may fairly be inferred from the close analogy of the bacillar structure of the insect compound eye with the retinal rods of the vertebrate eye, that a similar perception of colour as well as form may be predicated of the insect as well as of man himself. We should be paying an ill compliment to the readers of the Popular Science Keview by offering any apology for the lengthy and minute details of the structure and function of the insect eye which we have here attempted. The day is passed when popular science was supposed to be acceptable only when it was superficial and unscientific ! 28 POPULAR S3IE^X’E REVIEW. EXPLANATION OF FIGURES. Plate XXXVII. Fig. }) yt tf 1. Section tlirougli the compound ,^eye of Libelliila : a, cornea, continuous with chitin shin of insect; b, layer of ‘‘bacilli” be- tween cornea and optic ganglion — radially disposed so as to converge from periphery to centre ; c, pigment investing inner ends of the bacilli which are continuous with nerve fibres of optic ganglion : d, optic ganglion. 2. Surface view of cornea of Libellula : showing facets (six-sided). The division into facets is marked by a deeper-coloured shade, which corresponds to a more pigmented and denser portion of corneal substance. 3. Cornea with subjacent stratum of “bacilli” of Libellula : a, the exterior corneal surface shows lenticular facets ; b, vertical lines indicating tlie division of corneal substance (through its thick- ness) into constituent portions corresponding in width to that of the facets on its surface ; c, pigment investing outer ends of “ bacilli ” (d) which are enclosed in sheaths (see fig. 4) ex- tending from inner surface of cornea to surface of op tic ganglion; c, pigment investing inner ends of bacilli. 4. Two bacilli, composed of sheaths of membrane enclosing nerve substance, the outer swelling of which corresponds to the “ crystalline body ” of authors. To examine the bacillar struc- ture under the microscope, solution of caustic potash must be used to dissolve the pigment. 5. Section across the bacilli (horizontal section), showing the circular outline of the sheatlis, which are coated with pigment. The clear lumen within is occupied by nerve substance of bacilli. G. Vertic.al section of cornea and bacillar stratum of Libellula : a, outside corneal surface (curved facets) ; 6, inner corneal surface forming a plane curve — vertical lines through the thickness of cornea between the “ corneules ” — horizontal lines are more faintly perceptible, showing a disposition of the substance in zones or laminm ; c, on the right side of fig, 6, the membranous sheaths are shown w’ith their contents — nerve and crystalline body ; d, on the left side the sheaths are shown empty. The outer and inner ends of three sheaths (the middle portion having been cut away in the preparation) are seen attached to inner conical surface and outer surface of optic ganglion ; c e, optic ganglion — a tracheal tube runs ccncentric with its outer border; /, fibres of optic nerve. 7. .Siinjde eye of Salticus icneus. Vertical section show'ing a, cornea and lens formed by thickening of laminm of conical substance ; b, zone of pigment round the lens ; c, choroid pigment ; d, the “corpus vitrium ” of J. Muller (the bacilli of Lcydig continuous with); fi, nerve fibrils ; /, retinal cells. Plaxe IZZ^/III TuiTer: v'Tcjst ac \V//er* irrn' CoTiiponiid Eyes of Insects. r % THE COMPOUND EYE OF INSECTS AND CEDSTACEA. 29 Fig. 8. Simple e}’e of Vespa crabra. Vertical section showing cornea and lens as above (a, b) } c, bacillar stratum j d, choroid pigment j e, retinal cells. Plate XXXVIII. 9. Section of portion of eye of craj'-fish — Astacus fluviatilis: cornea ; b, bacillar stratum ; c, optic ganglion. „ 10. Sections across a bacillum at different points in its length (see 1, 2, 3, 4, fig. 11); showing its four-lobed shape where it swells to form the “ crystalline body ; ” next in order, its cruciform shape in the middle ; its four-ribbed club-like expansion below ; and lastly, its simple round form where it pierces the pigment lying on the optic ganglion. „ 11. Shows in detail all the parts lying under a corneule in direct (radial) line to the optic ganglion. Astacus fluviatilis. a, corneal facet; slieath — on the inner wall are seen three nuclei adhering to it ; c, four-lobed enlargement (^^ crystalline body ”) continuous below with (d) the quadrangular nerve rod ; e, inner four-ribbed club-like swelling ; f, optic ganglion. „ 12. Shows the same details in eye of Herbstia condyliata ; a, b, c, d, e, f, as in former fig. ; four-lobed (nucleated) expansion of substance situate between the crystalline body (c) and club- shaped swelling below (e). „ 13. The same details in eye of Dynastes, letters as before. „ 14. Ditto ditto ditto Procrustes coriaceus ; a,b, c, d, e,f, g, as before ; j, fine tracheae lying inside the sheath. The red lines denote muscle fibrils within the sheath. „ 15. From eye of Mantis religiosa, letters as before. „ 16. Ditto Schizodactyla monstrosa, letters as before. „ 17. Ditto Syrphus; a, trachial tubes; b, c, d, e, as before. „ 18. Ditto Acridium coerulescens ; a, four-lobed crystalline body ; b, sheath— with pigment deposit ; c, nerve ; d, muscle fibril. 30 POPULAR SCIENCE REYIEW. TKUE AND FALSE FLINT WEAPONS. By N. WHITLEY, C.E. IIoN. Secretary to the Koyal Institution of Cornwall. IF we endeavour to trace backwards the history of mankind in Western Europe, we have to pass from the vividly written history of our own times, through the dimness which envelopes the fragmentary records of the earliest historians, to the dark- ness of improbable traditions and monstrous fables. But where written history fades away into fable, there archaeology steps forward with the materials for the construction of the history of an age of which no written records remain. The works of prehistoric man have been exhumed from peat bogs, sepulchral mounds, lake margins, caves, and gravel-beds ; and a flood of light has been thrown on the history of the past from these materials, more authentic than that which is written — more faithfully preserved than most of the manuscripts of antiquity. There is a fascination in the study of these monumental records which has lured us on to push our enquiries so far back into the past, that this additional light there also gradually fades away, until we reach the darkness which shrouds the study of liigh antiquity ; when doubts arise which have never been dis- pelled, and probably mistakes made which have yet to be rectified. Adopting for convenience the division of the stone period proposed by Sir John Lubbock, that of Palceolithic for the first stone age, embracing tlie chipped but unground implements from the Drift; and Neolithic for the second or more modern stone age, characterised by beautiful weapons and implements of polislied stone; we find the domestic history of the early races of man exhibited with much clearness throughout the whole of the Neolithic period. The barbed arrow-heads, the finely-chipped daggers, the ground axes and chisels, call for our a of Dxrkyer’s “ Le.'imjns in -Vstroiiomy,’' which presents the same relations. THE PLANET MAES IN FEBRUARY 1869. 41 It will be well in tbe first place to examine the exact relations which Mars will exhibit as respects the presentation of his polar axis towards the earth during the approaching opposition. A general impression can be obtained of his presentation by con- sidering the indications of my chart of the orbits of the four interior planets. But as some persons find it difficult to grasp with clearness and distinctness the results which follow when two globes like Mars and the earth have a certain relative position — that is, to gather how one of them would appear to an observer situated on the other — I have thought it well to calculate the exact presentation of Mars with relation to the declination circles and parallels of the celestial sphere, because the knowledge of this point enables the observer to at once interpret the meaning of his observations without reference to the hour of observation or to the position of the planet with respect to the horizon. The following table presents all that is necessary to be known respecting the presentation of the planet, at bi-monthly inter- vals. Here d is the apparent diameter of the planet; is the apparent angle at wffiich the northern extremity of the planet’s polar axis is inclined to a declination-circle (towards the east in the present case) ; and I is the angle at which the line of sight from the earth to the planet is inclined to the plane of the planet’s equator (this line being on the northern side of the equator in the present instance). P d 1 December 16, 1868 11-2 12 29 E. 24 33 X. December 31, „ 130 13 50 „ 24 26 „ January 14, 1869 14-6 13 36 „ 23 50 „ January 29, „ 15-8 11 28 „ 22 50 „ February 13, „ 164 7 39 „ 21 39 „ February 28, „ 16-8 3 52 „ 20 24 „ March 15, „ 14-4 1 18 „ 20 7 „ March 30, „ 12-8 0 37 „ 20 32 „ April 14, „ 11-2 1 9„ 21 36 „ Since the apparent path of the planet across the field of view of the telescope indicates the position of the declination- parallel, there can be no difficulty in interpreting these results, and thus assigning the spots seen in the planet to their proper position on the globe of Mars. Figs. 1 , 2, and 3 (PI. XXXIX.) indicate the presentation of the planet on December 16, February 13 (opposition), and April 24, respectively, as seen in an inverting telescope. They will assist in interpreting the table given above. It will be noticed 42 POPULAR SCIENCE REVIEW. that the darkened crescent .which indicates the gibbosity of the planet does not, either in fig, 1 or in fig. 3, correspond with the position of the planet’s polar axis. Since, in fig. 1, the outline of the dark hemisphere clearly passes nearer to the planet’s pole than the outline of the hemisphere visible to us, we are to infer that the polar axis of the planet is less bowed towards the sun than it is towards ourselves at the period to which this figure corresponds. On the contrary, at the period correspond- ing to fig. 3, the planet is less bowed towards the earth than towards the sun. Since the last opposition of Mars a good deal has been added to our knowledge of the planet. I will begin with less impor- tant, but not, I think, uninteresting considerations. It may be remembered that in dealing in these pages with the rotation -period of Mars, I spoke of the values assigned to this element by Madler and Kaiser — the former giving 24 h. 37 m. 23*8 s. and the latter 24 h. 37 m. 22*6 s. But, some time after my paper was written, I had occasion to examine a large number of pictures of the planet for the purpose of combining the information they afforded, and so forming a chart of Mars. This work had already been done by Sir W. Herschel, then by ^Messrs. Beer and Madler, and more recently by Professor Phil- lips; but it seemed to me that Mr. Dawes’ admirable drawings of the planet promised to afford a chart of greater completeness than any of these, and, as the views which he had taken ex- tended over upwards of twelve years, it was necessary, in order that they might be fairly compared inter se, and the identity of the various features of the planet fully made out, that the rotation-period of Mars should be determined with great ac- curacy. The discrepancy between the determinations obtained by Madler and Kaiser, and the uncertainty I was in respecting the relative accuracy of these two astronomers, led me to test their estimates. I found that, for intervals of several years, either value corresponded very closely with observed appear- ances. In fact, it will be seen at once that a difference of a second in a Martial day would correspond to a difference of less than 3G5 seconds, or six minutes, in a terrestrial year. But when longer periods were taken, Kaiser’s value quickly showed a marked superiority, and I was led, as I had antici- pated (Kaiser’s being the latest estimate), to find a very close agreement between this value and the observed appearance of the planet at intervals of fifteen, twenty, or even thirty years. This was, in fact, all I wanted, since, as I have said, Dawes’ drawings covered only a period of twelve or thirteen years. But having gone thus far, I thought it would be well to enquire how far Kaiw-r’s period availed to account for the rotation of Mars (luring longer intervals, especially as there were several pictures Plate XXXIX. Kg.3. Fig.l. Fi^.2 s Fi^.5. IJlustraiing suggested eocplunatiori of Mhrs' bright limb. THE PLANET MARS IN FEBRUARY 1869. 43 by Sir W. Herschel in the years 1775-1783, one or two by Maraldi early in the eighteenth century, and two by Hooke in the year 1666, which seemed sufficiently distinct to be available for the purpose I had in view. I found that Kaiser’s value did not bring these several views into accordance. For example, in a period of seventy-nine years, Kaiser’s value brought out a discrepancy corresponding to an hour’s rotation of the planet ; and when the full period of 198 years which separated the earliest of Hooke’s from the latest of Dawes’ drawings was examined, a discrepancy resulted which there was no mistaking. In other words, when the aspect of Mars was calculated back- wards from the date of one of Mr. Dawes’ latest drawings, with Kaiser’s value of the rotation-period, a result was deduced which differed wholly from the view given by Hooke in 1666. This result was confirmed later, when I was able to make use of a drawing of Mars taken by Mr. Browning with one of his eight- inch reflectors in February 1867. Here a period of 201 years was made use of, and it need hardly be said that, when once one has obtained a value so near to the true rotation-'period as to be certain of the exact number of rotations which have taken place in so long a period, the error affecting the value of a single rotation is very small. In the following table I present the results of calculations applied to three long intervals, viz. from March 12, 1666, 12 h. 20 m. (astronomical time and new style), in each case, to (i) April 24, 1856, lOh. 50m. (ii) November 26, 1864, llh. 46m. and (iii) February 23, 1867, 6h. 45m. ,* the drawings corresponding to (i) and (ii) having been made by Mr. Dawes, the one corresponding to (iii) by Mr. Browning. Int. Interval in Seconds Cor. for Geo. Long. Cor. for Phase Corrected Interval in Seconds Number of Rotations Resulting Rotation Period (ii) (iii) 5999524200 6270650760 6341394300 0° -248 -273 -12° 0 + 3 5999521246 6270589()96 6341326590 67682 70740 71538 88642'737 88642-734 88642-734 It results that Mars’ rotation period lies between 24 h. 37 m. 22*73 s. and 24 h. 37m. 22*74 s. Within these limits, this result may, I think, be depended upon ; because an error of one- hundredth part of a second in a single rotation would mount up to 715 seconds, or nearly a quarter of an hour in the long interval numbered (iii) ; and the appearance of Mars changes very perceptibly in a quarter of an hour. But I would call attention here to the absurdity of assigning 44 POPULAR SCIENCE REVIEW. to Venus, as is sometimes done, a rotation-period carried to the second decimal place of seconds. Thus Di Vico’s period, 23 h. 21 m. 23*93 s., is often spoken of as if it might be trusted to the last figure, and as a veritable triumph of astronomical accuracy of observation. But, as a matter of fact, this determination, founded as it is on a comparison of Di Vico’s observations in 1840-2 with those of Bianchini in 1726-7 (a period of 116 years), could not be depended upon to the last figure, even if it were certain that the exact number of rotations taking place in the interval is known. But this cannot be the case, since observations of Venus have not been made often enough in the interval to enable us to carry back our estimate over gradually- increasing periods, as we can in the case of Mars ; and, without this precaution, it is quite impossible to be certain that no rotation is missed in the long interval. Even in a short period of two years. Sir W. Herschel dropped a rotation in the case of Mars ; and Venus is so much more difficult an object, and the spots upon her are so little recognisable (especially where tele- scopes of different power have been made use of by the observers whose views are to be compared), that there is much more likelihood of a similar mistake being made in her case. My former paper on Mars was accompanied by a plate pre- senting eight ideal views of the planet as it was to be seen during the opposition then approaching. These views were formed from the study of eight drawings of Mars by Mr. Dawes in 1864-5. I believe the attempt was the first that had ever been made to forecast the physical aspect of a planet in this way. But I was not wholly satisfied with the charting of the planet, and iis I had it in view at that time to draw up a mono- graph on Mars, I ventured to apply to Mr. Dawes for tracings of a few* drawings taken when the planet was presented in other ways to us. With the kindness for which he was so remarkable, and which endeared him so much to all who became acquainted with liim, he immediately sent me ten or twelve drawings and afterw'ards searched through his note-books for others. In all, if I remember rightly, he sent me tw*enty-one drawings, taken in 1852 (a most valuable series in this year), in 1856, in 1860, and in 1862. The task of charting Mars from these drawings was not so easy a one as might at first sight have been supposed. Mr. Dawes had taken them at various hours, and there were no ready means of determining the position of the planet’s axis in each case. A tentative ]>rocess had to be gone through — for I was anxious that tlie charting of Mars should be independent of all previous efforts in that direction. Having calculated the presentation of Mars for the date of each drawing, I drew on tracing-paper the meridians and THE PLANET MARS IN FEBRUARY 18C9. 45 parallels properly presented (on the scale — in each case — of the corresponding drawing by Mr. Dawes). Then beginning with the most promising view I placed the tracing-paper over the picture of the planet, giving that position to the polar axis which corresponded most closely with the assigned position of the polar snow-caps. Then on a projection of the meridians and parallels of a globe on the equidistant projection, I drew in the lands and seas of Mars as they appeared under the meridian-lines on the tracing-paper. I next repeated the process for other drawings in which the same features were presented. At first there was. little accordance between the results thus pencilled on my chart-projection. This was caused by erroneous selections of the axial line of Mars, which — it must be remem- bered— does not correspond with the position of the polar snow- caps. But gradually I began to get over this difficulty and the views began to show a much closer agreement. Still there were slight discrepancies, and these, when reduced as much as possible by shifting the assumed position of the axis, I was obliged to ascribe to such slight errors as could not fail to appear in drawings so full of detail and taken under such circumstances of difficulty as were Mr. Dawes’ pictures. Therefore, having drawn in all the outlines deducible from pictures nearly ap- proaching each other in phase, I took a mean outline through the others to be as nearly as possible correct. It must be understood that the amount of Mars’ surface covered by one such series of processes would be very much less than a full hemisphere, since — firstly, the part of Mars near the limb was not drawn in so distinctly in Dawes’ pictures as the rest, and secondly, a small mis-drawing in an orthographic pre- sentation of a planet becomes much more important as we leave the centre of the disc, so that I did not consider myself justified in using those delineations which were not near the centre. It must also be remembered that as the drawings were not taken at periods separated by regular intervals of Martial time, it was very necessary to apply to each a correction calculated according to the true value of Mars’ rotation-period. Thus it will be understood that before the whole of the surface of Mars had been charted a considerable amount of labour had been given to the subject. Those who have never tried work of this sort would hardly be able to conceive how perplexing it often be- comes. But one circumstance was very pleasing. I found that the more carefully I worked at the chart, the more thoroughly the true value of Mr. Dawes’ drawinofs came out. I had had little conception, when I began the work, either of the acuteness of his vision or of the accuracy of his powers of deline- ation. The tracings he sent me were partially covered with faintly marked streaks which I had at first supposed to be 46 POPULAR SCIENCE REVIEW. merely random touches thrown in to indicate the general ap- | pearance of that part of Mars to which they belonged. But I j soon found that every one of these streaks was to be taken as the indication of a Martial marking which Mr. Dawes had actu- ally seen. The strange variations of figure which a spot on a globe undergoes when the globe is looked at in various directions, had prevented me at first from recognising the identity of several large markings. Mr. Dawes himself was not aware in some cases, that a spot which was presented with one figure in one drawing w^as in reality the same as one which appeared with a totally different figure in another drawing. But when due , account was taken of the effects of foreshortening, the almost i perfect correspondence between the different views, indicated at ; once the accuracy of Mr. Dawes’ drawing, and the permanence of the spots which mark the globe of Mars. The result was the construction of a chart of Mars containing a number of features which had not before appeared in works of the sort. In my Half-hours with the Telescope,” (Plate VI.) a small copy of the equidistant chart originally drawn by me i is presented. Fig. 4 (PI. XXXIX.) represents the same features on Mercator’s projection. If a series of tracings be taken from figs. 1, 2, and 3, and the features represented in fig. 4 be drawn in, according to the meridians and parallels of the re- | spective figures, the aspect of Mars as he will appear during the ^ present quarter will be deduced. Plate XL. represents eight views ! of Mars in opposition ; so that if Mars be observed on any night, ! say from February 3 to February 23, he will be found (if the ob- : server’s telescope be sufficiently powerful) to present an appear- ance resembling one or other of the views in this plate. A feature of the planet Mars which has recently attracted some attention has been incidentally noticed above. I refer to the whiteness of the disc near the limb. This phenomenon is : worthy of a careful examination ; and I believe that the true S explanation has not yet been put forward. In the first place it is to be remarked that this phenomenon is real and not merely apparent. The edge of Jupiter’s disc seems to be brighter than the central part, but is in reality darker. I believe ninety-nine observers out of a hundred woidd be deceived regarding this feature of Jupiter, if they trusted to the unaided eye. Why it should be so, is not perhaps Very easy to say. Perhaps the contrast between the dark back- ground of the sky jind the illuminated limb of the planet tends to give to the latter a brightness which does not belong to it. P)C this as it may, a series of observations which Mr. Browning has lately made on Jupiter, with the express object of deter- mining tliis (juestion, has resulted in placing the greater darkness of the planet’s limb, as compared with the central part of the Plate IL . TPe Pla.Ti et Max s , P ePr uaxy , 18 6 9. 'AVvYcgl liQi?-' ■f THE PLANET *MARS IN FEBRUARY 1869. 47 disc, beyond a doubt. He used darkening glasses perfectly gra- duated from end to end, and by this means was enabled to obtain the most accurate estimate of the relative brilliancy of various parts of the disc. But the greater darkness of Jupiter’s disc near the limb is what was theoretically to have been expected. An opaque globular body directly illuminated by a distant luminous orb should appear brightest in the centre of its disc ; because the real illumination diminishes as the angle at which the light rays meet the surface diminishes, and the apparent brilliancy at any point of an object is always equal to the real illumination at the point. In the case of Mars then, the apparent illumination of dif- ferent parts of the disc, varies in a manner which is directly the reverse of what was theoretically to be expected. Therefore, it behoves us to determine with so much the greater accuracy whether the eye may not be deceived in this as in the former case. I believe the experiment applied by Mr. Browning to Jupiter’s disc, has never been applied to that of Mars. But, fortunately, a series of photometrical experiments by Dr. Zollner, although not directed to the question we are considering, but to the determination of the total amount of light received from Mars at different epochs, yet affords a satisfactory reply to our doubts. For it will be easily understood that when a globe is not illuminated strictly according to the usual law — but, from some reason unknown, presents an anomalous variation of bril- liancy— the total amount of light received from it at different times will not correspond with the estimate deduced according to the usual law. For example: the moon’s light at full does not bear to the moon’s light at the quarter the proportion which would exist if the moon were a perfectly smooth globe, and therefore illuminated strictly according to the law mentioned above (in dealing with Jupiter), and by assuming — what is practically the case — that the illumination of the hemisphere of Mars turned towards the sun varies according to some law depending merely on the distance from the central point of that hemisphere, it follows that, by noting the amount of light received from Mars at different times — and especially by com- paring the amount received from him in quadrature, with that received when he is in opposition — it becomes possible to deduce the law according to which different parts of his disc are illumi- nated. For although when Mars is in quadrature his gibbosity is not very remarkable (see figs. 1 and 3), yet the true centre of the illuminated hemisphere is removed a considerable distance from the centre of the disc,* and the total illumination is there- fore affected in a remarkable manner by the planet’s gibbosity. * Its place is marked by a small cross ia figs. 1 and 3. 48 rOrULAR SCIENCE REVIEW. Accordingly, Zollner was able to estimate the anomalous illumination of various parts of Mars’ disc. He had already done this in the case of the moon, and had come to the conclu- sion that the anomalies in the lunar illumination (mean) are due to the existence of irregularities over the moon’s surface, and he estimated the mean angle of inclination of the slopes of the lunar mountains to be somewhat over fifty degrees. As- suming that the same explanation held in the case of the ano- malies of Martial illumination, he found that the surface of Mars must be covered with mountains having a slope of about seventy-six degrees. But this view is utterly untenable. We accept Zollner’s ex- planation in the case of the moon ; in fact we may almost say that it is obviously the true one. We can conceive no other cause available to produce the effect considered, and further we see that all over the moon there are mountains having very .steep sides. But in the case of Mars we cannot admit such an explanation because a large part of the surface of the planet appears to be covered with water, and because also, a slope of seventy degrees and upwards is outrageously steep. Mars ought to be covered all over with hills shaped like sugar-loaves to account for his anomalous illumination in the way suggested by Zollner. To us a far more natural way of explaining the difficulty seems to be the following. We have every reason for believing that clouds form over the surface of Mars as over that of the earth. Secchi, Dawes, Lockyer, and Browning, agree in de- scribing effects which can scarcely be due to any other cause. And besides we shall presently see that there is good reason for feeling absolutely certain that the vapour of water exists in large quantities in the atmosphere of Mars. Now, it would not be a very bold speculation to argue from the observed anomalies in the illumination of Mars, that clouds prevail much more towards morning and evening (Martial) than in the middle of the day. If this were so, it would, of course, follow that the parts of ^lars which as seen from the sun lie near the edge of the limb, would be much more brilliant than the rest. For they are the parts where it is morning or evening with the Mar- tialists ; therefore according to the as.sumption they are cloud- covered ; but clouds reflect much more light than the solid or lifiuid surface of Mars ; therefore these parts of the disc would seem proportionately more brilliant. But we are not even required to make such an assumption as tlii.«. For if clouds were pretty uniformly distributed over the whole surfiice of Mars there would still result a greater brilliancy of the limb. Consider fig. 5 for example. Here a fourth part of the circumference of iSIars is supposed to be illuminated by the sun on the left, and clouds are represented which are THE PLANET MARS IN FEBRUARY 1869. 40 arranged with perfect uniformity all round this quadrant. When the light falls between the clouds it is supposed to be returned after a considerable absorption, corresponding to the shaded • spaces. When it falls on a cloud it is supposed to be returned after much less absorption — that is, to remain much more brilliant after reflection, corresponding to the unshaded spaces. And it is at once seen that near the limb all the light is (in this imaginary case) derived from reflection at the clouds, whereas, near the centre of the disc, the larger proportion is derived from reflection at the real surface of the planet. There is nothing doubtful in the above explanation except the assumed existence of small' clouds — invisible separately to the naked eye. But this assumption seems at once more natural, and to explain the difficulty better than the sugar-loaves of Zollner. It may be, however, that when the sun is near the horizon of Mars, heavy mists hang in the air, as happens commonly enough with us both in the morning and in the evening. This would account equally well for the observed peculiarity. I should be glad to hear that any one armed with a telescope of adequate power had done something to test the climatic re- lations of Mars, and also the diurnal changes in the state of the Martial atmosphere. By noticing at what part of the disc the features appeared most distinct (allowance being made for real differences in the distinctness of the markings), something might readily be done in this way. The spectroscope also might be rendered very efficiently available in this inquiry. It has been already noticed by observers that the winter hemisphere is per- ceptibly less distinct on the whole than the summer hemisphere. For example, the features marked in the upper halves of the figures in Plate XL. may be expected to be less distinct than those on the lower. But then, as there are places on earth where the winter climate is drier than elsewhere, so it may be that parts of the winter hemisphere of Mars may be more dis- tinct than others. In considering diurnal changes account must be taken of the gibbosity of Mars at the time of observation, because, as we have said, the centre of the disc of Mars may be far removed from the centre of the illuminated hemisphere. Perhaps the most remarkable discovery yet made respecting the physical condition of Mars, is that contained in a communi- cation addressed to the Eoyal Astrouomical Society, by Mr. Huggins, early in the year 1867. From this paper I extract the following particulars. On several occasions during the opposition of 1867, Mr. Huggins was able to make observations of the spectrum of the planet’s light, or, to use his own accurate phraseology, “of the solar light reflected from the planet.” During these obser- vations he saAv groups of lines in the blue and indigo parts of VOL. VIII. — NO. XXX. E 50 POPULAR SCIENCE REVIEW. the spectrum. But the faintness of this part of the spectrum (lid not permit him to determine whether these lines are the same as those which occur in the same part of the solar spectrum, or whether any of them are new lines due to absorption under- gone by the light at reflection from the planet. He also detected (as in former observations) several strong lines in the red part of the spectrum, and it is to these that the chief interest of bis paper attaches. He saw Phaunhofer’s c very distinctly, and another line about one-fourth of the way from c tow’ards b. As the latter line has no counterpart in the solar spectrum it was clearly due to an absorptive effect produced by the planet’s atmosphere. On February 14, Mr. Huggins was able to detect faint lines on both sides of Fraun- hofer’s D. These lines occupied positions in the spectrum ap- parently coincident with groups of lines which make their appearance in the solar spectrum when the sun is low down, so that its light has to traverse the denser strata of the atmosphere. It remained however to show that these lines were produced by the atmosphere of Mars and not by that of our own earth. This Mr. H uggins efiected in the following manner: — The moon w’as, at the hour of observation, somewhat loww down than Mars, so that if the lines were due to the absorptive effects of our atmosphere, they should have been more distinctly marked in the spectrum of the lunar light than in that of the light from Mars. But when the spectroscope was directed to the moon these lines were not visible, thus conclusively proving that the lines were caused by the absorptive action of the Martial atmo- sphere. ^Ir. Huggins noticed in confirmation of this that the lines seemed more distinct in the light from the margin of the disc, but he was not quite certain on this point. This observation proves the presence of aqueous vapour in the atmosphere of Mars, since the lines in question have been showm to be caused, in the case of our atmosphere, by the vapour of water. From the spectroscopic analysis of the darker portions of the disc of ^lars, Mr. Huggins Wiis led to the conclusion that these pirts are neutral or nearly so in colour. Jle considers also that the ruddy colour of Mars is not due to the eftecta of the planet’s atmosphere. Indeed, this seems almost obvious when we consider that the polar spots look perfectly white, or at least show not the slightest tinge of red, tliough, being situated upon the edge of the disc, they should exhibit the effects of the atmosphere’s absorptive powers on the rays from the blue end of the spectrum, more strongly than the central parts of the disc, where the light has passed throtigh a much smaller range of atmosphere. Clearly w’e may look upon the red colour of parts of Mars as due to the nature of the planet’s soil. 51 ON THE MOLECULAK OKIOIN OF INFUSOEIA. By JOHN HUGHES BENNETT, M.D., F.B.S.E., Professor of the Ihstituxes of Medicine in the University of Edinburgh, &c., &c. REVIOUS to the time of W. Harvey, life was considered to be an independent principle capable of being added to, or removed from, inert matter. Such was the opinion of the ancient philosophers as allegorically explained by the fable of Prometheus, who animated the marble statue by fire stolen from heaven. But our modern view of life is, not that it is independent of matter but a condition of matter; in other words, that material substances, found in the atmosphere and in plants and animals, influenced by certain forces, have peculiar properties communicated to them. These properties are con- tractility, sensibility, the power of growth in certain directions and mental acts — the existence and exercise of any one of which constitute life. Harvey put forth the law omne vivum ex ovo ; and since his day the belief has been general, that animals and plants are de- rived from eggs or seeds ; that vitality is always transmitted, and never created ; and that, where these fundamental principles cannot be recognised, the minuteness of the germs and their wide diffusion throughout nature, and more especially in the atmosphere, offer a sufficient explanation of what may appear mysterious. Nature, it was argued, must be uniform in her operations, and analogy warrants our supposing that the same law of generation, which applies to the higher animals and plants, is equally applicable to the lower. In later times, Buffon imagined life, like matter, to be in- destructible. According to him every living molecule had a life of its own, and the method by which it manifested its func- tion depended on its association with other molecules. Thus, the body of an animal or a plant was the aggregation of a multitude of minute living beings arranged in a particular way. The death of the complex compound was simply a disso- lution of one of these associations, and the organic molecules E 2 o2 POPULAR SCIENCE REVIEW. thus set at liberty wandered about until they once more com- bined with a plant or animal — here with a monad, there with a (juadruped. The materia vitce diffusa of John Hunter was somethinor similar. Jn the present day physiologists, with the assistance of those powerful microscopes which opticians have placed in their hands, have traced the changes which ova and seeds undergo during tlieir development in a vast number of animals and of plants. In this way it has been established that some forms of animal life may be propagated without generation by parents. Such interruption in descent Owen has called parthenogenesis, from nrap6£vsla, virginity. Thus, two winged insects will produce an animal without wings, from which ten or twelve generations of individuals may be derived without a fresh act of conception, until the last in the chain gives forth another winged insect, when the process is repeated — as in the case of the aphis. Lastly it has been shown that the very lowest forms both of vegetable and animal life cannot be traced back to spores or ova. The law of descent, therefore, from parents, homogenesis, which we recognise in the higher organisms, changes as we de- scend in the scale, first to parthenogenesis, where this direct descent is broken, and ultimately to heterogenesis in which it is lost. It is to the last of these processes attention is directed in the present article. On making a cold or hot infusion of any vegetable or animal substance, covering the vessel with a piece of paper so as to exclude the dust, and then watching it every twelve hours, the first change visible to the eye is a slight opalescence, and the formation of a thin scum or pellicle that floats upon the surface. This appears at times, varying from a few hours to several days, according to the temperature of the atmosphere or the nature of the infusion. On examining the pellicle or film under hio-h magnifying powers, it is seen to be composed of a mass of minute molecules, varying in size from the smallest visil)le point to that of one thirty-thousandth of an inch in diameter, d'hese molecules are closely aggregated together, and must exist in incalculable numbers. They constitute the primordial mucous layer of Burdach,* and the proligerous ])ollicle of Pouchet.t The same pellicle, examined six hours later, shows the molecules to be somewhat enlarged, and these se])arated by the pressure of the upper glass are already seen here and there to be strongly adhering together in twos and f.mrs, so as to form a little chain. Many twos, also, have ap- }»arently melted together so as to form a short staff or filament — bode) lain (fig. 1, />). Twelve hours after this, it maybe • “ I’hysiologiR, par Jourdau,*’ tome ii. p. 12d. t ‘‘ lldteiojunie/’ p. ON THE MOLECULAR ORIGIN OF INFUSORIA. 53 seen that the grouping of the molecules in twos, threes, and fours has become more general, and that several of these form new groups of eight lengthways. Many of them have melted together to produce longer bacteria. At the edges of the mole- Fig. 1 . a h c d e Fig. 1. — a, Molecular structure of the proligerous pellicle on its first appearance in a clear animal infusion, b, Molecular structure of the same, six hours after- wards. The molecules have been separated, and several are seen grouped together in twos and fours. Some of these have melted together so as to produce bacteria, which exhibit a trembling movement, c, The structure of the proligerous pellicle on the second day, separated. The molecules are coalescing in rows and melting together to form longer bacteria or vibrios, which move rapidly across the field of the microscope. As their development proceeds, they present the appearance seen in d, and in fig. 2. e, Long filaments composed of adhering molecules. 800 diameters linear. cular mass, and in the fluid surrounding it, may now be seen a vibratile movement in the shorter bacteria and a serpentine movement in the longer ones, whereby they are propelled for- wards in the fluid — vibrio (fig. 1, c, d). From the second or third to the fifth or seventh days, the vibrios are lengthened, evidently by apposition of groups of other molecules, to their ends. These melt together to form a filament, which may ex- tend a third or half, and in a few cases entirely across the field of the microscope (fig. 2). Fig. 2. Fig. 2. — a, Vibrio with a serpentine movement, h. Vibrio with one flexure, evidently formed by the union of two bacteria, c, Elongated vibrio with one flexure, the area of the movement marked by a dotted line, d, An elongated vibrio, not moving ; a bacterium evidently added at one extremity, e, An elongated vibrio with two flexures, moving rapidly across the field of the microscope. An observation of these vital structures evidently indicates aggregations of bacteria and vibriones of a certain length endways, the flexures occurring at the points of junction. 800 diameters linear. The movements visible in the molecules and filaments vary according to the amount of development. At first those v/hich float loose in the fluid exhibit gyrations which cannot be dis- tinguished from Brunonian movements. When short bacteria are seen these exhibit peculiar vibrations^ — often turn round 54 POPULAR SCIENCE REVIEW. on their own axis in various directions, and slowly change their place. They rarely dart rapidly through the fluid, or exhibit a serpentine motion. But when the vibrio is formed, the fila- ment is pushed forward with greater or less velocity, at first presenting a wriggling, but, as it becomes longer, a more decided serpentine motion. A distinct flexure can be se'en at certain points in the filaments, between the groups of molecular chains or filaments. Dumas says he has seen the molecules and bac- teria uniting endways, a statement the correctness of which Pouchet doubts.* On two occasions, however, I was fortunate enough to see this occurrence as represented in the accompany- ing figures. (See figs. 3 and 4.) The reason this actual union Fig. 3. — a, Position of two short bacteria, h, The lower bacterium was seen to sink down and unite itself to the upper, and then the two turned round in unison, as in 0 and d. Fig. 4. — a. Position of two bacteria, h, Altered position of the same, c, The lower one adhering to the upper, d, The two turning together to e. f, Vital flexure at the middle ; and g, four flexures, when I saw the vibrio so formed move forward out of the field of the microscope. 800 diameters linear.. has so seldom been seen is, 1st, That it only occurs at certain periods of development, and can only be followed by the eye, when the movements are slow ; 2nd, That amidst such a multi- tude of minute moving bodies it requires a long time before two can be found exactly on one plane, and can be brought so accurately into focus that they can be watched for a sufficient time. Having, however, in the two instances described and figured, actually seen the coalescence, I can have no doubt what- ever that such is the true method of elongation. It may frequently be observed, on again examining the fluid in which these bodies have been moving actively, that they are all motionless, evidently dead. This occurs at various periods. They now rapidly disintegrate, and thus a second molecular mass or pellicle is produced. In this, rounded masses may be seen to form, which strongly refract light not unlike pus cor- puscles, or the colourle.ss corpuscles of the blood. These soon begin to move with a jerking motion dependent upon a vibratile rilium attached to one of their extremities — Monas lens. In a day or two other cilia are produced, the corpuscle enlarges, is nucleated, and swims through the fluid evenly. Varied forms Fig. 3. Fig. 4. a b c d e f g abed * “Nouvelles Experiences,” p. 115, ON THE MOLECULAH OEIGIN OF INFUSORIA. 55 may now occur in the molecular mass, dependent on the tem- perature, season of the year, exposure to sun-light, and nature of the infusion, all having independent movements. They have been denominated Amcebce., Paramecia, VortiGellce, Kolpoda, Keronce, Glaucoma, Trachelius, etc., etc."* Pouchet describes the Paramecium as originating in the pro- ligerous pellicle, formed by the breaking down of the primary bacteria and vibriones. It is the secondary histolytic mass of molecules which arrange themselves as seen in fig. 5. Fig. 0. Formation of Ova in the 'proligcrous Membrane. a. Coalescence of molecules, h, The same more advanced, c, Still larger mass. d, The same assuming a rounded form, e, A membrane formed externally, f Complete differentiation of the now perfect ovum from the surrounding molecular mass, g, A nucleus apparent. — Fouchet. 250 diameters. It would occupy too much time to follow the development of all the forms that may arise. They always originate long after the primary vibrios are produced, in the secondary, tertiary, or even later molecular masses, resulting from the disintegration of previous forms. It frequently happens that soon after some of these higher infusoria are seen, that the pellicle falls to the bottom of the fluid, where it constitutes a dense precipitate, and slowly breaks down ; then another scum forms on the surface, and molecules, bacteria, and vibrios are again produced. The varied forms produced are spoken of by Ehrenberg and other naturalists as being different species but I think it will t Ibid. See Ehrenberg’s “Infusoria.’’ 56 POPULAR SCIENCE RE HEW. be found that the laws, not only of molecular but of alternate generation and parthenogenesis, prevail among them, and one frequently passes into another. Their production is largely dependent on temperature, state of the atmosphere, light — especially the sun’s rays — and other physical conditions. At other times, it happens that the molecular mass, instead of being transformed into animalcules, gives origin to minute fungi. In this case the molecules form small masses, which soon melt together to constitute a globular body, from which a process juts out on one side. These are Torulo3, which give off buds which are soon transformed into jointed tubes of various diameters, terminating in rows of sporules {Fenicil- limn), or capsules containing numerous globular seeds (Aspei^- (jillus). Occasionally filaments are formed from the direct melting together of molecules arranged longways {Leptoikvix), (See fig. 1, e.) Here also I think various forms regarded as distinct plants pass into one another — especially torulse, which are only em- bryonic forms of higher fungi. In all these cases no kind of animalcule or fungus is ever seen to originate from pre-existing cells or larger bodies, but always from molecules. That we should sometimes have animalcules, and at others fungi, is a well-known fact, the exact causes or conditions pro- ducing which are not yet explained. The Panspermatists, of course, are of opinion that the germs in the atmosphere are of many kinds, and that as they fall into various infusions they produce different results, in the same manner that varieties in ova or seeds develop themselves in peculiar localities or special soils. This assumption, however, seems to me opposed by the following experiment: — If an infusion be placed in a deep glass vessel, which again stands in the centre of a shallow vessel containing the same infusion, and the whole covered with a large bell glass, it will 1)0 found in eight da3^s that on the surface of the former are numerous ciliated animalcules, while on that of the latter only bacteria and vibrios exist. The experiment may be reversed, for if the shallow vessel be filled to the brim, and the deep vessel has only its bottom covered, then the ciliated microzoa will appear in the former, and the non-ciliated in the latter.* It is difficult to explain how germs falling from the air on the same infusion, under identically similar conditions, with the exception that the fiuid is in vessels of different forms, can vary the results. Whereas the fact that the higher infusoria are formed secondarily out of the disintegrated mass of the simpler • Pouchet’s ‘^Xouvclles Expdneuces,” &c.,‘ pp. 135, 243-245. Paris, ON THE MOLECTJLAH ORIGIN OF INFUSORIA. 57 ones, which can only take place where that mass is considerable and floating on the surface of deep fluids, directly confirms the molecular theory of growth, and offers an illustration of how successive disintegrations give origin to different formations.* I That the infusoria originate and are developed in the mole- cular pellicle which floats on the surface of putrefying or fer- i menting liquids, has been admitted by all who have carefully I watched that pellicle with the microscope, more especially by 1 Kutzing,f Pineau, J Nicolet,§ Pouchet,|| Jolly and Musset,^ ; Schaaffhausen,^* * § and Mantegazza.ff The question therefore is, I are the molecules that constitute that pellicle derived from the air or the fluid — are they precipitated from above, or do they float to the surface from below, like the globules of the milk : which produce cream ? Now, it was in consequence of having professed to demonstrate what had escaped all previous observers — viz. the germs in the air — that M. Pasteur has made his name so famous. He tells usj{ that he did so by causing a current of air to pass through a glass tube in which a pledget of gun-cotton had been placed. This was then dissolved in ether, and the sediment allowed to i collect in a watch-glass. This sediment, after being repeatedly I washed, and allowed to remain in distilled water for twenty-four , hours at a time, is allowed to dry. A portion of the dried matter is then put upon a slide moistened with a weak solution ! of potash, and, being covered with another glass, is examined with the microscope. The results he has figured ; and, very . properly, he has given the scale of magnifying power under which they were drawn (fig. 10), and which, by careful measure- ment, I have ascertained to be 180 times linear. These are his drawings, carefully copied. He says figs. 6 and 7 represent organised corpuscles from dust collected in twenty-four houis, from November 16 to 17, 1859. The manner in which the.e drawings, giving tLe volume and outline of the bodies, were made, is as follows : “ After the dust has been prepared in the manner described, 1 took a por- * See On the Molecular Theory of Organisation/’ hy the Author. “Proceedings of Koyal Society of Edinburgh/’ 1861. t See Schaaff hausen, “ Comptes-Rendus/’ tome liv. p. 1046. t “Annales des Sciences Naturelles,” 3me serie, tome hi. p. 182. This observer thinks he saw disintegrated fibres of meat and of other substances formed directly into vibriones ; in this he was incorrect. § “ Arcana Naturae/’ tome i. p. 2. II “ Heterogenie/’ p. 353. “ Nouvelles Experiences,” p. 111. ^ “ Comptes-Rendus,” tome 1. p. 934. ** Ibid, tome liv. p. 1046. tt “ Institut Lombard,” 1852, tome iii. Jt “ Annales des Sciences Naturelles,” 4me sdrie, tome xvi. p. 25. 58 POPULAR SCIENCE REYIEW. tion of it from the watch-glass, and diluted it with a solution of potash, co.jsisting of 5 parts of potash in 100 of water. As soon as I perceived a globule evidently organised under the microscope, I drew it. This is how fig. 4 was drawn.” * This description leaves it uncertain whether an exact copy was taken of any portion of the field of the microscope, and, therefore, wliether the figure represents the exact number of corpuscles present, and their relation to each other. It only gives their Fig. 6. Fig. 7. Fig. 8. Fig. 9. Fig. 10. Exact copies of the figures given by M. Pasteur of tlie dust he collected on gun- cotton, magnified 180 diameters. These should be compared with fig. 1, magnified 800 diameters, showing what is seen to take place when infusoria are forming. Fig. 10, scale of one-hundredth of a millimetre. form. But, assuming that the same kind of demonstration was made in each case, we have the relative numbers of these bodies taken from the gun-cotton in fig. 6. Fig. 7 is another demon- stration of the same after the addition of an aqueous solution of iodine. Fig. 8 represents the organised corpuscles associated w’ith amorphous particles obtained on June 25 and 26, 1860; fig. 9, the dust of an intense fog in the month of Feb- ruary 1861. In all these demonstrations he admits the organ- ised corpuscles are comparatively scarce, because, he observes (p. .31), it is frequently necessary to change the field in order to see one of them, whilst at other times several could be seen together. M. Pasteur thinks that these drawings indicate the number of organised corpuscles that may be arrested in a small mass of cotton through which 1,500 litres of air, in one of the less- frequented streets of Pari.s, have passed in twenty-four hours, about three or four yards from the ground. These he estimates at several millions in a btre (p. 29). Now, it must 1 e remembered that M. Pasteur is a chemist, and it will be admitted by every histologist that no method could be more unsatisfactory for determining either the nature or the number of the corpuscles than the one he adopted. The solution of the cotton in ether, the freipient soakings in water, ti e defecation, and then the addition of a solution of potash, must completely alter the character of any living corpuscles in * Annales dee Sciences Naturelles,” 4me sdrie, tome xvi. p. 25. ON THE MOLECULAR ORIGIN OF INFUSORIA. 59 the atmosphere. Then the forms he assumes to be organic, are not necessarily so. They are exceedingly frequent among mineral substances, and siliceous rounded forms are common, which of course resist sulphuric acid. Numerous investigations have been made, both before and since M. Pasteur wrote, to determine the nature of dust floating in the atmosphere — of that dust, for example, which a ray of sunlight reveals to us, when admitted into a chamber. It con- sists, for the most part, of different kinds of starch corpuscles ; the debris of clothing, especially filaments of cotton, silk, and wool ; the results of different kinds of combustion, wTiether of coal or of wood ; various mineral bodies, globular or ovoid, amorphous or crystalline ; and minute fragments of insects and vegetables ; very rarely small seeds and microscopic animal- cules. These constituents vary to such an extent in different locali- ties, as to enable the observer, in some cases, to determine whence the dust was collected. Starch corpuscles abound in the neighbourhood of flour^mills and bakeries ; fragments of clothing where there have been crowded assemblies of persons, cotton and wool being predominant if the persons belong to the poorer classes, and silk if the upper classes have been present ; the products of combustion predominate in smoky localities ; mineral particles on the roads and highways ; seeds, fragments of vegetables and insects, in market places, gardens, &c., &c. But although these constituents of the air vary in different places, infusoria, produced in all of them, are identically the same.* This has been tested in various ways. The dust has been ransacked to discover organic germs — collected and carefully examined with the microscope, near the soil, and on the sum- mits of the highest buildings, not only in frequented, but in desert places ; in crowded assemblies, as well as in empty Grothic cathedrals and ancient vaults — in the ancient palace of Karnack, on the banks of th^ Nile ; in the tomb of Ehamses II. at the extremity of the Desert ; as well as in the central cham- bers of the great pyramid of Grhizeh. The chief element of the dust collected in these places has been found to be starch cor- puscles.f Large quantities of air have been drawn through tubes by aspirators, and collected on cotton, in distilled water, or projected on glass. The feathery snow, which, falling through the atmosphere, may be well supposed to collect its contents, has been melted, and the precipitate carefully collected. The emanations of marshy places, such as those of the Maremma in * Poucket’s Nouvelles Experiences/’’ p. 73, et seq. t Pouchet’s Heterogenie,” p. 446. f)0 POPULAR SCIENCE REYIETV. Tuscany, have been specially investigated.* The larynges and mucous pulmonary surfaces of numerous animals have been explored, even to the inmost bone cavities of birds. On the summit of Mont Blanc, amidst eternal snow ; on the glaciers of the Jura and of the Pyrenees, and in the deep crevasse ;f on the burning plains of Egypt, and in the markets of Constanti- nople, the dust of the atmosphere has been microscopically examined, and in all with a like negative result as to the existence of germs. Nowhere could they be seen, nor if a few, in the opinion of some, were visible, could they in any way account for the multitude of minute infusoria, which, in all these localities, not only readily spring up in putrid fluids, but in every instance are identically the same.| Indeed, on examining the drawings of M. Pasteur (see figs. 6 to 9), let us suppose that the few bodies he has figured are truly sporules, as he believes them to be, which have preserved Fig. 11. 1. 2. 3. 4. 5. 6. if? I o OO CID CJTZ) COGQQ^ Stages in the Development of Vibriones. 800 diameters linear. their form — after the action of ether, several soakings of tweLty- four hours each in water, the desiccation, and subsequent mix- ture with a weak solution of potash. How, it may be asked, could these bodies produce the incalculable millions of minute molecules in the smallest fragment of the pellicle we can transfer to our microscopes, in which, as we have seen, the infusoria ori- ginate ? It has been supposed that, on falling from the air, they undergo rapid division, and spread over the surface wuth the greatest rapidity ; but no one has ever seen this remarkable phe- nomenon, and the slightest consideration must show that such an assumption is completely adverse to what can be readily de- monstrated on the surface of every infusion. Thus, there can be no doubt that the minutest molecules are formed first, and the bacteria, vibrios, and filaments, last. Supposing that the primary molecules, figured No. 1, in Fig. 11, enlarge to a certain point. No. 2, and then divide, how is it possible to explain the forma- tion of elongated filaments at all ? Surely the idea of their rapid multiplication by division is opposed to that of their power of elongating into bacteria and vibrios, whether by aggregation • L. rjigot’s “ Dechorches exp^rimentales sur la Nature des Emanations Tnarerageuses.” Tari.s, 18/59. “ Reclierches sur FAir des Maremmes de la Tosoanc,” par M. E. Bcchi. “ Comptes-Kendus,” tome lii. p. 862. + “ Comptes-Rendua,” tome Ivii. p. 668. X “ Nouvelles E.xpdiienccs,” p. 76. ON THE MOLECCLAR ORIGIN OF INFUSORIA. 61 or growth from their extremities. It may frequently be seen that No. 3 is composed of molecules of exactly the same size as No. 2, which are floating loose — a fact in favour of their coale- scence rather than of their division, as then they would be re- duced to half the size. It is more probable that although the smaller molecules may increase by imbibition of fluids, they have yet a constant tendency to aggregate together and melt into one another. No. 3 is not a proof of No. 2 dividing, but of two molecules coalescing; and when they unite, they form No. 4. Two or more of these uniting, form Nos. 5 and 6. When a similar process to this goes on in mineral bodies, as shown by Mr. Eainey, * it cannot suggest division, but union ; and this for the obvious reason, that the former would lead to disintegration, whereas, it can be seen in one case as in the other, that develop- ment is the result. In short, in the same manner as a tube is formed by a coalescence of cells, so is this minute vibratile vibrio formed by the coalescence of molecules. It may be argued, however, that each molecule elongates itself — that is. No. 2 is converted into No. 4; this into Nos. 5 and 6 ; and that No. 3 are sporules or ova, caused by the disintegration of No. 6. But this view is opposed by the fact that Nos. 1, 2, and 3 are seen before Nos. 4, 5, and 6 are produced. Of this all have satisfied themselves who have examined animal and vegetable infusions ; and the conclusion, therefore, cannot be resisted, that the vibrios are derived from the molecules, and not the molecules from the vibrios. But it may also be supposed, that while some have the pro- perty of dividing, others are capable of elongating or aggregat- ing ; but this view is not only opposed to observation, but is at variance with all that we know of embryonic development in plants and animals. When a plant consists of a single structural element, such as a cell or a tube, it will, I think, be admitted that growth in the sense of increased bulk, and growth in the sense of multiplication of parts by division, do not proceed at the same moment of time. Every plant and animal follows, in this respect, the same law. Nutrition is carried on up to a cer- taTn point of maturity, and then, and not till then, does gener- ation, or the separation of parts to form new creatures, take place. When plants and animals are complex in their structure, one organ or segment may be growing, while another is disin- tegrating; but in individual organs there is a period for growth and reparation, and a period for division or separation. Hence, it seems to me, I am correct in thinking that if the piimary molecules on the surface of an infusion possess the property of dividing, they cannot also, at the same moment, possess the * On the Mode of Formation of Shells/’ &c., p. 12. 8vo. London 1855. 62 rorULAR SCIENCE REVIEW. property of elongating and forming filaments. The one func- tion is subversive of the other. While, then, a cell or a vibrio may possess the property of growth and division, these two functions must be exercised at different periods of time — so that, in reference to the early stage of- formation, if the mole- cules divide, bacteria, vibrios, and filaments could not be formed. A mass of vibrionic molecules is not a compound organism ; it is a mere aggregation of similar simple elements. Each of these in passing through certain phases of development may be arrested, or reach maturity at various periods, so that we fre- quently see different forms present at one time ; but that the same forms and the same stages of growth should exhibit di- rectly opposite functions, is surely not in accordance with phy- siological knowledge. The conclusion we must arrive at therefore is, that the mole- cules seen on the surface of infusions out of which animalcules and fungi are produced, are not derived from the air. Neither can they be supposed to pre-exist in the fluid, as then they would be readily seen, which they never are at the commencement. On this point nothing can be clearer than the microscopical evidence, so that it results from the facts and arguments which have been stated, that the more simple in- fusoria do not originate from cells or minute germs at all, whether in the atmosphere or in the fluid. This is the almost universal conviction of histologists who have carefully investi- gated the matter. Again, it is almost universally considered that the heat of boiling water or cold at zero will destroy all kinds of animal and vegetable life. Indeed, to imagine that the minute mole- cules or vibrios of which we have been speaking, or small ova and sporules consisting of oleo-albuminous matter without any envelope, would remain in boiling water for hours and retain their vitality, must be regarded as a violent assumption. Three or four- minutes’ boiling of a hen’s egg not only kills it, but converts its whole substance into a hard mass. There is no seecrirnent : An open fhisk was plunged into and filled with a • See some conclusive experiments recently performed on this subject by Meunier. “ Comptes-Itendus,” tomelxii. p. See filso Pouchet’s ^‘Ex- p<,*rimentH on the Seeds of Medicago from Brazil.” Coinptes-Kendus,” tome Ixii. p. 041. ON THE MOLECULAR ORIGIN OF INFUSORIA. 63 decoction of barley which had been boiling for six hours. A stopper was introduced into it below the liquid, and on taking it out the whole neck of the flask was immediately plunged into melting sealing-wax, and hermetically closed. In six days some yeast was observed in it, at a temperature of 18° cent. The following day the temperature was raised suddenly to 27°, when the flask burst, and then it was seen by the naked eye, and by the microscope, that it contained a notable quantity of yeast.^ Now, yeast is a plant, which was thus proved to have grown in an infusion that had long been boiling, and from which all atmospheric air had been expelled. As, therefore, neither calcined air, sulphuric acid, liquor potassse, gun-cotton, or a boiling temperature have failed to prevent the production of infusoria, or destroy the supposed germs in the air or infusion, I determined, in 1863, to try the effects of all these destructive agents, with the exception of the first, at once, and with the greatest possible care. The results of numerous experiments carried on in this manner and varied in many ways demonstrate that when nothing but air, exposed to and filtered through agents most destructive to animal and vegetable life, is brought into contact with organic liquids, in- fusoria are still produced. It is now admitted by M. Pasteur that the boiling tempera- ture, that is, 100° centigrade, does not prevent the growth of the supposed germs in the atmosphere; but instead of consider- ing this fact hostile to his theory, he concludes from it that the germs have the power of resisting that amount of heat, and of being most tenacious of life; but he says 130° centigrade always destroys their vitality. M. Pouchet, however, has shown that the air, and the organic matter when placed in boiling w^ater, will germinate after they have been exposed to a heat of even 150°, and he says it may be raised to 200° centigrade, and yet animalcules and fungi will develop themselves.f In the same manner, air and infusions exposed to intense cold still produce animalcules, but, according to Pasteur, not so readily. Twenty flasks containing boiled infusions, and from which the air was expelled, were opened by him with excessive precaution on the Mer de Glace at Montan vert on the Jura. Notwithstanding the purity and extreme coldness of the air infusoria appeared in five of his flasks. As an illustration of the manner in which the controversy on this subject has been carried on in the Imperial Academy of Sciences in Paris, I may give a short account of that portion of it referring to the Glacier experiments. MM. Pouchet, Jolly, and Musset opened eight similar flasks used by M. Pasteur at * Heterog(^nie,” p. 629. f Comptes-Reudiis,” tome 1. p. 1015. 64 POPULAR SCIENCE REVIEW. Moiitanvert, on the Glacier of the Maladetta, in the Spanish Pyrenees, 9,000 feet above the sea, and 3,000 feet higher than that of Montanvert, using all the precautions required by M. Pasteur. In addition, before cutting off the ends of their her- metically sealed tubes with a file, previously heated by a lamp, they held the flasks above their heads. Notwithstanding, in- fusoria appeared in all the infusions a few days afterwards.* To this communicaticn, presented to the Academy, Sept. 2l, 1863, iSI. Pasteur replies, Nov. 2,f saying that he is rejoiced that his learned adversaries have gone to such an altitude to repeat his experiments ; but observes that they did not take the necessary precautions. They only had eight flasks, whereas he had twenty ; they shook their flasks before opening them, which he took care not to do ; and they had the imprudence to use a file instead of a pair of pincers with long bi’anches, heated in the flame of a lamp. He says that the thumb and fingers holding the file were too near the opening into the flask, and may have conveyed germs there, especially as they were not passed through the flame, as the file was.i He defies them, if they take sufficient precautions, to obtain infusoria in all their flasks.§ MM. Jolly and Musset accept the defiance of M. Pasteur, Nov. 16,11 in fact, on the 13th of June following, they send a memoir to the AcademyJ stating that they had returned to the Maladetta, this time with twenty-two flasks — that is, two more than were used by M. Pasteur — fulfilled all his conditions, not forgetting the yjincers with long branches, properly heated, and found that infusoria appeared in every flask without excep- tion in four days ;1[ and so ended this part of the controversy. The only conclusion I can draw from the numerous contra- dictory and ingenious communications presented to the Academy of Sciences during the last eight years on this matter is, that not the slightest proof is given by the chemists, with M. Pasteur at theii-»head, that fermentation and putrefaction are necessarily dependent on living germs existing in the atmosphere. They rather tend to show that these are phenomena of a chemical nature, as w;is ably maintained by Liebig.** We must conclude, therefore, that living germs are not necessarily the cause of putrefaction and fermentation; neither is it necessary to believe that ferments are living at all — they may be dead. This, if not admitted, seems to be implied by Pasteur himself, who tells us he can now excite these processes, not by fresh yeast only, but ♦ “ t ’omptf*8-Kei)du8,” tome Ivii. p. f Ibid. p. 724. * Ibid, p, 72/). § n»id. p. 720. II Ibid. pp. 842-84/), ^ Ibid, tome Ivi. p. 1122. “ Letters on Chemistry/’ letters 18 and 19. ON THE MOLECULAR ORIGIH OF INFUSORIA. 65 ' by the ashes of yeast.* That they may be induced by dead ' organic matter, which has been subjected to a direct tempera- j ture of 150° or 200° centigrade — a heat utterly incompatible I with the existence of life — we have seen to have been proved by Pouchet, Jolly, Musset, and others. Whilst, then, the chemists have entirely failed in proving their case, the micro- scopical evidence is wholly opposed to the existence of atmo- , spheric germs. I The idea that these imaginary germs were the cause of putre- , faction, of disease, of blights among vegetables, and other evils, ' originated with Kircher and the pathologists of the seventeenth I century. It has been frequently revived, but always shown to 1 be erroneous. In 1852, cholera was supposed to be occasioned j by a fungus that really existed in the dejections, but which Mr. Busk pointed out was the uredo segetum of diseased wheat, which entered the body in the form of bread. Certain well- known parasitic diseases are spread by contact, such as scabies, which, as it depends upon an insect burrowing in the skin, may be understood to crawl from one person to another. Favus, or scald head, which consists of a parasitic plant growing on the scalp, also, I succeeded, in 1841, in proving might be commu- nicated to otherwise healthy persons ; f but many of our un- questionably infectious diseases, such as smallpox, scarlatina, measles, and typhus, have no such origin. It has been attempted to be proved, indeed, by Lemaire,| that in the condensed vapours of hospitals and other putrid localities, vibrios may be found ; but that vibrios are the cause of these various diseases, is not only not proved, but from what has been stated, is highly improbable. What, then, it may be asked, is the origin of the infusoria, vegetable and animal, that we find in organic fluids during fermentation and putrefaction ? In answer to this question, I answer they originate in oleo-albuminous molecules, which are formed in organic fluids, and which, floating to the 'surface, form the pellicle or proligerous matter. There, under the in- fluence of varied conditions, such as temperature, light, chemical exchanges, density, pressure, and composition of atmospheric air, and of the fluid, &c., the molecules, by their coalescence, produce the lower forms of vegetable and animal life. Hallier, describing the development of Penicillium crusta- ceum, tells us that, after all movement in the primary molecular mass has ceased, the molecules arrange themselves in long lines, which he calls Leptothrix chains (fig. 1, /). From the melting * Comptes-Bendus,” tome Ivi. pp. 418, 419. I t See the Author’s paper on Parasitic Fungi, — Trans. Royal Society of I Edinburgh, 1842.” X Comptes-Rendus,” tome lix. pp. 317-428 VOL. VIII. XO. XXX. F POPULAR SCIENCE REVIEW. together of these, the delicate filaments forming Leptothrix biiccalis are evidently produced ; and these, according to him, by further development, pass into Penicillium crustaceum, AVhy the molecules should sometimes arrange themselves in long rows, and at others into rounded masses (compare fig. 1,/ and fig. 5, a), is probably dependent on varying degrees of limpidity and viscosity. But why both these forms of molecular matter should sometimes possess an inherent power of contrac- tility, and at others not, it is impossible as yet even to surmise. But, on the determination of this point, the variations existing between the different kinds of fermentation and putrefaction are evidently dependent. 67 REVIEWS. PKOFESSOE OWEN’S ANATOMY.* EOE more than two years we have waited patiently for the appearance of the volume completing Professor Owen’s treatise on Vertebrate Ana- tomy, and now that it has been issued, we must confess to being disap- pointed with it as a whole. We do not mean to imply that the book which is now before us is inferior to those which have preceded it, or that it is devoid of value or interest. But we had expected to find in it that the author had done justice to those fellow-labourers in the field of science whom he had previously overlooked or misinterpreted, and we are sorry to see that our anticipations have been unfulfilled. Nay, more than this, we find the author still ignoring the labours of our ablest anatomists, still slurring over the grave objections that have been urged against his views, and still indulging that bitter invective and that caustic sarcasm which we are accustomed to look upon as indisseverable from his writings. Further, indeed, we perceive that he has gone out of his way to expend his vituperative powers in a most unfair attack upon ourselves, because, in €ommon with the London Reviewer,” we were the first to show that he not only admitted the fact-basis of Mr. Darwin’s theory, but even went so far as to lay claim to being the originator of the theory itself. It would be needless to attempt now any justification of the course we then adopted; the mere fact that in the last edition of his Origin of Species ” Mr. Darwin fully recog- nises our position is quite sufiicient for us. If further explanation were required, it would be found in the very attack to which we refer, since Professor Owen’s remarks, when divested of that obscurity characteristic of his singularly verbose mode of expression, adequately support the belief which we still contend for, that Professor Owen has admitted all facts on which the theory of natural selection is based. It is for the above rea- sons, then, that we confess our disappointment. In an analysis of the portion of the volume devoted to anatomical considerations we shall be as brief as possible, avoiding quotation because of the author’s wordy mode of description and inexact and tedious style. The third volume continues the subject of mammalian anatomy dealt within the second, and treats upon the nervous, circulating, respiratory, alimentaiy. * “ The Anatomy of Yertebrates,” Vol. III., Mammals. By Richard Owen, F.R.S. London : Longmans, 1868. 68 POrULAR SCIENCE REVIEW. tegumentary, and generative systems, the subject of development being in- cluded under the last head. Besides the various chapters in which the anatomy is treated upon, there is a final chapter, in which Professor Owen lays down general conclusions, of wide range of application, of considerable interest, and in some instances of no little irrelevancy to the subject- matter of the work. Throughout the volume there is of course little that is new, seeing that the author has had to deal with points of structure already described in his various memoirs and communications to learned bodies. But there is even less of reference to recent researches than we had a right to expect from the Superintendent of the natural history depart- ment of the first scientific institution in the kingdom. Of all the anatomical chapters, that on the nervous system is, from its numerous associations with great biological problems, and from the well-known discrepancy between the author's opinion and the facts adduced by other anatomists, at once the most interesting and remarkable. Passing by Professor Owen’s tendency to employ a terminology peculiarly his own, and by no means constant, we find one of the most striking features in this chapter to be a repetition of the opinions laid dovni before, in reference to the characteristics of the mammalian brain. Our readers are doubtless aware that Professor Owen has formed a classification of Mammalia based on the structure of the brain. He divides the mammals into four gi’oups : 1. Archencephala, including man only, and especially cha- racterised by the presence of a fcerebrum which completely covers in the cerebellum. 2. Gyrencephala. The animals in this group have not this cha- racter of cerebrum covering the cerebellum, but then the two halves of the cerebrum arc united by a commissure called corpus callosum,” and the con- volutions are convoluted. 3. Lissencephala, in which, according to Professor Owen, the surface of the brain is smooth, but there is still a corpus callo- sum. And 4. Lycncephala, in which there is a negation of all the above characters : the cerebellum is uncovered by cerebrum, the latter is smooth, and there is no cor^ms callosum. This scheme of division was laid down some nine years ago by Professor Owen in a memoir before the Linnean Societv, and the definition of the groups or subclasses was pretty nearly as we have given it. There is, however, in anatomy, as in all other sciences an improvement in 18G8 on the knowledge of I860, and in ac- cordance with this improvement, it has been found necessary to reject very materially the grounds on which the author established this division of mammals. It might be thought that I’rofessor Owen would have seen reason to alter his views too. Not so. True to the vulgar proverb, lie has adhered with unusual tenacity to his views expressed nine years since. And meanwhile what are the changes in facts ? These changes — the author denies some of them, but the whole world of anatomists is against him — are : 1. That tlie cerebrum of man is not the only one which covers the cere- bellum, but that man holds this in common with certain Quadrumana — this Professor Owen admits; and 2. That certain lyencephalous mammals have an imperfect but still distinct corpus callosum — this Professor Owen denies. It is vorj' curious then, bearing these statements in mind, to observe the overstrained analogies, the unfair force given to certain facts, the general spccial-pleailing ingenuity, and withal the suppre.ssion of antagonistic ob- sei^ ntion, which the writer exhibits all through this chapter on the nervous 69 liEVIEWo. sj’stem. lie advances no new facts, takes little cognizance of later inquirers, and neveitlieless, with an audacity which no writer less gifted in weapons of fence would venture on, he urges the accuracy of this old system of classifi- cation. We cannot but regret this for the credit of English science abroad; for there is no intelligent foreigner, capable of reading Professor Owen’s writings, who can fail to see that the brain-division of mammals is now the merest shred of a worn-out marasmic and all but defunct generalisation. Of the other chapters in this third volume, we may say of them that they contain hardly anything that is not to be found in the original memoirs from which they seem to be taken bodily. Here and there, indeed, en parentMse^ we find a sneeiing reference to some opponent, or a foot-note explanatory of some new technicality, but beyond this nothing of special interest. The chapter on the digestive system, in which the teeth are classified and described, derives its highest interest from the circumstance that the author has adopted a rational system of classification, founded on development — a basis which, in nearly every other instance, he regards as unphilosophic. There is, too, in this chapter a feature of special import to the student of human histology ; it relates to the question of the development of teeth, which latter, according to Professor Owen, are essentially dermic structures. This, as a contemporary has pointed out, arises from a misconception which the author, in common with numerous other anatomists, has fallen into. The true relations of the derma to the epidermis, and of both to what is styled the basement membrane, was first, if we remember aright, pointed out by Professor Huxley in ids excellent article on Tegumentary Appendages,” in Todd’s Cyclopaedia of Anatomy.” Mr. Huxley there demonstrated that the skin consists of two strata, which become differentiated in opposite directions from a zone or belt of indifferent tissue (basement membrane), the outer one he called ecderon (epidermis), and the inner he termed enderon (derma). Taking this view of the homologies of the two structures (and it seems the only philosophical one), it is clear that the teeth would not be as Professor Owen represents them, purely dermal structures, but would come under the category of epidermal or ecderonic structures. The chapter on the circulatory system contains an account of the varied forms of apparatus employed in distributing the blood over the body of mammals, from the lowest group up to man. In this the author advances the opinion, which he says he urged many years ago, that the permanent or red globule of the human blood is derived by division from the white globule. He states that his obseina- tions on the blood corpuscle of Perameles “ suggested the idea that such blood disc was undergoing a spontaneous subdivision into smaller vesicles,” iind he thinks that the researches of Dr. Iloberts, of Manchester, and Mr. Wharton Jones bear out this view. But so far as the quotation from Dr. Boberts’s paper, which the author gives, is concerned it is clear that tlie opinion held is very different from that of Professor Owen. The latter says that the white corpuscle itself divides, but Dr. Iloberts, as cited by Professor Owen, evidently speaks of division of the nucleus, for he says, a number of the nuclei were seen in the process of division * * * There was evidence that these secondary nuclei were set free in the blood, and by subsequent enlargement,” &c., developed into red blood discs.” Again, we may say on uur own authority, that Mr. AVharton Jones’s observations do not in the 70 rorULAFv SCIENCE EEYIEAY. faintest manner confirm this observation of the author’s, as tliey go to prove that the red globule is the liberated entire nucleus of the white cospuscle • Indeed, this discovery of Professor Owen’s seems to be altogether unique. There are many other points in the histology of this volume on which we think the text requires correction. Such are, for instance, the accounts of the structure of the liver, the spleen, and the skin. The chapter on the development of the horns of mammals, and especially of the Cervida3, contains a good deal of original matter, and suggests many curious problems for the speculative physiologist. The same may be said of the section devoted to the peculiar glands of mammalia.” The account of the development of the ovum is little more than an abridgement of the results of Von Bar’s and Martin Barry’s inquiries. It is in the final chapter, which is headed “ General Conclusions,” that the author shows himself to most and least advantage, and in which he discusses all the gveat questions which have been such bones of contention among naturalists almost since the time of Cuvier, and especially within the last ten or fifteen years. Teleolog}'-, origin and extinction of species, the law of derivation, and Mr. Darwin, are here dealt with briefly and with vigour^ and in the last couple of pages the author declares himself the champion of spontaneous generation, and analyses the soul to an extent which will hardly satisfy divines. It is very difficult for one unpossessed of Professor Owen’s higher intelligence to grasp what it is exactly that the author does believe in ; and if, therefore, we once more misinterpret (?) him we must beg his pardon and plead his complexity of style as our excuse. But so far as we can gather from his pages, I’rofessor Owen ])ushes the question raised by naturalists just one stage back and no more. He denies the successive creation of types 5 he admits the formation of new groups as a result of variation, but he contends that all this is the operation of a definite law which was first established by the Creator. He thus, to our minds, differs but very little from the disciples of Mr. Darwin, save that lie holds that natural selection is inadequate to explain the preservation of species, whilst he otters no alternative expla- nation of his own. Clearly the distinction between the author and Mr. Darwin is in the rendering of the term natural selection.” Professor Owen wittingly misconstrues Mr. Darwin’s conception of the expression, and will persist in a.sserting that Mr. Darwin personifies nature as an intelligent entity. This is wrong; and it is grossly unfair to Mr. Darwin, who simply employed the word as a convenient mode of expressing a number of pheno- mena called “ natural.” AVe think, therefore, that Profes.sor Owen, who but two and a half years ago laid claim to being the originator of the principle on which the theory of natural selection is based, stands, by a series of admissions, convicted of Darwinianism. AVhether Mr. Darwin will welcome him among his numerous converts remains to be seen. Of one thing we arc quite convinced, that if the charge of temerity may be urged against Mr. Ifarwin for advancing an hypothesis he cannot demonstrate, it may with tenfold more justice be brought against the author. In the very page on which he repudiates natural selection as without basis in fact, he liimself starts the profoundly ridiculous theory that the horse and donkey were predestined and prepared for man, because the Creator felt that the two latter were essential to man’s welfare and civilization, assigning as an argu- BEVIEWS. 71 ment for tliis preposterous speculation, his own emotions on entering the saddling ground at Epsom before the start for the Derby,” "Will Professor Owen tell us whether he thinks the steam engine, and the compass, and the electric telegraph were prepared and destined in a similar manner, and if not, where he discerns that superior intelligence which selected the former set of influences rather than the latter ? The most startling phase of the author’s mental development is that which unfolds itself in his open conviction of the views of M. Pouchet. This will pain and surprise not a few of his ‘^creationist” supporters considerably. Yet we think it is the one “ saving clause ” in the volume, the one redeem- ing feature of a work which, however comprehensive, is so full of objection- able features that we trust it may not be accepted abroad as the reflex of British science. We are certainly of opinion that on this one point of spon- taneous generation Professor Owen has allowed his mind to arrive at an un- biassed conclusion, and in this solitary instance we think he is in advance of his confreres in this country, with the single exception of Dr. Hughes Bennett of Edinburgh, whose able essay in our present number is in great measure a demonstration of the principle of heterogeny. Professor Owen speaks his mind openly and honestly on this question, and lends the weight of his authority to the side of heterodoxy. But it is heterodoxy which we do not think we go too far in asserting will soon be very generally accepted. Looking at the work which Professor Owen has just completed as a whole we must say, as we did at first, that it disappoints us. On the other hand, we are bound to confess that it contains a huge store of anatomical facts, and that once the reader has mastered Professor Owen’s style he will find a peculiar fascination in the book. K. PACKABD, who is a constant contributor to the pages of our inte- resting contemporary, the American Naturalist, and who is a careful student of insect-life and structure, has in the work now published given us not only a guide to the study of insects zoologically, but a very excellent anatomical treatise on the class Insecta. In addition, he has offered some remarks of great practical value on the insects injurious and beneficial to crops. The illustrations, which, like those of most American works on Zoology, are printed in white on a black ground, are both handsome and accurate, and in some instances are taken from the fine memoir presented last year to the Boston Natural History Society by Professor Wyman. The account of the development of the ovum seems to us to be exceedingly well and intelligibly stated. The author has not merely transferred the state- ment of some text book to his pages, but has drawn abundantly on his own original observations, and has made frequent reference to the valuable in- vestigations of Zaddach and Kathke. We wish we had space at our disposal * ‘‘A Guide to the Study of Insects,” by A. S. Packard, jun.. M.D. Salem, U.S. 1868. THE STUDY OF INSECTS.* rOi’ULALi SC•IE^’Ci; LEVILIVr. to Jo justice to tl:e riUthor by quoting from liis descriptions, but as we can- not we must be content with expressing our entire and unqualified approval of his labours. In the second part of his work he treats upon the geo- graphical distribution of insects, their diseases, their habits and variations, and gives ample instructions (the best we have met with) as to their cap- ture and preservation. Finally, he supplies a most comprehensive entomo- logical bibliography, which he arranges under the heads of General Works, l^Iorphology, Anatomy and Physiology, Embryology, Fossil Insects, and Periodical Works now in course of publication. The illustrations intercalated with the letter-press are more than seventy in number, and there are several liandsome page plates. Type and paper have the usual excellent qualities of American books. Altogether, we are immensely pleased with this work. It is assuredly all in all the fullest, most modern, and most clearly-written treatise on insects we have ever seen, and we heartily commend it to our readers’ notice, feeling certain tlieir judgment of its merits will not be less favourable than our own. HEAT AND CHEMISTRY * Students who are going up for the matriculation pass examination of the University of London, are examined in certain branches of Physical Science, and among others, in the departments wdiicli form the above heading. It is for the readers of this class that the author of the manual under notice has attempted to provide. Mr. Guthrie evidently thinks that even elementary treatises like those of Balfour Stewart are of too diffi- cult a character, and that works like that of Lardner are too general for the requirements of the London University. He has therefore attempted to compile a book which, while avoiding the mathematical details of higher treatises, should bring together, in clear and intelligible language, the leading phenomena and laws of heat and of non-metallic chemistry. His endeavours have been in some measuie successful, and in some degree also have failed in their purpose. For instance, while he has treated the subject of heat in accordance with the aim he had in view, he has fallen short of his aim in dealing with the chemistry of the non-metallic elements. This statement of ours applies both absolutely and relatively — the physics is better than the chemistry ; and while the former, though general, is accurate and tolerably well in keeping with recent research, the latter is in all re.«pects an imperfect labour. The mode of an-angemeut pursued in treating upon Ixdh subjects is the convenient one of separate, numbered paragraphs ; and tRese latter are all the more useful to the student from the fact that the author has apjK*nded a number of examination questions, the numbers following which, are those of the paragraphs in which the substance of the answers is to be found. We question whether the author’s definition of heat — “ that it is the force which tends to cause the change in the tem- perature of bodies” — is m thoroughly satisfactory as our knowledge of tem- • “ The Elements of Heat and of Non-metal lie Chemistry.” By Frederick Guthrie, B.A. (I>ond.), Ph.l)., F.R.S.E. London; Van Voorst. 1808. liiiviEv/c. 73 perature plienomeua would enable us to construct; but peiliaps it is more easily comprehended by the student than any more lengtliy definition in- volving a reference to the vibrations of matter. The chemical part of the book is not at all what it ought to have been. Mr. Guthrie must surely be aware that neither in the University of London, nor in any of our metro- politan lecture theatres, is either his nomenclature or his notation likely to be received with favour. If Mr, Guthrie would be counselled by us, he would immediately set about the revision of this book ; and if he does, he will no doubt produce a clear, accurate, and useful handbook for candidates for the London University matriculations. AETIFICIAL SELECTION AMONG MEN.* rjlHAT the Anthropological Society of London should not exclusively con- -L fine its inquiries to man as he has been, but should give a little attention to the human race as it might be, is the view herein expressed by Mr. Bray. Whatever may be the force of this opinion, it does not follow from its reasonableness that it must necessarily fall exclusively to the E. S.A.L.s for its solution. Indeed, we see no reason why the problem should not be discussed generally in many other natural science bodies. But we fear that in the present condition of our social system there is an impassable barrier to researches such as that Mr, Bray suggests, so far at least as their practical application is concerned. And it is only by practical experiment that such questions as that of the improvement of the human race by artificial selec- tion can be satisfactorily decided. It is for this reason that Mr. Bray’s pro- posal strikes us as being extravagantly Utopian, It is from this circumstance also that we refuse to discuss it in our pages. We do not, however, on that account reject Mr. Bray’s idea as one unworthy of consideration in the abstract. So far from this, indeed, we think that those who are versed in the doctrines of modern philosophy ; those who have already seen the absurdity of those unreal entities called Pneuma and Phusis and Psuke will read the author’s remarks with a conviction that there is something in his theory. And even if they do not go so far, they cannot but derive pleasure from reading his forcible English, and profit from pondering on his very suggestive remarks on the physics of metaphysics, if we may use such an Llibernianism. The one blemish which the author shows, is his somewhat irrational advocacy of Gall’s Phrenology. This surprises us considerably, for Mr. Bray has paid no small degree of attention to some of our finest works on Physiology and Psychology, and we can only regard it as one of those prejudices which are often parasitic on even abler brains than his. * The Science of Man : a Birds eye View of the wide and fertile Field of Anthropology.” By Charles Bray. London : Longmans, 1868. 74 rorULAR SCIENCE REVIEW. THE EAST INDIAN AECHIPELAGOA- IT may be fairly laid down as a proposition to whicli there are very few exceptions, that books of travel contain a small amount of novel matter, diluted with an enormous quantity of vapid personal detail and ill-digested personal reliection. This is especially true of works on Africa, but it holds good for nearly all geographical literature, and we fear that it is in some measure applicable to the handsome volume which Mr. Murray has just issued. AVe would not be understood to imply that Mr. Bickmore has not added to our knowledge of the extremely interesting country he has travelled in, but we feel we are thoroughly justified in affirming that everything new in his narrative might easily have been stated in thirty or forty pages of the five or six hundred of which his book consists. The author went out, he tells us in his preface, to Amboina, to re-collect the shells figured in Kumphius’ “ Bariteit Kamer j ” and it is, in our opinion, to be regretted that he did not confine his published observations to the scientific points which came under his notice. In fact, Mr. Bickmore has given us an account of a scientific exploration, which has been productive of little or no scientific results. It is raost irritating, in reading this work, to find how many splendid opportunities of research have been overlooked in the desire to run rapidly over a huge tract of country, and in the effort to record sensational superficialities. "When we find a couple of our own countrymen going on a two months’ voyage to the Faroe Islands, and bringing us home facts and suggestions which throw light on a hundred scientific problems, it is with a feeling of inexpressible contempt that we accept the paltiy results which the author of the present volume has with wearisome mono- tony of style spread out over nearly GOO pages. When we think of what Darwin or Edward Forbes would have learned in the course of an expedi- tion like that of Mr. Bickmore, we cannot congratulate the friends of Science in Boston and Cambridge ” on their success in selecting the author to add to our scientific knowledge of the great Eastern Archipelago. As a pleasant book of adventure for those who know little or nothing of this part of the world, we can commend the volume ; as a luxuriously illustrated and ornamental appendage to the drawing-room table, we can speak equally well of it ; but as an addition to scientific literature it has little or no value. We have often in these pages protested against the petty self-vanity of travellers, who on every page of their works parade the common-place in- cidents of their domestic life before their readers, and who so often inflict upon us their efforts at “ magnificent composition.” But it would seem as if all travellers were alike, and ^Ir. Bickmore must be added to those who liave gone before liiin. There are numerous references in his Travels to scientific points of interest, and there is a list of birds given in the Appendix, but we find without exception that the problem or tlic observation or the • “ Travels in the East Indian .Archipelago.” By Albert S. Bickmore, Fellow of the Geo^aphical Society of London, Professor of Natural History in Madison University, Hamilton, New York. London: John Murray, 1808. EEVIEYfi. 75 plienomenon referred to in tlie text is deserted in limine, and tliat the author thrusts it aside to tell us of his own thoughts or of some other equally uninteresting or unprofltahle subject. By the way, we would suggest it as a metaphysical problem for those curious in these matters, why it is that when a man makes a voyage, and writes a book describing it, he fancies that the dreary recital of his breakfasts and his suppers, his emotions ex- cited by the beautiful, and wordy sentimentality that he would under other circumstances ridicule, prove a fascination suf&cieut to induce one to wade through some hundred pages of prolonged weariness ? If anyone could solve this, and propose a remedy, he ought to have a statue. To Mr. Murray our thanks are due for nearly forty handsome plates, which delineate numerous interesting, though hardly novel objects. POPULAK OPTICS.* I^OT WITHSTANDING the very high opinion that we hold and that Tl we have frequently expressed concerning scientific investigation in America, we must confess that the handbooks published by our brethren at the other side of the Atlantic are anything but representative of the present state of science. W^e find that is the case in nearly every department of science, so much so that it might be said that the best scientific treatises used by the Americans are reprints of English works. Is it not then a question whether the absence of an international copyright law is not the cause of this ? American publishers find it cheaper to print good English books for which they pay nothing, than to add an author’s to a printer’s bill. These reflections are suggested by Mr. Nugent’s “Treatise on Optics,” a book of which we can only say, that if it represents the knowledge of the laws of light in America, American science must be at a very low ebb. We have never in the whole course of our career of criticism met with so imperfect a work as this it is elementary without being clear, diffuse without being comprehensive. It contains no reference to the more modern applications of optics, and its account of the physiology of vision is simply ridiculous. The author alleges that such a treatise as his “ has long been a desideratum ” for schools and colleges. This alone shows how little he knows of the literature of the subject. With such excellent works as Gal- braith and Haughton’s “Manual,” and Ganot’s Physics, Golding Bird’s, Arnott’s, and Lardner’s general treatises, we think our schools have been very much better cared for than Mr. Nugent suspects. Such books as those named are in every respect superior both in clearness of style, appropriateness of illustration, and reference to recent progress, than the work upon our table. Mr. Nugent’s diagrams are in many cases quite antique, and, save in the photographic section, are insufficient. The following paragraph, containing the author’s hypothesis of “adaptation,” is a sample of this work, and is a Treatise on Optics ; or. Light and Sight Theoretically and Prac- tically treated.” By E. Nugent, O.E., ex-Principal of Commercial, Nautical, and Engineering College, New York. London : Virtue. 7G roruLAii scii::nce eeyiev/ a piece of rariingtonism of tlie worst style : 1 am strongly inclined to think that the eye adapts itself to different distances by a sort of galvanic or electric action (!) induced in it by the stimulus of light proceeding from external objects; the force of this action depending upon the distance from which the light proceeds, the intensity of the light,” &c. This is certainly -an explanation, but it hardly enlightens us much. The most interesting department of modern optics, that of Spectroscopy, has been left untouched, iiud altogether the book is a feeble and unsatisfactory production. OWNES'S CHEMISTRY had been so long the recognised text-book, at all events in medical schools, that it was with regret we found that its later editions were less suitable for the lecturer’s or teacher’s purpose than they should have been. Within the last ten years the science of chemistry has undergone such a change, that many who laid their foundation of know- ledge in this department in 1858 would, if they were to dip into a treatise of to-day, find it in many points quite unintelligible. Townes’s Manual had not kept pace with the age; and consequently it had for some years fallen into a little disrepute. In the present edition it regains its former high standing, and though the volume which Mr. Watts and Dr. Bence Jones have now given us extends over more than a thousand pages, and is there- fore no small labour for the student who would master its contents, it must be said to be unquestionably the best hand-book in our language. The plan of the present edition is much the same as before. The first part of the book is devoted to physics, the second to inorganic, and the third to organic chemistry. The terminology is that now universally employed both in this country and abroad, and the notation is the same as that used in Watts’s Dictionary, and very generally adopted among ICnglish chemists. The physical portion is the weakest part of the book, yet it is excellently done, and it includes reference to most of the new facts in natural philosophy. The subjects of electrical resistance and spectrum analysis might, perhaps, have been more fully given, but this is not of much importance. The cliemical division of the work is admirable ; especially so is the lucid and forcible chapter on chemical philosophy, which Mr. Watts has entirely re- written. The greater part of the organic chemistry is new, especially the sections on the hydrocarbons, alcohols, and acids. We have not space to refer to the system of classification adopted by the Editors, nor can we point out tlie many typographical errors which we have discovered. We must, therefore, conclude with a hope that the publisher may issue a list of errata, and a conviction that the student who po.s.sessos this manual is armed against nil the contingencies of modern examinations in chemistry. ** Townes’s Manual,” as it is popularly styled, is clear, comprehensive, modem, and easy of reference. • A Manual of Chemistiy', Theoretical and I’rnctical,” by George Townes, T.R.S., late I*rofess«)r of Chemistry in University College, London. Tenth edition. London : Churchill, 1808. TOWNES’S CHEMISTRY.* IlEVIEWS. / i PHYSIOLOGICAL ESSAYS.* The Reviews wMcli appear now-a-days in some of our heavy artillery of literature, partake more of the essay than the critique. Indeed, folk have come so much to disregard the criticism of writers, and to form their own judgment on hooks, that anything like a lengthy critical survey of a work would he received with disfavour and would he detrimental to the welfare of the journal in which it appeared. People like to read something that interests them, and if a notice of a hook is a long one, it will not he read unless it is something more than a notice. Hence it is the custom for a reviewer to (1) select a taking title ; (2) then to labour with scissors and paste to disembowel a number of hooks and so construct, by ingenious dove- tailing of quotations, a readable essay, and (3) to make a foot-note of the titles of the mutilated works, and finally serve up, as the cookery hooks say, with a little preliminary garnish. Of this kind of stutf is our modern Quarterly Review. In the hook upon our table, Dr. Child reprints such a series of es§,ays and otfers them in collected form to the public. We can say of them that they are interesting and even instructive, hut that they are critical we do distinctly deny. Even when they display an air of criticism as in the review (?) of the Memoirs on Heterogeny,” it is clearly the criticism of foregone conclusions and not of an impartial examination. Dr. Child’s volume is pleasant reading, hut it is a type of hook of which we cannot approve. SHADOW PERSPECTIVE.! The term Sciography is used to designate the science by which the shadows thrown by bodies illuminated from a certain point can he determined with geometrical exactitude. It is a science which as yet has been almost entirely unworked, and which we think ought, in art, to he productive of very good results. The perspective of form is already pretty accurately understood by artists, hut the perspective of shadow is in most cases arrived at as a result of experimental teaching, and is expressed much in the same way as the student who when asked on a right line to con* struct an equilateral triangle,” set about doing it with a pencil and tape- measure. In the very clever work which Dr. Puckett has prepared, the art and science of shadow perspective are fully given and amply illustrated. The author has given a scientific basis to his propositions, and has done more for this branch of art than can he j ust yet realised by the body to whom he addresses himself. We commend his book to all who are interested in accurate drawing. * Essays on Physiological Subjects.” By Gilbert W. Child, M.D. of Exeter College, Oxford. London : Longmans, 1868. t Sciography ; or, the Radial projection of Shadows. By R. Campbell Puckett, Ph.D., Plead Master of the Bath School of Art. London ; Chap- man and Hall. 1868, 78 POPULAR SCIENCE REYIEW. SEA-SICKNESS.* K. CHAPMAN has here enlarged his pamphlet on the use of the spinal ice-bag in the treatment of sea-sickness, and in doing so he has added fresh cases to his record and has considerably extended his observations on the physiological aspects of neuro-therapeutics. So far as the author’s () priori arguments are concerned we consider them unsound — not more so til an the great mass of such physiological reasoning, but dangerous, because all hypothetical arguments — and they are of this order — are objectionable. They are ingeniously put, and there is a categorical sequence about them which is pleasing, but they show many fallacies. For instance, we might remark in answer to Dr. Chapman’s belief that ice applied to the spine dimin- ishes the temperature of the sympathetic ganglia, that this statement is an assumption without a shadow of proof. It may be a convenient hjqio- thesis, but we could urge very different hypotheses which would meet the facts just as well. Indeed, it seems to us extremely improbable that ice applied to the spine can have any such effect. We might raise similar objections to many others of Dr. Chapman’s physiological views, but we refrain from doing so, because we think that his system of therapeutics must be taken as-an empirical fact, and judged on its own merits. Now we have no experience of our own to offer on the subject, but we must confess that there seems to be more in Dr. Chapman’s mode of treatment than some physicians will allow. The cases that the author records are both numerous and authentic, and though cases do not always prove the value of a therapeutic method, yet they should induce us to give Dr. Chapman’s plan a trial. This is what we would ask of our professional readers. The cases reported in the present work are of much interest, and they cer- tainly go far to assure us of the active influence of the spinal ice-bag in relieving the sjTuptoms of sea-sickness. Dr. Chapman writes with a force and vigour not always found in medical works, and even those who differ from him in opinion will find his book both clever and attractive. Sea-sickne.s8 and how to prevent it,” &c. By John Chapman, M.D., M.R.C.r. Second edition. London : Triibner, 1868. SCIENTIFIC SUMMARY. ASTRONOMY. f^HE Solar Erominences. — One of the most interesting- discoyeries ever effected by astronomers has recently rewarded Mr. J. Norman Lockyer’s spectroscopic researches. On a reference to our Summary of Astronomy for January 1867 (No, 22), it will be seen that more than two years ago Mr. Lockyer applied the spectroscope to the analysis of the solar spots, and that with such success as to enable him to refute the views which M. Faye had expressed respecting the nature of the spots, and to establish on a sufficiently firm and stable basis those which had been held by Messrs. De la Rue, Balfour Stewart, and Loewy. In the paper in which these results were presented to the Royal Society, Mr. Lockyer suggested the possibility that the spectro- scope might be applied to search for the spectra of the prominences. As the bright lines due to the burning hydrogen around the star T Coronse were rendered visible to our spectroscopists, he held that if the prominences are due to any similar cause we ought to be able to detect their bright lines by the same means. With the instrument he then made use of, however, Mr. Lockyer was unable to detect any trace of the spectra of the red pro- minences. Mr. Huggins also, with his 8-inch equatorial and the powerful spectroscopic apparatus made use of in his physical researches, could detect no sign of the prominences, nor could Mr. Stone with the great equatorial of the Greenwich Observatory. An instrument was being prepared for Mr. Lockyer, by Mr. Browning, the optician, which was to be specially adapted to the search for the spectrum of the prominences. Before this instrument had been rendered available, however, news came from India that the true nature of the prominences had been detected. These objects, as we men- tioned in our last summary, were proved to be gaseous. Accordingly, it became clear that there was a possibility of seeing the spectrum by full daylight. Let us consider lohy this is so : There is a little difficulty about the subject, as will be shown by the fact that at a recent meeting of the Astronomical Society, the Astronomer-Royal expressed his inability to see why the spectroscope can render the light of the prominence-spectra visible in the neighbourhood of the strong solar spectrum. We know that no means which have yet been devised have rendered the prominences visible. If we darken the sun we blot them out ,* if we hide the body of the sun by any artificial means, we still leave the illuminated atmosphere, and this is quite sufficient to obliterate the prominences. Now, since the reduction of 80 rorULAR SCIENCE REVIEW. the sun’s light, accompauied as it necessarily must he with the reduction of the light of the prominences, does not bring them into view, it may be asked why spectroscopic analysis should avail to that end. The formation of an ordinary solar spectrum is merely a mode of reducing the intensity of the sun’s light by dispersing it over a wider area than it would otherwise occupy. Hence, it is quite clear that if the spectrum of the prominences were similarly dispersed we should gain nothing by this mode, more than by any other mode of reducing the light both of the sun and of a pro- minence. But the spectrum of the prominences is not dis2)ersed] on the contrary, all the light is gathered into three fine lines. Therefore the spectroscope allows us to do what is not possible in any other way ; namely, to reduce the light of the photosphere without reducing the light of the prominences. Hence we are enabled to see the spectrum of a prominence side by side with the solar spectrum. ^ But now we have to record one of those singular and somewhat annoying coincidences which have so often marked the progress of astronomical in- quiry. The idea which had occurred to Mr. Lockyer, occurred also to M. Janssen (the head of the French expedition sent out to view the eclipse) so soon as he had discovered that the prominences are gaseous. The eclipse, it will be remembered, took place on August 18 j M. Janssen formed his views on the same day, applied them on the next, and thus, within thirty hours, solved the problem over which Mr. Lockyer (through no fault of his own, however, be it remarked) had been engaged upwards of two years. Janssen’s discover}' of the visibility of the prominence-spectra when the sun is not eclipsed, preceded Mr. Lockyer’s by two months. But the claim of the latter to the independent solution of a problem, which, so far as we know, he was the first to suggest, was not invalidated ; because M. Janssen’s letter announcing the discovery did not reach the French Academy of Sciences until after a full account of Mr. Lockyer’s processes had been read before that body. By a singular coincidence it anived a few minutes after. Without pretending to settle the rival claims of the English and French astronomers to a discovery which, if not one of the most important, is at least one of the most interesting, ever made, we may remark that, if on the one hand we cannot but admire the steady perseverance with which Mr. Lockyer clung to the notion which had occurred to him, and persistently pursued his ob- servations till they had been rewarded by success; on the other, we are filled with admiration at the Napoleonic rapidity with which the French astro- nomer grasped the bearings of the problem, conceived the mode of solving it, and carried out that solution to the successful end. ( )ne interesting feature of tlie discovery remains to be noticed. When the spectrum of a prominence is observed by the new method, it is seen in direct contact with tlie continuous solar spectrum ; and thus it becomes p<»8flible to determine the coincidence or non-coincidence of the bright lines of the prominence-spectrum with any of the dark lines of the solar spec- trum. In tliia way it has been shown that the red lino of the former spectrum agrees exactly with the line c (a hydrogen line) of the solar spectrum ; the orange line, however, is not coincident with (though near to) the dark line d (the double sodium line) of the solar spectrum ; lastly, the greenish-blue line of the i)rominence-spectrum very nearly agrees with SCIE.XTIFIC SUMMARY. 81 tliB line r (a Lyclrogen line) of tlie solar spectrum. We must confess^ how- ever, that we are rather perplexed by this result. We may he ready to reject the view that the orange line is due to the existence of sodium in the flames which surround the sun,* but the exact coincidence of the red line with the solar line c compels us to believe that these flames consist in part of burning hydrogen : this being so, how is it that the green line of hydrogen is not seen, though one very near to it makes its appearance ? In the spectra of the nebulse the green line r of hydrogen is seen, while the red line c is not seen. This phenomenon, though perplexing, is not so per- plexing as that presented by the prominence-spectra. Is it possible that the two phenomena may be in a sense correlative ; that hydrogen is in reality a compound substance, and that the line c belongs to the spectrum of one of its elements, the line F to that of another? The Transit of Mercury. — This phenomenon was well observed by many of our leading astronomers j amongst others, by Messrs. Stone, Dunkin, Lassell, Huggins, Professor Smyth, Captain Noble, and Mr. P>rowning. We have little to add to what is already known respecting Mercury. Some observers (amongst others Mr. Huggins with his fine 8-inch refractor) saw one spot ; others (including Mr. Browning, with his great 12^-inch reflector) saw two ; and Mr. Stone (with the great Greenwich equatorial of I2|-inch aperture) saw none. It appears to us that this diversity proves beyond dispute that the phenemonon is purely optical. On the other hand, Mr. Huggins noticed that a ring of light could be seen round the planet even when a very strong darkening glass was made use of. This would seem to show that the ring has a real existence ; though it is still possible that the appearance may be due to irradiation. One observation of the transit strikes us as important. All the observers we have named noticed an apparent change of figure in Mercury as the planet approached the edge of the sun's disc ; but Mr. Henry Pratt, who observed the phenomenon by projecting the solar image on a screen of finest white cardboard placed in a darkened room, noticed that the last internal contact took place without the slightest ap- pearance of elongation or distortion in the shape of the planet’s disc. This circumstance seems to suggest important considerations with respect to the observation of the transits of Venus in 1874 and 1882. The Kovemher Shooting-Stars. — Contrary to the general expectation of astronomers, the November star-shower was well seen in England. The display lasted until five in the morning of November 14, having commenced shortly before midnight. The display was also well seen in America, at about 11 o’clock, local time, corresponding (for the eastern parts of the United States) to the hour at which the display ceased in England. The visibility of the display, after all that had been predicted by astronomers, suffices to show that we are not nearly so well acquainted with the habitudes of the meteoric system as we had imagined ourselves to be. Probably many years will elapse before we shall be able to predict the character and extent of an approaching shower, and the places at which it will be visible. The niajority of the meteors seen this year were orange, but a few pre- sented a blueish light. The Sun's Distance. — Astronomers have long been discontented with the explanations which have been put forward from time to time, to account for VOL. YIII.— NO. XXX. G 82 rOPL'LAR SCIENCE IlEVIEW. the ^vaut of agreemeut between the determination of the sun’s distance^ founded on the transit of 1709, and the results which Hansen, Leverrier, Stone, 'Winnecke, and Foucault, have deduced from a variety of other methods. It was easy to show that the difference, although it amounted to three or four millions of miles, yet coiTesponded to an almost infinitesi- mally small eiTor in the estimate of the solar parallax. But then the method founded on the transit of Venus is precisely such a one as should serve to get rid even of so minute an error as this. And indeed the fact that astronomers had been in the habit of stating the sun’s parallax as 8"'5770 showed that they looked on the result as ti’ustworthy to at least the third decimal place ; whereas the mean of modern measurements gives the parallax as 8' '-9. It is satisfactory to find that the whole error of the com- putation founded on the observations made in 1769 may be laid on the effects of the peculiar phenomena which attend the egi-ess of a transiting planet. Professor Simon Xewcombe had done a good deal towards the solution of the problem ; but we believe that the credit of completely accounting for all the observations of 1769 in a consistent mamier, with a result according closely with that obtained in recent times, must be assigned to Mr. Stone. In a paper lately read before the Astronomical Society, he shows that by taking the mean between the formation of the black drop ” which precedes the second internal contact and the apparent moment of real contact, and doing the like for the first internal contact, a result is obtained agreeing perfectly with the mean of the determinations obtained by other methods. The discovery is important in itself, and doubly important just now, as showing what is the principal point to be attended to in the observations which are to be made on the transits of 1874 and 1882. The PUtnets. — Mercury will be well situated for observation as an evening star towards the end of January and until nearly the middle of February! Venus will be a morning star throughout the three next months, and well situated for observation in January. Mars will be well placed during the next quarter, coming to opposition on February 13. His path between the two stationary points lies in Leo, being almost equally divided opposite the bright star Begulus. On the day of opposition he will be near v Leonis. Neither .1 iipiter nor Saturn are very favourably situated for obser- vation during the next quarter. Throughout January and February, Uranus will be well situated, and will be an interesting object for those possessed of first-class instruments. Eclipse of the Moon. — There will be a partial eclipse of the moon early in the morning on January 28. The eclipse begins one minute before half- past twelve, and will end at 2 h. 47 m. A.ir. The gi'eatest phase takes place at 1 h. 38 m. a.m., when rather less than half the moon’s diameter will be obscured. Interest w'ould attach to the careful spectroscopic analysis of the moon’s light during this eclipse, and we trust our observers will not lo.*^ the opportunity thus alforded them. SCIE.NTIFIG SUMMARY. 83 BOTANY. The Ordeal Poison-Nut of Madacjasoar. — A description of tlie Tamjhinia mnenijlua, wHcli is now naturalised in New Soutli Wales^ is given by Dr. Bennett in tbe Journal of Botany for October. The largest and finest tree in the Sydney Botanic Gardens is twenty feet in height^ with a circum- ference of the branches full fifty feet. It flowers in November and Decem- ber^ and is often observed at the same time covered with fruit in different stages of maturity produced from the blossoms of the preceding year. The flower-buds are of a beautiful crimson colour j and, when expanded, the corolla is white, with tlie edges and under surface tinged with crimson ; the flowers are very fragrant, and their odour is retained for some time after they are withered. The fruit is oviform and about the size of a hen’s eggj it contains a hard stone or nut, enveloped in a dense fibrous substance. On this fibrous part being removed, there is seen a dark-brown shell, which, on being opened, is found to contain a white kernel, in size and appearance like an almond, and of a slightly bitter flavour. The fruit is at first of a green colour, then changes to a purplish-red tint on one side, but when fully ripe becomes wrinkled, and the entire fruit assumes a deep purplish-red colour. The whole of the tree yields a quantity of milky juice, very adhe- sive, and of a sweet creamy taste. The Potentilla Norvegica in England. — Mr. G. S. Gibson has found this gi’owing in Burwell Fen. He says it did not extend far, but was scattered around some thirty to fifty feet. It appeared quite at home, and at any rate must have been there for years. The plant is inconspicuous and likely to be passed over, except when in flower. Cinchona Bark from Eastern Bolivia. — On the 1st of October a cargo of bark was sold in London at from ten to twenty-five per cent, above the ordinary prices of the best Bolivian bark. Hitherto the large mountainous tracts of this district have been practically of no value, though producing quinine-yielding barks to perfection, because of the supposed impossibility of finding any means of communication from them to the sea for the purposes of commerce. This, however, seems now to have been overcome by Senor Pedro Bada, who brought his cargo across the continent and to this country by way of Para and Liverpool. Mr. J. E. Howard states in the Journal of Botany for November, that the specimens of bark received by him from Senor Bada agree with those of the morada and the zaniba (or negro) and zamhita (or negrilld) collected by Dr. Weddell in his last journey in Bolivia. A 'peculiar Carpical Structure in Elceagnus gonyanthes. — In this plant, which grows abundantly in thickets of a rocky islet in Macao harbour, the accres- cent, carnose, perigone-tube, covering the fruit, is most densely clothed inside with a close long white silky cotton, matted together into a pannose structure, so as to resemble more than anything else the cocoons of ‘‘ shep- herd-spiders.” This web has not the slightest attachment to the putanien. — Dr. Hance in the Journal of Botany for December. A Seaweed new to the British Flora. — The Elachista stellaris of Areschong’s Dried Scandinavian Algae ” has been discovered growing on Arthoclodia, on the Cardigan Bay side of the Carnarvonshire promontory at Pwllheli, G 2 84 rorULAR SCIENCE REVIE-W. and four miles further west at Llandwrog. Elachisia stellaris is laiown from all the species of the genus by the lilaments being nearly simple, radiating from a small, dense, hemispherical tubercle ; the threads are rather narrowed below, and very much attenuated and produced into a long slender tip above; the joints of the lower part of the thread are as wide as long, and of the upper part two or three times as long as wide ; the spore is oval shortly pedicelled. — Dr. Gray in Annals of Natural History for December. The Adulteration of Tobacco. — The Journal of the Quekett Club for October contains a paper on this subject by Mr. J. A. Archer. There is little that is new pointed out by the author, but the paper is, nevertheless, an inter- esting and useful summary of our knowledge of the varieties of adulteration and of the modes of detecting them. Germination of the Sjmres of Varicellaria. — Dr. W. Nylander’s obser- vations on this point have been translated for the Annals of Natural History (December) by the Rev. W. A. Leighton, and are of interest. The spores of '\’’aricelhiria, which are the largest spores of all lichens, were placed by him in a humid atmosphere, and— as seen by De Bary and others— were soon covered with slender circumradiant filaments. In the course of a month or so these filaments acquired a mucedinous character, and produced monili- form hyaline penicillate acrospores, and thus constituted a slender penicillium. This subsequently disappears under culture. But before it disappears, he has observed in the endospore a hyaline protoplasm turbid in the middle, composed of very minute white granulations, which as it were by coagu- lation formed a solid white corpuscle in the cavity of each cell of the spore, ;ind that this afterwards gradually increased after the fashion of an embryo, and at length in the tliird month filled the entire cavities of both cells of the endospore. At the same time, the wall of the two cells showed the con- centric strata to have become sensibly looser, and was fissured by several fine transvei'se rimuloe preparing for its future dissolution, which a parasitic mucedinous vegetation would also promote. Dr. Nylander has noticed these phenomena from March till June. Then the spores denuded of penicillium, sliow a white corpuscle in each cell which distends the spiral wall, and ultimately expels an oblong corpuscle which, when free, enlarges, and is most probably the commencement of the thallus of the lichen. The Morpholoay of Malvales. — We have received from Dr. Masters a copy of his paper on tliis subject intlie Lhinean Society's Journal (vol. x. Botany). Having examined very carefully the relation of tlio families Malmcecc, Stercidiacea:, and Tiliacece of Bentham and Hooker’s Cohors VI., he has arrived at tlie conclusion that though it may be desirable for convenience sake to separate the two former from each otlier, yet that tiiey are so closely related in morphological construction that it is hardly possible to comprehend the peculiar structural relations of tlie one witliout comparing them with the corresponding parts of the others. Dr. Masters looks on the stamens as being the organs of greatest importance in cl a.ssiti cation. Not c»nly, he says, does the connection of the stamens furnish one of the best characters of the entire group, but even in the discrimination of the tanaller sub-divisions (genera) the appearances presented by the column are of the greatest value. A Synopsis of the South African Rcstiacea; is tlie title of another excellent SCIENTIFIC SUMMARY. 85 paper in the above journal^ by Dr. Masters. This extends over sevent^^ pageS; is illustrated by two plates drawn by Fitch, and is an important monograph in continuation of researches already published in the Linnean Journal by the author. How Fern spores are scattered. — An American botanist, Dr. W. L. Wells, has been studying the phenomena of rupture of the sporangium of Foly- podium vulgare. Under the microscope the sporangium could be seen to open at a point near its stem, and the opening grew very slowly larger until the continuation of the stem which previously encircled the sporangium was nearly straight. It then suddenly shut with a jerk, scattering the spores in every direction, and generally sending the sporangium itself out of focus. In the cases in which it was not thrown entirely out of focus, the same operation could be seen to be repeated two or three times. In no case were any spores scattered during the opening, which always took place very slowly. Dicecism in Epigcea repens. — In the Proc. of the Academy of Nat. Science of Philadelphia, Mr. Thomas Meehan speculates on the fact which he has observed of the practical dicecism of Epigaea repens, the hermaphrodite flowers proving sterile. There would seem, he says, to be two distinct principles in relation to form going along together with the life of a species. The tendency of the one force is to preserve the existing form ; the other to modify it, and extend it to newer channels. The first we represent by the term inheritance.^ the other we understand as variation. Inheritance struggles to have the plant fertilise itself with its own pollen, while the effects of variation are towards an intermixture of races or even neighbour- ing individuals, rather than with members of the one brood or family. May it not be possible that at some time in their past hist Dry all species of plants have been hermaphrodite? that dicecism is a later triumph of variation, its final victory in the struggle with inheritance ? There are some difficulties in the way of such a theory, as there are with most of these theories ; but it seems clear from this case of Fpigcea that cultivation has not so much to do with changes as it gets credit for, and we may readily believe that independently of external circumstances there is a period of youth and a period of old age in form as well as in substance^ and that w-e may therefore look for a continual creation of new forms by a process of vital development, just as rationally as for the continued succession of new individuals. Monoecismin Sugula campestris. — The same observer, Mr. Thomas Meehan, has determined the practical moncecism of Sugula campestris. The three stigmas are produced through the apex of the flower-bud some days before the sepals open and expose the anthers. The stigmas are fertilised by the pollen of other flowers and wither away before their own flowers open. CHEMISTRY. Vegetable Tar as a Bye-Stuff. — M. Lefort proposes to use vegetable tar for dyeing purposes. It contains on an average about one per cent, of oxyphenic acid, which it readily gives up to water, forming thereby a liquid 8G rOrULAR SCIENCE REVIEW. whicli turns of a dirty green colour on tlie addition of a solution of per- chlorido of iron from the formation of oxyphenate of iron. Animal and vegetable fibres are dyed by the mixture of an ash-gi’ey colour of gTeat solidity. ]\r. Lefort’s process is as follows : The fibres are steeped in a solution of perchloride of iron for several hours, and when sufficiently drained, transferred to a vessel of filtered tar-water containing one of vege- table tar to ten of water heated to 60° or 80°. After several hours’ mace- ration they are withdrawn, washed with water and afterwards with soap, to remove the aromatic and resinous principles. — Chemical Neivs, Oct. 23. The Chemical Constitidion of Uric Acid. — In a note communicated to the Munich Academy of Sciences, Ilerr Strecher shows that uric acid may be regarded as a combination of glycocol and cyanuric acid (or 3 molecules of cyanic acid), just as hippuric acid may be regarded as a combination of benzoic acid and glycocol j for when it is heated for some time to 170° with concentrated hydrochloric acid, or, preferably, with a cold saturated solu- tion of hydriodic acid, it yields, after removal of the acid by oxide of lead, a considerable quantity of glycocol, together with carbonic acid and ammo- nia.— Vlnstitut, Oct. 28. Artificial Production of Tartaric Acid. — Along with his note on Vric Acid, Herr Strecker communicated to the Munich Academy another, on a new mode of forming tartaric acid. This consists in boiling for some time with dilute hydrochloric acid a mixture of glyoxal and prussic acid. The tartaric ac-id produced is precipitated from the solution by lactate of lime, and then obtained in the usual manner. IleiT Strecker has not yet studied its action on polaiised light. He considers its formation to be due to the union of glyoxal, prussic acid, and water, with the liberation of ammonia. — L'LiKtitut, Oct. 28. Phenomena of Combustion 'under Pressure. — M. II. Deville, in a lecture to the French Academy (Nov. 30), explains the fact established by Frankland, that the temperature of combustion of a gas is raised by making it burn under strong pressure by his theory of “dissociation.” When hydrogen burns in oxygen, only half the gas ever enters into combination in the hottest part of the flame, because the tension of dissociation resists it j and this is the reason why the temperature only reaches to 2,800° instead of 6,000°, the theoretical maximum temperature. By increasing the pressure on the gas, the influence of this tension of dissociation is lessened. Analysis of the Ashes of a Diseased Oranye Tree. — The orange plantations along the south-eastern coast of Spain, and in the adjacent Balearic Isles, having been visited with a severe epidemic, the rapid progi’ess of which rendered it of great commercial importance to the people there. Professor Bunsen, on a visit to tlie Baleaiic Isles, obtained specimens of the roots, stems, brandies, and fruit of the diseased trees. Mr. T. E. Thorpe has mailo analyses of the ashes of these part.s, and communicated his results to the Chemical Society. Comparing these results with those of analyses made f-omo years ago by Me.ssrs. Bowney and How of the ashes of liealthy St. Michael orange trees, tlie comparison of the two series of results shows a great dillerence between them ; but, then, so would a comparison of the results of analyses of the ashes of specimens of any species of plant in a healthy condition, but grown under different circumstances of soil, season. See. 87 SClEiNTii'iC EUjj'^iALY. Eor this reason, therefore, it would he unsafe to draw any conclusion from this comparison respecting the nature of this disease, and also because the analyses were made by different operators at a long interval of time, during which analytical processes have been modified, and improved ones intro- duced. However, the differences pointed out by Mr. Thorpe are certainly very marked, viz., an undue proportion of lime, and a comparative lack of phosphoric acid in all parts of the unhealthy tree, with the exception of the fruit ; and the concentration of potash in the fruit of the diseased tree. — Journal of the Chemicxil Society for December. Diniethyl.—'M.T. Darling has prepared this h}^drocarbon, CgHg, in dif- ferent ways, and transformed it into etliyl chloride, etl]}d acetate, alcohol, aldehyde, acetic acid, &c. ; confirming, by these results, Schorlemmer’s conclusion, that the hydrocarbons of the above formula, from whatever source prepared, are always identical in nature. — Journal of the Chemical Society for November. Products of the Oxidation of Parafdn. — By boiling paraffin for three or four days with potassic dichromate and sulphuric acid, Messrs. Gill and Mensel have obtained cerotic acid, acetic acid, and the intermediate mem- bers of the series. Somewhat similar results were obtained by boiling paraffin with dilute nitric acid; but, in addition to the acetic series of acids, succinic (already obtained by Hofstaedter) and anchoic acids were also produced. — Journal of the Chemical Society for November. Compounds isomeric with the Sulphocyanic Ethers. — In a second commu- nication to the Royal Society on this interesting class of bodies. Dr. A. W. Hofmann gives a further account of several of them, which, from their being ■either homologues or analogues of oil of mustard, he calls mustard oils. To this account he appends a theory of their constitution, and that of the isomeric sulphocyanic ethers. Selecting for illustration methylic mustard oil and its isomer methyl sulphocyanide, he shows that if in the latter body we interpret its reactions as signifying that the sulphur-atom is the link of connection between the two carbon-atoms of the compound, we must con- sider that it is by the nitrogen that the carbon-atoms of methylic mustard ■oil are chained together. The subjoined formulse illustrate this view : — Methylic mustard oil Sulphocyanide of methyl H3C SC H3C NO On a Neio Series of Chemical Reactions produced hy Light. — Under the above heading. Professor Tyndall has presented to the Royal Society an account of some experiments attended with very remarkable and beautiful phenomena. By passing beams of concentrated electric light and of sun- light through tubes containing air and other gases charged with vapours of volatile liquids, chemical decompositions of undetermined nature were caused, their occurrence being manifested by the production of clouds. As the nature of the gas employ^ed did not affect the phenomena of the production of clouds from the vapour with which it was charged, it is to be inferred that the chemical action must be in the vapour itself. The portion of the beam of white light which effects the decomposition is inferred, from the experi- 88 rorOLAIl SCIENCE EEVIEW. inonts recorded, to le the portion ahsoihed. Thus a screen of chlorine was found to be most ell'ectual in depriving the beam of the electric lamp of its power of exploding a mixture of chlorine and hydrogen. For desciiptions of the symmetrical and fantastic forms and motions of the clouds of decomposed vapours, we are compelled, by their length, to refer the reader to the memoir itself, in the Pi'occeduujs of the Itoijcd Societ]/, No. 105. On the Estimation of Phosphorus in Cast Iron. — A process for the estima- tion of pliosphorus in cast iron is given by M. Tantin in the Comptes-Pendus, similar in principle to the excellent method for the estimation of sulphur. Instead of attempting to oxidise the phosphorus to the state of phosphoric acid, whereby some of it, by escaping oxidation, is not determined, he pro- ceeds to separate it from the iron in the form of pliosphoretted hydrogen, wliich he aflirms can be coinpletely accomplished by the action of hydro- chloric acid. First passing the gas evolved through a solution of potash, to remove the sulphuretted hydrogen, he transmits it to a solution of silver nitrate, which precipitates the phosphorus as an insoluble phosphide, and converts the arsenetted hydrogen, always present, into the soluble arsenite of silver. The precipitated and Avashed silver phosphide is then oxidised and converted into phosphoric acid and chloride of silver by aqua regia, and the phosphorus weighed as magnesian phosphate in the usual manner. Electro-capillary Phenomena. — M. Becquerel has added a sixth to his previous memoirs on the chemical reactions which occur between liquids communicating with each other through the capillary spaces of cracked glass, layers of fine sand, parchment-paper, and other porous septa. In this memoir {Comptes-Pendus, Nov. 30) he describes the formation of crystallised hydrates of chromium, aluminum, silicates, carbonates, t&c. For example, by placing chromium chloride in solution on one side of a parch- ment-paper septum, and potassium aluminate on the other, he obtained crystals of hydrated chromium oxide and crystalline plates of hydrate of alumina. M. Becquerel believes that he has proved that the infinitely thin layer of liquid adhering to the walls of capillary spaces separating two different liquids, acts as a solid conductor to the two electricities set free during the chemical reaction of the liquids on each other in these spaces. Tliere is thus formed an electro-chemical couple, giving rise to a current, called by M. Becquerel clectro-capi'lary, to recall its origin, Avhich has- sufficient energy to reduce solutions of metals to the metallic state, and to produce, with the concunence of other causes, a large number of com- fiinations end decompositions. In this couple the layer of liquid adhering to the walls of the capillary cavities, which acts as the solid conductor of ordinary arrangements, has a molecular constitution differing from that of the adjacent liquid not submitted to the attractive action of these walls. M. d(‘ la Hive (in the liihliothl (pie Univ. de Ceneve and I'hil. May. Dec.) supposes that, in>tead of the liquid enclosed in the capillary space acting as a solid conductor of electricity, the observed phenomena are the effects of chemical action alone, more or le.ss modified by the fact that the .space is caj)illarA', and, in particular, that the action can only take place on a small number of molecules at a time, and succes.‘'ively, inste.ad of acting on the wlioh* of the two solutions at once. It is very probable, says 1\I. do la liive, that the chemical action is modified by the so-called molecular attraction SCIENTIFIC SUMMARY. 89 to whicli capillaritj is attributed j and possibly, also, that this molecular attraction is only one form of affinity (or rather, that the two forces are one), so that in the capillary spaces the liquid is not in the same conditions, physical or chemical, which it presents when it is en masse. Not admitting that electricity has anything to do in causing these phenomena, he prefers to distinguish them as chemico- capillary instead of electro- capillary . A new Secondary Alcohol. — M. Lieben has obtained an alcohol isomeric with butyric alcohol by first treating ethylated chlorethyl with hydriodic acid, which gives ethylated iodethyl, and then treating this substance with moist silver hydrate. Together with the alcohol some butylene is formed. Oxidised by chromic acid the alcohol yields acetic acid, but neither butyric or isobutyric acids. It boils at 99°, and at 0° has a density of 0-827. Its constitutional formula is (C1I3 c C3H3 loH He has communicated his results to the Vienna Academy. A neio Synthesis of Hydrocyanic Acid. — The Comptes-lRcndtis for Dec. 7 contains a paper by M. Berthelot on the formation of hydrocyanic acid from nitrogen and acetylene gases. It is sufficient to pass a series of sparks from a Ruhmkortf’s coil through a mixture of these gases in a state of purity to form the acid. But as a simultaneous but separate decomposition of the acetylene occurs, the dilution of the gases with hydrogen gas is practised in order to avoid this decomposition. Any other hydrocarbon will form prussic acid with nitrogen because of the fact that the electric spark passed through it will produce acetylene. M. Berthelot compares the formation of prussic acid from acetylene with that from cyanogen thus : — C2H2+N2=2CNH C2N2+H2=r2CNH GEOLOGY. The Causes of the Distribution of the Iron in Variegated Strata. — The November number of the Quarterly Journal of the Geological Society con- tains Mr. George Maw’s paper on the Disposition of Iron in Variegated Strata, read some time since before the Society. It is an elaborate memoir on the subject, and is accompanied by forty admirable chromolithographs of sections of variegated rocks. His conclusions are, first, that the great majority of cases of variegation are independent of altered chemical com- binations, and more often than otherwise seem to have been induced by agencies not directly connected with chemical change. The very small proportion of them that can be accounted for by chemical change are due to the occasional conversion of the red anhydrous sesquioxide, or the lower 90 rorULAR SCIENCE REVIEW. hydrates, into fully hydrous sesqiiioxide, the reduction of sesquioxide to protoxide of iron in the production of green slates, and the exceptional cases of the alteration of colour of red beds by the decomposition of bisulphide of iron. Eyen the agency of organic matter, in inducing chemical changes in the state of combination of the iron, will not, in most cases, account for the bleaching — the segregational motion of the colouring oxide — which is the ultimate cause of the yariegation, being supplemental to the simple chemical changes of combination. Secondly, that the transferrence of the colouring oxide from one part of the stratum to another has taken place by the simple mechanical agencies of infiltration and dissolution, as well as by segrega- tion ; but that the latter, above all other agencies, has played the largest part in the yariegation of ferruginous rocks. The Qualcrnanj Gravels of England. — From a comparison of the gravels of the Aire Valley at Bingley, of the Taff Yale between Quaker’s Yard junction and Aberdeen junction, and of the Valley of the Rhonda near its junction with the Taff, and of the angles of deposition of gravel-beds con- cealing the escarpment of the chalk in the sections exposed at Crayford, Erith, and Salisbury, with the same conditions at Brighton and Sandgate, Mr. A. Tylor concludes : 1. That the dehris was deposited by land-floods, and that the mode of deposition was quite distinct from that of moraines produced by the melting of ice. 2. That the character of the deposits in the valleys of the Aire, Talf, and Rhonda, proves that they were formed under similar conditions. 3. That these givavel-beds point to a Pluvial period of great intensity and duration. 4. That the ice action, of which there is evidence, was subordinate to the aqueous action. 5. That the fossiliferous quaternary deposits have been best preserved where they have been formed in cavities lying between the edge of the bank of a river, estuary, or sea, and an escai-pment running parallel with it at no great distance. 6. That the immediate source of the gravels was the high land adjoining the rivers, whence they have been washed down by rain, with the assistance of lateral streams, into the lower ground, w’here they had come into contact with larger quantities of runnhig water, had been mixed with rolled materials, and spread in thick beds over the bottoms and slopes of valleys or the sides of escarpments. 7. That the surface of such a deposit rarely slopes at more than from 2° to 4°, while the slope of the beds lower in the series nearer the escarpment averages 12°. — Quart. Journ. Geol. Soc. Nov. tSimilaritg between the Geological Structure of North-westcni Sibei'ia and that of Jtussia in Europe. — The following facts have been communicated to Sir R. L. ^Murchison by Count A. von Keyserling : The district between the rivers Lena and .lenissei is occupied by upper Silurian rocks of the same typo as those found in the region of Petchora, and by Carboniferous rocks containing seams of coal. Tlio chief secondary' deposits are of Oolitic or Ida: ,dc age, and agree witli tliose of the Petchora region, wdiich is the next adjacent tract on the west to the Siberian region in question. Similar rwks are found in Spitzbergen. 'I’lic banks of the .lenissei are covered with post-])liu^enc accinnulations similar to those found near Archangel. It is thu.'i seen that the vast, slightly undulating, and to a great extent horizontal anfl unbroken fonnations, each of -which occupies so wide an area in European Ru.Hsia, are repeated on the eastern side of the Ural Mountains. SCIENTIFIC SUMMARY. 91 In this range of mountains only arc to be found igneous and eruptive rocks. — Geol. Mag. Dec. The Deltas of the Po, Mississipi, and Ganges. — Mr. A. Tylor has compared together the deltas of these rivers and the alluvial plains above them, and states that a parabolic curve drawn through the extremities of each river, and through one point of its course, nearly represents its longitudinal sec- tion— the greatest deviation being 30 feet in some of the largest deltas. — Geol. Mag. Dec. Glaciers in Central France. — M. Martins has examined the valley of Palheres in the eastern part of the granitic massif of the Logere, and foimd evidence of the former existence of a glacier. It was a glacier of the second order, one of those which, limited to the cirque which contains them, do not descend into the valley.’ The crest of the vast cirque into which the valley of Palheres rises is capped by an elevated ridge, the summits of which, to the north and east, are formed of a white refractory granite. M. Martins found the fields and woods round the hamlet of Costeiladi within the eirqiie to be sown with innumerable erratic blocks, extending far up both the contreforts of the mountain. No signs of polished and striated surfaces or grooved pebbles were to be expected, as the base and contreforts of the valley are formed of mica-schist, too soft, of course, to streak granite or to take and retain a polish. The Foraminifera of KosteJ. — Herr Karrer has laid before the Vienna Academy his monograph on the fauna of foramicifera of Kostej, a place situated in the mountains forming the south-eastern boundary between Hungary and Transylvania. This fauna includes nearly 250 species, a great number of which are new, and particularly remarkable — such as Dactylopora miocenica, Peneroplis lantei^ and numerous and beautiful [Mi- liotides. The fauna is that of a deposit of marine origin, corresponding to the miocene stage of the Vienna and Hungary basins, and marking thus a horizon intermediate between the oldest deposits of this middle tertiary sea (Baden clay) and the littoral formations of more recent date (calcaires ley- fhiens). — FPistitut, Dec. 2. Ormerod's Geological Index. — A second edition is, we believe, now nearly complete, and contains the papers in the Quarterly Journal for 1868. Mr. Ormerod’s address is Chagford, Exeter, and geologists who find errors in the Index are requested to communicate with the author of the Index. The genus Trimerella (Billings) is the subject of a paper (translated) by Dr. Lindstrom in the Geological Magazine for October. The specimens de- scribed were found in limestone beds in the upper Silurian of Gotland. The author, having received drawings and descriptions of the specimens of Mr. Billings, found in Canada, declares that the two series of specimens are the same, those of Gotland being the more perfect. A plate accompanies Dr. Lindstrom’s paper, in which the shells are well figured. The greatest peculiarity of the genus the author thinks consists in the presence of two siphons or tubes that penetrate the shell along the median axis of the valves or on both sides of it. These siphons, by degrees, taper off, and cease in the vicinity of the apex of the valves ,* their openings are of an ovate oblique form on the interior surface of the valves, and almost in the centre. An elevated shield, hiding the continuation of the siphons in its interior, is 92 rorULAR SCIENCE REVIEW. formed by the conceutric shell-layers that envelop the siphons, and, on the surface, by the mantle and other soft parts. This median elevation is smooth, having no impressions of muscular parts, and is deeply concave along the median axis. The lateral walls of both siphons are contiguous to the median axis of the valve, and continue as a straight ridge for a con- siderable distance down towards the inferior margin of the valve. The soft parts that secreted the concentric layers of the siphons, by degrees moved downward during the growth of the animal, filling the place they once occupied with shelly matter. Thus the apices of the siphons are generally found filled with concentric layers. Some faint longitudinal striae are seen on the interior walls of the siphons. The concentric layers around the siphons form two strata that are quite distinct from the rest of the shell- matter, and are embedded in it. They cannot, therefore, the author thinks, be confounded witli septa, which, when they do occur in the shells, are in immediate contact with the valves, and compactly united with them. The siphons of the dorsal valve are shorter than those in the ventral valve, and often more divergent. Dr. Lindstrom thinks we gain the true interpreta- tion of the nature of these siphons, if we attentively examine the interior surface of the valves in the genera Lingula and Oholus. The corresponding part of the valve of Lingula being occupied by two impressions of the ad- ductors, situated on each side of a broad, faint, shield-like elevation. Though in some points he admits the relation between Trimerella and the Lingulidcej he thinks there are many features, especially characters of the dorsal valve, which widely separate it from this family. The valves, he states, attain a thickness of fifteen millimetres, and consist in their perfect state of cal- careous spar. Chemical Geology. — Mr. David Forbes, F.R.S., has sent us a very interest- ing paper (reprinted from Chemical Netos, Oct. 23) on some points in Che- mical Geolog}’. Tn this Mr. Forbes deals in trenchant and forcible language and conclusive logic with the question of the constitution of the earth. Criticising M. Delaunay’s late memoir before the French Academy of Sciences, he argues, with M. Delaunay, against the views of Mr. Hopkins and Archdeacon Pratt. Ho demonstrates that the reasonings of these writers were very correct so far as they went, but that they were based — as not a few mathematical reasonings are — on purely arbitrary premisses. Mr. Forbes’s paper is one that will be read with the deepest interest, and though his conclusions, like many scientific inductions, cannot be accepted as defini- tively proved, they certainly appear to us much more on the side of truth than those of the opposition. The Mi)u-ral nature of Eozoon. — INIessrs. King and Ilowney, persisting in their views on this subject, sent in a memoir on the so-called Eozoonal rock ” to the Geological Society on Wednesday Dec. 23. SCiENTinC SUMMAIIY. 93 MECHANICAL SCIENCE. Radiation from Steam Boilers. — Some interesting experiments have been made by Messrs, Fox, Head & Co, at Middlesborough-on-Tees, on the effect of a non-conducting coating of cement in reducing the radiation of heat from the surface of steam boilers. The boiler experimented on had a superficial exposed area of 280 square feet. In the first experiment with the boiler un- covered, 14-8 cubic feet of water were evaporated per hour ; in the second experiment, the boiler having been covered with non-conducting cement, the evaporation was at the rate of 20-4 cubic feet per hour. The coal used, and the circumstances under which the water was evaporated, were exactly the same in the two cases. Liquid Fuel on Shipboard. — Messrs. Dorsett and Blythe, of the Patent Fuel Company’s Works, have ^fitted on board the Retriever, a screw steamship of 600 tons burden, an apparatus for the generation of steam by the combustion of creosote and other liquid hydrocarbons. The creosote is first evaporated in two small vertical boilers, or generators, and the vapour is then conducted to the furnaces of the steam boilers, in which it is burnt. At starting, an ordinary fire is kindled in the generators, and when the pressure of the creosote vapour rises to about 20 lbs. per square inch, a portion of the vapour is conducted into the firebox of the generators, and supplies all the heat subsequently needed for the evaporation of the liquid fuel. The Retriever has been tried on the Thames with perfect success, the apparatus working without a hitch, and the combustion being apparently perfect. It remains to be seen whether any practical difficulties in the application of the system will be found on more extended trial, and whether the economical results are such as to j ustify its adoption. Apparatus for exhibiting the Laws of Wave Motion. — An extremely in- teresting paper on the laws of wave motion, and on an apparatus for illus- trating them, by Professor 0. S. Lyman, will be found in Fngmeering , Nov. 6. The apparatus exhibits to the eye not merely the motions of the surface contour of a wave, but also the motions that are at the same time taking place below the surface, in the whole mass of liquid affected. Solar Engine. — Captain Ericsson has been making experiments on the utilisation of solar heat in the production of mechanical force. According to a notice transmitted by him to Engineering (Nov. 27), his experiments, in which the radiant heat of sunbeams of from 650 to 5180 square inches in section was concentrated on a small surface, do not altogether confirm the results obtained by Pouillet and Herschel with the small instruments hitherto employed for measuring the quantity of radiant solar heat. Further experiments are to be prosecuted, and in the mean time he states that several experimental engines have actually been constructed, actuated by the sun’s radiant heat. In some of these engines, atmospheric air heated to 480° by concentrating the sun’s rays is used ; in others, steam generated in the same way. A regular and continuous rate of 300 revolutions per minute has been attained by some of these engines. Lntercommunication in Railway Trains. — It has now been made imperative on railway managers to provide means of communication between passengers 94 POPULAR SCIENCE REVIEW. nnd guards in all trains running greater distances than twenty miles without stopping. "With a view of determining on the best means of complying with the requirements of the Board of Trade, a meeting of engineers and others interested in the matter has been held at York, and a series of expe- riments were carried out on the various systems proposed. Amongst these systems we may mention that of Mr. Ivamsbottom, in which a whipcord line is extended from the engine to the rear van, attached on the former to a whistle and at the latter kept in tension by a weight. If the rear guard pays out line, or if a passenger cuts the cord, the whistle sounds, being opened by a spring as soon as the tension on the cord is diminished. ?>Ir. Harrison has a rope system in which the whistle is opened by a pull on the cord, the lengths of rope being permanently attached to the carriages, and joined between them by hooks and eyesj when the rope is pulled a semaphore is released and fixes itself so as to indicate the point from which the signal has been given. Various electrical systems were also tried. More recently, Mr. Latimer Clarke has produced a pneumatic system, on which experiments have been made at Sevenoaks. This consists of a heavy gong on the engine, and a smaller one in the guard’s van. Both gongs are struck by hammers actuated by the train itself. The gear which actuates tlie hammers is connected with vacuum cylinders connected with a pipe running the whole length of the train, from which the air is continuously exhausted by a pump on the tender. The pipe is in communication with plugs in the carriages. Any passenger pulling out one of these plugs de- stroys the vacuum in the pipe, the mechanism of the gongs falls into gear, and the gongs are sounded. This system of Mr. Clarke answered its pur- pose admirably in the experimental trial, and certainly appears to possess many merits. MEDICAL SCIENCE. Bacteria in Glanders and Farcy. — MM. Christot and Kiener have found bacteria in the blood of glandered horses, and very abundantly and of large size in the spleen and in the pus. Along with this presence of bacteria there was usually leucocytlia3inia. — Coinptes-Rcndus, Nov. 23. Re-cstahlishmcnt of tSensihility after Resection of Nerves. — A memoir by .MM. Arloing and Tripier was read before the French Academy, Nov. 23, on the efiects of resection of certain nervous trunks. Clinical facts have several times shown tliat after wounds which have altered or destroyed a portion of a nerve, sensibility returns in the integuments to which the nerve is distributed. MM. Arloing and Tripier made nervous resections in dogs, and saw sensibility reappear after a certain time in the integuments to whicli the branches of the nerve were distributed, and in the peripherical end of the nerve itself. The Use of Fryotin after Operations. — M. Bonjeau states that the mortality from amputations has in the Ilopital de St. Andr(S in Bordeaux been greatly reduced by administering ergotin, 30 to 50 grains per diem, for a fortnight, Vx'ginning its use immediately after the operation. The result lias been the absence, or at least the marked diminution, of suppuration. It appeared to SCIEISTIFIC SEMMAIiY. 95 act nearly as well when Applied to the wounds themselves. — Co7nptes-Hendus for Nov. 30. Creatine in Milk. — In a note to the French Academy^ M. Commaille announces that he has obtained creatine from putrefied whey. This is^ without doubt^ derived from creatine by dehydration, so that, according to M. Commaille, the latter substance must be a constituent of new milk. Its presence has not been hitherto made out on account of the large quantity of other matters with which it is united in new milk. M. Commaille finds in the presence of creatine a new analogy between milk, blood, and meat, and doubts whether creatine is an excrementitious matter. hifluence of Vei'atrwn 07i the Heai't. — M. Oulmont, who has been con- tinuing his experiments on the physiological action of Veratrmn viride and on its therapeutical effects, recently read his second paper on these subjects before the French Academy of Medicine. He finds that the resinous extract in doses of about a centigramme every hour lessens and steadies the pulse, and considerably diminishes the temperature. Tie has tried it in pleurifcis, pneumonia, and typhoid fever, and while it gave bad results in the first and third, it proved of immense service in the second. Muriate of Aimnonia as a cure for Neuralgia. — Many of our non-profes- sional readers have no doubt heard of sal-ammoniac as a remedy for certain forms of toothache, and perhaps have tried it with advantage. There has hitherto been a great dearth of scientific information on the action of this remedy. We therefore direct attention to an able paper on Muriate of Ammonia in certain nervous disorders,” which has been written by Dr. F. E. Anstie of Westminster Hospital. Dr. Anstie shows that while the muriate is surprisingly beneficial in some cases it is inert in others. But he recommends that it be given a fair trial. Our own observations fully accord with Dr, Anstie’s published views. — See The Tractitioner for December. Vih'iones developed after administration of Cyclamine. — In the third num- ber of the Archives de Physiologie, M. Yulpian describes some experiments made on frogs by injecting the active principle of Cyclamen Europceum beneath the skin. After death the blood is found loaded with vibriones, and these in some cases are seen within the substance of the corpuscles themselves. Methyl- and Ethyl- Strychnia. — MM. Jolyet and Cahours have, in a recent number of the Co^nptes-Re^idus (November), at last recognised the splendid inquiries of Messrs. Fraser and Crum Brown. But singularly enough they express an opinion to the effect that this field of research — the influence of substitution on the physiological effects of alkaloids — is especially their own. We don’t agree with them. Devonshire as a health-resort. — As one of the chief peculiarities of the Devonshire climate is supposed to be its moisture, we would refer those of our readers who are anxious to obtain some scientific knowledge of the hygrometric facts to a valuable paper on the rainfall of Devonshire, by Mr. W. Pengelly, F.R.S., in the Transactions of the Devotishire Associa- tion for the Advancement of Science for 1868. After giving numerous care- fully drawn up tables, the author says : In brief, Devonshire stands first among the English and Welsh counties, and in descending order thirteenth OG rorULAU SCIEAX'B REVIEW. in its mean annual fall, ninth in the average number of wet days, and twelfth in its mean daily Ml. Compared with the entire country, its rain- fall is 23 per cent, ; its wet days G per cent., and its daily fall 15 per cent, above the average. Liebtff's Extract of Meat. — Baron Liebig has forwarded to us some samples of his improved “ extract,” prepared by the Fray-Bentos Company. These we have not yet satisfactorily examined, but there is reason to believe that this extract is in point of flavour a great improvement on the previous pre- paration. We may, in passing, call attention to the fact, that the experiments recently made by Herr Kemmerich, and held by some to prove that the extract is in large doses injurious, have been of so inexact a character, and made in such a peculiar manner, that they must be regarded as inconclusive. The Practitioner was the first journal to call attention to them in this country, and it by no means concurred in Kemmerich’s expressed opinions, but, on the contrar}", stated that they required confirmation. Journals like Once a Week and others, which make a sort of ill-digested meal of the thoroughly scientific periodicals, copied part of the paragraph in the Prac- titioner, but not all, and occasioned a good deal of mischief, through leading the public to believe that the extract of meat is poison. As the first journal which drew attention to the Extractam carnis in this country, we may be allowed to express our protest against crude experiments and hasty conclu- sions like those of Dr. Kemmerich. For a complete exposee of Kemmerich’s opinions, our readers should refer to a letter by Baron Liebig, which ap- peared recently in the Lancet (November). Spontwieous generation. — In reference to this questioned phenomenon, a paper of M. Tr^cuFs has lately been laid before the French Academy. The author's conclusions relate especially to the formation of yeast in beer, and are as follow: 1. Yeast cells maybe formed in the must of beer without .spores being previously sown. 2. Cells of the same form as those of yeast, but with difterent contents, arise spontaneously in plain solution of sugar, or to which a little tartrate of ammonia has been added, and these cells are capable of producing fermentation in certain liquids under favour- able conditions. 3. The cells thus formed produce Penicillmjn, like the cells of yeast. 4. On the other hand, the spores of Pcnicillium are capable of being transformed into yeast. Finally, he states that spontaneous gene- ration is the great obstacle to satisfactory observation.^, because it mixes its own products with those placed by the observer for experiment. — Vide JMnditut, December 23, 18G8. The Phg biological Action of Cganogcn Gas. — Ilerr Dr. Laschkewitsch, from his experiments with cyanogen on blood, and on frogs and other cold- blooded animals, and birds, guineapig.s, &c., draws the following conclu- sions: 1. Cyanogen does not enter into chemical combination with hnemnglobin, although it changes it as it does other albuminoid bodies. 2. The ciliary motions of tho epithelium are increa.sed by a weak solution of cyanogen, and arrested by a concentrated solution, cyanogen in this respect agreeing with ammonia. 3. The strong tetanic cramps are caused by the action of the cyanogen on tho central nervous system. 4. Tho stoppage of tho heart arises from irritation of the vagus nerves. 5. On the p.Tipheral nerves cyanogen acts ns a powerful irritant. G. The blood SCIENTIFIC SUMMARY. 97 of animals poisoned with cyanogen shows clearly in^ its spectrum both the lines of oxyhaemaglobin. — Archiv f. Anat. u. Phys., November. The Conduction of Sensory Impressions. — In an article in the December number of the Archives de Physiologic, Dr. Brown-Sequard states that the conductors of sensory impressions do not cross in the base of the brain but reach it already crossed, and that, therefore, their intercrossing must take place in the spinal marrow. Experiments on Transfusion, — At a recent meeting of the Vienna Aca- demy of Sciences, Herr Mittler read a paper detailing his numerous experi- ments on this important problem. He finds that transfusion is a much less dangerous operation than has been supposed by medical men generally. He repeated the old experiment of introducing birds’ blood into the vessels of mammals, and found, as did previous physiologists, that the oval cor- puscles may be distinguished for several days, but that ultimately they dis- appear. Ills results may be summed up as follows : 1. Blood directly transfused from one vessel to another does not provoke coagulation in the circulation of the animal submitted to the operation, whether it be allied or not to the one from which it receives the blood. 2. Blood directly trans- fused continues its functions within the vascular system of a kindred animal much more completely than blood injected after having been deprived of its fibrin. 3. Blood directly transfused from an animal not allied to it is gene- rally borne by an animal better and in markedly larger quantity than blood defibrinated previous to injection. 4. The blood-globules of mammifers can be seen for two or three days after in the blood of birds submitted to injection. 6. The narrowest capillaries of mammalian animals present no obstacle to the passage of the large elliptical corpuscles of birds. 6. Sup- positions still strongly believed in, as to the toxic action of foreign blood are either inexact or erroneous : the coagulation of this blood, and the existence of the carbonic acid which it contains have no influence on the symp- toms caused by it. 7. Blood injected or transfused is some time after the operation secreted in many cases by the kidneys. Sometimes effusions of blood are observed in the parenchyma of the wounds caused by the operation. 8. It may safely be admitted that blood corpuscles thus secreted first lose their colouring matter and then perish like those placed without the vascular system. 9. The experiments in question have not definitively cleared up whether the transfused blood loses its physiological powers immediately on being received into a foreign vascular system or whether these powers continue to exist for a certain period. — VInstitut, Nov. 18. METALLURGY, MINERALOGY^, AND MINING. On the Application of Chlorine Gas to1 the Toughening a?id Pejinmg of Gold. — A paper on this subject by Mr. f^Francis Bow3^er Miller, assayer in the Sydney branch of the Royal Mint, was read at the Chemical Society in November, which appears to be of great practical importance. If Mr. Miller’s process proves as successful in otherj^hands as in his, its simplicity and eco- nomy will ensure its extensive employment in this coimtry and elsewhere VOL. TUT. NO. XXX. II 98 POrULAR SCIENCE REVIEW. It consists in passing chlorine gas into the molten gold by means of a clay pipe dipping down to the bottom of the crucible containing it. No difficulty is experienced from the projection of globules of gold, as might perhaps be expected would be the case. The greater part of the chlorine seems to be absorbed at once, and no violent ebullition consequently takes place. The chlorine converts the silver into chloride, which floats in the liquid state on the gold. With the apparatus used by Mr. Miller, about eight ounces of silver were thus separated as chloride from gold alloyed with it, and at nearly a imiform rate, whether the gold contained much silver or little. To obviate the loss of the fused chloride of silver by inflltration into the substance of the clay pot, the latter is to be prepared by dipping it into a hot saturated solution of borax in water so as to be thoroughly impregnated therewith, and then drying it. No absorption of chloride then occurs with it. The volatilization of all but a very minute proportion of chloride of silver is prevented by the use of borax to form a fused layer over the chloride. The time required for the operation to bring the gold to a fineness of, say, 993 parts in 1000 is only a few hours, while the apparent loss of gold is very little more than what is known to occur in ordinary gold melting, being 2^^ parts in 10,000, whereas in ordinary mint melting the apparent waste is about two parts in 10,000. By apparent loss is meant the loss at the end of an operation, without taking into account the amount recoverable from ^ sweep,’ &c.” The slab of argentic chloride is reduced to the metallic state by placing it between two flat pieces of wrought iron, and immersion of the whole in sulphuric-acid water. But previous to this, as the cake contains a little gold (apparently in chemical combination), Mr. Miller recommends its refusion and treatment with a little carbonate of potash, which separates the gold and a little silver, leaving the chloride free from gold. Lastly, as regards the quantity of chlorine necessary, about twice the theoretical quan- tity only is required, half of it passing unused into the chimney. — Journal of the Chemical Society for December. The Differed Colours of Lahradorite. — A microscopical exammation of a number of specimens of this mineral in the collection of the Ecole Polytech- nique des Pays-Bas, all from the Labrador coast, has enabled M. Vogelsang to give an explanation of the splendid play of colours often exhibited by it. In the coloration of lahradorite its more or less crystalline structure plays an essential part, for the coloured specimens show usually a better cleavage than the colourless ones. The bright blue reflected by some specimens de- pends upon a certain crystalline state of the mineral, and is a phenomenon of polarisation produced by the passage of rays refracted by one lamina into another lamina, the planes of vibration of which do not coincide with those of the first, the result being a diflerence of phase and an interference of the luminous rays on reflection, just as with the ordinary colours of polarisation. Tlie golden-yellow colours proceed from a total reflection from interposed microlites which consist of magnetic oxide of iron, or else of diallage ; the red colour results from the reddish colouring of small lamella) of diallage j the association of these colours with the bliieish reflection accounts for the green and violet play of colours ; lastly, the coloured metallic reflection from lamina) of diallagc gives rise to the efiects of coloured aventurine. — Ar- chives nCcrlandaises des Sciences e.vacles ct naturellcs. SCIENTIFIC SUMMARY. 99 Titanifei'ous Magnetites. — In an article in the Chemical News for December lltb, Mr. David Forbes says that tbe only objection to tbe use of titani- ferous ores for smelting is that they are found to be more and more refractory in tbe blast-furnace in proportion as they contain a greater percentage of titanic acid. If much titanium is present, they require so much larger an amount of charcoal to smelt them as not to render their employment profit- able in a country where other ores free from titanium can be obtained at a reasonable rate. Employing a mixture of stamped quartz and lime as a flux Mr. Forbes obtained very satisfactory results •, and when the amount of titanium in the ore did not exceed 8 per cent., or was reduced to this per- centage by admixture of other ores of iron free from titanic acid, no difficulty was experienced in working this ore cleanly and profitably. The cast iron produced contained no phosphorus, only a trace of sulphur, and afforded 0-05 per cent, titanic acid, equal to 0’03 per cent, titanium, which Mr. Forbes imagines was rather mechanically intermixed than chemically combined with the iron. The cast iron, however, possessed a peculiar fracture, not easily described, but easily distinguished by the furnace-men, who could at once recognise the pig from these ores even after it had been remelted in the cupola. Assay of Silver in the Wet way. — It is well known to assayers that a diffi- culty in the application of Gay-Lussac’s process for assaying silver has to be got over, arising from the fact that in adding to the silver solution the standard solution of salt, a point is reached when the liquid will give a precipitate by the addition of either silver solution or'chloride of sodium. M. Stas points out in a letter to M. Dumas that this is entirely avoided by substituting bromide for the chloride. — Comptes-JRenduSj Nov. 30th. Convei'sion of Pig Iron into Steel. — The Mining Journal speaks very highly of the working of Mr. Heaton’s patent at the Works close to the Langley Mills Station of the Midland Dailway. The process by which the iron is converted is by the use of nitrate of soda, by which the whole of the phosphorus is evolved. The pig iron is put into an ordinary furnace for about three-quarters of an hour, and then is run into the converter, and in the course of four or five minutes the converting process has been com- pleted. The process for melting the pig iron is an ordinary one, there being an inclined tramway leading to a platform, and thence to the charge- hole. There are tuyeres for supplying air to the cupola, without any blowing engine. The steel is of uniform character, and appears to be capable of being adapted for almost every purpose for which steel is generally used. The cost of the plant necessary for the Heaton process does not exceed 600^. METEOEOLOGY, The Carbonaceous Matter of Meteorites, — By applying to the carbo- naceous matter found in some meteorites his method of hydrogenating organic carbon compounds so as to convert them into their corresponding carburetted hydrogens’, M. Berthelot has obtained carbo-hydrogens, both liquid and gaseous, which are similar to those of petroleums. A new aua- n 2 100 rOPULAR SCIENCE REVIEW. logy is tliiis shown between the carbonaceous matter of meteorites and that of organic origin on the surface of the globe. The Errors in the Measiirement of the Temperature of the Solar Radiation hy the Black-Bidh Thermometer. — In consequence of the diathermancy of black glass, of which black-bulb thermometers are usually constructed, Mr. It. L. J. Ellery has compared the indications of one of the ordinary black-bulb thermometers with another thermometer with its bulb coated with lamp-black. These thermometers read the same in the shade, and as ordinary thermometers w^ere accurately intercomparable. In the sun, the coated bulb always attained a higher temperature than the other, and the difference was found to vary with the temperature — the greater the tempe- rature the greater the difference. For example, when the coated bulb thermometer indicated 77*3°, the black-glass bulb one indicated 70°; when the former indicated 155*7° the latter marked only 140°. Part of this differ- ence Mr. Ellery points out must be due to the polished surface of the black glass bulb reflecting many rays, which are absorbed by the dead surface of the blackened bulb. — Trans, of Roy. Soc. of Victoria^ pt. i. vol. ix. PHOTOGRAPHY. Use of Printing Press to Photographers. — In the Photographic News for December II, Mr. Thomas Gulliver recommends the use of the printing press to photographers for the purpose of printing their own circulars. Removal of Silver Stains from the Hands. — The same journal gives the following receipt as better than that recently recommended by Mr. Carey Lea : ‘‘ Put half a pound of glauber salts, quarter of a pound of chloride of lime (the sanitary disinfectant), and 8 ounces of water, into a small wide- mouthed bottle, and, when required for use, pour some of the thick sediment into a saucer, and rub it well over the hands with pumice-stone oi a nail brush, and it will clean the fingers quite equal to cyanide, but -without any danger. This will do to use over again until exhausted, and should Ikj kept corked up. The disagreeable smell may be entirely avoided by the lil)cral use of lemon juice, which not only removes the smell, but whitens the hands. Rotten ones may be used, and answer well.” Carrier's Sensitive Alhumenized Paper has thus been reported on by one of our contemporaries, whose editor had recently received a sample from Mr. Solomon. The specimen had been prepared nearly twelve months: ^^AVe found it perfectly unchanged in all respects, -vNuthout a trace of discoloration; and printed and treated throughout side by side with that just received from Mr. Solomon, there was no difference in result, both being perfectly clean and pure. The unchangeable character of this sensitive paper is thus proved }>eyond a question. Its qualities remain just the same as we before described them. It gives an exquisitely delicate and soft print, but lacks a little vigour, unless a negative with full contrast be employed. A special toning bath is recommojided, which wo before tried with success; this time we used an old sulphocytQiide of gold bath, made some months ago, with perfectly good re-*iflt4i.” SCIENTIFIC SUMMARY. 101 Lamps for Thotograpliy . — Two forms of lamp have been recently devised which deserve notice. One is the ingenious Electric Lamp of Mr. Browning, and the other the Magnesium Lamp of Mr. Solomon. Mr. Browning’s lamp is so contrived that the charcoal points are always kept together by means of an electro-magnet and armature. The upper bar containing the upper charcoal point, is the one which is clamped by the magnet when the current travels through it. This lamp is especially suitable for lanterns, giving a good 9 feet disc with a Grove’s battery of about 8 cells. Mr. Solomon’s Magnesium Lamp has, as usual, clockwork for uncoiling the ribbon off the bobbin. The ribbon is about 50 yards long, and will give a steady light for about two hours. Landscape Photography in Cloudy Weather. — Mr. M. Whiting, Jun., sends the following note to our interesting contemporary. The British Journal of Photography, No. 449: When taking distant views and a variety of scenery on a dry plate (especially in Scotland), on a cloudy day, where a part of the view may contain dark woods or other foliage, which, with an ordinaiy exposure would hardly come out sufficiently distinct, great assistance can be secured by the following plan : Suppose the whole exposure will require four minutes : first give two or three minutes with the average light, and, for the remainder, only uncap the lens when that part of the view you wish more fully to expose is lit up by the sun and the other part is in shadow. This is far more easy to do than it appears to be.” A new Mount for Photographs has been brought out by Mr. Fox, and is favourably spoken of. The new mount, instead of having a tint for imme- diate contact with the picture, surroimded by a broad white margin, is printed with a broad tint, which constitutes the margin, with a space of plain white in the centre, leaving a margin of white to come into contact with the picture itself. This effect with many pictures is very pleasing. For instance, in landscapes where the sky has printed through to a delicate tint, the print, if mounted on an India tint, would appear to have a white sky \ mounted, however, in contact with the white portion of a board having a tint beyond, the atmospheric tint of the sky receives its full value, and the picture becomes effective. The same is true of vignetted portraits in which the background softens into a grey tint instead of into white, and in a number of other cases the new style will produce a more pleasing result than any yet devised. Cheap Magnesium. — A writer in the Builder says : “ There is now a fair prospect of a reduction in the price of magnesium through some recent im- provements in its manufacture, and it is probable that in the course of next year we shall see the metal retailed at or under one shilling per ounce.” Photographic Paper. — A contemporary states that a prize of 2,000 fr. has been oftered in France for the production of the best photographic paper. The prize will be awarded in 1869. — Photo. Neics, Dec. 15. Treating Negative Baths. — Mr. M. Carey Lea gives the following results obtained by Dr. Jacobsen when treating disordered negative baths with per- manganate of potash : The first bath tried was an ordinary negative bath which had ceased to work clean. A solution of permanganate was dropped carefully in, so long as its deep red colour was destroyed by stirring up the bath. As soon as a drop of permanganate left a coloration which did not 102 POPULAli SCIENCE REVIEW. disappear the bath was filtered and gave clean pictures. The second was a bath which had been used with Harnecker’s collodion, and was choked up with organic matter producing fog. With this bath, four or five times as much permanganate was required as the other. When enough had been added the bath was filtered, and, at Jirst, gave clear pictures, but, after standing a little, fogged. On being acidulated with dilute nitric acid it worked perfectly. The explanation of this last lies in the tendency of the permanganate to render a bath alkaline ; therefore the proper mode of treat- ment is, if much permanganate has been added, to acidulate the bath. If but little has been needed the bath may be tried, and no acid need be added unless a tendency to veil show itself.” — See “ Spirit of the American Jour- nals ” in British Journal of Photography, Dec. 18. PHYSICS. A Neio Constant Battery. — This battery, intended rather as an intensity ” than a quantity ” battery, has been devised by Messrs. De la Rue and Muller. Having experimented with it since its construction was first made known in February, and more especially tested its electro-motive force, the inventors have recently given a detailed account of it to the Chemical So- ciety. The battery is compact and always ready for use j no porous cell is needed, and, witli the electrodes disconnected, the elements may be left im- mersed for several weeks, as the electro-positive metal is then scarcely acted on in consequence of the electrolyte being solid and very nearly insoluble. The positive metal is, as usual, zinc. It consists of Belgian zinc wire (English being objectionable from its impurity) 2f inches long and 0 2 inch thick. The negative element is pure silver in the form of wire 0-03 inch thick ; and round this is cast the electrolyte, a cylinder of chloride of silver 0*22 inch in diameter. The silver wire projects about 0*2 inch beyond the bottom end of the chloride of silver, and about 1 ^ inch above the top of it, so as to permit of its connection with the zinc of the next pair of elements. The cells are conveniently formed out of 1-ounce vials by cutting off the necks with a diamond or an ignited splint coal. The zinc and chloride of silver rods pass through, and are supported by a lath of varnished mahogany. The ends are pierced by two holes large enough to allow of it sliding freely up and do\Mi two vertical supporting rods of glass. Upon these glass sup- ports it is retained at any desired height by vulcanised caoutchouc collars ; tliese grip the glass rods with adequate iirmncss to support the mahogany bar, but at the same time permit of its being moved up and down with sufficient freedom to immerse tlie elements partially or wholly or to raise them entirely out of tlie liquid. Tlie raising is conveniently performed by placing the two forefingers ofeacli liand under the collars and pressing the thumbs on tlie top of tlie glass rods ; the lowering can be efiected by pressing down the two ends of the bar. The glass rods should not be vaniished on that portion over which the vulcanised collars have to slide, as the varnish causes too much friction ; below this point they may be varnished with ad- vantage. They are cemented into a base of varnished mahogany, in which SCIENTIFIC SUMMAKT. 103 is made a series of recesses to fit the cells and keep tliem in their places. This base rests on feet of vulcanite to increase the insulation. The zincs pass through holes in the bar and are kept in position by vulcanised collars. Above these collars another on each zinc serves as a clip for making con- nection with the silver wires, which is done by passing the wire between the zinc and the collar. The silver wires pass through holes pierced in pieces of gutta-percha or ebonite, fitted into the mahogany bar, the holes being only just large enough to permit of the wire being drawn through them. The zincs are better amalgamated, but need not be so. The cells are charged with a solution of salt in distilled water, 25 grammes to the litre. When the chlorine is more or less completely exhausted by the reduction of the cylinders through their entire thickness, the resulting rods of spongy silver can be renewed and reconverted into chloride with scarcely any loss of silver, so that the cost of the renewal of the battery is chiefly one of labour. The inventors find that their battery has about the same electro-motive force as Daniel’s battery. They also give experiments showing the constancy of the battery. TAe delation of Mechanical Strain of Iron to Magneto-electric Induction,-^ Mr. G. Gore has established, by means of an apparatus he describes in the Philosophical Magazine for December, that a magnetised soft iron wire during the ^ct of being stretched (either with temporary or permanent elongation) increases in magnetism and produces in a coil of insulated copper wire sur- rounding it, a current of electricity in a contrary direction to that of the hands of a watch when we are looking towards its south pole. A Molecular Change in Tin produced hy Cold. — At St. Petersburg last winter, according to Herr Fritsche, tin exposed to a temperature of 40° below zero, was converted into a semicrystalliue mass, containing cavities like basalt. Some of these cavities in masses of 25 or 30 kilos, of tin had a volume of 100 cubic centimeters. According to M. Dumas facts of this kind were not new in Russia in one case the organ pipes in a church were so altered by the cold as to be no longer sonorous. The fracture of axles by cold is perhaps a fact of the same nature. — Comptes-Pendus, Nov. 30. A New Method of measuring the Intensity of Light. — A simple instrument for this purpose has been devised by Mr. Roger Wright, and has been recently described in the Proceedings of the Royal Society, for measuring approxi- mately the intensity of total daylight for comparative purposes. It consists of a solid rod of metal standing perpendicularly on a heavy base. The top of the cylinder is painted white vdth a black spot in the centre. A hollow tube blackened inside is made to fit exactly and slide over this rod. The rod is marked with a scale, beginning with zero at the base. To use the instru- ment, the tube is pushed over the rod down to the zero-point j it is then drawn slowly up, the observer looking steadily at the black spot, and when the spot vanishes in the gloom, the point is read off* on the graduated scale. This point will, of course, vary with the intensity of the light, and thus a measure of the intensity is obtained. A Neiv Differential Refractor for Polarised Light. — M. Jamin has de- scribed to the French Academy an instrument adapted to all the purposes of his differential refractor for ordinary light, by which polarised light may be employed instead. 104 rorULAE SCIENCE EE VIEW. Origin of the Heat developed, in the Cells of a Battery. — According to !M. Favre, the heat which is not found in the galvanic circuit, hut confined within the cell, can only be traced to the intervention of the following cir- cumstances, alone or united : 1st, the condensation of hydrogen on the pla- tinum (of a Smee’s couple), wdiich becomes an obstacle to the transmission of the current ; 2nd, the local action due to the passage of hydrogen from the nascent to the ordinary state ; 3rd, the action, also local, due to the con- version into sulphate of the zinc deposited on the platinum of the couples by the electrolysis of the sulphate of zinc constantly increasing in the liquid in the cells. — Comptes-llendus, Nov. 23. The Illuminating Potocr of Flame. — M. Deville cannot agree with Dr. Frankland in considering the degree of luminosity of a flame to be dependent upon the density of the gases forming it. The illuminating power of a flame entirely gaseous is a specific property connected with the production of the spectral lines furnished by the matters it contains j and is as inexplicable as the specific properties of the bodies themselves, such as density, colour, &c. For a flame to be luminous it is only necessary for it to be white, that is, for its spectrum to be extended. When the tempe- rature is raised all metallic spectra acquire new lines, take all the difierent colours which together form white light, and consequently acquire a greater illuminating power. — Comptes-Bendus, Nov. 30. Why Soap-Bubbles can be blown, and not Water-Bubbles. — Viscosity, as ordinarily understood, is quite insufficient by itself to explain the bubble- forming capability of certain liquids. According to M. Plateau (Comptes- Jiendus), “the superficial layer of liquids has a viscosity peculiar to it, and independent of the viscosity of the interior of the mass; in certain liquids this superficial viscosity is stronger than the interior viscosity, and often very much so ; in other liquids it is, on the contrary, weaker than the inte- rior viscosity, and often also very much so and he is led to conclude from his experiments, that for a liquid to be capable of being spread out in sheets at once large and persistent, and consequently for it to permit of being blown into bubbles, in the first place its superficial viscosity must be great ; but besides this, its tension must be relatively feeble ; in other words, the ratio of its superficial viscosity to its tension must be sufficiently high. Researches on Calorific Spectra. — Further experiments by M. Desains serve to establish the statement he had previously made to the French Academy, that if in perfectly pure spectra pencils are isolated, composed of rays whose deviations through the same prism are almost identical with each other, they will be found to be very unequally transmissible through the same absorbent medium when they proceed from difierent sources (Comides- Rendus^ Nov. 30). F Instil ut remarks that this discovery of M. Desains gives the coup de grace to the error firmly rooted in the minds of physicists, that a colour or a radiation is perfectly determined either by its wave-length or by the duration of its vibration. Similitude of Jlydraulic Trajectories. — According to M. Brettes, hydraulic trajectories appear to be similar when the initial velocities of the water coming out of similar orifices make the same angle with the horizon, and are proportional to the square roots of the diameters of these orifices if they SCIENTIFIC SUMMARY. 105 are circular, or of their homologous diameters if they have any other form. — Comptes-Rendus, Nov. 2 and 30. Mode of Conduction of Heat hy Bodies. — M. Magnus has read an important paper before the Berlin Academy of Sciences, furnishing the proof of the proposition already asserted by him, that heat is propagated in bodies by transverse vibrations like light, or, at the very least, that transverse vibra- tions play a most important part in the transmission. M. Magnus had shown in a previous memoir that heat radiating at an angle from a red-hot and polished plate of platinum proceeds both from its surface and from its interior, this being a consequence of the polarisation of the heat which radiates from this surface. The plane of polarisation has the same situation as that of light refracted at a certain angle. It must therefore be admitted that a portion at least of the rays is refracted at the surface ; but for this re- fraction to be possible the heat must come from the interior of the platinum. This polarisation is effected according to the same laws as those of light, and therefore the interior propagation must be performed, like that of light, by transverse oscillations. M. Magnus had asserted his proposition on the grounds that the motion called heat cannot be double, and that its pro- pagation when made through air, through a vacuum, or through any other diathermanous substance by means of transverse oscillations, must be of the same kind as in the interior of athermanous bodies which we call conductors. But this conclusion was not a certain one j the only point of it made out was that heat was polarisable. But if it is proved that heat radiating at an angle at any temperature whatever, and therefore at a very low one, is also polarised in part, it will be established, even for opaque bodies, that the heat radiated by them proceeds partly from their interior, and is propagated in them by transverse oscillations. It would then be proved, M. Magnus believes, that the conductibility of heat, or its propaga- tion in athermanous bodies, rests on transverse oscillations. In his present communication M. Magnus has furnished this part of the proof required, by experiments which establish that bodies heated to 100° radiate polarised heat. — I! Institute Nov. 18. A nev) Exciting Liquid for Galmnic Batteries. — A French chemist sug- gests the following compound liquid for electro-galvanic batteries : Twenty parts of protosulphate of iron in thirty- six parts of water, seven parts of sul- phuric acid, and one part of nitric acid. He declares this to be the most powerful and exciting liquid, attacking iron, zinc, and other metals, without any evolution of hydrogen or binoxide of nitrogen. — Nev) York Medical Record, Dec. 1. A neio way of Detecting the Discordance of Diapasons. — A means of dis- covering a want of accordance between two diapasons has been pointed out by M. Lissajous, in a note to the French Academy. They are to be made to vibrate, and then put in connexion wdth a bath of mercury. When they are in accordance the surface of the mercury remains perfectly calm. If there is discord between them waves are produced on the surface directed towards that instrument of which the vibrations are the less in number. — Elnstitut, Dec. 16. 106 rOPULArv SCIENCE EEYIEW. ZOOLOGY AND COMPARATIVE ANATOMY. The Frcsh-ivater Cmstacea of Belgium. — M. F. Plateau has given the following abstract (^Co7nptes-BenduSj Nov. 23) of his memoir on the genera of Gammarus, iywcci/s, and C^jpris. Gammai'us puteanus (Koch) is a species and not a variety ; its rudimentary eyes perceive light. The species of Lynccus have maxillre for trituration, furnished with a crown of conical tubercles ; their digestive tube, instead of being simple like that of Baphnia 2ndex, is distinctly divided into oesophagus, stomach, small and large intes- tines ; the other members than the antennae affect three different forms : natatory appendages (first pair), appendages for the production of the aqueous current (second and third pairsj, appendages exclusively respiratory (fourth and fifth pairs). The male reproductive apparatus is lodged in a pouch borne by the last joint but one of the tail ; it is formed of two sacci- form testes and two deferent canals, opening at the base of the caudal plate. The females, like the Daphnise, carry well-marked ephippiumsy but they are composed of two distinct capsules. Opposed to what Rathke has said of the Daphnire, the eye in the embryo is a single pigmentary mass, which aftenvards divides into two. IM. Plateau has confirmed by new observations the researches of Herr Zenker, who discovered the males of Cypris, and thus upset the old theory of the hennaphrodism of tliese animals. He shows, further, that the seat of formation of the spermatophores in the male Cypris is not the deferent canal, but the axial tube of the mucous gland ; that the form of the valves in the young is generally at variance with that which they assume in the adult j lastl}’-, he shows that Cypris, although resisting the privation of water for a certain time, does not manifest this property in a higher degree than most other small aquatic animals. The Scolex of Phyllohoth'ium in a Dolphin. — M. E. vanBeneden has found in the body of a male Delphinum deljjhis the Scolex of Phyllobothrium, a cestoid living in the angel-fish, and several sharks. Here, then, remarks M. van Beneden, is a cestoid which begins its evolution in a cetaceous, and completes it in a plagiostomous fish. The Animal “ Cell ” not essentially different in Functmi from the Vegetable. — In a paper read before the Association of German Naturalists, at its last session in Frankfort, on the Physics of the Cell, Hen* Wundt stated as fol- lows:—It used to be thought that the vegetable cell had to form organic matter, and that the animal cell had to destroy it in order that, by its alter- nation of creation and destruction, the general end of life might be attained. At present we are compelled to admit that, if the vegetable cell is the seat of a phenomenon of reduction by which carbonic acid is decomposed into its elements, a similar phenomenon is produced in the animal cell. Non- nzotised combinations, it is now known, can be formed in the interior of the animal cell. Alexander Schmidt was the first to observe that, after the addition of carbonic acid to blood, the total contents of carbonic acid dimi- nished in certain circumstances. This observation furnishes direct support to the idea of a phenomenon of reduction. The blood globule plays, there- fore, a part analogous to that played by chlorophyll in the vegetable cell in contact with the carbonic acid of the atmosphere. The only difference SCIENTIFIC SUMMARY. 107 whicli exists is, that in the blood-cell there is, besides, a process of oxidation going on which surpasses the process of reduction. Just as the chlorophyll of the vegetable cell absorbs carbonic acid, so does its colourless protoplasm absorb oxygen, and this corresponds completely to the absorption of oxygen by the blood-cell in the lungs. The Fauna of the South-west Coast of France. — Examining a great num- ber of specimens from dredgings and soundings off the south-west coast of France, M. Fischer has made out the following species of Molluscs : — Ncerea costellata (Deshayes) ; Fsammohia costulata (Turton) ; Lepton niti- dum (Jeffreys) j Leda tenuis (Phillipi) ; Area pectwieuloides (Scacchi) j Lima subauricidata (Montagu) ; Scissurella crispata (Fleming) ; Cyclostrema nitens (Phillipi) ; Rissoa soluta (Forbes) 5 Eulima bilineata (Alder) ; Man- gelia borealis (Loeven) ,• Mangelia elegans (Scacchi), &c. — most of which have not hitherto been found in France. M. Fischer points out that it was impossible to obtain these species along these coasts, on account of the shore sloping gradually towards the west, so as to form a vast terrace bounded by depths of more than 200 fathoms. In England and in Norway they are dredged a short distance from the shore at great depths. The existence of the submarine terrace on the French coast has made it neces- sary to go several leagues out to look for the deep fauna ; hence the appa- rent poverty of the French shore. It has been remarked by English authors, says M. Fischer, that a certain number, at great depths in the Mediterranean, are found in the English seas, without being present at intermediate stations ; and they have therefore concluded, without any geological evidence, that at the end of the tertiary epoch the Mediterranean communicated with the ocean by an arm of the sea traversing Aquitaine and Languedoc. The result of these dredgings spoils this conclusion, for it clearly demonstrates the continuity of the habitat of the species once con- sidered to be localised at points so remote. — L'lnstitut, Dec. 9. The relation of the Auditory Organ in Cephalophora to the Nervous Ganglia. — A memoir was read to the French Academy, at its first November meet- ing, by M. Lacaze-Duthiers, on this subject. From observation on more than thirty species of gasteropoda, he can no longer share the opinion of MM. Leydig, Claparede, and Huxley, which points so clearly to the imion of the otolite and the pedal ganglion. The acoustic nerve always takes its origin in the suboesophageal or cerebral ganglion, and though the auditory pouch may rest upon the locomotor pedal ganglion, its nerve never arises in this ganglion. So that the suboesophageal ganglion presides over all the organs of sense, which, to the pedal ganglion more particularly, motion is to be attributed. Sensibility and motor power are, therefore, distinct in all the groups of the cephalophorous molluscs as they are in vertebrate animals. A new Batrachian. — At the meeting of the Zoological Society, on Nov. 12, Mr. St. George Mivart gave a description of a new species of frog in his own collection, which appeared to constitute a new genus and species of Batrachians, and which he proposed to call Pachybatrachus robustus. Nature-painted Butterflies. — Dr. John Lowe, of Lynn, has sent us a note in reference to a notice in one of our recent numbers, of a collection of 108 rorULAR SCIENCE REA^IEW. butterflies, the wings of which are mounted and the bodies painted in, sepia. He says : “ It may interest your readers to hnow of a somewhat difl'erently prepared collection, the work of a deceased lady, in this neigh- bourhood, which for beauty and perfection exceeds anything I have yet seen. They comprise two large volumes, one of butterflies, the other of moths, and though executed between thirty and forty years ago, retain all the brilliancy of the recent insects. The mode of mounting is as follows : The wings, carefully separated, are laid on the paper, which is previously gummed to the exact extent of the surface to be covered, the surplus gum removed, blotting-paper laid over them and pressure applied until they are dry. The wings are then removed, leaving a correctly nature -printed representation. The body, legs and antennae are then painted in colours. In the collection are many of our rarest British species, such as the Camber- well Beauty, &c. They are not always laid out open, but are in every natural position : with expanded wings, in postures of rest, or poised upon leaves or flowers painted with extreme accuracy and with much artistic talent. The sheets on which they are displayed are mounted in a volume, furnished with a lock, and are thus kept from light and air. The result in the preservation of all their colours is most remarkable.” Xaturalist's Directory. — The excellent directory, which is being published in the Proceedings of the Essex Institute, Salem, United States, is not yet com- pleted. In the two last numbers of these Proceedings (Nos. VI. and VIL, vol. 5), the list of writers on insects is continued and completed ; those on crustaceans, worms, molluscs, radiates, protozoa, and parasites, are also com- pleted. An .appendix is furnished supplying names received since print- ing some of the list^. This includes five pages of names of workers in the following subjects : — geology, physical geogr.aphy, minerals, metallurgy, palaeontolog}', anatomy and physiology, microscopy, botanj", archaeology, ethnology, mammals, birds, fishes, insects, .and molluscs. A Catahyuc of the North American Birds in the Museum of the Essex Institute has been prepared by Hr. Elliott Cones, and is published in No. VII. of the Proccedi/if/s of the Essex Institute. Fhscidaria Campanulata. — There is a very excellent paper, accompanied by two good illustrations, on this subject in the Last volume of the Proceed- infjs of the Bristol Naturalists Society, which we have just received. The pap<;r was read about twelve months since by Hr. C. T. Hudson, M.A., but it contains such excellent matter that we have much pleasure in bringing it under the notice of our readers. The author deals with some important anatomical points, and he gdves .some interesting facts in connection with the habits of Elo.scularia. The Silhworm culture. — A paper on this subject, in which the history o-f tlie progress of the silkwonn disease, and of the mode of comb.ating it, is accurately and })opularl}- stated, will be found in the Ilcrue des Deux Mondes for t)ctober. It is from the pen of M. Bayen, of the Academy of Sciences. The same number contains a sketchy but instructive p.aper by M, Laugel on the eye and vision, in wliich the recent works of Helmholtz and M.ax Schultze are reviewed. Structure (f the Shell of Crustacea. — Mr. J. Shidc has a short paper in the Journal of the Quehtt Club for October, in which he describes tho SCIENTIFIC SUMMARY. 109 microscopic structure of the shell of Crustacea. He'refers to the inquiries of Williamson, Carpenter, and Huxley, and agrees Tvith the latter in deny- ing the cellular character of the uppermost of the inner layers. This quite agrees with our own observations on this point. It is to he regretted that no illustrations are given. Deep-sea Dredging. — On Thursday, December 17, Dr. B. W. Carpenter read the report of his researches in the North Atlantic, undertaken under the direction of the Government. It would be impossible to give anything like a satisfactory summary of the results he has arrived at in the short space of a paragraph. We may, however, mention one or two facts ascer- tained by Dr. Carpenter and Professor Wyville Thompson : 1. They have found at a certain point between the north of Scotland and the Faroe Islands that the water at the sea-bottom, at a depth of 500 fathoms, has a temperature of 32° Fahr., while the surface temperature was, as usual 52°. From the bottom of the sea were dredged up several boreal species and a large quantity of mud containing the peculiar protoplasmic substance which Professor Huxley has termed Bathyhius. 2. They have found that (so far as their researches went) the sea-bottom over which the Gulf-stream flows consists of a calcareous mud composed of living and dead Globigerinse, and coccoliths, and coccospheres embedded in Bathyhius, and seeming to have the same relation to it that the spicules of sponges or of Eadiolaria do to the soft parts of those animals. 3. That vegetable life is entirely absent at these depths, the Bathyhius seeming to be a sort of Protozoan of low type, and capable, like plants, of sustaining itself on the mineral kingdom alone. 4. That dredging may, with suitable apparatus, be carried on at almost any depth in the ocean. Dr. Carpenter is disposed to look on the cretaceous sea-bottom as the still-existing Chalk-formation, and he thinks this view flnds support in the fact that its basis is nearly the same as that of the creta- ceous deposits, that certain shells common to both exist, and that siliceous sponges are extremely abundant. Dr. Carpenter is now busily engaged in preparing an account of the Ehizopods collected during the expedition, and Professor Wyville Thompson is equally busily occupied with the siliceous .sponges. Professor Huxley and Professor Frankland have also special sec- tions allotted to them. Among the novelties we may state that these researches have clearly demonstrated the sponge character of Hyalonema. The Fauna of the Montana Territory in the Rocky Mountains has been dealt with by Dr. J. G. Cooper in the American Naturalist for December. Dr. Cooper’s paper is more general than technically zoological, but will be read with interest. The Ilahits of Spidei's have been very well and graphically described in this journal by Mr. J. H. Emerton. He takes as instance the Epeira vulga- ris, and gives the details of his numerous observations of this Arachnid. The Colorado Potato-Bug (Doryphora 10 lineata) is the subject of a very long paper, accompanied by numerous woodcuts, in the American Ento- mologist for November. This, the third number of the journal, seems to contain a good deal of gossiping information of interest to entomologists generally. The ciliary Muscle in Fish, Birds, and Quadnipeds is the title of a paper by Mr. R. J. Lee, in the Journal of Anatomy for November. We must say that 110 rOPULAR SCIENCE REVIEW. •we are dissatisfied with the author’s facts and illustrations. If there is any point in connection -with the ciliaiy muscle of great interest it is the minute relations which exist between it and the choroid on one hand and it and the cornea on the other. These, it seems to us, have in great measure been overlooked by Mr. Lee, who gives us enlarged but not microscopic figures of his dissections. If Mr. Lee would look over some of the specimens in Mr. Lockhart Clarke’s collection he would then see how much good work he has left undone. En passant, we would remark that the Reports ” on ^Vnatomy and Physiology in this journal are the most carefully and discrimi- nately arranged abstracts we have ever seen. The Lymphoid Organs of Amphibia. — A paper by Herr Dr. Toldt has been read on this subject before the Vienna Academy. The so-called thyroid gland in frogs is described, and its relations in functional analogy with the lymphatic glands in Mammalia pointed out. The situation and structure of the organ in the amphibia called the thymus are described in detail, and its probable functions indicated. — Elnstitut, Dec. 2. ■ S 1 Plate XlI W Went imp Pi.r^onaat , Nautilus an 1 Ammonite Ill THE CUTTLE-FISH. BY ST. GEOKGE MIVAKT, E.Z.S. Lecturer on Comparative Anatomy at St. Mary’s Hospital. [PLATE XLI.] IN the number of the Popular Science Keyiew of October last, we gave a short account of the structure of the Lobster, to serve as a type of one of the great primary groups into which the animal kingdom is divided. We now select another animal of an altogether different build to serve as a type of another great primary group. The Cuttle-fish is really no fish at all, as we shall soon see, and is almost, if not quite, as unlike a true fish as we have already seen the lobster to be. Its appearance is unprepossessing enough — a short swollen body (all soft externally — not shelly, as in the lobster), with a considerable head, from the crown of which radiate ten long arms, give it a fanciful resemblance to a great marine spider ; not that there is any real affinity between the two, the spider being formed on the same type of structure as is the lobster. The head (which is sometimes called the prosoma^ or front body) contains the organs of sense, and the mouth opens in the middle of its upper surface, in the midst of the radiating arms. The body, or abdomen (sometimes called metasoma, or hind body), is a great bag enclosing the circulating, digestive, and generative organs. This body is enclosed in a great fieshy envelope, which is called the mantle (or pallium), and which is firmly adherent to the body behind, but free in the front — like a smockfrock sewn down the back to the waistcoat beneath it, but quite unattached at the chest, where a space is left between the body and its investing garment. This space is called the pallial chamber; in it are placed the gills, and into it the intestine and certain ducts open. On each side of the body the mantle is, as it were, pulled out into a sort of fin (fig. 1 1). On the front surface of the body a sort of pipe (termed the funnel) is placed, which is open at VOL. VIII.— NO. XXXI. I 112 POPULAR SCIENCE REVIEW. each end. Its summit (fig. 1 /) projects upwards above the top margin of the mantle ; its lower end opens into the pallial chamber. The arms are ten in number :* eight of these are of moderate length ; but two (called tentacles) are very long, retractile, and expanded at their ends (fig. 1 t and i'). Each arm, on its inner surface, is furnished with a number of suckers {acetahula), each one of which may be compared to a small cupping glass on a short stalk. Each acetabulum has a toothed horny margin, and its interior, when it is in a passive state, is nearly filled by a muscular papilla, or small fleshy mass. This papilla, however, can be contracted, and then occupies but a small space at the bottom of the cup. The cuttle-fish seizes objects in this fashion. First it closely applies the horny margins of the acetahula to the surface of the object seized. It then immediately contracts the papillae, and thus produces a vacuum inside each acetabulum, causing a most intimate adhesion by atmospheric pressure. Yet, in spite of the excessive tenacity of the grasp produced by the simultaneous action of hundreds of acetahula, the cuttle-fish can let go its hold in a moment, by simply relaxing the con- traction of the papillae, and allowing them to return to their passive condition. The male cuttle-fish has a certain space on one of its arms devoid of suckers. * On each side of the head there is a very large and brilliant eye, constructed on essentially the same plan as the human eye, except that there is no iris, its place seeming to be supplied by a deep groove which runs round the lens of the eye. Moreover, the transparent coat outside the lens, i.e. the cornea^ is per- forated, thus presenting permanently a condition which tran- sitorily exists in higher animals. When the cuttle-fish is irritated, peculiar flushes of colour pass over its skin. This appearance is produced by the pulling open, by the contraction of very small muscular fibres, of little bags of bright coloured and differently coloured pigment, and which little bags when in their contracted state appear as small dark specks on the skin. These little bags are termed chroma- tojjJcoreSy i.e. “ colour-carriers.” Everybody knows the cuttle-bone. Its technical name is sejAostaire. It is a cellular, calcareous substance, the use of which is problematical, as, although it is light (with its inter- spaces filled with air), it can hardly have much effect as a float. Perhaps it serves rather as a point (Vappui, or possibly as a • in the Poulpc, and certain other forms, there are but eight arms, whence such are termed Octopods. THE CUTTLE-FISH. 113 protection to the animal while swimming backwards, situated as it is on the dorsal side of the body, and within the substance of the mantle or pallium. From its position it is termed a pallial shell (fig. 2 s). The action of breathing is so performed as to have a certain resemblance to the respiratory actions in ourselves, as it is accompanied by alternate contractions and expansions of the body. The mantle is first expanded, and the consequence is an inrush of water into the pallial chamber in which lie the gills. Then the margin of the mantle is closely applied to the body (becoming, as it were, buttoned up by the application of three cartilaginous prominences to corresponding depressions) and afterwards contracted, driving the water violently out of the funnel, which is provided internally with a valve so con- structed as to freely allow the egress of water, but to oppose its ingress. Locomotion and respiration are thus simulta- neously effected, as the stream of water issuing from the funnel drives the cuttle-fish in an opposite direction — that is, back- wards. This continual contraction and expansion of the mantle supplies the gills in the pallial chamber with a continually renewed supply of water for respiration. The mouth of the cuttle-fish is situated, as before said, in the middle of the circle of arms and tentacles, and within its lip is a horny beak quite like the beak of a parrot, except that the lower jaw, instead of the upper one, is the longer. These jaws are moved by powerful muscles, and bite vertically, and are altogether very different from the jaws of such a creature as the lobster. The tongue is a very peculiar organ, and one the presence of which characterises many creatures more or less allied to the cuttle-fish. It is termed an odontophore (tooth-bearer), and consists of an elongated ribbon-like structure (bearing small teeth), which plays to and fro, by means of special muscles, over a cartilaginous cushion, and acts much as a chain-saw. The mouth is moistened by the secretion of salivary glands, and there is a sack attached to the stomach which probably gives out a similar product. The gullet (which is furnished on one side with a crop) leads down into a gizzard-like stomach. The liver is much more solid and compact than in the lobster, thus approximating to the structure of higher animals. The cuttle-fish is provided with another, and a very peculiar gland, the secretion of which is of great use in helping it to escape its enemies. This is the ink-bag, which opens near the arms, and which produces an intensely coloured substance. When alarmed, the cuttle-fish suddenly expels some of this very dark product, which so colours the surrounding water that the animal is enabled to escape under cover of the obscurity so 114 POPULAR SCIENCE REVIEW. occasioned, like the gods of Homer rescued from perils on the plains of Troy by an overshadowing cloud. This “ ink ” is so capable of preservation, that some extinct fossil forms have had their portraits taken by means of the very pigment they had themselves secreted so many ages bygone, and which had been, of course, buried with them. Certain kinds of cuttle-fish which have the cuttle-bone (or sepiostaire) replaced by an elongated horny structure amazingly like a quill pen (fig. 5), have been . called on this account, and on account of their ink-bag, pen- and-ink fishes.” The circulating system of true blood is much more complete than in the lobster. The blood is brought back from all parts of the body to a large vein (the vena cava), which bifurcates its branches, going one to each of the two gills. As soon as each branch has arrived at the base of the gill to which it is destined, it dilates into a contractile sac called a branchial heart,” which pumps the blood up into the gill. The two gills are formed on essentially the same type of structure as are the gills of the lobster, being similarly formed for subject- ing the venous blood to the oxygenating action of the air me- chanically mixed up in the water. As in the lobster, also, they are destitute of vibratile cilia. The very substance, however, of the gills themselves is contractile, and the blood having traversed them is transmitted in its aerated state to the ven- tricle, or systemic heart. It reaches that ventricle by two contractile vessels, which may be considered as auricles, each auricle taking origin at the root of one of the gills, and passing thence to the systemic heart, which thus (as also in the lobster) distributes to the system oxygenated blood only. The kidneys are in the form of two bunches of grapes, situated one bunch on each of the branches of the vena cava. Each is placed in a chamber termed the atrial or water chamber. » This chamber is part of the true somatic or body cavity, and is separated from the perivisceral cavity {i.e. from that which surrounds the intestine, &c.) by the mesentery enclosing the viscera. The renal secretion (urine) is washed out, as it were, by the water of the atrial chamber, which chamber communicates with the pal Hal cavity by two small openings, one on each side of the anus. The nervous system is well developed, though very con- centrated, and consists mainly of what are primitively and essentially three pairs of ganglia, named respectively “ cerebral,” “ pedal,” and “ parieto-splanchesic.” The two latter, however, are quite fused together. The cerebral ganglia may be considered as representing the brain, and thence issue the nerves of sight and smell. This THE CUTTLE-FISH. 115 brain is close to the anterior part of the alimentary canal, and is sheltered by a cartilaginous framework, which is thus a fore- shadowing, as it were, of part of the true internal skeleton (viz. the skull) of higher animals. Unlike the lobster, all the muscles in the cuttle-fish are composed of unstriated fibres. The organs of smell consist of a pit between each eye and the tentacles, and, as has been said, their nerves are supplied by the cerebral ganglia. The eye has been already noticed. The ears are two small sacks, one placed on each side of the head in the lower part of the cartilage before mentioned, thus strongly recalling to mind the internal ears of higher animals. Each sack contains certain hard parts termed otolithes. The auditory nerves come not from the cerebral, but from the pedal ganglia. The sense of taste is probably effected by the agency of papillae situated at the base of the tongue. With regard to the reproductive system, each individual is either male or female, and the male, as has been said, has a suckerless space on one of his arms on the left side of the body. The sexual gland, whether testis or ovary, is situated at the lower end of the body, and its duct opens into the pallial chamber. Each sex is also provided with an accessory gland which in the female coats the eggs with a viscid substance, which connects them together, so that they resemble a bunch of grapes. The corresponding gland in the male, as we before saw to be the case in the lobster, coats the spermatozoa with its secretion, and thus they become enclosed in peculiar cases which from their office are termed Spermatophores, and which possess the property of expanding with force when wetted, and thus, becoming everted, scatter the contained spermatozoa. During the congress of the sexes, the male transfers these bodies from his own pallial chamber into that of the female. The egg is shaped much like that of the common fowl, but is full of yelk. Only part of this undergoes division, and the divided surface {blastoderm) gradually spreads itself all over the yelk. It is the haemal surface of the body which is first formed, and not, as in the lobster, and in higher animals, that part of the body at which the nervous system is situated. The surface of the blastoderm soon exhibits rudiments of the principal ex- ternal parts. In the centre appears what is ultimately the lower end of the body. On each side of this a fold is developed, and these two folds afterwards unite to form the funnel in the adult. At the anterior ends of these two folds respectively the eyes come into view, and between them the indication of the future mouth in the middle line in front, and of the future 116 POPULAR . SCIENCE REVIEW. anus in the middle line behind. On each side five small and similar buds appear, and these become ultimately the eight arms and the two tentacles. After a little time the essential similarity of the cuttle-fish to other nearly allied forms, such as the whelk or snail, becomes more evident as the body is more and more elevated above the egg. Then, while the embryo is still only bilaterally symmetrical, it is plainly to be seen that the incipient arms are nothing more than external outgrowths from, and prolongations of, that organ on which the whelk, snail and such creatures walk, viz. the foot, while the fold on each side above the incipient arms, and which is ultimately to become half the funnel, is seen to answer to a similarly placed expansion in certain exceptionally-formed creatures allied to the whelk, and which expansions have been named epipodia. As development goes on, the mouth is gradually brought into the centre of the radiating arms, which increase greatly in length, while the body mounts higher and higher, the pallial chamber gradually assumes its permanent form, the two halves of the syphon unite, and the intestine becomes convoluted, &c. Such is a short account of the more salient points in the structure of the cuttle-fish, which is a nocturnal marine animal preying on fishes, lobsters, and other sea-dwelling animals, which it seizes in its wonderfully tenacious grasp, while it tears them to pieces with its powerful horny jaws. The cuttle-fish is interesting, because it presents us with the most fully developed and complex condition of that type of structure to which it belongs. All snails, slugs, whelks, limpets, periwinkles, pteropods,* the argonaut, the nautilus, the extinct ammonites and belemnites, &c., all pretty closely resemble the cuttle-fish in structure ; while even all oysters, cockles, mussels, and the exceedingly numerous other creatures of that kind belong to the same essential type as does the cuttle-fish ; the whole of the above enumerated forms, with their allies, con- stituting one great primary division of the animal kingdom called AIollusca, just as all the creatures similarly allied to the lobster constitute another such great primary division termed Annulosa. A few words must be said, however, about some of the above- mentioned forms which most closely resemble the cuttle-fish in build, and are on that account associated with it in a subordi- nate group termed a chiss, and to which class the name Cepha- lopocLa has been applied, on account of the aggregation of the • These nre small, free, surface-swimming creatures, which abound in myriads on the surface of the open ocean, both in hot and in cold latitudes, n the latter they fonn the principal food of the whale. THE CUTTLE-FISH. 117 arms round the head. These forms are the argonaut and the nautilus and ammonites. The argonaut, sometimes called the paper-sailor, is best known by its beautifully delicate and translucent shell (PI. XLI. fig. 3), which, unlike the cuttle bone, has no organic connection with the body of the animal possessing it. The creature has eight arms, but two of these are enormously expanded towards their ends ; and the popular belief was that the argonaut sat in its shell with these expanded arms raised to act as sails, while with the others it propelled its boat by rowing. Its mode of locomotion, however, is really by the ejection of water from the funnel, and these expanded arms serve the singular office of secreting the shell over which they are externally applied (PI. XLI. fig. 3). Hence this shell is termed a pedal shell,” from its mode of formation, while the sepiostaire of. the cuttle- fish is called a pallial shell,” because it is formed in the sub- stance of the mantle. The argonaut presents another very singular peculiarity. For a long time — indeed, until the last few years — none but females were found ; but Cuvier discovered in the pallial chamber of one of these an elongated organised body covered with suckers, and containing a hollow chamber. The great naturalist placed it amongst the parasitic worms, and named it Hectocotylus. Subsequently Hr. Kolliker noticed the presence of chromatophores, and also of a multitude of spermatozoa in the hollow chamber ; and he concluded that the organism was a male argonaut, which thus would be an animal quite dissimilar in form to the female, and rudimentary in size as compared to her. Such sexual discrepancy, however, is well known to exist in many of the lower animals ; so that the idea, though start- ling, was by no means incredible. Since Kolliker’s observations, however, the true male (fig. 4) has been found by Henry Miller andVerany of Grenoa, and it turns out to be an animal like the female, except that it is consider- ably smaller, and has no shell and no expanded arms. What, then, is the Hectocotylus of Cuvier ? Why, it turns out to be nothing less than one of the tentacles of the male (fig. 4 A), who, in paying his addresses, not only offers his hand, or rather arm, but actually leaves it behind him in the pallial chamber of the female ! This peculiar action is not known to occur in any other cephalopod ; nevertheless, all of them are sexually distinguished by some modification of one of the arms, as has been already noticed with regard to our type. The nautilus (fig. 6) is an animal more different from the cuttle-fish than is the argonaut, though still belonging to the same class. It is found in the Chinese Sea and Indian Ocean, but is 118 POPULAR SCIENCE REVIEW. a rare animal. Unlike the cuttle-fish, it has a large shell, which, though pallial in its origin, is external in position. Moreover this shell is divided transversely by a succession of partitions, connected by a tube traversing them, all termed the “ siphuncle ” (fig. 6 s). The animal itself only inhabits the last chamber of its shell, which serves well for its shelter and pro- tection. The nautilus differs from the cuttle-fish mainly in the presence of this peculiar external shell, in having four gills in the mantle cavity instead of only two ; in there being a great number of tentacles all devoid of acetabula, instead of not more than ten, and these %vith acetabula; in being destitute of branchial hearts ; in having the beak partly calcareous, instead of entirely horny ; and, lastly, in having no ink-bag, the protection afforded by its shell no doubt rendering the sheltering obscurily producible by such a secretion much less necessary. The characters of this animal are of interest because it is the type of a very large group of cephalopods, which, as living forms, have now passed away from the surface of this planet — that is, unless deep dredging should bring to light any ancient form still holding out, as has been lately done by Dr. Carpenter for Echinoderms. The ammonites (fig. 7) are fossil forms, essentially resembling the nautilus as to the hard parts, and no doubt similar also in their softer structures. The nautilus, the ammonites and their allies appear, one or other, to have existed during the whole primary and secondary geological periods ; but what is more singular is that these four-gilled cephalopods appear in ancient times to have represented in the economy of nature creatures of the w^helk class, which do not then appear to have existed in any number, while with the progress of time the four-gilled cephalopods have all but disappeared, while the whelk-like class of molluscs has increased more and more, and now has com- pletely taken the place of their more highly organised and complex predecessors. Returning once more to the cuttle-fish (and recalling to mind the concluding observations previously made as to the lobster), we may note sundry fundamental facts of structure. 1 . The nervous system is disposed in three pairs of ganglia, and is not in the form of a chain either dorsal or ventral. 2. No elongated solid structure separates the nervous centres from the alimentary canal. .3. The most anterior part of the alimentary canal passes between the nervous centres. 4. The limbs are more than four in number. 5. There is no portal system. , 6. In development no visceral clefts appear. 7. The jaws are not modified limbs. THE CUTTLE-FISH. 119 8. In development the embryo does not present a longitu- dinal median groove. 9. The body is soft, is protected by a calcareous shell, and not by a hard chitinoiis envelope. 10. It does not consist of a longitudinal series of similar segments, either internally or externally. 11. The heart is auriculo-ventricular in structure. 12. In the embryo the haemal not the neural surface is first developed. The cuttle-fish differs from man by those of the above characters which are numbered 1, 2, 3, 4, 5, 6, 10, and 12. It differs from the lobster, on the other hand, by those of the above characters which are numbered 1, 7, 9, 10, 11, and 12. The cuttle-fish, moreover, agrees with the other ceplialo- pods, and with all snails, slugs, whelks, limpets, periwinkles, and pteropods, not only in the above twelve characters, but also in the presence of a head and of an odontophore ; in the gills not being in the form of lamellar plates ; and in the shell, what- ever its form, being single, and not divided into two valves, one on the right and the other on the left side of the animal, as is the case in all oysters, mussels, cockles, and other similar creatures. No animal known to exist now, or ever to have existed in past time, presents us with any intermediate condition tending to bridge over the chasm which yawns between the cuttle-fish type and the lobster type on the one hand, or between the cuttle-fish type and the human type on the other. Other types, however, exist, which are perhaps as distinct from any of these as they are from each other. Hereafter one of the other types here alluded to may form the subject of yet another zoological sketch. EXPLANATION OF PLATE.* Fig. 1, Sepia. Ventral aspect. t tentacle. m moutli. t' ditto, partly retracted. I lateral fin. f funnel. * These figures have been drawn (hy the kind permission of the Museum Committee of the Poyal College of Surgeons) from some specimens which form part of the educational series lately added so advantageously to the College of Surgeons’ Museum hy its zealous Curator, Mr. W. H. Flower, F.R.S. 120 rOPULAR SCIENCE REVIEW. Fig. 2. Sepia. Dorsal aspect. s sepiostaire, tlie mantle being cut and reflected. „ 3. Female Argonaut. p expanded arm applied to tbe outside of the pedal shell. „ 4. Male Argonaut. h the arm which becomes detached (hectocotylus). „ 5. Pen. „ 6. Nautilus, with its external siphunculate chambered pallial shell partly cut, to show s the siphuncle traversing the septa sepa- rating c y A. S. Packard, Jun., M.D. Part V. Salem, U.S., 1801). t “Disinfectants and Disinfection.” Dy Robert Angus Smith, Ph.D., F.K.S., etc. lOdin burgh : Edmonston and Douglas, 1860. X “ Handbook of Natural I’liilosophy.” Dy Dionysius Lardner, D.C.L. “Optics.” Edited by T. Olver Harding, D.A. London: Walton, 1869. REVIEWS. 177 publisher has done well in bringing- out a new series. The volume edited by Professor Carey Foster was devoted to magnetism and electricity, and was modified by him in accordance with the advance of scientific know- ledge. The present volume, on Optics, has been entrusted to Mr. T. 0. Harding ; but the result in this case has, though good, been by no means so successful as in the former instance. The chapter on the eye, the micro- scope, and on photographic optics, are to our mind not at all what they should be, and give us the idea that the editor has more mathematical knowledge than general experience in matters optical and physiological. The following remarks, which he has introduced to give novelty to the old edition, will certainly be new to ophthalmic surgeons : Since the rays of light which produce the sensation of different colours differ in wave- length, or, what is the same thing, since the vibrations they excite in the eye differ in rapidity, it follows that if the retina, whilst perceiving the exist- ence of the vibrations, be unable to appreciate the difference of their rapidity, vision will be unimpaired as to form and position, but differences of colour will not be perceived. Such a defect on the misorium of the eye is fortu- nately rare, hut not unyrecedentedr This is certainly a mild way of stating a defect so common, that candidates for situations as railway guards and engine-drivers have been so frequently found to display it, that they are now invariably put to the test as to their power of discriminating colours. Ophthalmologists know that this condition is by no means unfrequent. There are other parts of this book to which we object. Nevertheless, the volume is a sound one on the whole, and we can recommend it. Tommy Try, and what he did in Science, by C. 0. Groom Napier, F.G.S. Chapman and Hall, 1869. Tommy seems to have achieved so high a degree of scientific knowledge, at an age when most of the commonplace members of the British nursery still maintain an affectionate regard for lolly pops, that we fear to push his biography beyond the point at which Mr. Napier’s narrative commences. At this tender epoch of his existence, he had reached his seventh year, but he had already mastered the Linnean system of classification of plants, understood the laws of refraction of light, had been stung by a dead medusa, had distinguished the species from another, one also duly appreciated, and had experimented with mordants on the dyes of some cryptogamic algae.” To pursue Tommy further, would really be to travel out of the domain of Popular Science ; so Mr. Napier must excuse our leaving his young Crichton to other hands than ours, Catiset'ies Scientijiques, 1868. Paris : Rothschild, 1869. Is a year-book of scientific facts, and, like all such, is interesting and imperfect. 178 SCIENTIFIC SUMMARY. ASTRONOMY. ^RANSITS of Venus in 1874 and 1882. — If the next pair of transits of Venus should fail to afford a satisfactory determination of the sun’s distance, it will not be for want of due care on the part of our astronomers to prepare for the necessary observations. So far back as 1857 the Astro- nomer Royal called the attention of the scientific world to the requirements of each transit. He pointed out that the method wdiich was pursued in, 1761 and 1769 will be wholly inapplicable in 1874, and is embarrassed in 1882 with the difficulty of finding a proper station on the almost unknown Antarctic Continent. The recent publication of Leverrier’s new tables of Venus, and of calculations founded upon them by the indefatigable Mr. Hind, have induced the Astronomer Royal to re-examine the whole subject. He has come to the conclusion that it will be unsafe to trust exclusively to the chance of securing obseiTations on the southern continent in 1882 ; and that it will be desirable to make observations, both in 1882 and 1874, directed specially to the determination of the acceleration and retardation of the planet’s ingress and egress, as affected by parallax. In order to under- stand the principle on which this method is founded, let the reader suppose himself placed at that point of the sun’s surface where (as seen from the earth) first contact takes place, and that he watches from thence the passage of Venus across the earth. It is clear Venus would appear to him larger than the earth ; the disc of Venus would come up to the edge of the earth’s disc at a certain point and sweep across that disc, until at a point almost exactly opposite to the former the occultation would be complete. The proce.ss would last about ten minutes : the first point reached would clearly be that part of the earth’s surface at which the ingress of Venus would take place earliest; the second would be the part where the ingress would take place latest. And it is obvious that if two observers were placed at these spots, one at eacli, and severally timed the moment of apparent ingress, the knowledge of the exact interval would be available as a means of determin- ing the sun’s distance. Similar considerations apply to the egress. In practice, the pf»ints we have named would not be available, because the sun, as seen from them, would be upon the horizon at the moment of ingress ; but spots could be so chosen a.s to give a sufficiently large interval, and yet to allow the sun to be well raised above the horizon at the moment of ingress. So also for the egress. SCIENTIFIC SUMMARY. 179 As the cabsolute time of each phenomenon would require to be known, this method would not be available unless the longitude of each place of observation were known within a second or so. It is on this account that the Astronomer Koyal calls the attention of men of science to the necessity of preparing for the coming transits by carefully ascertaining the longitudes of places suitable for the proposed observations. Observation of the Transits of Venus by means of Photography. — Mr. Warren De la Rue, at the desire of the Astronomer Royal, has placed before the Astro- nomical Society a statement of the means by which photographic views of the sun taken at different places during the course of the transit, might be rendered available for the determination of the sun’s distance. What would be required would be— 1, the determination of the epoch of each photographic record ; 2, proper corrections of the photographs for optical distortion ; and 3, corrections (if experiment should suggest any) for shrinkage of the collodion. Mr. De la Rue proposes that six precisely similar instruments should be prepared and mounted equatorially, but without circles or driving clock, and sent to six convenient stations. The optical distortion of each instrument could be determined beforehand, and no further experiment would be necessary, as all the parts would be rigidly fixed. Major Tennant's Photographs of the Great Eclipse. — For several months after the receipt of Major Tennant’s telegram from India, announcing that six photographs of the sun had been taken, the scientific world had con- tinued in suspense respecting their value. Major Tennants letters had indeed rather tended to convey the notion that the photograph.s were com- parative failures, than that he had been completely successful. It was, therefore, a pleasing surprise when, at a recent meeting of the Royal Astro- nomical Society, Mr. De la Rue announced that the photographs were eminently valuable and interesting. After all the care and expense devoted to the preparation of the expedition, and the skill with which Mr. Browning had overcome the difficulties attending the construction of the 9-inch New- tonian for photographing, it would have been a matter for regret had the expedition been rewarded with anything but complete success. We shall await the publication of trustworthy copies of the photographs taken at Aden before considering Major Tennant’s photographs at length. One im- portant point will probably be settled by the comparison of the two sets of photographs. From direct observations of a great pointed prominence which attracted the attention of nearly all the observers of the eclipse, it appears probable that during the interval between the earlier and later views, this prominence underwent remarkable changes of figure. As it is depicted in Major Tennant’s photographs as an enormous spiral with convolutions diminishing in range from base to summit, it seems likely that processes of a remarkable character were at work at this part of the sun’s surface. As Aden and Guntoor are so far apart, there is every reason for hoping that the indications of change will be sufficiently marked when the two sets of photographs are compared. Indeed, from a drawing in the Engmeery which purports to represent the aspect of this prominence as seen at Aden, it seems tolerably clear that such a change had taken place. The Nebula in Argo. — It appears that, after all, there have been no such changes in this nebula as Mr. Abbott’s communication had led the astrono- 180 POPULAR SCIENCE REVIEW. mical world to suspect. Lieutenant Herscliel, at liis father’s request, has carefully examined the nebula with the five-inch telescope (refracting), supplied by the Eoyal Society for the eclipse-observations. From his drawings it appears that the stars in the nebula have not shifted their places, and that the nebula itself, so far as can be judged from the comparison between views taken with an 18-inch reflector and with a 5-inch refractor, has a shape now very much resembling that which it had when Sir John Ilerschel was at the Cape. It is brighter, or seems to be so j but the change may partly be ascribed to the change of v Argus (around which the nebula clings) from the first to the sixth magnitude. Method of viewing the Solar Prominences without an Eclipse. — It is an- nounced that Mr. Huggins has been successful in applying means to render the solar prominences visible when the sun is not eclipsed. If it should appear that the method is one which may become generally available, this discovery will be undoubtedly of extreme importance. Nothing seems now wanting for the determination of the exact nature and purpose of these sin- gular objects except the means of watching the processes of change which they may be undergoing. The Nehidar Hypothesis of Laplace. — Professor Kirkwood, of America, has discovered some very singular relations in (1) the asteroidal system, and (2) the system of rings and satellites circling around Saturn. He takes a list of 97 asteroids, and having arranged them in the order of their dis- tances, he examines those instances in which the gap between successive distances is considerably in excess of the mean interval. He finds that in every instance the gap corresponds to a mean distance such that an asteroid revolving at that distance would have a period commensurable with that of Jupiter. Thus, having first taken the 72 nearer asteroids (because the remoter, as more difficult of detection, require to be placed in a class by themselves), he finds that the mean interval between the first and the last of this set is 0-0081. The greatest gap in the order of distances occurs between Ariadne and Feronia, whose mean distances are respectively 2-2034 and 2-2G54 — so that the interval 0-0620 is nearly eight times the mean. Now a planet having a period equal to two-sevenths that of Jupiter would have a mean distance of 2 -2569, which it will be seen lies between the two values given above. Again, the interval between the mean distance of Thetis (2-4737) and that of Hestia (2-5178) is 0-0441, or more than five times the mean ; and a planet having a period equal to one-third that of Jupiter would travel at a mean distance of 2-5012. In the outer section, the mean interval is 0-0286. The greatest hiatus occurs between the mean di.stances of Undina and Freia (3-1917 and 3-3877), the breadth being 0-1960, or more than eight times the mean. A planet having a period equal to one-half that of Jupiter would revolve at a mean distance of 3-2776. And one or two other similar coincidences are noted. Undoubtedly this result is well worthy of notice ; and if these researches should be confirmed when the number of known asteroids is very much increased, they would seem to point to a physical cause as the only possible explanation. As it is, the doctrine of chances is largely in favour of Ih-ofessor Kirkwood’s view th.at such a cause has been in operation. He points to the efiect of com- mensurability of the sort considered, in causing disturbances in the motion SCIENTIFIC SUMMAEY. 181 of a small planet. Extending this view to the particles supposed upon the nebular hypothesis to have been travelling in a sort of cosmical cloud around the space now occupied by the zone of asteroids, he shows how all the par- ticles travelling in periods nearly commensurable with the period of Jupiter would be so disturbed as to take up eccentric orbits and so come into collision with outer or inner zones. Thus the zone they had belonged to would become vacant. Extending these considerations to the Saturnian ring-system, as affected by the nearer satellites, he shows how the theory supported in Proc- tor’s Saturn,” that the rings consist of multitudes of small satellites travel- ling nearly in one plane around Saturn, would require (on his hypothesis) that there should be a division in the rings wherever the small satellites would have a period nearly commensurable with that of one of the large satellites. Applying this consideration to determine whether a physical cause can be assigned for the great division, he has detected the following very singular relation. The period of a satellite revolving at a distance equal to the inferior limit of the great division is 10 h. 52 m. 11 s., while that of a satellite revolving at a distance equal to the exterior limit is 11 h. 35 m. 18 s. Now, between these limits lie the following proportional parts of the periods of the four inner satellites— one- sixth of the period of Dione (10 h. 66 m. 53 s.), one-third of the period of Enceladus (10 h. 59 m. 22 s.), one-half of the period of Mimas (11 h. 18 m. 32 s.), and one-fourth of the period of Tethys (11 h. 19 m. 36 s.). Certainly these coincidences are very remarkable, and go far to establish Professor Kirkwood’s interpretation of the gaps in the asteroidal zone, and of the general bearing of all such facts upon Laplace’s nebular hypothesis. The Lunar Crater Linne. — This crater is beginning to be a weariness of the soul to astronomers. The rival views respecting the supposed volcano in eruption at this point of the moon’s surface have been maintained with equal energy and acumen by many of our best observers. But so much uncertainty hangs over the whole question at present that we may be per- mitted to look with less interest upon the discussion of opposite hypotheses, than we should feel if the indications of activity had been more satisfactory. Mr. Birt has been diligently engaged in examining the observations of Mr. Huggins, Captain Noble, Baron Miidler, Professor Tacchini, and others j and he has constructed a section of the crater, which appears satisfactorily to account for the phenomena which have been observed. He remarks, that if any changes are taking place in the surface round the orifice of the crater, these changes can hardly fail to be indicated by corresponding variations in the epochs of the disappearance and reappearance of the shadow after sun- rise at the crater, and before sunset. In a letter to Mr. Birt, Baron Madler remarks that the great whitish spot surrounding Linn^, as shown in the English observations and in Tacchini’s drawings, was never seen by him in 1831. The crater was then surrounded by the greenish colour of the Mare Serenitatis. The Planets during the next Quarter. — Jupiter will be in conjunction with the sun on April 16, until which time he will be an evening star, though daily becoming less favourably situated for observation. Saturn is slowly returning to our nocturnal skies, and will be very favourably situated for observation from the end of May. His ring-system, being fully open, will 182 POPULAR SCIENCE REVIEW. form an interesting subject of study to our telescopists. At present Mars is tbe only planet well situated for observation ; he will continue to be a con- spicuous object in our evening skies throughout the quarter. Venus is throughout the quarter very unfavourably situated, passing her superior conjunction on May 8. BOTAXY. Difference between the Akazcja and Strychnia Plants. — The distinction be- tween these two is a matter of some importance to the physiological botanist, and it has been very clearly determined in a paper lately published by Dr. T. R. Fraser of Edinburgh, which he has been good enough to send us. In reference to the structure of the pith and wood-cells the differences are as follows : — In Akazga, the consists of complete parenchyma. Its cells have, in transverse section, a more or less regularly hexagonal form, and, in longitudinal section, they present the appearance of four-sided parallelo- grams. Their transverse diameter varies from to jg— of an inch, being usually, however, about ; while their longitudinal diameter is from — to — of an inch. The majority of the cells are indurated and marked by radiating canals. A few non-indurated cells occur irregularly throughout the pith, and these contain starch granules. I'he luood-cells have pretty constantly a diameter of g—g of an inch, and are greatly indurated, the cavity being so much reduced in size as to appear, in cross-section, like a point. Such a section also shows that the wood-cells are divided into regular four-sided groups ; by numerous medullary rays, which vary greatly in thickness— some consisting of only one layer of cells, and others of three or four. In Stnjchnos Nux-vomica, the pith is only slightly indurated ; and in the sections examined, its cells almost invariably contain starch granules j a very few nearly perfectly indurated cells are, however, present. These cells vary considerably in diameter, some being met with of of an inch, and others of The majority of the smaller cells occur at the circumference of the pith. The ivood-cells are of the same character as those of Akazga. The cylindrical tracts of delicate parenchyma are, how- ever, larger, and much more numerous than those in Akazga. Botanical Lectures at Cambridge. — The Botanical Professor will commence his course on Tuesday, April l‘i, in the south-western lecture-room of the mmseum, at 1 o’clock. They will be continued on Tuesdays, Thursdays, and Saturdays at the same hour. Gentlemen who wish to pass the special examination in botany for their degi'ee must obtain a card from the regis- try' ; by them no fee is paid to the professor. The fee required of other students is one guinea each for this course of lectures. The Priparation of Fungi. — At the meeting of the Botanical Society of Edinburgh on December 10, Mr. James English presented a paper on this subject. About three years ago he hit upon a method of preserving fungi, whic hhe then recorded. The process adopted is that of waxing the speci- mens, and thus preserving their natural pileus and stipe. Specimens pre- served in 1800 are now as fresh ns when first prepared. A series of fungi SCIENTIFIC SUMMARY. 183 thus prepared by Mr. English, and now in the Museum at the Royal Botanic Garden, were exhibited to the meeting. Distribution of Aster salignus. — Miss Beever records the occurrence of this plant on the shore of Derwent Water, where it was collected by Miss Edmonds, in 1868, in flower. This plant also occurs near Cambridge, and in several places on the banks of the Tay, between Dalguise and Seggieden. In one locality below Perth, Dr. White remarks that it is associated with several introduced plants, such as Linaria repens, Petasites alba, Sanguisorha Canadensis, Mimulus luteus. Crocus vernus, and Narcissus Pseudo-narcissus, which are all more or less common, and well established, along the banks of the river. In France, Aster Novi Belgii seerns to hold the same place as A. salignus does in Britain — that of an exotic plant, well established on the banks of several rivers, as near Strasbourg, Laugre, and Lyons.” The Lichen Flora of Greenland has been explored by Dr. Lauder Lindsay. In a paper read before the Botanical Society of Edinburgh (January 14), Dr. Lindsay states that his attention has been drawn to the lichen flora of Green- land by being requested in the winter of 1867-8, by Mr. Robert Brown, to examine and determine the lichens collected by him in West Greenland in the course of the West Greenland Exploring Expedition of 1867. On studying, in connection with the determination of the species so submitted, the literature of Greenland lichenology, he was surprised to find that there was no recorded modem list of the lichens of that country. Accordingly, he had drawn up a list of all the lichens which to the present day had been found, or recorded to have been found, in Greenland, compiled from all the sources of information accessible to him. The list included 268 species and varieties. Tinting Vegetable Tissues. — At the meeting above referred to. Dr. W. R. M^Nab described the results of his recent attempts at staining tissues with various dyes. He mentioned a large series of experiments he had made by staining certain microscopical structures with acetate of mauvine and Beale’s carmine solution. He showed that by means of staining, the high powers of the microscope can be used to bring out points of structure not easily demon- strated without being so treated. The process of staining does not seem to be attended with any great difficulty, and the author believes that very important results may be obtained by careful study of its action on ger- minating plants. Greenland Diatomaeece. — Professor Dickie, who has recently examined the collection made by Mr. Robert Brown, says that all the species were British with the exception of Hyalodiscus subtilis, originally described by the late Professor Bailey, from Halifax ; found also on the shores of North-West America, and now on the shores of Greenland. Death of two eminent Botanists, Von Martius and Schnitzlein. — Dr. Philipp von Martius died at Munich on December 13, 1868, at the age of seventy- five. He w'as born at Erlangen, and prosecuted the study of medicine at that university, and was a contemporary of Theodore Nees von Esenbeck. He was for a long time Professor of Botany in the University of Munich, and director of the Botanic Garden. He is well known for his large and splendid work on Palms, and his works on the geography and natural history of Brazil. He published a Flo7'a Brasiliensis, and numerous other works and 184 POPULAR SCIENCE EEYIEW. papers. — Dr. Sclmitzlein died on October 24, 1868, at the age of fifty-five, lie had suffered for upwards of four months from an accident which he met with while botanising on the Tyrol. He was Professor of Botany at Er- langen, and director of the Botanic Garden. His chief work is the ^^Illus- trations of the Natural Families of Plants ” {Iconographia Fumiliarum Natw'alium Regni Vegetahilis), which, unfortunatel}’’, is not completed. The Colon r-reactio7is of Lichens. — It has recently been asserted by the Bev. Mr. Leighton and by Herr Dr. Nylander that the chemical reactions of lichens afford a clue to their specific qualities. This assertion, however, receives very distinct denial from Dr. Lauder Lindsay, who has given con- siderable attention to the subject. The various experiments conducted by Dr. Lindsay lead him to the following conclusions : — 1. The same specimen, in the hands of the same operator, in its difterent parts, at different times, fre- quently exhibits colour-reactions different at least in degree. 2. The same species, in the hands of the same operator, and, still more so, in those of different experimenters, in different specimens from the same ©r different localities, differing in freshness of collection or age, occurring in different varieties of forms, or in different conditions of growth (fertile or sterile, hypertrophied or degenerated), frequently shows colour-reactions differing equally in kind and degree. 3. Colorific quality is determined by circum- stances (not fully understood) connected with («) locality of gTOwth in rela- tion to climatic, geographical, topographical, geological, or other conditions. (h) States of development, in relation to sterility, hypertrophy, or degene- ration of the vegetable tissues proper. 4. This inconstancy of colorific property leads the archil manufacturer never to depend on laboratory testings in the purchase of his orchella weed,” or in determining its commercial value j for it not unfrequently happens that a most promising Roccella even proves worthless, and is, as such, cast aside. 5. Colour- reaction, though interesting in itself in connection with the general subject of lichen colorific or colouring matters, affords no aid that can he depended on, either (a) to the systematist in defining species, or (6) to the dye manu- facturer in determining the value of his ‘^orchella weed.” — Scientific Opinion, March 3. How to Bleach Wood Pulp. — This is a question of some importance in re- lation to the manufacture of a certain form of paper, and it is answered by a French chemist in a paper in a recent number of the Rcmie de Chimie, which appears in abstract in the Journal of the Society of Arts. M. Ouvli states that chloride of lime, if it happens to be in the slightest excess, has a tendency to give a yellow tinge to the pulp ; that all energetic acids, without exception, tend to give a reddish colour to the paper when exposed for a long time to the effects of the sun or of moisture, and that the least trace of iron is sufficient in a very short time to blacken the pulp. He says he has succeeded in avoiding all these inconveniences by the use of the following mixture : — For a liundredweight of wood-pulp, he employs 400 grammes (four-fifths of a pound) of oxalic acid, which has the double advantage of bleaching the colouring matter already oxidised, and of neutralising the alkaline principles which favour such oxidation ; he adds to the oxalic acid one pound, or a little more, of sulphate of alumina, entirely deprived of iron. The principal agent in this mode of bleaching is the oxalic acid, the SCIENTIFIC SUMMARY. 185 power of wHcli over vegetable colouring 'matters is well known; the alum has no bleaching power of its own, but it forms with the colouring matter of the wood an almost colourless lake, which has the effect of increasing the brilliancy of the pulp. Cultivation of Cinchona in India. — It appears from Dr. Anderson’s report on the number and distribution of Cinchona plants in the Government grounds at Darjeeling on 1st September last, that the cultivation of bark pro- gresses. The total number in the various plantations at that date was 2,075,078 — viz. C, succiniba, 1,118,557; C. Calisaya, 20,354; C. micranthaj 29,667 ; C. officinalis and vars., 901,408 ; C. Pahudiana, 5,092. The Microscopiccd Structure of the Brazil Nut has been lately investigated by Professor Dickson, who has resigned the chair of Botany in Trinity College, Dublin. Microscopic Fungi. — The forms of fungi which are assumed to have rela- tion to cholera have formed the subject of a series of papers in the Lancet (January 2, 9, and 16). The papers constitute a series of reports by Drs. Lewis and Cunningham on the results of their interviews with MM. Dr. Bary, Hallier, and Piltenkofer. The conclusions arrived at were rather vague and extremely discordant. The Vitality of Desmids. — Dr. Wallich, in a note on the Desmidiaceee of Greenland, points out the extraordinary vitality of these plants. Botanists fancy that the resistance to the conditions of death, which the diatom possesses is due to its coat of silex ; but Dr. Wallich gives instances where, in Greenland, in the midst of melting ice, even desmids grow abundantly. ^‘In July,” he says, the specimens were certainly somewhat inferior to those of similar species met with in more genial climates. But, otherwise, as regards luxuriance of growth, the rate and extent to which the para- doxical multiplication by division appeared to be taking place, and the brilliance of the green colour of the chlorophyll, there was no inferiority whatever. The period of the ye^r was the middle of August, when, during two or three hours, about mid-day, the sun’s heat is very great, even in these boreal latitudes ; but this only makes the circumstance the more wonderful, inasmuch as the temperature, for at least twenty out of the twenty-four hoiirs, is very low indeed.” — Monthly Microscopical Journal^ rebruaryj., 1869i,. The Morplwlogy of Leaves. — In a paper having the'title of the Composite ...Structure lof Bimple Leaves,” Mr. John Gorham states that he conceives . that .a philosophical morphology can be founded on an examination of adult leaves,', and of the metamorphosis which certain leaves occasionally undergo. The typei of all leaves is, he thinks, to be found in the simple leaf. Of the four or five simple leaves described in botanical works, he thinks there are two which demand special attention ; these are, the true netted leaf and the feather-veined leaf. These two, he believes, enter into the composi- tion of almost all compound metamorphosed and simple-lobed leaves. Mr. Gorham’s paper is one of considerable length, and although it leaves the main pointr— that of development — untouched, it is of much interest. — y'l^CjSIonthly. Mici'oscopical Joimial, March, 1869. Bacteria in the Protoplasm of Plants. — This fact has been already, as pointed out in one of our recent numbers, well established. The question. 186 POPULAR SCIENCE REVIEW, as to how the bacteria became developed in these situations, however, is a point by no means so well determined. It is to this problem that M. B^champ has directed his attention, and to which he endeavours to reply in the Coinptes^Rendus of February 22, 1869. M. B^champ states his belief that the reason why these organisms are found in the cells of plants is that the plants themselves contain the germs of bacteria in the so-called microzymas which enter into their own constitution. He describes a number of interesting experiments on foreign plants, and then tabulates the follow- ing conclusions : — (1) Bacteria may easily be developed even in acid solu- tions. (2). The normal microzymas of plants, like those of animals, may readily become evolved into bacteria. (3). It is likely that when plants are inoculated- with bacteria, these bacteria do not continue either to live or propagate. (4). Previous observations on spontaneous generation have overlooked the existence of the small molecular bodies (the microzymcB). With reference to this last conclusion of the author’s, we must remark that it is quite a gratuitous assumption. Dr. Hughes Bennett, and also Pouchet and others, admit the existence of the molecular basis, though they may not admit its power of movement. M. B^champ’s paper appears elsewhere in our pages. * CHEMISTRY. The Derivatives of Benzine. — In a paper lately read before the Royal Academy of St. Petersburg, M. Zinin stated that, while pursuing his researches on the derivatives of benzine, he found that chlorobenzile is easily attacked by reducing agents, and that in its alcoholic solution it is transformed into desoxybenzine by the action of zinc and hydrochloric acid. The reaction is thus expressed : — C,JI,oOCL+H,-CL=C,JI,,0. The product obtained is almost pure, and exempt from all foreign matter. — Vide V Institute March 10, 1869. The Varieties of Graphite. — M. Berthelot, who has been recently giving much attention to this important subject, has published some of his conclu- sions in the Comptes Be^idus ; and our contemporary the Chemical News (March 5th) has given a translation of them. M. Berthelot describes the following process for separating these several forms of graphite : Mix with the powdered carbon five times its weight of chlorate of potassium previously pulverised, and gradually form into a sort of paste with fuming nitric acid ; leave it for some hours in a small open flask, and then heat it for three or four days without intermission to about 50 deg. or 60 deg. C. ; after this dilute it with water and wash by decantation with tepid water until the salts of potash are dissolved. This will give the following results : — 1st. In the case of a mixture of amorphous'carbon and diamond, the amorphous carbon is entirely dissolved after a few repetitions of the process, while the diamond remains unaltered. 2nd. In a mixture of graphite and amorphous carbon, the amorphous carbon is completely dissolved after repeated treat- ment, whilst the graphite gives rise to an insoluble graphitic oxide of a SCIENTIFIC SUMMARY. 187 yellow or greenish-yellow colour, decomposable with deflagration. The graphitic oxide may be decomposed, as will be shown, in such a way as to cause the disappearance of the whole of the carbon. 3rd. In a mixture of diamond, graphite, and amorphous carbon, the amorphous carbon is entirely dissolved, leaving a mixture of graphitic oxide and diamond. This cannot be dissolved by solvents, but the diamond may be isolated as follows : Dry the mixture ; then heat in a tube closed at one end. The graphitic oxide is destroyed, leaving pyrographitic oxide. This, reoxidised by chlorate of potash and nitric acid, forms soluble products, and a proportion of graphitic oxide much smaller than that first destroyed. On decomposing this new graphitic oxide by heat, and then reoxidising the new pyrographitic oxide, only traces of graphitic oxide will be discovered. After three or four operations the whole of the graphitic oxide will disappear, leaving only the diamond. Detection of Mercury in Cases of Poisoning. — This is a point of much importance to medical men and to professional toxicologists. The following method was recently employed by M. Buchner in a case of poisoning with corrosive sublimate. The organic remains having been disintegrated by a hot mixture of chlorate of potash and hydrochloric acid, the solution was diluted and saturated with sulphuretted hydrogen. After the lapse of some hours, the sulphide formed was collected, dissolved in aqua regia, and reduced by evaporation to a small volume. A little water being added, a bright piece of copper wire is placed in the liquid ; and when mercury is present the wire becomes grey, at the latest, in two days. The copper is withdrawn, dried between folds of blotting-paper, and heated in a wide test tube. The mercury is more easily distinguished by removing the wire^ and placing in the tube a drop of tincture of iodine. M. Eiederer, having remarked that the sulphide of mercury which is formed by this process always contains organic matter, has recourse to dialysis. He operates in the following manner. After disorganisation by chlorate of potash and hydro- chloric acid, the mercury in solution is precipitated by sulphuretted hydrogen, the sulphide collected dissolved in a mixture of chlorate of potash and hydrochloric acid, and dialysed with 500 c.c. of water. At the end of five days, the water is evaporated and the dialysis repeated. After this treat- ment, the solution is again saturated with sulphuretted hydrogen ; the precipitate is washed with ammonia and sulphide of ammonium, then with weak nitric acid, and finally treated afresh with hydrochloric acid and chlorate of potash. Operating upon dogs with calomel, M. Eiederer has recognised that the greater part of the mercurial compound is eliminated by the excrements, and that, for the rest, more collects in the liver than .in the muscles. — Paris correspondent of Chemical Neivs, January loth. JIo2v to prepare Nitrogen. — According to a recent number of Cosinos, a new method for this purpose has been devised by Signor Levy. He heats bichro- mate of ammonia, by which means he changes it into green sesquioxide of chromium, with evolution of water and nitrogen. Action of Sulphate of Alumina on Turbid Water. — The Photographic News, quoting the Technologist, states, what is already well known to chemists, that, whatever be the nature and quantity of the earthy substances held in suspension in turbid water, it becomes fit to drink 188 POPULAR SCIENCE REVIEW. in from seven to fifteen minutes if to each litre there be added -04 grammes of finely-povrdered alum, care being taken to agitate the liquid ■when the alum is introduced (this is about fib /per ton of water). If potash alum is used, the alum is decomposed into sulphate of potash (which is all dissolved by the water) and sulphate of alumina, which, by its decomposi- tion, purifies the water. The alumina separates in an insoluble form, and carries down with it, as it precipitates, the matters which render the water turbid, and the organic matter. The acid attacks the alkaline and earthy carbonates, and transforms* them into sulphates. The water becomes slightly richer in bicarbonates and free carbonic acid, whilst all organic matter is destroyed. Seven parts of sulphate of alumina will purify as much water as ten parts of rock alum or potash alum, and the sulphate of alumina does not introduce any alkaline sulphate into the clarified water. Antidote to Phos}ihorus. — It is asserted by a writer in one of the late num- bers of the Bulletin de Therapeutique that turpentine is a very useful antidote in cases of phosphorus poisoning. What is the explanation of this quality ? The Determination of Nitrous Acid. — In a paper recently laid before the Fi’ench Academy, M. Chabrier, who has been studying the difierent oxides of nitrogen, gives these two conclusions: — (1) in liquids containing at the same time nitrites, nitrates, and organic matter, the nitrous acid of the nitrites may be determined by the decolorising action which hyposulphite of soda exerts on the iodide of starch, produced by the reaction of the nitrites on iodide of potassium, in presence of starch and dilute sulphuric acid ; (2) in the absence of nitrates and organic matter the determination can be more easily made by the decoloration of indigo solution, operating with the aid of heat, but out of contact with the air. The Purijicaticm of Metallic Bisinuth. — In the Pharmaceutical Journal for January, Mr. C. II. Wood states that the officinal process for the purification of bismuth is in accordance with the method indicated by most chemical authorities. Gmelin, Watts, and other authors state that the impurities of bismuth are removed by fusion with nitre. Schacht’s experiments suffi- ciently demonstrate the possibility of removing the whole of the arsenic by this means. It is true, says Mr. Wood, that, in some fusions, Schacht found a portion of the arsenic still remained in the metal j but we are not informed what the proportions were before and after, and we have every right to assume that, by continuing or repeating the process, the whole might have been removed in these as in the other cases. Ilis own experiments have sufficiently satisfied him that the Pharmacopoeia method is an efficient one for the complete removal of arsenic, antimony, and sulphur. The most careful application of Marsh’s test lias failed to detect either of the former substances in any sample of the metal he has purified. The Preparation of Cerium. — A note in the Scientific American for Feb- ruary gives the following a.s the mode of preparing this metal adopted by Wohler: — A solution of the oxide in hydrochloric acid is mixed with equal parts of chloride of potassium and chloride of ammonium, and evaporated to dryness, fused, and poured out to partially cool, and then coarsely pulverised and mixed while still warm with pieces of sodium, and the whole projected into a clay crucible previously heated to redness. In this manner the cerium is reduced, and appears in the slag in the form of two pellets, which can be collected and fused into one mass. SCIENTIFIC SUMMAEY. 189 The Chemical Properties of Nitro- Glycerin have been thus defined by M. F. Tilberg. Nitre-glycerin (from the works at Stockholm) is decomposed when acted upon by potassium hydrate j amongst the products of decom- position are potassium nitrate, glycerin, ammonia, cyanogen, oxalic, humic, and nitrous acid. When ignited in a vacuum with copper oxide and copper, two volumes of carbonic anhydride and one volume of nitrogen are obtained, from which numbers the formula G3H5(N02)30 is deduced. Nitro-glycerin dissolves in concentrated sulphuric acid, forming with it a new compound acid which yields crystalline salts. A combustion gave three volumes of carbonic anhydride to one volume of nitrogen. If nitro-glycerin is regarded as a sub- stituted glycerin, and the relation between it and the new acid the same as that between glycerin-sulphuric acid and glycerin, the new compound will be dinitro-glycerinsulphuric acid. — Oefvers. af Ahad. Fdrh.j 1868, 25, No. 2, 75 ; and Journal f. Ch. cv. 254 ] and Chemical News, Jan. 8. Preparation of Ellagic Acid hy means of Gallic Acid. — By heating (says M. J. Lowe, in the Chemical News, Jan. 22) nearly to the boiling-point for several hours in an aqueous solution of two equivalents of gallic acid and one of arsenic acid, a crystalline precipitate is deposited, which is none other than ellagic acid ; the best way is to mix the two acids in the proportion indicated above, add water, evaporate to dryness, heat in an air-bath to 120° and extract with alcohol at 90°, which does not dissolve ellagic acid. The reaction is the following — ^28^12020 + 20 = CggHgOjg + 6HO. In commercial tannin there is always gallic acid, and consequently ellagic acid proceeds from it. A cold extract of oak bark gives by degrees a yellow deposit of ellagic acid, and it is, indeed, this same acid which constitutes that gelatinous covering which is formed over tanned hides. Extraction of Sugar from Molasses. — At a recent meeting of the French Academy M. Dumas exhibited some crystals of sugar extracted by a process of M. Margueritte’s from molasses. M. Margueritte has been enabled to extract from 100 kilogrammes of molasses 35 to 38 kilogrammes of true sugar, which brings up the total product of the beet-root to 25 per cent. M. Margueritte treats the molasses by alcohol at 85 degrees, which dissolves the sugar. He also obtains a supersaturated solution of sugar. By project- ing powdered sugar into this solution it crystallises, and nearly double the weight of sugar introduced into it is obtained from it. This sugar only con- tains one-hundredth part of impurity, and can consequently be immediately subjected to the refining process. — Vide Comptes-Pendus, Feb. 21. Carhonic Acid decomposed hy Plants. — From a large number of experiments recently made, M. Boussingault concludes that the chlorophyll is the agent of decomposition, and he states that wherever the chlorophyll exists it has the power of decomposing carbonic acid. The Chemical Food of Plants — In the Comptes-Pendus (March 1) M. Peli- got has a note on the employment of sea- salt in agriculture which relates to this subject. M. Peligot thinks that scientific agriculturists labour under delusions in reference to the action of salt ; he believes that in the case of impermeable soils, through which water passes slowly, the influence of salt is more hurtful to crops than beneficial. Analyses have shown him, con- 190 POPULAR SCIENCE REVIEW. trary to the received opinion, that soda is present in the ash of plants to a far slighter extent than is generally believed. Most cultivated plants have no soda in their ash even when grown upon a soil rich in this salt. M. Peli- got is opposed to the notion that chloride of sodium undergoes a change in the soil by which it first becomes carbonate and then nitrate. In fact, the only use of salt which he recognises is that due to its antiseptic action, by which it retards the decomposition of ordinary manures. This he thinks is why English farmers add it to guano. Phenijlrbichlorncetic Acid. — The last Bulletin of the Royal Academy of Belgium contains a paper on the relations of atoms in chemical molecules, in which the author gives the following mode of preparing the above sub- stance : “In a flask of three litres capacity I place 24 grammes of phenyl- monochloracetic acid. I fill the flask with dry chlorine, and, having sealed the mouth hermetically, I expose it to the heat of the sun. After five or six hours the colour of the chlorine disappears, and I then open the flask and allow the dry chlorhydric acid to escape. The new body, washed with cold water on a filter, is then transformed into a soda salt, and the solution of this salt is decomposed by pure chlorhydric acid. It precipitates an oily liquid which partly solidifies, while the supernatant liquid becomes filled with quadrangular plate-like crystals. These crystals are carefully removed, dried with bibulous paper, and recrystallised from ether.” M. Dumas' Lecture in London. — The Chemical Society has invited M. Dumas to lecture to us in his own language. The lecture will probably take place in May, and at the Royal Institution. The subject is not yet an- nounced. The Hydrogen Flame Colour on Porcelain. — The blue colour produced when a jet of hydrogen is allowed to play against a piece of porcelain has been ex- plained in a note recently published by M. Sallet. He says it is due to the presence of sulphur in the form of sulphate of soda in the atmosphere. If we mistake not, Mr. W. F. Barrett suggested this explanation two years ago. — Vide L' Lnstituty February 15. Estivating Sulphur. — A note has been published by M. Lefort, who states that he uses aqua regia in the solution and determination of sulphur. He describes the action of aqua regia on sulphur to be, firstly, the formation of chloride of sulphur; secondly, the destruction of this compound by nitric acid or its derivatives; and consequently the regeneration of the chlorine, the evolution of nitrous vapours, and the formation of sulphuric acid. In pro- portion to the amount of nitric acid present, is the solution of the sulphur quickly arrived at. The most convenient mixture of hydrochloric and nitric acids for dissolving sulphur is made with one volume of the former and three of the latter. — Vide Chemical Neivs, February 12. GEOLOGY AND PALAEONTOLOGY. The Dinomis in Xciv Zealand. — Dr. .Tillius Haast lately sent a paper on the remains of the Dinornithic birds in New Zealand to the Academy of Sciences of Berlin. Dr. Haast stated that the deposit in which most of the SCIENTIFIC SUMMARY. 191 bones were found was at a depth of 30 ft. from the surface. From this and some other facts he concluded that the different species of Dinornis existed in New Zealand before, during, and after the great Glacial Period, and that in point of fact these birds, which had conquered external conditions, were only extinguished by man. The Wollaston Gold Medal and Donation Fund of the Geological Society has been awarded to Mr. H. C. Sorby. At the annual meeting the Presi- dent, Professor Huxley, referred especially to Mr. Sorby’s researches into the structure of rocks and minerals, and of meteorites ; and to his explanation of the phenomenon of slaty cleavage, now universally adopted, and fully in accordance with the results obtained by physical investigators who have approaches! the same question from a very different side. The balance of the proceeds of the Wollaston Donation Fund has been presented to Mr. W. Carruthers, F.G.S., of the British Museum, in aid of his researches in fossil botany ; the President in handing it to Mr. Carruthers remarking, especially with regard to his researches on the structure of fossil fruits, that these are so valuable that Mr. Carruthers might justly look upon the award as an expression of gratitude for his labours. At the same time. Prof. Huxley observed that scientific gratitude was of the kind which had been defined as a lively sense of favours to come. Geological Survey of Ohio, U. S. — It is intended to introduce a bill into the American House of Representatives to provide a thorough and new geological survey of the state of Ohio. The former survey was made by Colonel Charles Whittlesy, Colonel J. W. Foster, Professor J. P. Kirtland, Dr. C. Briggs, Professor W. W. Mather, Professor John Locke, and Dr. S. P. Hildreth. The last three named of the above are dead. The Geology of China forms the subject of a communication made to the Geological Society (Dec. 23) by Mr. T. W. Kingsmill. The sedimentary deposits of the south of China were described as commencing at the base with a series of coarse grits and sandstones, having a thickness of about 12,000 ft., and overlain conformably by limestones and shales (with coal in the lower part), attaining a thickness of between 6,000 and 8,000 ft. The whole of these rocks were described by the author as the ^^Tung-ting series.” In the Nanking district this formation is succeeded by sandstones, grits, and conglomerates, which the author has grouped together under the name of the Chung-shan series.” Its uppermost member contains beds of coal, and possesses an unknown thickness \ but the remaining beds are together about 2,400 ft. thick. Mr. Kingsmill described in detail the geo- logical relations and geographical extension of these rock-masses ; he then gave a sketch of the superficial deposits, which occupy an important position in the geology of China, and from the older of which Mammalian bones and teeth have been obtained \ and he concluded by stating that he had been uniformly unsuccessful in his frequent searches for traces of Glacial action. Palceontology of the Alpina Tertiaries. — Herr Reuss, in the second part of the great work which he lately presented to the Royal Academy of Vienna, deals with the Actinozoa and the Bryozoa of the Crosara beds. The beds belong to a lower geological horizon than the coral-beds of Castel-Gomberto. In the strata marked No. I, he has found but a few isolated corals of the genera Trochocyathus, Acanthocyathus, Flahelhmi, and Trochos7nilia. There VOL. VIII. — NO. XXXI. O 192 POPULAR SCIENCE REVIEW. are also two species of Escliara, though these are generally in a badly- preserved state. Those marked No. 2 abound in compound corals, some of them of very considerable size. The following families predominate : — Calamophyllidoi, Symphyllidm^ Astreidce, Thamnastreidce, and Fongidce. Forty-nine species were determined; and of these eighteen belonged to Castel-Gomberto district. They were associated with numerous Bryozoa, especially species of Lepralia and Memhranipora. Is Eozoo)i a Minei'al Production? — Professors Bowney and King have again raised this question and answered it in the affirmative, in a paper laid before the Geological Society of London. It was found when the paper had been read that all the microscopists who were present differed from the con- clusion of the authors. Dr. Carpenter’s observations, which we reproduce, strongly supported the opinion he has formed of the animal nature of Eozoon. Dr. Carpenter said that he need not repeat the grounds on which he regarded this as an organic structure. He objected to criticisms unless founded on examination of actual specimens. Sir William Logan had been first led to regard the Eozoon as organic by finding alternations of calcareous and siliceous layers in various minerals. A' specimen which Sir William had brought from Canada contained much iron, and had the canal system wonderfully preserved; and it presented this character, that the larger branches were infiltrated with serpentine, and the middle branches with sulphide of iron, while the smallest branches were filled with carbonate of lime, of the same nature as the matrix. It was only under a favourable light that these smaller tubes were visible, as the calcite in them was of the same crystalline character as the surrounding network. This was conclusive evidence of the structure not arising from the mere infiltration of one chemical substance into another. Moreover, this foreign matter could not penetrate the cleavage-planes. When cut, some specimens had given out a strong odour of musk, which they to some extent still retained. This, again, seemed to be evidence of organic origin. He regretted that Professor King had not examined the large collection of specimens in his (Dr. Car- penter’s) collection. Recent Foraminifera, when decalcified, exhibited pre- cisely the same asbestiform layer round the chamber-cast as the fossil Eozoon. Different genera of Foraminifera in recent seas were infiltrated by different minerals, which presented some analogy with the condition of the fossil under consideration. In the great seas of the present day, at various depths and temperatures, was a large extension of sarcodic substance, and in this there were Rhizopods with and without shells, but of similar low structure ; and such forms might have continued in existence through any length of time, so that the occurrence of Eozoon so far down as Jurassic times could afford no matter for surprise. He would not be a.stonished even if such a structure as Eozoon were found in deep-sea dredgings of the present day. TJic lidationsnf Lepidodcndron. — Some time since !M. Brongniart discovered a fossil cone containing both microspores and macrospores, and showed that it belonged to a plant of the Carboniferous epoch. It has long been supposed that Lfpidostrohus was the fi’uctification of Lepidodcndron^ but no further evidence of the fact had been adduced than that which Dr. J. D. Hooker, F.R.S., had given by finding the cones in the insides of Lepidodcndron SCIENTIFIC SUMMARY. 193 Harcourtii and elegans, which could only he considered of a very unsatisfac- tory nature. In a cone in Mr. E. W. Binney’s possession in every respect similar to the late Dr. Eobert Brown’s celebrated specimen of Tr^jlosporitej but having the column in a more complete state of preservation, there is most conclusive evidence from internal structure that the Triplosporite is the fruit of Lepidodendron Harcourtii, the pith vascular cylinder, vascular bundles communicating with the leaves or scales, and the outer cylinder being the same in the cone as in the stem, thus justifying Mr. Carruthers’ opinion that the cone was a Lepidostrohus. The large spores found in a Lepidostrohus described by Dr. Hooker in the second volume of the Memoirs of the Geological Survey, as well as similar specimens found by the author in coal at "Wigan, and described in the Quarterly Journal of the Geological Society for May 1849, are most probably both macrospores of the fructification of Lepidodendron, and have come from the lower portion of a cone, whilst Dr. Browne’s were from the upper part. The same may be said of Professor Morris’s specimen belonging to Mr. Prestwich, from Colebrook Dale, described and figured in vol. v. of the Transactions of the Geological Society, published in 1840, which clearly came from the lower portion of a cone of Lepidodendron. In the new genus Flemingites, described and figured by Mr. Carruthers in vol. ii. of the Geological Magazine for October 1865, there are two kinds of sporangia ; those in the upper part of this long and slender cone being something like the sporangia of the Lepidodendron, Wt arranged in whorls and probably filled with microspores, whilst the lowest scales supported sporangia containing macrospores. This Mr. Binney gathered from much more perfect specimens than those which Mr. Carruthers had to work upon. Most certainly the little flattened discs which he described as sporangia are found on scales at the base of the cone, and not in the middle or upper portions of it, as many of the other specimens clearly prove. When Professor Brongniart’s paper is published and drawings of his specimens are given we shall, in Mr. Binney’s opinion, be better able to understand the relation of the genus Flemingites to Lepidodendron. — Paper read by Mr. Binney before the Manchester Literary and Philosophical Society. The Red Chalk of Hunstanton. — In a paper before the Geological Society the Eev. T. Wiltshire described the section exposed in Hunstanton Cliff as showing: — 1. White chalk with fragments of Inocerami. 2. White chalk with having its base undulated and the cavities fiUed up with a thin bright-red argillaceous layer, resting upon (3) the red chalk, which is divisible into three sections — a, hard, containing Avicula gryphes- oides and Siphonia paradoxica, and with fragments of Inocerami at its base ; h, hard, rich in Belemnites ", c, incoherent at its base, rich in Terehratuloe. 4. Carstone, a yellow, coarse, sandy deposit, resting on a bed of clay, con- taining no fossils in its upper part, but with a band of nodules containing Ammonites Deshayesit and other species about thirty feet down, together with ironstone nodules like those of the lower greensand of the Isle of Wight, and bearing impressions of fossils which correlate the lower part of the carstone with the base of the English lower greensand. The author gave a list of these fossils, and also of those of the red chalk, the latter amounting to sixty-one, and presenting a mixture of forms belonging to the lower chalk, upper greensand, and gault. On comparison with the gault 194 POPULAR SCIENCE REVIEW. section at Folkestone, the author considered it evident that the red chalk of Hunstanton was equivalent to the upper part of that formation. He mentioned that ten miles south of Hunstanton, in artificial sections, blue gault has been found resting upon the carstone, whilst rather nearer to Hunstanton the same place was occupied by a red clay, connecting the two dissimilar deposits; which, however, were shown by analysis to contain nearly equal quantities of iron. If the upper greensand be represented in the Hunstanton section, the author considered that its place must be in the band numbered 2, containing Siphonia paradoxica and Avicula gi'ypJicBoides. The Recent and Fossil Beaver. — Professor Owen states that a recent ex- amination of the bones of Castor and Trogontherium confirm his conclusion that the latter is ‘‘an extinct sub-generic type” of Castoridse. He has given some very good drawings of the bones of the Trogontherium. Vide Geological Magazine, February. “ Man and the Mammoth ” is the title of a very interesting paper in the above-mentioned journal, by Mr. Henry \Voodward, F.G.S. Hyperodapedon. — Professor Huxley has given the following description of this extinct lacertilian reptile : — “ The head presents indications of a bone forming a second zygomatic arch on each side ; the upper jaw is produced and bent downwards, forming a strong beak ; and the lower jaw is produced on each side of the symphysis into a pointed process, between which the decurved beak of the upper jaw is received. The maxillary and palatine teeth are arranged in rows, and present some resemblance to the large nails in the sole of a boot ; they are inserted on each side of the upper jaw upon the sloping sides of a deep grove, and are worn down and polished by the action of the mandibular teeth, which form a continuous and very close single seiies along the upper edge of the mandible. This peculiarity of ar- rangement enables the teeth of Hyperodapedon to be recognised wherever they may occur. The vertebrae have their centra slightly concave at each extremity. The other known parts of the skeleton are the ribs, scapula, coracoid, and part of the humerus, the pelvis, femur, and proximal ends of the tibia and fibula, and the abdominal false-ribs, which are largely deve- loped in this reptile.” The Officials of the Geological Society. — The following list of changes has been published : — 1. Mr. Henry M. Jenkins, F.G.S., who has for the past six years filled the post of Assistant Secretary, has been appointed to the position of Secretary and Editor to the Royal Agricultural Society of England. Mr. W. S. Hallas, F.L.S., who, during the past ten years, has been the Curator to the Yorkshire Philosophical Society’s Museum at York, has been elected to the post of Assistant Secretary, Librarian, and Curator, in the room of Mr. Jenkins. 2. Mr. Skertchl}', the Library Assistant, has resigned, in order to accompany Messrs. Rauerman and Lord to E^ypt. Mr. Frederick Waterhouse, second son of G. R. Waterhouse, Esq., Keeper of the Geological Department, Rritish Museum, has been elected in Mr. Skertchly’s stead. A Sandstone in course of formation was described by Mr. James Haswell at the meeting of the Edinburgh Geological Society, on January 21. This sandstone occurred at a point in the section of the Carboniferous strata be- tween Elie and St. Monance, near the railway bridge at Ardross. Resting upon the Carboniferous strata was a bed of tenacious clay containing recent SCIENTIFIC SUMMARY. 195 shells, above which was blown sand, which was washed down by the rain over the clay, and deposited in ledges formed by the projecting beds of shale, while the siliceous particles of which the sand was composed were cemented together, partly by carbonate of lime held in solution by the rain water, and derived from the shells occurring in the sand and in the clay, and partly from a ferruginous cementing material contained in the latter. A hard sandstone was being formed, not unlike one of much older date, in some places enclosing one or two recent shells, thus making the resemblance more complete. A new Cycadean fruit has been described by Mr. W. Carruthers, who has given it the name of Beania, in honour of Mr. Bean, the successful explorer of the fossiliferous beds of the Yorkshire Oolites. Mr. Carruthers’ attention was drawn to the specimen (in the Bean collection) in the British Museum by Mr. Henry Woodward. It is from Phillip s “ Upper Shale ” at Scar- borough. It is not associated with any Cycadean remains on the small slab on which it occurs, so that there is no indication to which of the several leaf species it belongs. A small fragment, however, of Acrostichites Wil- liamsonis occurs on the slab. — Vide Geological Magazine, March. MECHANICAL SCIENCE. Concrete Arch, — A remarkable experiment in the use of concrete has been made on the Metropolitan District Railway. Over one of the cuttings an arch of concrete has been constructed, of 75 feet span, 7^ feet rise, and 12 feet width, resting on concrete skewbacks. The thickness of the arch at the crown is 31 feet and the thrust on a section through the crown due to the weight of the structure alone is 7 tons 17 cwt. per square foot. When complete, rails were laid over the arch and a train of seven trucks, weighing 49 tons, with a wheel base of 57 feet, was run over the bridge. Ballast weighing 170 tons was then spread over the arch and the train again re- peatedly run over the bridge. The maximum average thrust at the crown during the experiments reached the high value of 15 tons 2 cwt. per square foot. The arch showed no signs of failure or distress. The concrete con- sisted of gravel and Portland cement in the proportion of 6 to 1, and was laid in mass on close boarding set upon the centering. Centrifugal Governor. — Sir W. Thomson has designed a centrifugal governor, in which the increase of centrifugal force due to increase of speed produces the regulating action without change of radius. The centrifugal force is made the normal pressure for a frictional arrangement simply and directly resisting the rotary motion. In an instrument exhibited at the In- stitute of Engineers in Scotland, the weight of the revolving masses and the power of the springs by which they are controlled was so adjusted as to require an increase of one foot-pound per second in the driving power for an increase of one per cent, in the speed above the desired amount. Suez Canal. — Mr. Fowler, C.E., has recently published in the Times a careful report on the present condition and prospects of the Suez Canal, which is very favourable as to its success from an engineering point of view 196 POPULAR SCIENCE REVIEW. whatever may he its commercial fortune. In regard to various points about which doubt has been expressed, he gives opinions founded on a careful ex- amination of the data accumulated during the progress of the works. The Nile alluvium, which is already perceptibly altering the coast line at Port Said, penetrates the western breakwater in such quantities that he believes it wiU be better to render the breakwater solid than to keep the harbour clear by dredging. As to the filling up of the canal by desert sand, he states that, fortunately, only about 17 miles lying on either side of Lake Timsah are affected by drift sand to an extent requiring consideration. Into that portion of the canal 310,000 cubic yards drifted in twelve months, and in addition to the precautions taken by the company of planting trees and shrubs for some distance on either side of the canal, he is of opinion that powerful dredges will have to be maintained at this part of the canal, to keep the passage clear. To protect the banks from the wave of passing vessels he recommends protecting them throughout by stone pitching. From the Bitter lakes, exposing an area of 100,000 acres, the daily evaporation in summer will amount to the enormous quantity of 250,000,000 cubic feet, and this waste will have to be made up almost entirely from the Red Sea. Currents will thus be created in the Chalouf excavation, probably reaching, if not exceeding, in velocity two miles an hour. These currents will not be sufficient to inj ure the canal if properly protected, but may retard or assist navigation. Screw steamers are to be allowed to navigate the canal with their own power, and other vessels are to be taken through by steam tugs. Mr. Fowler thinks the commercial success of the enterprise will largely depend on the willingness of traders to construct sailing vessels with suffi- cient auxiliary steam-power to take them through the canal and down the Red Sea, and by their means to divert the large traffic now carried round the Cape. Stca?n Carriage. — Mr. Fairlie and Mr. Samuels are working together in the production of a steam -carriage, or combined carriage and engine, for working the traffic on light railways laid on ordinary roads and branch lines. The carriage and engine are combined on a single frame, carried by two four-wheel bogies, and the wheels of the front bogie are coupled and driven by a pair of 8-inch steam cylinders supplied with steam by a “Field” boiler. Tlie entire structure with 80 passengers weighs 20 tons, half of which is utilised as adhesion weight. The ratio of unpaying to paying load is only 2^ to 1, and the adhesion is sufficient to enable the carnage to ascend a gradient of 1 in 10 if sufficient steam-power were provided. With the cylinders proposed it would surmount gradients of 1 in 35 or 1 in 40. Armour Plate. — An immense armour plate, 12 feet 8 inches long by 8 feet C inches wide and 5 inches tliick, was recently rolled at the works of Sir .Fohn Brown & Co. on a new plan. In the manufacture of large plates it has liitherto been a great difficulty to heat piles of the necessary width. The plan adopted for the above plate was to heat a comparatively narrow pile ; to roll it first in the direction of the width until sufficient breadth was attained ; la.stly to turn it and roll it lengthways. It is expected that by this plan plates 8 feet wide and 20 to 30 feet long will be obtained. Injector Condemer. — Very great interest lias been excited by an invention claimed by Mr. Morton and by Mr. Barclay, which, if it prove as successful SCIENTIFIC SUMMARY. 197 in practice as it has done in experiments, will introduce a fundamental change in the construction of the condensing engine. Hitherto the conden- sation of the exhaust steam has almost always been effected in the large separate condenser introduced by Watt, the condensation- water being pumped out by a large so-called air-pump. In a few instances surface condensation is employed, but the bulk of the condensing apparatus is then even larger than with Watt’s condenser. Mr. Morton and Mr. Barclay have succeeded in dispensing with the separate condenser and air-pump, by a beautiful application of the principle of Giffard’s inj ector, at the same time reducing the bulk of the condensing apparatus to very small dimensions. In Giffard’s injector there are two concentric nozzles, one communicating with a boiler containing steam under pressure, the other with a tank of feed- water. The steam rushing through the steam nozzle condenses on the jet of water and communicates its vis viva to the water, thus driving it forwards into the boiler. In the injector condenser the exhaust steam at the moment of condensation similarly communicates its vis viva to the water jet and discharges it, against the atmospheric pressure, without the need of employing an air-pump. A paper on this condenser was read by Professor Bankine before the Scottish Institution of Engineers, which will be found in Engineering of December 25. The chief results of Professor Eankine’s experiments are given in the following abstract Power saved by dispensing with air-pump Power of engines Mean back pressure in cylinders Mean vacuum in cylinders . Temperature of cold water Temperature of waste water 1-0 Ind. H. P. 23-8 „ 4-0 Ibs.Jper sa. in. 10-7 ,, 47° E. 8310 Y. Graphic determination of Stress. — Mr. J. H. Cotterill, M.A., has described in Engineering of January 7, the beautiful graphic methods of obtaining the bending moments and stresses on transversely-loaded structures, introduced by Professor Culman of the Zurich Polytechnic School. MEDICAL SCIENCE. Action of Alkaline Sulphates when injected into the Veins. — The experiments which have been recorded by MM. Jolyet and Cahours in the Archive de Physiologic for February are of much importance, and show how much yet remains to be learned concerning the physiological action of even mineral substances. These chemists introduced into the veins on various occasions sulphates of soda, potash, and magnesia, and they believe they are justified in drawing these conclusions : — I. That the injection into the veins of neutral salts (sulphates of sodium or magnesium) produces no purgation, although these salts are active purgatives when introduced into the intestines. 2. These injections, by their poisonous results, enable us to distinguish between the sulphates of the three salts. In reference to this latter point, the authors state that similar experiments have been tried before by M. Grandeau, who 198 POPULAR SCIENCE REYIEW. investigated tlie action of the salts of sodium, potassium, and rubidium ; and who showed (1) that sodium salts maybe introduced into the blood in very large doses without producing serious results ; (2) that the salts of potassium similarly introduced are extremely poisonous, and have an immediate toxic effect, even in small doses. M. Bernard’s experiments show that the potassium salts exert their action on the muscular tissue, and that death caused by injection of them into the blood is the result of cessa- tion of heart action, due to arrest of the respiratory movements. MM. Jolyet and Cahours record numerous experiments on dogs, which show conclusively that the potassium salt has a very seriously poisonous in- fluence on the heart, causing an immense increase in its actions. Similar experiments with sulphate of sodium prove (1) that this salt has no pur- gative effect in this way ; and (2) that by diminishing the coagulability and plasticity of the blood, it promotes haemorrhages, and retards cicatriza- tion. Temim'aturc of the Body in Health. — Dr. Sydney Binger gives an abstract of a paper lately laid before the Koyal Society on this subject. He gives the results of the experiments made by himself and the late A. P. Stewart. The following are the conclusions. The average maximum temperature of the day in persons mider 25 years of age is 99°T Fahr. ; of those over 40, 98°'8 Fahr. There occurs a diurnal variation of the temperature, the highest point of which is maintained between the hours of 9 a.m. and 6 p.m. At about the last-named hour the temperature slowly and continuously falls, till, between 11 p.m. and 1 a.m., the maximum depression is reached. At about 3 A.M. it again rises, and reaches very nearly its highest point by 9 A.M. The diurnal variation in persons under 25 amounts, on an average, to 2*^’2 Fahr. ; but in persons between 40 and 50 it is veiy small, the average being not greater than 0°-87 Fahr. ; nay, on some days no variation whatever happens. In these elderly people the temperature still further differs from that of young persons ; for in the former the diurnal fall occurs at any hour, and not, as is the case wdth young persons, during the hours of night. Concerning the influence of food on the temperature of the body, the authors have concluded that none of the diurnal variations are in any way caused by the food we eat. The experiments to prove this conclusion are very numerous. Some were made with the breakfast, others with the dinner and tea; but all point to the conclusion just stated. This important question is very fully discussed in the section devoted to it. By cold baths both the surface of the body and the deep parts were lowered in tempera- ture. The temperature of the surface was in some instances reduced to 88° Fahr. ; but the heat so soon returned to all parts as to show that the cold bath is of very little use as a refrigerator of the body. The cold bath produced no alteration in the time or amount of the diurnal variation. This began at the same hour, and reached the same amoun t ns on those days wlien no bath was taken. By hot-water or vapour baths the heat of the body could be raised very considerably. Thu.s, on some occasions, when using the general hot bath, the temperature under the tongue was noted to be Ixjtween 103° and 104° Fahr. — a fever temperature. The body being heated considerably above the point at which combustion could maintain it, t was then shown with what rapidity heat may be lost, simply by radiation SCIENTIFIC SUMMARY. 199 and evaporation. Tlie experiments tend to prove that hot haths in no way affect the diurnal variation of the temperature. Injiuence of Medicaments on the Heart. — The Proceedings of the French Society for Thei'apeutics contains a paper on this point by M. Bordier, who recommends that in all therapeutical experiments the sphygmograph should be employed. By the use of this instrument, M. Bordier has been able readily to distinguish between drugs which increase and those which dimi- nish the tension of the vessels. Leptandra and Leptandrin. — The Practitioner for March gives an account of some experiments on these substances recently made by two American physicians, Dr. Adolphus and Butcher. Leptandra is the name of a plant belonging to the Scrophularece. Adolphus recommends it as a cholagogue in doses of two grains of the root, or five drops of Merril’s tincture. He says it acts at the same time as a tonic, so that it is possible and even ad- vantageous to administer this remedy even in typhus and typhoid with much diarrhcea (! !), as it increases the digestive power, and also the appetite. He says that in desperate cases of typhoid, with extreme collapse, and colliquative diarrhoea, he has seen twenty doses of two or three drops of the tincture produce marvellous results, and he attributes the action to a specific infiuence on the portal circulation. He also recommends, in the early stages of the fever, leptandrin one grain, and bicarb, sodse two grains every hour. Leptandrin must be given in doses of seven or eight grains to act as a pure drastic. In small and medium doses it acts on the liver and pancreas. He treats dysentery and cholera infantum with tincture of lept- andra and glycerine, and explain its good effects by its supposed stimulant action upon the digestive secretions of the small intestines, which increases the powers of nutrition. Ammonia in combination with leptandra relieves the nervous symptoms in infantile choleraic diarrhoea. The addition of leptandra to quinine in intermittent and remittent fevers, according to Adolphus, greatly increases the efficiency of the latter. He also reports that enlargements of the abdominal viscera are greatly reduced by the use of an infusion of leptandra and gentian. In obstinate constipation of children, one-eighth grain doses of leptandrin are recommended j and the same drug proves useful to habitually constipated adults who become affected with bilious remittent. Dr. Butcher by no means confirms the general con- clusions of Adolphus. Aggregation of Blood-corpuscles in the Vessels in Fever. — Dr. C. H. Bastiau, of University College, has published some interesting observations on this point. He found, in a case of erysipelas of the scalp accompanied by delirium during life, that the small arteries and capillaries throughout the grey matter of the brain were more or less occluded by aggregated masses of white blood-corpuscles. The same capillary embolisms were met with in the kidneys and liver, leading to commencing degenerations of these organs. From observations which Dr. Bastian had previously made on the microscopical characters of the blood in cases of febrile disease associated with high temperature, he was led to believe that the white corpuscles, which seemed to show an increased irritability in these affections, might cohere so as to form masses capable of occluding small vessels. He is dis- posed to attribute the delirium occurring in this and in some other similar 200 POPULAR SCIENCE REVIEW. febrile affections to these obliterations of vessels in the grey matter of the brain ; and he is also disposed to think that the albuminuria so frequently met with in these affections may be explained by a similar affection in the kidney. These observations, says the British Medical Journal, open up an extensive field of further pathological research and clinical deduction. The Contractions of the Heart. — In a lecture delivered at the Royal In- stitution on February 11, which formed part of his course on the Involun- tary Movements of Animals,” Dr. Michael Foster exhibited the heart of a recently killed tortoise, which heart was placed in a platinum dish, where it continued to expand and contract with great steadiness. A long lever arm of straw had its shorter end fixed in contact with the heart, so that the other end of the lever moved up and down two inches with each motion of the organism, thus making the motions visible to the whole audience. The motion of the heart of another recently killed tortoise was made visible in the same way, though in the latter case the heart was not removed from the body. The lecturer said that he could not exhibit the heart of a warm- blooded animal in this way, because in such animals it ceases to beat within a few minutes instead of hours after the death of the brain, in consequence of the rapid way in which such hearts consume their nutrition. Cold- blooded animals like frogs have plenty of capital in the shape of nutrition inside their bodies, and can go without food for a long time. When the heart of a frog is cut into two or more pieces each part continues to beat, except the lowest point of the heart, which exhibits no motion when it is cut off. The nerves entering the great muscle, called the heart, have cells attached to them after their entrance, and to these nerve cells, which are found in all parts of the heart except the lower point, the observed motions seem to be in some way due. Skin Tissue affected in Small-pox. — Herr Erismann has explored this pathological region, and has laid his results before the Academy of Vienna. He believes that the first trace of the disease is seen in the upper layer of the derma, and in the Malpighian layer of the epidermis ; the blood-vessels of the papillae of the derma exude liquid matter, which forms cells that penetrate into the Malpighian layer, and form the true small-pox pustule. The capillary follicle is only secondarily affected, and the capillary papilla hardly ever is involved in the destruction of parts. In haemorrhagic variola the affection commences in the corium around the capillary follicle, and penetrates into the papilla, whose vessels are crowded with exudative corpu- scles. He has found no traces of cryptogamic vegetation in any of the morbid specimens, which he placed in chromic acid for examination. Influence of Pneumogastric Nerves mi liesjyiration. — A paper by Herr Voit and Rauber appears in the report of the Academy of Sciences of Munich. It has been concluded from previous experiments of other physiologists that the amount of carbonic acid exhaled after section of the nerve is the same as that before. Herr Voit and Dr. Rauber find now that this is true only for the first few hours after the operation. At a later period, when the issue of the lung has begun to undergo a change, tlie quantity of carbonic acid dimin- ishes rapidly, and tliat of oxygen is increased. Sulphurous Acid in the Atmosphere. — Mr. Peter Spencer, in a paper on the presence of this acid in the air of Manchester, makes the following SCIENTIFIC SUMMARY. 201 observations. Believing, as I do, that tbe evils of our town smoke are in a much larger degree due to tbe gases wbicb result from our coal consumption than to tbe black smoke wbicb is tbe one thing generally complained of and legislated against, it occurred to me that one of these gases, wbicb has a most pernicious influence upon vegetation, and wbicb can hardly be favourable as a constant breathing medium to animal life, could be made visible in its efiects to tbe eye. This is sulphurous acid gas, a very considerable product of tbe combustion of coal, containing 2 per cent, sulphur on an average. Tbe experiments I have made have been repeated some 15 to 20 times, and in two locabties j tbe results are evident, and they show that tbe substance is present in tbe air to a considerable extent.” — Scientific Opinion, March 10. Morphia as an Antidote to Atropia. — The following case, reported in tbe Ally. Med. Cent. Zeit. No. 80, has been going through tbe provincial papers, and is no doubt reliable. A strong little boy, aged three and a half years, drank more than tbe half of a solution of a grain of atropia in three drachms of distilled water. He immediately succumbed to tbe poisonous influence. An eighth of a grain of morphia was injected under tbe skin of tbe foot. In ten minutes tbe beneflcial efiects of tbe morphia began to be manifested, and in a few hours tbe patient was out of danger. Tbe pupil remained dilated for some days. Irfiuence of Common Salt in assistmg the Absorption of certain Substances, — L'Institut for March contains an account of a paper read before tbe Academy of Sciences of St. Petersburg, by MM. Zabeline and Wassilewski, On tbe Influence of Chloride of Sodium on tbe Absorption of Tribasic Phosphate of Lime and Metallic Lon.” Tbe authors bad conducted their experiments on dogs. Tbe facts seem to justify these two conclusions: — I. Phosphate of lime when introduced into tbe stomach with caseine is found to be absorbed in greatest quantity when tbe food contains much chloride of sodium. 2. Chloride of potassium, while it helps tbe organism to absorb iron more quickly than chloride of sodium, also assists in removing this metal through the secretions more rapidly than the former. The Pathological Development of Lichen. — Scientific Opinion, March 17, in a report of a recent meeting of the Vienna Academy of Sciences, states that Herr Dr. Kohn described some of his microscopic observations on the lichen of scrofulous subjects. This morbid alteration of the skin attacks only young patients, and manifests itself in numerous flat nodules, arranged in groups, and as a rule more frequent on the trunk than other parts. These nodules last for several months, and when they disappear, they leave a cicatrix and an accumulation of pigmentary matter. The essential patho- logical character of this morbid condition is the existence of an exudation of cells within and around the hair follicles and the accompanying sebaceous glands. In the first stages these cells may be seen lying in the vessels, then they make their way to the base of the sebaceous glands, and ultimately they gain the interior of the follicle, and completely fill it, expelling the normal secreting cells. Ein'ors of Architects as to Ventilation. — Dr. Edward Smith, who read a very lengthy and interesting paper on ventilation before the Society of Arts (February 24), states that architects in regard to this point fall into error: I. In not duly estimating the practical limits of the law that heated air 202 POPULAR SCIENCE REVIEW. ascends, and the relation of numbers of inmates and size of rooms in the application of the law. 2. In not duly considering that air-shafts, acting under that law, cannot act in all seasons, and with or without fire alike. 3. In not duly estimating the amount of air which can be admitted by windows and doors alone. 4. In not duly estimating the practical limits to which an entering current may be carried, whether from one or both sides of a room. 5. In not duly considering the effects of currents upon inmates, and the limitation thus demanded upon the amount, force, and elevation of currents. 6. In not duly estimating the inverse relation of ventilation to temperature in its effect upon inmates, and particularly upon the old and the young. 7. In not duly estimating the influence of the winds, and the impediments of suiTOunding buildings, &c., upon each aspect of a building. 8. In having incorrect views as to the direction of the current through ventilators at different elevations. Medical Photograj)1is. — A contemporary states that among other papers which have been forwarded to the French Academy of Sciences to compete for the Montyon prize of I860, given for the encouragement of medicine and surgery, are a collection of photographic studies of the nervous system of man and several of the superior animals, taken from sections of congealed nervous tissue. Medical Nomenclature. — The volume containing the future nomenclature of medicine has been issued by the Eoyal College of Physicians. We think it will have to undergo revision at some future time, for we cannot assent to the philosophical principles, or the ideas of precision involved in such a classification of stomach affections as the following : Pyrosis, hsematemesis, gastric ulcer, vomiting and dyspepsia. Why has the convenient and now much employed term gastric catarrh ” been omitted ? What is dyspepsia as distinguished from pyrosis ? And what is vomiting as an individual disease of the stomach ? Snake Poison and its Cure. — Several cases have lately been recorded from Australia. It is said that Professor Halford treats snake bites successfully by injecting solution of ammonia into the veins ! We suppose on the general principle that desperate cases demand desperate remedies. Professor Huxley continues his course of lectures on the Comparative Anatomy of Vertebrates,” at the Royal College of Surgeons. METALLURGY, MINERALOGY, AND MINING. Assaying Silver- Compounds in the Wet Way. — M. Stas makes the follow- ing remarks on tliis point : — Tlie mode of testing in the wet way in order to fix the standard of silver substances, as established by Gay-Lussac, is open, under certain conditions, to a source of eiTor, arising from the solubility of chloride of silver in the very liquid to which its origin is due. This solution, whatever its mode of production may be, is precipitated equally by a decimal solution of silver and by chlorhydric acid. The extent to which this preci- pitation ensues is uncertain. At the ordinary temperature, there may be a variation of from one to six thousandths in 100 c.c. of the liquid. Prac- SCIENTIFIC SUMMARY. 203 tically, it is quite possible, while still preserving the simplicity of the wet method, as invented by Gay-Lussac, to substitute a bromide for a chloride in precipitating silver, and thus remove absolutely those anomalies which have been observed to be attendant upon the use of a chloride or of chlor- h}^dric acid. — Vide Chemical News^ Jan. 1. The Characters of the Mineral Kotchouheite. — The Duke de Leuchtenberg recently sent a paper to the Academy of Science of St. Petersburg in which he gives a comparative examination of the minerals kotchouheite, hammererite and 'Pennine. The author referred especially to the great importance of an optical examination of minerals, such as had been conducted in the re- searches of M. des Cloizeaux and others. In proof of this, he stated that M. KokcharolF, while examining with a polariscope-microscope a mineral brought from the Oural by M. de Morny, and supposed to be kammerite, found that it presented two optic axes. On this fact he founded a new species, to which, in honour of M. Kotchoubey, he gave the name ot Kotchouheite.” This mineral, he says, presents itself ordinarily under the form of pyramidal crystals. It is of a reddish violet, transparent in thin sections, and translucent in thick ones. It is flexible, but is hardly elastic. Its hardness is = 2, its density is 2-679. Divided into thin plates and heated over the spirit-lamp, it becomes green without losing its transparency ; it assumes a violet hue in cooling. In the blowpipe, or under a great heat, it loses its water, ceases to be transparent, and becomes of a yellow colour. It is attacked by acids, and especially so by sulphuric acid. — Vide L'lnstitut, March 10. Molecular Phenomena in Iron. — In a paper read before the Koyal Society in January, Mr. Gore, F.R.S., of Birmingham, described a novel phenomenon in connection with iron wire. The following abstract is given by the Mechanics Magazine : — A strained iron wire was heated to redness by a current of voltaic electricity, and then, the current being discontinued, was allowed to cool. It was observed that there arrived a moment in the pro- cess of cooling at which the wire suddenly elongated, and then gradually shortened, until it became perfectly cold, remaining, however, permanently elongated. No other metal besides iron exhibited this peculiarity, which Mr. Gore attributes to a momentary molecular change, and he points out that this change would probably happen in large masses of wrought iron and would come into operation in various cases where these matters are sub- jected to the conjoint influence of heat and strain, as in various engineering operations, the destruction of buildings by fire, and other cases. The pheno- menon deserves a further investigation, since every fact relating to iron is of importance to us. A Crystalline Modification of Silicic Acid. — In a paper presented to the Berlin Academy of Sciences, and subsequently published in Poggendorff’s Annalen, Herr Buth gave an account of the above. There are as yet, he said, only two forms of silica known with certainty to exist — one is the crystalline and the other is the amorphous. The crystalline silica is quartz whose specific gravity is 2'6 ; the amorphous form has a density which varies between 2-2 and 2-3. The amorphous silica appears in nature as opal and hyalite; such is also the silica dissolved by steam, and that found in organised bodies. Herr Jerzsch tried to prove that dense crystalline silica 204 POPULAR SCIENCE REVIEW. is dimorphous and may also crystallise in the triclinic system, hut this has not been universally admitted. The opinion that silica of low density is always amorphous is, said the author, erroneous : it exists in crystals. These crystals are colourless and limpid, with polished brilliant faces. Their measurement is difficult, because of their small size (hardly one milli- metre). They are arranged in groups of twos and threes, and the latter being the most common, the term Tridymite has been given to this new mineral. Its system is the hexagonal, but very different ^from that of quartz. The fundamental form is the hexagonal dodecahedron. The hard- ness is equal, or nearly so, to that of quartz, and separate crystals are very rare. The specific gravity, taken at from 15° to 16° C., is from 2-326 and 2-312 to 2-295. Tridymite is infusible in the blowpipe, and its blowpipe reactions present no remarkable features. The analysis of the crystals (pounded in a steel mortar and fused with carbonate of soda) gave the following results in two cases : — 1st 2nd Silicic acid 96-1 95-5 Oxide of iron 1-9 1-7 Magnesia and alumina , . .1-3 1-2 Loss 0-66 0-66 99-96 99^ The iron, the author thinks, was derived from the mortar, and the other elements from the matrix in which the crystals presented themselves. Alloys of Copper and Tin. — The Paris Correspondent of the Chemical News (whose letter, by the way, is always full of interesting details) states that in a note communicated to the Academy by M. Kiche, the following facts concerning the alloys of copper and tin are given. The question of density is first taken. Some determinations were made upon bars of these metals, weighing from 50 to 60 grms., but the results obtained were unimportant, owing to the great difference which exists in these alloys. The same metals, reduced to fine powder, were afterwards operated upon, when it was observed that the contraction increases very regularly from the very rich alloy in tin to the mixture SnCu2, and from this point it increases suddenly, arriving at a maximum, when the copper and tin are united in the relation of 1 to 3. The density diminishes from this point, then rises again nearly regulai’ly ; the density of the richest copper alloys is inferior to the mixture SnCug, which only contains 62 per cent, of copper. Besides,' this alloy may be distinguished from all the others by its properties ; it is brittle enough to be pounded in a mortar, and forms crystals of a bluish tint, not resembling in the least either copper or tin. M. Riche gives a number of formula), expressing the composition of the definite compounds which copper forms with tin and their properties. Refemng to liquefaction, he then observes : “In order to separate these alloys, the mass should be moved about wlien becoming solid, to separate the crystals whilst forming.” The fusibility of these alloys has been determined by the thermo-electric pyrometer. M. Itiche has operated comparatively with these alloys, and with metals whose fusing points have been settled by various experimenters. Numerous determinations show that the solidification of the alloys SnCuj and SnCu^ takes place at a temperature somewhere between the fusion point SCIENTIFIC SUMMARY. 205 of antimony and the boiling point of cadmium. — Vide Chemical NewSy March 5. The Mode of Formation of Precious Stones. — One of the most interesting papers presented for some time to the Eoyal Society is that which appears in the number of the Pi'oceedings just issued, and which was read on February 18 by Mr. H. C. Sorby. It deals with the natural structure of the different precious stones, and it leads to the following conclusion : On the whole, the various facts seem to show that ruby, sapphire, spinel, and emerald were formed at a moderately high temperature, under so great a pressure that water might be present in a liquid state. The whole structure of diamond is so peculiar that it can scarcely be looked upon as positive evidence of a high temperature, though not at all opposed to that supposi- tion. The absence of fluid-cavities containing water or a saline solution does not by any means prove that water was entirely absent, because the fact of its becoming enclosed in crystals depends so much on their nature. At the same time the occurrence of fluid-cavities containing what seems to be merely liquid carbonic acid, is scarcely reconcilable with the presence of more than a very little water in either a liquid or gaseous form. “ We may here say that we do not agree with those authors who maintain that the curved or irregular form of the fluid-cavities is proof of the minerals having been in a soft state, since analogous facts are seen in the case of crystals deposited from solution.” METEOROLOGY. The Mean Temperature of the Superficial Structure of the Earth has formed the subject of a communication to the French Academy by M. Becquerel. The paper contains too many details for a full abstract, but some of its conclusions are of interest. If, says the author, we take the mean of flve years, which is the most rational method, we deduce the following inferences : — I. The mean temperature presents but slight variations from 6 to 21 metres, and from 21 to 26 metres. 2. From I to 36 metres the diffe- rence has been from I°-36. But if it is demonstrated that during the five years the mean temperatures have been sensibly the same from 6 to 21 metres, it does not necessarily follow that the temperature at these various points has been stationary. To establish a rule in the matter, we must investigate the varia- tions of temperature in the course of the year, according to the seasons ; that is to say, the differences between the mean, annual, maxima, and minima. The variations decrease to 21 metres, where they are nil; at 26 metres the variation is half a degree 5 then up to 36 metres there is no variation. Thus all the earth strata have a constant temperature at 21, 31, or 36 metres. Where, then, shall we place the stratum of invariable temperature ? Is it at 21, at 31, or at 36 metres ? Or might we not find it still lower, if we could extend our observations beyond this point ? A New Anemometer, which costs less than other forms and is both accurate and durable, has been described by Mr. W. Oxley at the meeting of the Manchester Literary and Scientific Society (February 2). The 206 POPULAR SCIENCE REVIEW. anemometer itself is a circular box, 11 in. diameter and 2^ in. deep, which moves freely on its centre on a pivot at the top of a rod fixed firmly into a foot plate, so as to prevent oscillation. The box is horizontal, provided with a space on one side, in which is placed a well-tempered steel spring, which gives a range of in. from zero to what represents 40 lb. pressure on the square foot. To this spring is attached a brass rod, or rack, which works the pinion, on the axle of which are placed two fingers, one live and the other dead. These fingers move according to the pressure given (or move- ment of the pillion), and thus the force is shown by looking at the dial- plate ; and the figure to which the live finger points shows the present force of the wind, whilst the dead finger is opposite the figure, showing the maximum pressure that the wind has attained during a given period. This is effected by a small pivot, or pin, at the point of the dead finger projecting above the live one, so that as the live finger is forced by the pressure it carries the other with it, and leaves it at that point if the wind decreases. In front of the spring, in the space ah’eady referred to. is a small disc attached to a rod, on which is placed a wind-plate of 6 in. square. This plate is kept to the wind by a vane on the opposite side of the circular box, and as its area is just one-fourth of a square foot, the graduated' dial figures being multiplied by four, gives the same result as though the plate were a foot square. This size of plate gives lightness, and reduces the friction to a minimum. The working parts of the instrument are protected from the weather by a glass lid or cover. MICROSCOPY. The Monthly Mici'oscojncal Journal constitutes one of the most important features of the quarter in this department. A glance at it shows that the Fellows of the Royal Microscopical Society receive a much larger return for t'leir subscription than they did under the reyime of the old journal, which was published quarterly. For example : let us compare, what are strictly comparable, the January number of the Quarterly Journal of Micro- mopical Science and the numbers for .Fanuary, February, and March, of the Monthly Microscopical Journal. The first contains some ten or eleven articles, all good in their way. The contents, merely in original contributions, of the three latter are as follows : — January. — Structure of Papilhc and Termination of Nerves in Muscle of Common Frog’s Tongue. By Dr. R. L. Maddox. Witli Plate. — Re- lation of ^Microscopic Fungi to Cholera. By Dr. .1. L. W. Thudicum. — lleliostat for I’iioto-Micography. By Dr. R. B. Maddox. With Plate. — lleliostMt for Plioto-Micography. By Lieut.-Col. .1. .1. Wood- ward, M.D. U.S. Anny Medical Department. With Plate. — A Modi- fication of the Binocular Telescope. By M. Nachet. Illustrated. — The Vital Functions of the Deep Sea Protozoa. By Dr. G. C. Wallich. — The Formation of the Blastoderm in Crustacea. By MM. Van Beneden and Bessels. SCIENTIFIC SEMMART. 207 February. — On the Classification and Arrangement of Microscopic Objects. By James Murie, M.D., F.L.S. — Immersion Objectives and Test Objects. By John Mayall, Jun., F.B.M.S. — Notes on Mounting Animal Tissues for Microscopical Examination. By H. Charlton Bastian, M.D., F.R.S. — Some Undescribed Bhizopods from the North Atlantic Deposits. By G. C. Wallich, M.D., F.L.S. — On the Construction of Object-Glasses. By F. H. Wenham. — The Organ of Hearing in Mollusks. By M. Lacaze-Duthiers. — On a New Infusorium. By J. G. Tatem^ F.L S. March. — The Address of the President of the Royal Microscopical Society. — The Composite Structure of Simple Leaves. By John Gorham, M.R.C.S. — On the Construction of Object Glasses for the Microscope. By F. H. Wenham. — On a New Growing Slide. By C. J. Muller. — On Triarthra Longiseta. By C. T. Hudson, LL.D. — Professor Owen on Magnetic and Amcebal Phenomena. By Lionel S. Beale, M.B., F.R.S. Had the Fellows of the Royal Microscopical Society continued the old journal, they would have been furnished during the quarter with about >eleven articles, and 112 pages of letter-press. Under the new organisation they have received their reports monthly^ they have been supplied with tioenty ■original communications, and they have received exactly 196 pages of matter. Preparing Sections of Teeth. — The following formula is given by Professor Cutler in the American Dental Register. Procure a fresh pulp, and at once split it open from end to end ; then lay it on a slip of glass slightly coated with balsam pitch, and spread it out, after slightly rounding the glass (some- thing like a hunter stretches his coon skin on a barrel to dry) ; then remove as much of the cell contents as convenient, by washing with a piece of sponge and acetic acid or ether,, rubbing lengthwise with pulp. This will show more clearly the septum of filaments, and also show the countless openings through the pulp membrane, where the fibrils pass out into the dentine. These specimens will not keep well for permanent use, unless mounted in pitch on both sides \ even then changes take place. A Substitute for a Nose-piece is thus described by Mr. James Vogan, in Science Gossip for January, but we do not think it will be found very useful, viz.; Divide the circumference of the screw, both of the ^^object-glass” and body,” into four equal parts ; then file away all the thread in two opposite quarters, leaving the remaining two opposite quarters intact. It is better in practice to remove slightly more than one-fourth on each side, so as to allow free clearance. The object-glass may now, by placing it so that the remaining portions of thread come opposite the corresponding gaps, be passed into the body, right up to the shoulder, without turning it round at all; and about one-eighth of a turn fixes it in its place as firmly as if screwed in. The adoption of this plan does not prevent the use of the altered object- glasses with other instruments, nor does it preclude the use of unaltered object-glasses with altered bodies. Hoiu to Count the Lines in Nobert's Plates. — The following method is given in a late number of Silliman's Journal of Science. If a cobweb micrometer is used, the micrometer eye-piece should be firmly clamped in a stand screwed to the table, so that the eye-piece is close to the end of the micro- scope-tube, but does not touch it — a piece of black velvet being used to VOL. VIII. — NO. XXXI. P 208 POPULAR SCIENCE REVIEW. complete the connection. The motion of the micrometer-screw now com- mimicates no tremor to the microscope, and all difficulty in counting the lines seen (whether real or spurious) disappears.” Still better than this is the following method : — The microscope being set up in a dark room, as though to take a photograph, and the eye-piece being removed, the image of the band to be counted is received on a piece of plate-glass in the plate- holder, and viewed with a focussing-glass, on the field-lens of which a black point is marked ; as the focussing-glass is moved on the plate from side to side, the black point is moved from line to line. The lines may thus be counted with as much ease and precision as though they were large enough to be touched with the finger. — Monthly Mia'oscopical Journal^ Februaiy. Mow to Construct Object-Glasses. — Those who wish to know not only the scientific principles on which the best object-glasses are made, but the most satisfactory methods of manufacture, should read the excellent papers of Mr. F. H. Wenham which are now appearing in the Monthly Microscopical Journal. The Quekett Club Soiree was held at University College on the evening of March 12. It was an immense success. More than 1,500 persons were present, and the 200 microscopes on the table were provided with objects of more than usual interest. ' A new Growing Slide, which is simple and convenient, is described by Mr. C. J. Muller in the Monthly Microscopical Journal of March. Any ordinary glass-slide is pierced with a minute hole, at about three-tenths of an inch from the centre on one side. When an object under investigation is put upon it immersed in water, the thin glass cover is so placed as to include this hole, which may be near the margin of the disc. When it is desired to keep the specimen moist while off the stage of the microscope, the slide is placed in the undermentioned piece of apparatus j viz., a fiat trough 7 inches long, 2^ inches wide, with straight sides f of an inch high. In this the slide is placed, object uppermost, with one end (that nearest the hole) resting against the bottom of the vessel on one side, and the other end resting upon the edge of it. Sufficient water is put into the vessel to admit of the liquid reaching within a quarter or half an inch of the glass cover on the uppermost side, when it will be found that, by capillary attraction, the water on the under- side reaches beyond the centre of the slide, and consequently beyond the hole with which it is pierced. In this state the object will remain moist so long as the trough contains a sufficient quantity of water. When required to be placed on the stage of the microscope, the water is easily wiped off without disturbing the object. Obtaining Diatoms from Guano. — In a paper which he read before the Natural History Society of Armagh on January 17, Dr. Lewis 13. Mills said that in the guano usually to be liad in this country the diatoms form a very small percentage of the entire mass, and to prepare the deposit for mounting in the rough, according to the usual process, would generally give very poor resulte, and discourage all except those well skilled in manipulation. How- ever, the most unproductive samples of guano contain some diatoms, and fair slides may be prepared from the material, if the process of selection be lidopted in their preparation. For this process, it is not needful to use more SCIENTIFIC SUMMARY. 209 nitric acid in the previous cleaning than that which may he necessary to clean the diatoms themselves ; and the use of sulphuric acid and chlorate of potash is not required, as the bleaching of the unsightly foreign material would be useless. A large drop of the prepared material must bespread near the edge of a glass slide ; the appearance of this under a simple micro- scope with a glass of one-inch focus will be that of much dirty material containing a few clean diatoms ; the best of these latter may be pushed out of the water by means of a needle, and nicely arranged near the centre of the slide. The slide may now be raised, and the water may be carefully wiped off ; the turning of the slide on its edge, or the wiping away of the water, will not disturb the diatoms selected and placed, as they remain attached to the glass sufficiently firmly to admit of the movements required. In this way the choice diatoms may be selected out of many drops, and be perfectly free from an unsightly speck of the half-cleaned foreign material. PHOTOGRAPHY. New Fhotocrayon Process. — Mr. Sarony, photographer to the Queen, Scarborough, has recently introduced what he designates photocrayon portraits. They have furnished material for discussions at the London photographic societies and in the journals devoted to the art. The position of Mr. Sarony as the principal of one of the largest photographic establishments in the kingdom, and as an artist of skill and taste, has secured for his new crayon photographs the favourable attention of his brethren. The portrait is executed on a glass plate fourteen inches in size, and is an enlarged vignette from an ordinary carte negative. The method by which they are produced is simple in the extreme. The negative is inserted, as a slide, into a magic lantern, and the enlarged image is thrown upon a sheet of glass previously made sensitive by being collodionised and excited in a 40-grain nitrate of silver bath. When magnesium ribbon is employed as the source of illumination, an exposiu’e of half-a-minute suffices to impress an image, which, after development with a solution of pyrogallic acid one grain, and citric acid one and a-half grain in each ounce of water, is fixed with hyposulphite of soda, washed, and varnished. In this state it is a trans- parence, the whites of the picture being represented by clear glass, and the shadows by a dark deposit of silver more or less intense. It is now backed by a piece of drawing paper of any desired tint, on which hatchings by a crayon have been made so as to surround and, where necessary, merge into the figure. The effect of the whole is that of a photograph on drawing paper, skilfully finished in crayon or chalk, the hatchings by which the vignetted subject merges into the ground of the picture conferring what is termed an artistic’’ appearance, and conveying the belief that the picture has been elaborately worked upon by the artist j whereas the hatchings on the backing papers are printed by lithography. It is a mechanical method of producing art imitations of wrought-up photographic enlargements which will probably be much adopted. The rough texture of the backing 210 rOPULAR SCIENCE REVIEW. proper confers a peculiar and good effect, and even skilled artists liave been deceived by these bold imitations of elaborate work. Pnnting Photographs by Mechanical Means. — The expense, loss of time, and other disadvantages attendant upon the usual method of printing photographs by the agency of silver salts have for several years back acted as an incentive to have them printed by mechanical means, so as to provide, among other things, for the wants of book illustration. Within the past few weeks a process of printing photographs by means of fatty ink, discovered by Albert of Munich, has been much spoken of. The complete details of the process have not yet been published, but as far as it is known it has a strong resemblance to the photo-lithographic process of M. Tessie du Motay. A very thick plate of glass is first coated with a layer composed of albumen, gelatine, and bichromate of potash, which is then rendered insoluble by exposure to the light. On the surface is poured a* similar sensitive layer of gelatine and bichromate of potash' dissolved in water. When dry, the plate is exposed to light under a negative, after which it is washed and treated as a lithographic stone ; for a surface so treated possesses the property of absorbing water, and consequently resisting the application of fatty ink in the inverse ratio of the action of light, or in proportion as the light passing through the negative has not acted upon the sensitive layer. The photographs thus printed are said to be very fine, and nearly a thousand can be obtained fi’om one plate. Plain Paper Prints. — Many photographers are now employing plain as well as albumenised paper. Although for several years the latter has been almost exclusively used, there now appears to be a disposition to test the capabi- lities of plain paper more thoroughly than has previously been done. M. de Constant produces fine, delicate, and yet vigorous pictures by employing a stout paper sized with arrowroot, sensitising in a neutral silver bath of eight per cent., and, when dry, exposing it for ten or fifteen minutes to the vapour of ammonia. It is then printed, toned, and fixed in the usual manner ; only the gold toning bath must be alkaline, and weaker than that commonly employed for albumenised paper. When washed and dried, the prints are treated with a warm solution of gelatine, and are afterwards finished by the application of weak negative varnish. New Lime Light. — A lime light of a simple yet efiective nature has re- cently been introduced, and, from the purity and actinic power of the light, it is expected that it will prove of great use to photographers. It is the ordinary oxyhydrogen or lime light, with a slight difference, however, but one which, in its results, may be fraught with importance, being nothing less than a substitution of common atmospheric air for the pure oxygen hitherto employed. A stream of air is caused to pass through a gas flame issuing from a suitable burner, and to impinge upon the lime as in the ordi- nary’ o.xyhydrogen light, but the lime is so arranged as to present a number of jagged edges to the blowpipe flame, in preference to the smooth surface of the common lime cylinder. Lime of a soft quality appears to answer better than hard lime ; and magnesia, mixed with lime and asbestos, has also been employed with advantage. The cost of the light is thus reduced to that of the common gas used, and as from a given volume of common gas a more intense light can be obtained in this manner than by the ordi- SCIENTIFIC SUMMARY. 211 nary method of combustion, the economy of this light, when employed for domestic and other ordinary lighting purposes, is a subject which merits at- tention. The Messrs. Darker, of Lambeth, who have introduced this light, are engaged in the construction of burners to suit the various requirements of photographers. Another nevj Dry Process. — Dr. George Kemp, who is well known as a careful experimentalist in photographic science, as well as a clear writer on the subject, has communicated to the pages of the British Journal of Photo- graphy the details of a dry process which has engaged much of his attention and which has yielded him highly successful results. The most efficient preservations for dry plates, according to Dr. Kemp, are those that contain nitrogen. In some of these this element presents itself in such wise that the aggregate body may be assumed to exist as a compound of nitrogen and hydrogen combined with a complementary organic group, from which the ammonia has, in a theoretical point of view, been eliminated. In most of the cases, the ammonia can be liberated by familiar chemical devices, and a considerable number of such bodies usually designated vegetable bases were examined in relation to their conduct as connected with actinic reactions. From the experiments made. Dr. Kemp has deduced the law that all bodies which contain ammonia in the condition alluded to are more or less efficient when applied as preservative agents. From this theory he has worked out the following process : — On an ounce of distilled water place twenty grains of fresh powdered cocoa nib ) mix and allow to digest for an hour, no heat being employed. Filter this fluid and add two drops each of glycerine and glacial acetic acid. The plate, being collodionised and excited as in other processes, must be thoroughly washed, after which the preservative solution is applied and made to permeate all the fllm ; after which it is again sub- mitted to a thorough washing, and when dried by a strong heat is ready for storing or for immediate exposure. The sensitiveness is nearly, if not quite, as great as that of wet plates. The picture is developed by a two- grain solution of pyrograllic acid containing acetic acid and nitrate of silver. Danger of using India-Rubber, — Mr. Samuel Fry, in Photographic Neivs, warns photographers against employing india-rubber either as a substratum for the negative collodion fllm, for which it has been much used in certain dry processes, or as a varnish for protecting the flnished negative. It is, he says, a very destructible gum. Under changes of temperature or hygro- metric variation it loses its elasticity, becomes first brittle, and is ultimately reduced to a brown powder, having neither coherence nor any of the pro- perties of the original substance. In consequence of this instability, many negatives have been destroyed. Cracking of Negative Films. — Mr. Matthew Whiting having had some negatives which presented a honeycombed appearance within a few months after they were taken, has restored to them their original homogeneity of surface by pouring over them a little warm alcohol, which softened the varnish and caused the film to lie flat. The Truth of Photography versus Artistic Licence. — Mr. K. H. Bow, C.E., of Edinburgh, has recently been applying the theodolite to ascertain in a scientific manner the truth of art as displayed in certain well- known pictures by artists of reputation. The result of this crucial test is 212 POPULAR SCIENCE REVIEW. that artists are found to have been taking liberties with nature. The declivities in the mountains of Samuel Bough’s Loch Lomond,” a picture that has been engraved and published during the past year by the Associa- tion for the Promotion of the Fine Arts in Scotland, are shown by Mr. Bow’s scientilic test to be exaggerated to the extent of fifty per cent. Similarly, comparing the famous pictiu’e by Mr. Waller Paton, Edinburgh from the Echoing Rocks,” with a photograph taken from the same spot and verified by the theodolite, he finds that the true slope of the notable debris of Salis- bury Crags forms an angle of thirty- eight and a-half degrees with the horizon, while the artist (one of the highest standing), has made it to be not less than fifty degrees. In like manner science makes the moon to subtend a certain angle ; artistic licence makes it to be seven and a-half times larger than it really is. Apropos of this, in a recent political parody of ‘‘ The Fighting Temeraire,” in which both sun and moon are visible, the artist had apparently considered scientific accuracy so little a matter of moment that he had actually turned the crescented moon, in its relation to the sun, back side foremost. Photographs of Authors. — A bookseller in Paris has just started a novel idea, that of placing a photograph of the author on every book which he places in his window. He has evidently studied human nature to some purpose. PHYSICS. Cohesion-figures. — In a recent communication on these extremely inter- esting physical phenomena, Mr. Charles Tomlinson gives an account of the substances which may be employed to exhibit cohesion-figures. Solid carbolic acid, in small fragments, rotates on the water surface with immense velocity, after the manner of camphor. (Camphor also may be tried, but the fragments should be scraped from a freshly-cut surface with the point of a pen-knife.) If a needle of the commercial acid be placed on the water, it darts about suddenly, liquefies, forms into a disc, from which angry-looking waving forked tongues proceed, and so it wastes away. If the liquid acid be used, care must be taken to deliver it gently to the surface, or it will slip through and form an inert globule at the bottom of the water. Carbolic acid, or a mixture of this and cresylic acid, forms an active vigorous figure, and if a drop be placed on the same surface with what is left of the lavender figure, the mutual attractions and repulsions form a surprising sight. Cresylic acid leaves delicate silvery flakes on the surface of the water, and in this way the presence of a few drops per cent, of this acid in carbolic acid can be detected. — Vide Chemical Neivs, No. 447. Telescopic Photography. — The Photographic News states that M. Schroder, of Hamburg, is at present occupied in constructing a telescope to be fitted with clock-work, for photographing the heavenly bodies. The instrument is so arranged that the object to be reproduced will be considerably enlarged before it is thrown upon the sensitised plate. A Method of Mewing the S’olar Prominences. — At a meeting of the Royal Society, in February, Mr. W. Huggins stated that, on the 13th of that SCIENTIFIC SUMMARY. 213 montli, lie had succeeded in distinguishing the form of a solar prominence. A spectroscope was used ; a narrow slit was inserted after the train of prisms before the object-glass of the little telescope. This slit limited the light entering the telescope to that of the refrangibility of the bright line coincident with c. The slit of the spectroscope was then widened sufE- ciently to admit the form of the prominence to be seen. The spectrum then became so impure that the prominence could not then be discerned. A great part of the light of refrangibilities removed far from that of c was then absorbed by a piece of deep ruby glass. The prominence was then distinctly perceived. Metals in the Galvanic Current. — The Chemical News (January 1) describes the following experiment, which has recently been made by Herr Wohler, and which is supplementary to others of a similar kind: — Palladium as positive electrode of two Bunsen’s cells, immersed in acidulated (sulph. acid) water, becomes gradually covered with an almost black film of peroxide (PdOj). Upon lead and thalium brown peroxide and black oxide are deposited. Osmium, in the ordinary porous condition, is freely converted into osmic acid (OsOJ. If, as electrolyte, a dilute solution of sodium hydrate is employed, the solution assumes a deep yellow colour, while on the negative electrode metal is deposited. The same is the case with ruthenium. Osm-iridium, in its natural state, readily dissolves in the alkaline electrolyte. Hmu to Take Oleographs. — Dr. P. C. Moffat has given the following account of a method of producing these interesting results: — The oil patterns* uninjured can as readily be transferred from the surface of the water, and permanently fixed to be placed in our albums, as we can pour water from one vessel to another. No matter what colours we desire, we can obtain them of any hue we please. They rival the most beautiful photographs. The faintest tracery is brought out with the most perfect fidelity. Two well-known photographers, to whom they were shown, declared they were excellent photographs, and yet not a trace of the chemicals photographers use was employed. The process can be described in three lines : — Obtain the oil pattern, note the time, lay a piece of glazed surface paper on the pattern for an instant, take it off, place on the surface of a plate of ink for a moment, remove and wash oft' the excess of ink with water, and your pattern is there as it was on the water. You now have an exquisite representation in black, as fine as any photograph. A scarlet is obtained by employing a solution of cochineal or any of the scarlet coal-tar colours. We have them in orange, red, scarlet, black, blue, and other tints. A good result is got by first passing the paper containing the pattern of oil through ink and then through cochineal. The principle of the matter is this. The paper absorbs the oil at several parts to the exclusion of the water. The ink colours the water parts, but at the; same time tints the oil parts very faintly, which gives it the appearance of relievo. Any kind of paper almost will do. Tissue, green, glazed, white, t&c. give pretty good results. Glass for Lenses. — It is stated that glass having a density of 4-4 is now manufactured by Messrs. Chance, the great Birmingham firm. Use of J^elegraphy in Ascertaining Longitude. — M. Quetelet has recently laid before the Belgian Academy of Sciences an account of the observations 214 rorULAR SCIENCE REYIEW. made in August and September last to determine the differences in longitude between the observations of Leyden and Brussels. These inquiries had been made at the request of M. Kaiser, of the University of Leyden and the director of the Leyden Observatory. The method used was that of telegraphic signals. The two observatories determined to make simul- taneous observations of the same bodies, and to signal the results to each other. Relative to this mode of determination, M. Quetelet states that in 1853 the galvanic method was employed to determine the longitude of Brussels in relation to the Royal Observatory of Greenwich. It was the first time, he said, that this mode — of American origin — was employed on so large a scale. The enterprise succeeded, and Mr. Airy made it the subject of a memoir which appeared in vol. xxiv. of the Proceedings of the Astrono- mical Society of London, under the title On the Difference of Longitude between the Observatories of Brussels and Greenwich, as determined by Galvanic Signals,” a translation of which memoir appears in the Annates de V Ohservatoire Loyal de Lruxelles. How to ascertain the Heat of the Stars. — Mr. Huggins a few weeks since published his description of an ingenious contrivance for this purpose. He thus described how the observation of temperature was taken ; — The ap- paratus was fixed to the telescope so that the surface of the thermopile would be at the focal point of the object-glass. The apparatus was allowed to remain attached to the telescope for hours, or sometimes for days, the wires being in connection with the galvanometer until the heat had become uniformly distributed within the apparatus containing the pile, and the needle remained at zero, or was steadily deflected to the extent of a degree or two from zero. 'When observations were to be made the shutter of the dome was opened, and the telescope, by means of the finder, w'as directed to- a part of the sky near the star to be examined w^here there were no bright stars. In this state of things the needle was w^atched, and if in four or five minutes no deviation of the needle had taken place, then by means of the finder the telescope was moved the small distance necessary to bring the image of the star exactly upon the face of the pile, which could be ascer- tained by the position of the star as seen in the finder. The image of the star w*as kept upon the small pile by means of the clock-motion attached to the telescope. The needle wa.s then w’atched during five minutes or longer ; almost always the needle began to move as soon as the image of the star fell upon it. The telescope w\as then moved, so as to direct it again to the sky near the star. Generally in one or tw*o minutes the needle began to return tow'ards its original position. The Constitntion of Clouds. — Dr. Tyndall’s recent investigations on this subject are of the highest interest to physicists. Speaking of toluol, he says : — “ Every cloud-particle has consumed a polyhedron of vapour in its formation, and it is manifest that tlie size of 'the particle must depend, not only on tlie size of tlie vapour polyhedron, but also on the relation of the density of the vapour to that of its liquid. If the vapour w'ere light and the liquid heavy, other things being equal, the cloud-particle would be smaller than if the vapour w’ere heavy and the liquid light. There would evidently bo more shrinkage in the one case than in the other. These con- siderations were found valid throughout the experiments. The case of toluol SCIENTIFIC SUMMARY. 215 may be taken as representative of a great number of others. The specific gravity of this liquid is 0°-85, that of water being unity ; the specific gravity of its vapour is 3°*26, that of aqueous vapour being 0°-6. Now, as the size of the cloud-particle is directly proportional to the specific gravity of the vapour, and inversely proportional to the specific gravity of the liquid, an easy calculation proves that, assuming the size of the vapour polyhedra in both cases to be the same, the size of the particle of toluol cloud must be more than six times that of the particle of aqueous cloud. It is probably impossible to test this question with numerical accuracy ; but the compara- tive coarseness of the toluol cloud is strikingly manifest to the naked eye. The case is representative. In fact, aqueous vapour is without a parallel in these particulars,- it is not only the lightest of all vapours, in the common acceptation of that term, but the lightest of all gases except hydrogen and ammonia. To this circumstance the soft and tender beauty of the clouds of an atmosphere is mainly to be ascribed. The sphericity of the cloud-particles may be immediately inferred from their deportment under the luminous beams. The light which they shed when spherical is continuous ; but clouds may also be precipitated in solid flakes, and then the incessant sparkling of the cloud shows that its particles are plates and not spheres. Some portions of the same cloud may be composed of spherical particles, others of flakes, the difference being at once manifested through the calmness of the one por- tion of the cloud, and the uneasiness of the other. The sparkling of such flakes reminds one of the plates of mica in the River Rhone at its entrance into the Lake of Geneva, when shone upon by a strong sun.” — Paper read before Royal Society, March 8. A Form of Actinometer is described by Mr. Louis Bing in the Photographic News for February. It consists of a rectangular box, to one side of which a square tube is applied. At the aperture of the tube there is a slide with a rectangular opening, by moving which he can either admit light into or exclude it from the tube. One side of the tube is made of yellow non-actinic glass, and the opposite or interior side is made of white glass. By looking- through the yellow glass one can watch the action of the light in the tube by simple inspection. A scale is marked on the strip of white glass by means of a standard tint. The side of the box to which the tube is fixed is made to take off, and is held in its place by means of four little springs, like the back of a dark slide. A cylinder is placed vithin the box, against which the white glass of the tube is pressed, and which is surrounded with sensitive paper. The top of the box, which has a milled head, is also made to take off. This milled head is fixed to a rod which passes through the cylinder, and by means of which the photogi-apher can turn the cylinder either way. By unscrewing this little top-piece he can remove the milled head, and then the top of the box. The cylinder can also be lifted out of the box for the purpose of charging it with sensitive paper. This is done once, in the morning, for the work of the whole day. After inserting the cylinder the top of the box is replaced, the milled head and its little screw. Fix the side with the tube, and you have only for every fresh exposure to give a slight turn to the cylinder, by means of the milled head, in order to bring a fresh part of the paper forward, at the back of the white glass.” Flecti'o-Chemistry in Metallurgical Operations. — M. Becquerel has recalled 216 POPULAR SCIENCE REVIEW. the attention of the French Academy to a method proposed many years ago by him for the separation of ores containing lead, copper, and silver. The general principle of the method consists in the employment of galvanic ^‘couples ” composed of zinc, iron, and lead, associated with plates of copper or a piece of well-baked carbon. The plates of non-oxidable metal or the uon-metallic conductive substances are put in immediate contact with the argentiferous metallic solution, whilst the plates of oxidable metal are placed in a permeable diaphragm made with untanned hide. This is filled with salt and water, and the plates are then put in metallic commimication with each other. The mineral is placed in the vessel containing the saline solu- tion, and is rapidly stirred by machinery for the purpose. The mineral bemg deposited, the liquid is decanted into other basins, in which the galvanic couples are placed. Experience has shown, M. Becquerel says, that this process may be well employed for silver ores containing copper and lead, at least when sea-salt is cheap and when sufficient wood exists in the neigh- bourhood.— Vide ComiTitcs-Rendm^ March 1. The Electric Conductihility of Metals has had devoted to it a memoir which has been lately laid before the Berlin Academy of Sciences by Herr Paalzow. The paper is one of interest. The experiments recorded by the author are numerous, and the results obtained are of some importance. Many of them confirm the views formerly expressed by Beetz. Herr Paal- zow concludes from his researches that there is no relation between the con- ductibility for heat and that for electricity. He has experimented on the following substances, and found that they have the following order in point of conductihility of heat and electricity : — Heat : Mercury, water, sulphate of copper, sulphuric acid, sulphate of zinc, solution of sea-salt. Electricity : Mercury, sulphuric acid, solution of sea-salt, sulphate of zinc, sulphate of copper, water. — Vide E Institute Feb. 27. The Mechanical Descent of Glaciers. — The Bev. Canon Moseley, who has been studying the movement of glaciers, has inquired into the forces which impede the descent of these masses of ice, and thus summarises them : — 1st. The resistance to the sliding motion of one part of a piece of solid ice on the surface of another, wliich is taking place continually throughout the mass of the glacier, by reason of the difierent velocities with which its different parts move. This kind of resistance will be called in this paper (for shortness) shear, the unit of shear being the pressure in pounds necessary to overcome the resistance to shearing of one square inch, which may be pre- sumed to be constant throughout the mass of the glaciers. 2udly. The friction of the supenmposed laminae of the glacier (which move with dif- ferent velocities) on one another, which is gi-eater in the lower ones than the upper. Srdly. The resistance to abrasion, or shearing of the ice, at the bottom of the glacier, and on the sides of its channel, caused by the rough- ness of the rock, the projections of wliich insert themselves into its mass, and into the cavities of whicli it moulds itself. 4thly. The friction of the ice in contact with tlie bottom and aides so sheared over or abraded. He has gone into a mathematical calculation of the value of these forces, and he considers, ns the result of his inquiries, that the weight of a glacier is in- sulficicnt to account for its descent — that it is necessary to conceive, in addi- tion to its weight, the operation of some other and much greater force, which SCIENTIFIC SUMMAKY. 217 must also be sucb as would produce those internal molecular displacements and those strains which are observed actually to take place in glacier-ice, and must therefore be present to every part of the glacier as its weight is, but more than thirty-four times as great. The Magnetism of Chemical Comhinations. — Herr Wiedemann has laid a paper on this difficult problem before the Academy of Berlin. Working on the principle that the salts of metals showing magnetic properties possess those properties in some degree, Herr Wiedemann has found that “ in all the salts of the same metal which are in an analogous combination, the pro- duct of the temporary magnetism excited by the magnetic force in the unit of weight of the salt by its atomic weight is a constant number ; or, in other words, that the magnetism of an isolated atom of one of these salts is constant. Salts in the solid state give nearly always the same result, espe- cially when they contain water of crystallisation. In case these solid salts contain no water of crystallisation, their atomic magnetism is generally a little more feeble : this is especially seen in the case of the anhydrous salt of copper. The magnetism of the salts of copper is peculiar, especially the bromide 5 for here there are two diamagnetic bodies combining to form a magnetic compound.” Temperature and Refraction. — The importance of considering the relation between these two conditions was well shown in a paper addressed to the French Academy quite recently by M. Faye, who has been writing on the subject of astronomical errors of observation in this paper. M. Faye said that, with the astronomical instruments of Gambey, we obtained not only an immediate estimate of seconds, but even of the tenths of seconds 5 and it is, he observed, by seconds that the errors of observations are to be recorded, especially observations by reflexions in the mercury bath. M. Faye, in trying to discover the causes of errors (not merely due to personal observa- tions), thinks he has discovered them in the very imperfect manner in which the corrections for refraction are made. In the observatory of Green- wich, for example, he said, the external temperature is considered, but not the temperature of the room in which the observations are being conducted j this, he said, was a most fertile source of error. — Vide Comptes-Rendus, March 8. What is meant hy the term Catharismf ” — At a recent meeting of the Chemical Society of London, Mr. Charles Tomlinson explained the sense in which he applied the new term catharism ” (from tcadapSs, pure or clean') j distinguishing between clean ” in its ordinary and in its chemical sense. The finger could not be made chemically clean by any process, whereas a glass rod, cleansed with strong acids or alkalies, and well washed, was chemically clean, and no longer possessed the power of liberating either salt or vapour from liquids. The action of solid bodies in determinating these changes he ascribed to the greasy film which, after exposure to the air, they are sure to acquire. For this film, the adhesion of the solid or vapoiu’ is greater than it is for the glass, and hence the effect of the solid. To such chemical uncleanness all phenomena of this kind should, he thought, be ascribed, and he defined a nucleus as a body which has a stronger adhesion for the gas, or the salt, or the vapour of a solution, than for the liquid which holds it in solution.” He repudiated the notion that temperatme has 218 POPULAK SCIENCE REVIEW. an}i;bing to do with the phenomenon of supersaturation, and described experi- ments in which supersaturated solutions of various salts were kept for hours in catharised vessels at a temperature of 10° F., without crystallisation taking place. — Scientific Opinion, March 17. The Life of Faraday. — In the Proceedings of the Poyal Society (No. 106) Dr. Bence Jones has written a very touching biography of Faraday. It differs from Dr. Tyndall’s sketch in being made up in great part of Faraday’s letters, and in being divided into chapters corresponding to each year of his life. An Electric Clock. — The following is the specification of a patent quite recently taken out by Mr. K. C. Eapier of Westminster. Two or more breaks are employed for the purpose of making simultaneous contact, the object being to secure certainty of action. In order to hang a pendulum, a bar of steel or other metal, with one edge turned up, is supported on a frame. The pendulum stem does not reach quite up to this bar, but is sus- pended on it by two cheeks or plates fastened to the sides of the stem of the pendulum. This bar is fitted with a stud or pin midway between the cheeks, and on this pin turns a friction roller which offers far less resistance to the working of the pendulum than any kind of dead collar would do. Hydrogen and Palladium. — Perhaps the greatest physico-chemical disco- very of the quarter is that by Professor Graham, of the undoubted metallic qualities of hydrogen. The Master of the Mint has demonstrated that hy- drogen when absorbed by palladium combines with it to form an alloy. The following account of one of the experiments lays the result before our readers, the hydrogen being termed hydrogenium. Expei'iment I. — The wire had been drawn from wielded palladium, and was hard and elastic. The diameter of the wire was 0-462 millimetres; its specific gravity was 12-38, as determined with care. The wire was twisted into a loop at each end, and the mark made near each loop. The loops were varnished, so as to limit absorption of gas by the wire to the measured length between the two marks. To straigliten the wire, one loop was fixed, and the other connected with a string passing over a pulley, and loaded with 1-5 kilogramme, a weight suf- ficient to straighten the wire without occasioning any undue strain. The wire was charged with hydrogen by making it the negative electrode of a small Bunsen’s battery, consisting of two cells, each of half a litre in capa- city. The positive electrode was a thick platinum wire placed side by aide with the palladium wire, and extending the whole length of the latter within a tall jar filled with dilute sulphuric acid. The palladium wire had, in consequence, hydrogen carried to its surface for a period of one and a- half hoiins. A longer exposure was found not to add sensibly to the charge of Iiydrogen acquired by the wire. The wire w'as again measured, and the incrfa.se in length noted. Finally, the wire being dried with a cloth, was divided at the marks, and the charged portion heated in a long narrow glass tube kept vacuous by a Sprengcl a.spirator. The whole occluded hydrogen was thus collected and measured ; its volume is reduced by calculation to Bar. 7. 4. 0. DESCniPTION OF PLATES. Plate XLY. Portion of a shoot of GoxoTnTK.EA LoviiNi, highly magnified, .r. The coenosarc, or common flesh, y. The horny cuticle, or polypary. z z. Calycles. e e. Reproductive buds (gonophores) that have passed beyond the orifice of the capsule, and continue attached externally, e' e'. Planulae, or ciliated em- bryos. A single gonophore, more highly magnified j showing the ova wdth germinal vesicle and spot. From drawings by Professor Wyville Thomson, F.R.S. Campanularia neglecta, highly magnified, a. The point w'here the coenosarc communicates with the stomach of the polypite. Lafoea pygju.ea, highly magnified. From drawings by the late Mr. Alder. A young Campanularian soon after the attachment of the embryo. The medusiform sexual zooid (gonozooid) of Clytia Johnstoni. a. The digestive sac. h b. The umbrella, or swimming-bell. c. One of the radiating canals, d. The circular vessel, e. One of the lithocysts (organs of sense). From drawings by the Author. Plate XLVI. Dipiiasia pixxata (female), natural size. Im Portion of a pinna, magnified, bearing a male capsule, lb. Litto, with female capsules. DipriASiA PINASTER (female), natural size. Dipiiasia fallax, natural size. Plemulauia frutescens, natural size. Capsule of Dipiiasia rosacea, showing the fixed reproductive buds (o o), with ova. All the figures but the last are by Mr. Tuffen West. Plate ZD7I. w ] I ;|f 233 HYDEOaENIUM. 13Y EGBERT [HUNT, F.E.S. HE attention of experimental philosophers has, for some time past, been gradually drawn to the phenomena pre- sented by the operation of some obscure force, or forces, ever active in the molecular interstices of matter. Under a variety of terms they have been explaining, or rather endeavouring to explain, peculiar attractions manifested by the surfaces of bodies, and assuming different conditions, according to the peculiarities belonging to the surfaces under examination. The force known as capillary attraction — whether exhibited in tubes or between plates of glass — is tolerably familiar to all, and the mechanical power shown by the fibre-tubes of cotton will have been tested by almost every intelligent schoolboy. The absorption of water by a lump of sugar or of chalk, and the sucking up ” of water by a sponge, is so common, that few stop to ask by what power the phenomenon is brought about. We are now, however, beginning to discover that, in these, apparently, simple things, we may observe the opening of a door, disclosing a way, which promises to lead us to a knowledge of nature’s most secret operations. The simple adhesion of water to a perfectly clean plate of glass, informs us, that a power resides on that surface ; and, if we bring two such surfaces near together with a fluid between them, we see that the fluid is lifted against the gravitating influence of the whole Earth. In this we have hitherto detected a simple mechanical force only. Of late, however, M. E. Becquerel has informed us that this surface force has a power equal to the breaking up of strong chemical affinities. That, metallic solutions being employed, the metal is gradually separated from the solution and deposited in thin films upon the glass plates. In the fine fissures of green-stone rocks we often find films of native copper; and the films of gold in the cracks of the gold-bearing quartz are well known to the miner. These are doubtless due to the force resident on the surfaces of the rocks, in the same way as it is shown in action in M. E. Becquerel’s experiment. 234 POPULAR SCIEKCE REVIEW. The influence of surface is discovered again in the ordinary process of flltration. It was shown by Dr. Hofmann and Mr. Witt, in their report on •the water supply in London, that the water which passed through the filter beds of the water companies’ reservoirs, was robbed of some portion of the salts held in solution. The late Dr. Normandy, when engaged in his experiments on the production of drinkable water from the sea, discovered that sea water was rendered free from salt, or nearly so, by being filtered through about thirty feet of siliceous sand or powdered glass. The re- moval of organic colouring matter from water, by passing through a few feet of earth, is another example of the same power in action. These phenomena are shown, yet more strikingly, by charcoal. Hence its employment for purifying water, and its use for removing the annoyances arising from putrefactive fermentation. Experiments have shown that char- coal possesses the power, by virtue of its porosity, of condensing within itself many times its own volume of certain gases and vapours. This property is not peculiar to charcoal — all porous bodies exhibit it to a greater or less degree — but the power is strikingly manifested b}^ this substance. It maybe incidentally mentioned here, that Dr. Stenhouse has, by connecting a piece of charcoal with a voltaic battery, and plunging it into a solution of platinum, succeeded in coating all its interstitial spaces with a film of that metal. This is, in itself, another example of the surface action to which it is desired to draw attention. This platinized charcoal possesses all the powers of ordinary charcoal greatly exalted. It acts, indeed, as spongy platinum does, and not only condenses the gases escaping from putrid matter, but combines them with oxygen and slowly burns them away. An instantaneous light lamp was common enough some years since. Hydrogen gas was produced, by a simple arrangement, by the oxidation of zinc in water, and stored in a bottle for use. When, by turning a stop-cock, a jet of hydrogen gas was pro- jected upon a piece of spongy platinum, it was rapidly condensed and, at the same time, forced into combination with oxygen. The result of this was the production of heat sufficient to ignite the jet of hydrogen gas. Faraday showed how directly this depended on surface action. Taking a piece of perfectly clean platinum, he plunged it into a mixture of oxygen and hydrogen gases. These united to form water on the surface of the metal, and by the heat evolved, in this process, the metal became red hot. It may appear too much to sa}^ that the solution of sugar or of salt in water is an analogous process to those which have been thus liastily and popularly described. A little attentive consideration will, however, carry conviction to the mind, that in the solution of a lump of sugar in water, we see the diffusion of HTDROGENIUM. 235 it, through the interstitial spaces of the fluid, up to the point of saturation ; when the solution-power ceases, and that it is a case of a similar nature to the solution of sulphuretted hydrogen in charcoal. Mr. Graham has, long since, beautifully shown the power of this surface force in water. Anyone can repeat a simple experiment, and greatly interested will he be in watching the result. If to a solution of sulphate of copper some liquid ammonia is added, we produce that beautiful purple solution which marks the shop of a druggist. Fill a small bottle with this solution, and, placing a little bit of window-glass over the mouth of the bottle, lower it, by means of a string, into a con- fectioner’s jar full of water. When it rests steadily at the bottom of the jar, carefully, with a rod, strike off the glass cover from the bottle. The water and the ammonia-sulphate of copper are in contact, but they do not mix. Gradually it will be observed that the purple solution loses colour, becoming a pale blue. The chemical combination has been overthrown — the ammonia has left the sulphate of copper and diffused itself through the water. In a similar manner, yet more powerful chemical combinations may be broken up. We are acquainted with other phenomena, in which modified conditions of the force which we have been considering are strikingly shown. Exosmose and endosmose — or, as Mr. Graham terms it. Osmose Force — exhibits phenomena of a pecu- liar character, yet a cautious examination appears to lead to the conclusion that there is little essential difference between it and the forms of force which have been described. A porous tile, a wall of clay, a piece of animal membrane, dividing two fluids, differing but slightly in their character — say, for example, sugar and water — shall be on one side of the partition, and water only on the other. Porosity immediatel}^ begins its work : the solid substance in solution (this mode of expression can scarcely be avoided, but the substance in solution does not exist in the solid state) passes through in one direction while a little of the purer fluid passes through in the other direction. Flowing in and flowing out goes on until all the sugar, or other substance, leaves its own cell and settles itself in the other. By this process numerous chemical decompositions can be effected, as in the cases already cited. In each and all of these phenomena, it is tolerably certain that we are dealing with an obscure, but a most energetic force, possessing more resemblance to gravitation than to any other known power, but distinguished from it by broad lines of difference. In gravitation we discover a power acting, irresistibly, amongst the particles of matter, drawing all to a mathematical centre, while, at the same time, we detect an influence — is it diffusive ? — which binds mass to mass in space and regulates the motions of worlds. In the sur- 236 rOPULAR SCIENCE REVIEW. face force under consideration we find a power acting in perfect independence of gravitation — often in opposition to it ; but it is a caved giant, whose power is limited to the cave in which it dwells. Pursuing a series of investigations, all of them being remark- able examples of experimental induction, and which may be regarded as originating in the more simple phenomena referred to, Mr. Grraham was led to the discovery that certain metals not only absorbed some of the gases, and especially Hydrogen, but that they retained those metals, or as the discoverer termed it “ occluded ” * them. When iron or platinum or palladium in a state of tolerable purity — whether in the form of sponge, or aggregated by hammering — is heated, and allowed to cool slowly and completely in a hydrogen atmosphere, those metals are found to have absorbed many times their volume of the gas, and to hold it in a state of occulsion ” for any length of time ; until, indeed, it is dispelled by heat. It was the discovery of this fact, and the examination of meteoric iron, which led to the remarkable discovery that these meteoric masses must have passed through — and indeed cooled in — an atmosphere of hydrogen gas. Mr. Graham advanced from this point to a knowledge of a new method of charging metals with hydrogen at low temperatures. When a plate of zinc is placed in dilute sulphuric acid, hydrogen gas is liberated from the water by the oxidation of the metal, and it is evolved from the surface of the zinc, but no hydrogen is occluded. Mr. Graham remarks, “a. negative result was to be expected from the crystalline structure of zinc.” We are disposed to ask why crystalline structure should interfere with this power of retention ? If, however, a thin plate of palladium is immersed in the same diluted acid, and brought into metallic contact with the zinc, the hydrogen is transferred to its surface, and the gas is largely absorbed. The charge taken up in an hour by a palladium plate, rather thick, at 12° amounted to 173 times its volume. “ The absorption of hydrogen was still more obvious when the palladium plate was constituted the negative electrode, in acidulated water, to a Bunsen battery of six cells. The evolu- tion of oxygen gas at the positive electrode continuing copious, the effervescence at the negative electrode was entirely sus- pended for the first twenty seconds, in consequence of the hydiDgen being occluded by the palladium. The final absorp- tion amounted to 200 volumes.” The hydrogen enters the palladium and no doubt pervades the whole mass of the metal, but it exhibits no disposition to • Occlusion is a good old English word, signifying to ^ shut up,’ which had fallen out of uw, until Mr. Graham restored it as a scientific term. HYDEOGENIUM. 237 leave the metal, and escape into a vacuum, at the temperature of its absorption. Pieces of palladium charged with hydrogen have been sealed up in exhausted glass tubes. After two months the glass has been broken under mercury, and the vacuum found perfect, no hydrogen having vaporised in the cold, but on the applicatiou of heat 333 volumes of gas were evolved from the metal. Another experiment was of a very striking character. A hollow palladium cylinder was made the negative electrode in an acid fluid, while the closed cavity of the cylinder was kept exhausted by means of a Sprengel aspira- tor. No hydrogen whatever passed into the vacuous cavity in several hours, although the gas was no doubt abundantly absorbed by the outer surface of the cylinder, and pervaded the metal throughout. It appears that when hydrogen is absorbed by the metal palladium, the volatility of the gas may be entirely suppressed ; and hydrogen may be largely present in metals without exhibiting any sensible tension at low temperatures. Occluded hydrogen is certainly no longer a gas, whatever may he thought of its 'physical conditions. It has often been maintained on chemical grounds that hy- drogen gas — the lightest bod}^ in nature — is the vapour of a highly volatile metal. Sir Humphry Davy and others have drawn attention, from time to time, to certain conditions which appeared to connect hydrogen with the metals, and now the results obtained b}^ the Master of the Mint appear to confirm those views. Mr. Graham remarks : “ The, idea forces itself upon the mind that palladium, with its occluded hydrogen, is simply an alloy of this volatile metal, in which the volatility of the one element is restrained by its union with the other, and which owes its metallic aspect equally to both constituents.” The following brief statements of the conditions of palladium — and of palladium charged with hydrogen — will elucidate this point. It should be stated, in the first place, that palladium in the state of thin films, as thrown down from a solution of the chloride by a voltaic battery, when heated to 100° in hydrogen, and allowed to cool slowly for an hour in the same gas, was found to occlude 982*14 volumes of the hydrogen. This is the largest absorption of hydrogen which has been observed, and certainly it is not a little remarkable to find a dense body, such as the metal palladium is, absorbing and retaining nearly one thousand times its volume of so light a body as hydrogen is. The density of palladium when charged with eight or nine hundred times its volume of hydrogen gas is perceptibly lowered. A palladium wire before exposure measured 609*144 millims (23*982 inches). This wire received a charge of hydrogen amounting to 936 times its volume, and increased in length 9*779 millims (or 0*385 238 POPULAR SCIENCE REYIEW. inches) ; it measuring, when charged, 618*923 millims. The density of the charged wire is reduced from 12*3 to 11*79. The e:^^pulsion of hydrogen from the wire, however caused, is attended with an extraordinary contraction of the latter. On expelling the hydrogen by a moderate heat, the wire not only receded to its original length, but fell as much below that zero as it had previously risen above it. That a very remarkable change is produced in the palladium by the absorption of the hydrogen is shown by the manner in which it burns. A wire so charged with hydrogen, if rubbed with the powder of mag- nesia (to make the flame luminous), burns like a waxed thread when ignited in the flame of a lamp. It has been proved that the tenacity of palladium is altered by the occlusion of hydrogen. The tenacity of palladium wire being 100, the tenacity of palladium and hydrogen was found to be 81*29. Dr. Faraday determined, by many experiments, that palladium is “ feebly but truly magnetic,” and he placed this element at the head of what are now called paramagnetic metals. The experiments of Mr. G-raham show that, with occluded hydrogen, palladium becomes so magnetic that it must be allowed to rise out of the paramagnetic class, and to take place in the strictly magnetic group with iron, nickel, cobalt, chromium, and man- ganese. Many chemical peculiarities distinguish this compound from ordinary palladium. The conclusions which appear to flow from this enquiry are, that in palladium fully charged with hydrogen there exists a compound of palladium and hydrogen in a proportion which may approach to equal equivalents. The charged palladium is represented by weight as ralladium . . 1‘0020 grm . 99-277 Hydrogen . . 0*0073 grm . *723 100^00 It is in the proportion of one equivalent of palladium to 0*772 equivalent of hydrogen H= 1, Pci = 106*5. The evidence is therefore strong that a true alloy is produced, and to this alloy the name of Hydrogeniam has been given. In this alloy hydrogen appears to be reduced to the metallic state, and the great problem of the chemist, as it regarded the physical condition of hydrogen, is satisfactorily solved. The magnetic character of this alloy may have its bearing upon the appearance of hydrogeniiim in meteoric iron, in association with certain other magnetic elements. The absorption of hydrogen by palladium is a striking fact. That this gas is absorbed by platinum and by iron has also ])cen proved. The occluded hydrogen found in meteorites points to a condition in space, upon which we can only ob- scurely speculate. Spectrum analysis is teaching us that this HYDROGE^sIUM. 239 element — hydrogen — forms an important constituent of the nebulous groups and cometary films., The examination of surface forces instructs us that the element which, oxidised, becotues water, and which, in its combinations with carbon, plays so important a part in the animal and vegetable economy, is no less essential as an agent modifying the conditions of the mineral world. From the stud}^ of little things — the solution of sugar, the absorption of water by a sponge — we are advanced to the discovery of truths which bear on the mysteries of mole- cular structure, and on the constitution of worlds in space. VOL. VIII.— NO. xxxii. R 240 POPULAR SCIENCE REVIEW. THE STEUCTUKE AND AFFINITIES OF THE SEA-SQUIETS [TUNICATA]. By JOHN CHARLES GALLON, M.A. (Oxon.), F.L.S., : Lecturer on Comparative Anatomy at Charing Cross Hospital. ^^Profecto enim a summis molluscis ad infima zooplijta, ^ Natura non facit saltum.’ ” — Chamisso. HOUGH the animals which are the subject of the present article are well known to the naturalist, they are by no means familiar objects to the ordinary sea-side rambler ; partly because some members of the order are oceanic, in part for the reason that those which are inhabitants of our coasts are either unattractive in appearance, or, if better-favoured, are concealed by rocks and the fronds of sea-weeds. Some, however, of our readers, when wandering along the edge of a shore strewn with the litter of a recent storm, count- ing the dewy pebbles, fix’d in thought,” may perchance have stumbled across a curious object, combining the consistency of leather with the appearance of a lump of dirty ice, to which, maybe, sticks an empty sh el 1-valve, a mass of pebbles, or a root of tangle. This, after being handled, is very probably squeezed, and out shoot two jets of sea- water into the face of the observer. The creature, not inaptly termed a sea-squirt,” is an Asci- dian ; * belonging to a class called Molluscoida, from a zoologi- cal, rather than an external and obvious, resemblance to the Mollusca — e.g., limpets, whelks, razor-shells, mussels, oysters, cuttle-fish, sea-hares. Tlie Tiinicata, or Ascidioida — that division of the Mollus- coida with wliich we are at present concerned — comprise, besides the sedentary “ sea-scpiirt,” some roving oceanic members [PLATF XLYH.] • Derived from the Greek amcn^, a wine-skin (the leather-bottel ” of the Orientals), to which the animal in question bears no slight resemblance. S(] Lurty CaRot) del cL liU'i THE STRUCTUEE AND AFFINITIES OF THE SEA-SQUIRTS. 241 which have no popular designation, but are known to naturalists as the genera Salpidce and Pyrosomidce. Before, however, proceeding to survey the almost Protean variations which the Timicata present, we will examine, some- what in detail, the structure of a representative, both of the nomad tribes, and of those which have a fixed habitat, the lease of which expires only with life. To begin with the latter. The outer coating of the Ascidian, which varies in consistence, is termed the test.” * This is pierced by two openings, situated at a varying distance from one another, sometimes occupying the extremity of two necks, which render the creature a caricature of the Wolff ” bottle, known to workers in the laboratory. One of the two orifices (the uppermost, if they be on a different level) admits water (air- laden) and food ; the other gives exit to excretions, intestinal and generative, and to water (airless). (Figs. 1 and 10, T.) A most important point in connection with the test is that it contains cellulose (no less than 60 per cent.), the possession of which substance was once held to be the exclusive privilege of the vegetable world. Its presence, however, is supposed to be due to a destructive rather than to a constructive chemical change. It is significant that the fresh -water polype, or Hydra^ con- tains chlorophyll, and this, moreover, not derived from vege- table food, but elaborated in its own tissues. The test is the true homologue of the shell of bivalves — e.g., the river-mussel (Anodonta Cygnea). Beneath the test lie two inner coats — namely, the muscular ‘‘inner tunic” (Hancock), which is homologous with the “ man- tle ” of bivalves ; and the “ lining membrane ” ( “ inner tunic,” Huxley). These two tunics are generally closely adherent, ex- cept where the viscera and blood-channels intervene. (Figs. 1 and 10, M.) The mantle and test are usually free (this is very evident in spirit -preserved specimens), except at the two respiratory orifices mentioned above, where they are adherent, and at points where vessels pass to the test, serving as slings or side-stays. The bag formed by the combined mantle and lining mem- brane copies in its outline that of the inner surface of the test ; and has, moreover, two orifices corresponding with those pierced in the latter. A little distance within the passage of entrance (“ inhalent ”) into this bag is a circlet of tentacles, pointing downwards and * From the Latin testa , a piece of baked clay, a potsherd, a wine-jar. “ Quo semel est imbuta recens servabit odorem Testa dill.” — Har. 242 POPULAR SCIENCE REVIEW. forming the upper margin of a fold of the lining membranCy termed the ‘‘anterior collar ” (Hancock). Most of the muscles of the mantle run in a more or less longitudinal direction, interlacing in a manner which reminds us of the arrangement of muscular fibres which Dr. Petti- grew has so clearly demonstrated in the stomach of man and other mammals. Some fibres are disposed in a circular manner round the two orifices, and, as Van der Hceven says, “ Sphinc- teres veluti efficiunt.” (Fig. 1.) They are of the smooth variety. A certain space, termed the “pallial chamber ” * or “atrium” f (at)', fig. 10), intervenes between the lining of the mantle and a sac or bag, yet remaining to be described — ‘‘Apparet domas intus, et atria longa patescunt.” This “ domus intus,” which comprises the gill-sac, the diges- tive tube with its accessory glands, and the organs of reproduc- tion, lies almost free in the pallial chamber. The gill-sac {hr, fig. 10) which has a texture like that of coarsely-woven gauze, has, at its upper end, a wide mouth, the margin of which is attached to the mantle a little below the “ anterior collar.” At its lower extremity is a much smaller aperture, the true mouth of the animal. What anatomists would call the “ vis- ^ ceral ” portion of the lining membrane is closely adherent to J the gill-sac, besides being reflected over the heart and other , | viscera, in the manner of a peritoneum. || Along that side of the body which is farthest from the aper- ture of exit, the two lateral lobes, into which the gill-sac is sup- ' \ posed to be resolvable, are separated by certain folds of the '* lining membrane which are converted into a longitudinal rod, ' termed the “ endostyle.” These folds diverge above, to become i ■ j continuous with the lower portion of the anterior collar. On i the opposite side of the sac intervenes a similar fold of the lining I membrane, the “oral lamina,” which is continuous above, after bifurcation, with the anterior collar; and below forms, with the lower extremity of the endostyle, the “ posterior cord.” ' ‘ Ttie gill-sac is made up of a number of large transverse ^ blood-channels, crossed by smaller longitudinal ones, which form the margins of narrow elongated windows (“stigmata”) »- fringed with cilia, and often having a very beautiful structural arrangement (figs. 2 and 4). A nurnbei* of stout longitudinal }>ar8 run from one end to the other of the gill-sac, attached only where they cross the transverse vessels. At these points there is situated a ciliated papilla. The water which traverses the sac, after parting with its oxygen to the blood circulating • From Lnt. pallium, a mantle. t Atrium, the entrance hall of a Foman house. ii THE STRUCTURE AND AFFINITIES OF THE SEA-SQUIRTS. 243 through the vascular sieve, passes out through the stigmata ’’ into the ‘‘ atrium,” and leaves the body of the animal by the exhalent orifice. The circulation in these animals is indeed — to borrow an expressive v/ord from G-oethe — a “ Zauberfluss,’* for instead of a definite onward current there is actually a tidal ebb and flow. The heart is a muscular tube of considerable length, open at either end, but having no valves. It lies in the region of the lower border of the stomach, between the mantle and lining membrane, and is invested with a fold of the la|ter, in the fashion of a pericardium. The arrangement of the vessels has been most carefully studied and clearly described by Mr. Hancock, but is somewhat com- plicated; so that, were there sufficient space iiere for descrip- tion, our readers would weary. Suffice it to say that there are two main longitudinal trunks, which eventually terminate at either end of the heart ; one of which runs along the endostyle, while the other courses along the opposite side of the gill-sac. These are brought into relation by means of the transverse vessels of the gill-sac, and by a circular channel situated just below the anterior collar.” Owing to the connection of the main trunks, either imme- diately or mediately, with certain networks which ramify in the mantle and over the digestive tract, and with vessels which serve the test, the blood which is returned to the heart by either of these channels in its turn, arrives in only a partially aerated condition ; that trunk, however, which courses along the endo- ,style being the carrier of the least pure fluid. The number of heart-pulses in either direction is not constant, but varies considerably. As regards their duration, Mr. Han- cock found that it “ required 2-j- minutes to accomplish the beats during a single oscillation.” The digestive system is comparatively simple. The mouth, which is situated at the bottom of the gill-sac, leads almost directly into the stomach, upon the floor of which there is a longitudinal fold, which is continued into the intestine. The tube fo^ed by this latter and the stomach is folded twice upon itself, the concavity of the first loop looking toward the heart (haemal flexure, Huxley). In the second loop the reproductive organs usually lie. The anus opens into the atrium, in the neighbourhood of the exhalent orifice (fig. 10, m, st, i, and a). The food, which is sedimentary, consisting of Diatoms, &c., is not selected by the animal. It is sifted from the water which traverses the gill-sac by ciliary action, accumulated at the “ oral lamina,” before mentioned, and conducted along this organ, formed into a cord by a mucous secretion, to the mouth. . The liver is a gland made up of delicate branching tubes which 244 POPULAR SCIENCE REVIEW. end in rounded extremities. It thinly coats the intestine, and opens by two ducts into the stomach. Overlying the liver, and burrowed into by the reproductive organs, is a ductless glandular mass, permeated by blood-chan- nels, which may “act,” as Mr. Hancock says, “as a sort of packing” (like Paley’s spleen?) “to these organs.” Its vesicles may also aid the heart “ by their resiliency when the mass is gorged with blood.” The two sexes are combined in one individual. Though separate organs a^’e devoted to the secretion of the male and female elements, they are associated in one mass, reminding us of the so-called “ ovo-testis,” which occupies the last whorl of the liver in Gasteropods (e.g. snails and slugs). Their ducts, which are distinct, follow the curvature of the last loop of the intestine, and terminate at the atrium, by the side of the anus {gr and ov, fig. 10). The ova are prolDably impregnated in the “ cloaca” — that portion of the atrium into which the generative ducts and anus open. In each is developed a tadpole-like embryo (fig. 12), which is hatched about thirty hours after fecundation. The fore part of this tadpole — as we may term it — is furnished with three sucker-like projections. By these it attaches itself to some suitable spot before undergoing subsequent changes. A pigment spot may also be seen in the middle line of the back, and a second one laterally (fig. 12 e). These were at first supposed to be eyes ; but Krohn, from his observations, considers this not proven. They persist for a long time after larval existence, but, after fusing into a single mass, finally dis- appear. The tail of the larva, after being retracted into the interior of the now attached body, where it is rolled up into a spiral coil, breaks up eventually into a lobular mass, and becomes no longer visible. A cylindrical axis has been lately discovered in the larval tail, resembling in structure the noto chord of the lancejet {Amjjhioxus), the lowest of the fishes. It is significant that the late Professor Goodsir pointed out the likeness between the enormously dilated, ciliated, and perforated pharynx of this very fish and the gill-sac of the Ascidian. The nerve system is very rudimentary, there being^but one ganglion, situated betwixt the inhalent and exhalent orifices, and lying between the mantle and lining membrane. From it radiate a few nerves to the respiratory tubes and mantle, and to the “ branchial tubercle,” a supposed organ of special sense (taste or smell ?) which lies immediately in front of the upper end of the oral lamina. We will now pass on to a brief survey of the erratic Tunicata, taking the Safjjidw as representatives of this division. These animals are of especial interest to the naturalist, seeing THE STRUCTURE AND AFFINITIES OF THE SEA-SQUIRTS. 245 that it was in them that Chamisso * discovered a peculiar mode of reproduction, termed by him ‘‘alternation of generations,” a discovery since verified by the late observations carried on by Huxley on board the “ Eattlesnake.” A Salpa (fig. 11) is a somewhat irregular, hollow, translucent cylinder, open at both ends, each orifice being furnished with a valve. Though the animal swims “ indifferently,” says Huxley, “ with either end forward, and with either side uppermost,” that end where the mouth opens may be considered as anterior, and that side as dorsal where the heart is situated. There are two tunics, adherent only at the margin of the two orifices. The outer corresponds to the Ascidian test, while the inner is made up of the homologues of the mantle and lining membrane, which are in close contact, except where blood- channels intervene. (Fig. 11, M and T.) A few bands (five or seven in number) of striped muscular tissue run across the inner tunic, transverse to the long axis of the body {hm. hm, fig. 11). A band (“ hypopharyngeal band,” Huxley), composed of two laminae adherent along their dorsal edge, crosses the body-cavity (“pallial chamber”) obliquely from behind forwards and downwards (br, fig. 11). This has been called a gill, but “ somewhat too exclusively, as there can be little doubt that the whole respiratory cavity performs the branchial function.” A tongue-shaped body, the “ languet ” (“langlicher Organ,” Eschricht), at the base of which lies a ciliated sac, projects into the body-cavity, where its ventral wall is joined by the an- terior end of the so-called “ gill.” It is supposed to subserve the sense of taste. (Fig. 11, cci) A single ganglion lies just behind the languet, to which, as well as to the walls of the body, it sends nerves. To its lower surface is attached a vesicle containing pigment and calcareous bodies, leading to which is a depression in the outer tunic. (Fig. 11, g.) This probably corresponds to the auditory organ in those orders of which the snail and river-mussel are repre- sentatives. The digestive tract is very simple, being included in a small knob — the “ nucleus ” — situated at the hinder end of the body. (Fig. 11, It is connected with the mouth by a furrow running along the ventral aspect of the animal. The intestine is spirally coiled, and has a sac — the stomach — attached to its left side. The anus opens above and to the right side of the mouth. Over the last portion of the intestine is spread a network of trans- * Better known, no doubt, to most of oiir readers as the author of “ The Shadowless Man ” (Peter Schlemihl), I 246 POPULAR SCIENCE REVIE'^V. parent tubes, which may perform the function of a liver, or represent a rudimentary absorbent system. ; Though the circulatory system consists of “ sinuses,” i. e., i blood-channels without distinct walls, many of these are con- stant in position ; namely, the dorsal^ enclosing the endostyle ; the ventral, in which the ganglion lies — lateral sinuses connect- ing the two former — a sinus surrounding the viscera, and a channel which traverses the “ gill.” These communicate round the oesophagus ; above and in front of which lies the heart (fig. , 11, h) — an imperfectly tubular organ, having walls of stripped muscular tissue. There is a blood-tide, with intervening pause, as in the Ascidia. It had long been noticed by naturalists that the Salpido3 oc- curred in two well-marked forms ; one, as a solitary specimen ; the other consisting of a number of individuals joined together in a chain, which moved through the waters of the ocean in a serpent-like course. These two forms were described as distinct species until Chamisso discovered that they were but phases in the existence of one and the same zoological individual. It will be advisable to term them, after Huxley, “ Salpa A,” and Salpa B,” in order to avoid the use of a theoretical nomenclature. ■ Though these forms are ver}^ similar internall}^, they differ outwardly in certain points, such as shape, texture of the inte- gument, number of the muscular bands, and length of the en- ^ dostyle. Pincircling the nucleus of a specimen of Salpa A, may often be found a cliain of embryonic B Salpce, which are at- : tached in pairs to the side of a cylindrical tube which takes j origin just in front of the heart, and is an outgrowth from the i sinus-system. The cavity of this ‘‘gemmiferous tube” com- S municates with the dorsal sinus of each embryo ; and Professor I Huxley “has seen one of the large blood-corpuscles of the I parent entangled in the heart (which was not more than | of an inch long) of a very young foetus.” I Each embryo is attached to its neighbour by means of a com- I municating channel bet\yeen their sinus systems. This channel ^ gradually narrows until it becomes a mere pedicle ; and, finally, J all communication ceasing, the young S(dpa B is free. > “It is clear, therefore,” says Professor Huxley, “that the gemmiferous tube is nothing more than a stolon, containing a diverticulum of the circulating system of the parent, and the whole process of reproduction as it is manifested in Salpa is one of gemmation. Salpa B is a bud of Salpa A.” Before its liberation from the chain, each B Salpa generally contains a Holitanj fcetus, attached by a pedicle to the upper and hinder ^ part of the wall of its respiratory cavity. This connection be- h tween parent and offspring is, moreover — most wonderful to re- g THE STTIUCTURE AND AFFINITIES OF THE SEA-SQUIllTS. 247 late — like that of the highest Vertebrata, iiwly 'placental. The ^‘placenta’’* (fig. 11, pi.) consists of two sacs; the outer of which, concave and cup-shaped, communicates with the dorsal sinus of the foetus; while the inner, which is spherical, and received into the concavity of the outer sac, opens into a sinus arising behind the heart of the parent. Each sac is divided internally by an incomplete partition, so that a current sets dowm one side and up the other. There is no communication hetiveen the sacs, the flow of blood in each being independent of that in the other. In process of time this bond is snapped asun- der, and the offspring is launched into the wide waters as “ Salpa A.” To sum up, in the words of Professor Huxley, “ There is no ‘ alternation of generation,’ if by generation sexual generation be meant ; but there is an alternation of true sexual genera- tion with the altogether distinct process of gemmation.'’'’ Professor Huxley, after clearly pointing out the difference between a zoological and metaphysical individual,” proposes to term each form of Salpa — namely, A and B — a “ zooid ;” seeing that these are only collectively equivalent to the in- dividual” of higher animal forms, being in structure but part of an individual, namely, organs.] The male reproductive gland of Salpa B surrounds the intes- tine like a network. Since its stages of development are later than those of the ovary of the same zooid, it may be inferred that impregnation takes place from without. In a young A Salpa may be seen at the hinder part of the sinus surrounding the viscera a mass of oil-containing cells, termed by Krohn ‘‘ elmoblast” J (fig. 11*). The function of this organ is unknown ; but its occurrence in an animal possessed of a placental circulation suggests an analogy to a ‘^thj^mus” gland. The Salpidce are said by Chamisso to be luminous, but no reference is made by Huxley to this point. Having now described a representative both of the fixed and wandering Tnnicates, but small space is left at our command for mention of the varieties of these two groups. * This structure, which forcibly reminds us of oue of tlie cotyledons ” of the placenta of a cow, “is identical in structure with a single villus con- tained in a single venous jcell of the mammalian placenta, except that in the Salpian placenta the villus belongs to the parent, the cell to the foetus ; the reverse obtaining in the Mammalia.” t The process of generation just detailed is termed by Quatrefages, “Ge- neagenesis.” See cliaps. xiii. — xvi. inclusive, of his 3IetamorpIwscs of JIan and the Loiver Animals. Translated by TIenry Lawson, M.D. London, 1864. f From the Greek tXaiov (olive) oil, we suppose. 248 rorULAR SCIENCE REVIEW. The Ascidia proper comprise — a. Those which are isolated, e.g. Boltenia and Phallusia (figs. 1 and 10) — Compound Ascidians. fS- Those connected by stolons” — trailing prolongations like the “runners” of strawberry-plants — into which blood- channels are continued, e.g. Clavelina {fig. 5) — Social Ascidians. 7. Those in which the tests are fused into a common gela- tinous mass, in which the individuals are imbedded in groups, frequently star-like, e.g. Botryllus (figs. 6, l)^Gompound Ascidians. The oceanic members not yet mentioned are, Pyrosoma, Doiiolum, and Appendicularia. The Pyrosomata are elo- quently described by Professor Huxley as “ miniature pillars of fire gleaming out of the dark sea, with an ever-waning, ever- brightening, soft bluish light, as far as the eye could reach on every side.” To speak more prosaically, each animal consists of a hollow cylinder, closed at one end, open at the other, somewhat like a test-tube (fig. 8). At the open end is a kind of valve. In the walls a number of zooids are imbedded perpendicular to the axis of the tube, whose anterior orifices look outwards, while the posterior open into the interior of the cylinder. The cylinder moves by the reaction of forced-out water against its closed extremity. Keproduction takes place in two ways ; both by an asexual budding, and by impregnated ova, each of which gives origin to four aggregated zooids. Doiiolum, as its name implies, is cask-shaped.* Both ends are open, the hinder being fringed. The gill is represented by two bands (“epi-” and “ hypo-pharyngeal ” of Huxley, respec- tively) which are connected by transverse bars. Appendicularia (fig. 9), a minute animal, is the lowest form of Tunicate. In it the larval tail is persistent, while the gill is entirely absent. There is, however, a “ ciliated band” on the ventral surface of the respiratory cavity. Appendicularia differs from all other Tunicates in having no reversal of the blood-current, and in possessing individuals of separate sex, of which, however, the male only has at present been discovered. Prfjfessor Huxley divides the Tunicata {Ascidioida) into three orders — 1. Brancldalia, in wliich the gill-sac is so large that the digestive and generative organs are pushed to one side of it. The solitary Ascidians, Boimyllus, Salpa, and Pyrosoma, belong to this order. 2. Ahdominalia, in which tlie gill-sac, being comparatively Diminutive of Lat. dolium, a cask. THE STRUCTUKE AND AFFINITIES OF THE SEA-SQUIRTS. 249 small, lies in front of the generative and digestive organs. This order includes Clavelina and the Compound Ascidians. 3. Larvalia, comprising only Appendicularia, A few words on homologies. 1. Between the different members of the Tunicata. — As but a portion of the work of respiration is fulfilled by the so-called gill ” of Salpa, so is this organ a homologue of but a portion of the gill-sac of the Ascidian, namely, the “ oral lamina.” Two ciliated bands, which in Salpa encircle the anterior end of the respiratory cavity, and in Appendicularia remain rudimentary, seem to answer to the “ anterior collar ” of the Ascidian. The branchial tubercle ” of the latter appears to be homo- logically, as well as functionally, represented by the “ languet ” of Salpa. Lastly, the elgeoblast ” of Krohn may turn out to be the representative of the erectile structure which coats the digestive tract of the Ascidian. 2. Between the Tunicata and other sub-classes. — Though Pro- fessor Huxley declared long ago that “ great as are the apparent resemblances between a Lamellibranch and an Ascidian, they all vanish upon close examination,” the belief is not yet given up by some anatomists that true comparisons may be made between these two divisions. According to this view, which is adopted by Professor Eolleston, of Oxford, in a forthcoming manual on comparative anatomy, the gill-sac of the Ascidian corre- sponds to the branchial cavity or to the left gill of the river mussel, and not to a dilated pharynx ; while the entrance and exit orifices of the former will respectively answer to the in- halent and exhalent siphons, rudimentary in the river mussel, well developed in the gaper ” {Mya). The anterior end of the Ascidian will be that at which the animal is attached, and the line of the endostyle will indicate its dorsal aspect, while the oral lamina will represent the haemal region of the river mussel. The single ganglion of the Tunicata will, finally, answer to the parieto-splanchnic ” ganglion of the Lamellibranch. The crown of tentacles of the Polyzoa (of which the sea- mat” — Flustra—msij be a familiar representative) is supposed to answer to the gill-sac of the Ascidians by some ; by others to the fringe within the inhalent orifice, the gill-sac corresponding to the dilated pharynx of the Polyzoa. To others, lastly, these structures do not present any homologies. The Tunicata were not unknown to ancient naturalists. Aristotle, the father of philosophic zoology, gives a capital account of the Ascidians under the name of ry'/Oua.^' * See the first half of cap. vi. lih. iv. of his Historia Animalium. 250 POPULAR SCIENCE REVIEW. The same animals seem, moreover, to have formed a not un- important item in the “ Materia Medica ” of the Komans ; for Pliny writes : — Tethea torminibus et inflationibiis occurrunt. Inveniiintur hsec in foliis marinis sugentia, fungorum verius generis quam piscium. Eadern et tenesmum dissolvunt re- numque vitia.” * The Tunicates well illustrate what Darwin has so aptly termed “The Imperfection of the Greological Kecord,” for no remains which can with certainty be referred to this group — which might be expected, from their lack of a calcareous shell — have yet been discovered in any formation. EXPLANATION OF PLATE XLVU.f Fig. 1. Boltenia (from the educational series in the Museum of the lloyal College of Surgeons). A vertical section has been made through the test, which has internally a cartilaginous appearance. Lying free in the exposed cavity is the body of the animal, invested with the muscular mantle. Glass rods are inserted into the orifices of entrance and exit. „ 2. Portion of gill-sac of Ascidia Parallelogramma, highly magnifi.ed. After Alder. „ o. Clavelina p'oducta, natural size. After Milne-Edwards. „ 4. Cones of gill-sac of MoJgida arenosa, seen in profilq, highly magni- fied. After Alder. „ 5. Clavelina lepadiformis^ natural size. After Mihie-Edwards. ,, G. Botnjllus bivittatus, on a piece of sea- weed. Natural size. After Milne-Edwards. „ 7. The same species, magnified. After Milne-Edwards. „ 8. Byrosoma. From the educational series, Eoyal College of Surgeons. „ 9. Ajjpcndicularia Flagellum, highly magnified. After Huxley. The letters N S indicate a scale of the natural size of the animal. „ 10. Phallusia nigra, from a Hunterian specimen. Royal College of Surgeons. One side of the test, mantle, and gill-sac has been removed, in order to display the digestive tract and the organs of reproduction in situ. * Faturalis Ilistoria. lib. xxxii. Gl. t Through the courtesy and kindness of Mr. W. II. Flower, F.R.S., Con- senator of the Museum of the Royal College of Surgeons, permission was gained from tlie Museum Committee to make drawings from preparations contained in the Museum of the College. "NVe are also greatly indebted to Mr. Charles Robertson, Demonstrator of Anatomy at the University Mu.seum, Oxford, for some magnificent specimens of Ascidia Arachnoidea, by the aid of which the memory has been refreshed on several important points. THE STEUCTUBE AND AFFINITIES OF THE SEA-SQUIKTS. 251 Fig. 11. Salpa {Africana, Forskalil). A young solitary zooid. After Pro- fessor H. Miiller. „ 12. Fully-developed larva (or tadpole) of Ascidia Ampulloides. After Van-Beneden. The same letters indicate corresponding parts in all the figures. The arrows point in the direction of water-currents. T. Test. st. Stomach. M. Mantle. pi. Placenta. B. Gill-sac. i. Intestine. E. Position of Endostyle. gr. ■ Reproductive gland. 9- Ganglion. on. Oviduct. m. Mouth. cc. Ciliated cavity. a. Anus. A. Inhalent orifice. P. Exhalent orifice. hr. Hypopharyngeal hand. e. So-called eye. atr. Atrium, or respiratory cavity. ax. Axis of “caudal appendage.’ # Elaeohlast. hm. hm. Muscular hands. n. Nucleus. h. Heart. 252 POPULAR SCIENCE REVIEW. THE PLANET SATUKN IN JULY 1869. BY RICHARD A. PROCTOR, B.A., F.R.A.S., Author of Saturn and its System,” Half-Hours with the Telescope,” &c. &c. There is no object in the heavens which is so well calculated to excite our admiration as the planet Saturn, when ob- served with a good telescope. The nebulae exhibit to us systems which are in reality incomparably more magnificent. The double stars, rightly understood — and especially those binary systems whose periods extend over many hundreds of years — afford stronger evidence of the grand scale on which the universe is created. But the evidence which Saturn affords is more readily appreciated. The mind must be dull, indeed, which does not recognise at once, in the splendid architecture of the Saturnian system, the fashioning power of the great laws which the Creator has set His universe. The beauty of the system, the perfect regularity of the gigantic rings, the delicate varieties of colour which the practised observer can detect both in the planet and its attendant ring-system, and the magnificent scale on which all these features of interest are exhibited, attract and impress the attention; while the singular problems suggested by the stability of the rings, or st’ll more by the slow processes of change to w^hich they appear to be subjected, invite the exercise of the fullest powers of the observer and of the mathematician. The return of Saturn to our skies is rendered this year more than usually interesting, by the fact that the rings have now attained their full opening ; so that it will be possible to renew, under favourable circumstances, that examination of their structure w’hich, on the last occasion of the sort, led to the discovery of the dark ring and other singular features. The planet will not indeed attain a high elevation during the coming months, and therefore the opportunities for the ap- plication of high powers will be comparatively few. But there can be little doubt, that the numerous able observers, who now nightly scan the heavens with powerful and w'ell defining tele- THE PLANET SATURN IN JULY 1869. 253 scopes, will avail themselves of every interval of good observing weather to scrutinise the Saturnian system. The spectroscope, too, which has already afforded singular and interesting infor- mation respecting the rings, will probably be brought to bear afresh upon the question of their structure. We propose now to consider some of the discoveries which have been recently made respecting Saturn and his system, and to suggest some processes of observation which, if well carried out, might afford valuable information on the subject of the rings. I shall assume a knowledge on the reader’s part of all those features of the Saturnian system which are usually described in treatises on astronomy. Nor shall I enter at any length into the circumstances which have led astronomers to recognise, in the system of rings, the presence of a multitude of discrete particles or minute satellites, revolving for the most part in one plane around the globe of the planet. I must make one or two pre- liminary remarks on this interesting hypothesis, however, lest some portions of what follows should not seem intelligible to those who may not happen to be familiar with the views now received. It had been shown, by Laplace, that the stability of the motion of such rings as were supposed to surround Saturn could only be maintained by a considerable over-weighting of one portion of each ring, and an equally remarkable eccentricity of position. Later astronomers, admitting this view as the basis of their inquiry, came to the conclusion that the disturbing action of the satellites might cause a balancing motion in the ring-system, sufficient at least to secure stability, somewhat as the slight motions by which a rod is balanced in an upright position, although these motions are severally opposed to the rod’s stability, yet by their united effect give to the rod a com- ^ parative fixity of position which the most perfect quiescence of the support could not secure. These views maintained their ground until the discovery of the dark ring, and of the strange fact, that the planet’s body could be seen through this forma- tion without apparent distortion. The discovery of this ring led to a renewed examination of the problem ; and finally Professor Maxwell of Cambridge proved, liy a most convincing process of mathematical demonstration, that no solid ring could by any possibility continue to exist as an attendant upon a planet. Either the ring would crumble into frag- ments under the influence of the forces to which it would be subjected, and these fragments would continue to revolve as a broken ring round the planet ; or the ring would be more com- pletely destroyed, and would be brought to the planet’s surface. Hence we are forced to conclude that the rings, though con- 254 POPULAR SCIENCE REVIEW. iniioiis in appearance, consist of flights of minute bodies, each travelling on its own orbit around the planet.* But altliough to the mathematician capable of following Professor Maxwell through all the processes of a complicated proof, the demonstration of the satellite theory of the rings may seem complete, there can be no doubt that the more convincing evidence of observation is wanted to bring the fact home to the minds of the general student. Now we cannot hope that the most powerful telescopes which man can con- struct will suffice to reveal the separate bodies which form the ring. When the ring’s edge is turned towards ul it appears as an almost evanescent line of light, and doubtless if that line had not length as well as breadth, we could not detect au}^ trace of its existence. Yet there is every reason to believe that the apparent breadth of that fine line of light is many times larger than the apparent diameter of any single satellite be- longing to the rings. In this way, then, observation is not likely to help us. But there is a mode in which evidence might be gathered respecting the conformation of the rings, by any observer who had patience to conduct the requisite series of observations. If we consider the case of a series of flat rings (whose thick- ness may be neglected) formed as of old the rings of Saturn were supposed to be, we shall see that the apparent brilliancy of the rings ought to vary with the amount of opening. We do not refer to the total amount of light received from the ring, but to the apparent brilliancy of any point upon the system. When a plain surface is illuminated, the science of optics tells us that the illumination is proportional to the cosine of the angle of incidence. In fact, we know from experience that the higher ^the sun is above our horizon the greater is the amount of light received on the earth’s surface around us. Precisely so would it be with the rings if they had plane surfaces. And further, it is a law of optics that the apparent brilliancy of any point of a luminous object is equal to the real brilliancy at that point, whatever may be the distance of the object, or the angle at which the line of light meets the surface (neglecting alwa}^s what does not here concern us — the influence of any absorptive medium which may be interposed between us and the object). Now, this being so, it is very evident that if the rings were • I know not w’ny this conchision sliould he commonly atlrihuted to my- self. Notliin^r, I think, can he clearer than the terms in which while dealing with the subject of the nature of the rings, in chapter v. of my treatise on S.ilnr.i, I have nssi^-ned to I'rof. Maxwell the full credit for a discover}' with wliich I have had absolutely nothing whatever to do, save t ) admire and describe it. THE PLANET SATURN IN JULY 1S69. 255 flat the total amount of light received from them (the ball being supposed removed) would be increased, through two causes, as the rings opened. Firstly, the increased apparent size of the luminous surface would have an obvious effect. Owing to this cause the illumination would vary as the sine of the angle at which the line of light from the earth is inclined to the plane of the rings. Secondly, the apparent brilliancy of each point of the ring-system would be increased as the sine of the angle at which the sun’s rays are inclined to the plane of the rings. Thus the total amount of light would increase as the product of these two sines, or assuming what is commonly the case, that the earth and sun are almost equally raised above the surface of the rings, the total amount of light received from the rings would vary as the square of either sine. But if the rings consist of a multitude of discrete satellites, there must result a different state of things. Take a single satellite, and we see at once that so long as the whole of this satellite can be seen we get the same amount of light from it, whatever the elevation of the sun above the mean plane of the rings. And though the problem seems to get somewhat com- plicated when we consider the case of a multitude of satellites, yet it will be found, on examination, that there is no longer the same variation to be looked for as was shown to exist in the former case, owing to the sun’s change of elevation. In fact, we have a case somewhat resembling that of the moon ; the illumination of whose disc has been shown by Zollner not to diminish towards the edges according to the varying inclination of the solar rays to the moon’s surface, but rather to increase ; while calculation has shown the probable reason to consist in the fact that the moon is not a smooth globe, but covered with hills and mountains, whose sides are inclined at greater or less elevations to the mean level of the lunar surface. This being so, two means of observation seem available. First, a definite part of the ring’s width might be compared with the equatorial bright belt of the planet ; the brilliancy of that belt being we may assume constant. This method would probably involve difficulties ; but from the success with which Mr. Browning gauged the relative brilliancy of different parts of the disc of Jupiter last spring, I have no reason to doubt that, with suitably prepared and graduated darkening glasses, the comparison might be satisfactorily carried out. Then the change of brilliancy of the particular part of the ring examined, as the system gradually closed, would afford evidence of the nature of that portion of the ring, according to the principles enunciated above. Secondly, a process might be applied to Saturn corresponding to that which Dr. Zollner recently applied to the planet Mars. By determining the total amount of light VOL. VIII. — NO. XXXII. S 256 POPULAR SCIENCE REVIEW. received from Saturn at successive oppositions, and - deducting” therefrom that portion which calculation (founded on the light received from the planet when the ring disappears) shows to be due to the globe, it would be possible to determine according to what law the ring varies in brilliancy as its amount of opening changes, and thus to determine generally what may be the nature of the ring’s surface. The result of the application of spectroscopic analysis to the rings has been at once interesting and perplexing. The spec- trum of the planet’s light exhibits certain absorption-lines indicative of the presence of vapour. Now Mr. Huggins has discovered that the same lines are present in the spectrum of the ring’s light also ; and that, of the two, the latter spectrum exhi- bits these dark lines somewhat the more distinctly. This result is remarkable. It indicates that the amount of vapour through which the light from the globe has passed before reaching us is less than the amount passed through by the light from the rings. We are accustomed to recognise the probability that the globe of Saturn is surrounded by an atmosphere proportional in extent to the enormous volume of the planet. On the other hand, the small bodies forming the rings if they had atmo- spheres at all, would have vapourous envelopes so limited in extent, one would suppose — the volume of each of these satel- lites being so minute — that the most powerful spectroscope should fail to reveal any trace of its existence. Supposing them to resemble our own satellite, but on a much smaller scale, their atmospheres would be a million-fold too small to produce any distinctive dark lines in the spectrum of their light ; for though the moon is so much the nearest of all the celestial bodies, its spectrum has no dark lines other than those belonging to it as formed by reflected solar light. When we remember that Saturn, when at his least distance from the earth, is upwards of 820 millions of miles from us, or more than 3,000 times farther from us than the moon is, the visibility of distinctive dark lines in the spectrum of the ring will appear one of the most interesting and remarkable results of spectroscopic research. It would be per- plexing in the extreme if we supposed the rings to be conti- nuous bodies ; but accepting, as we are bound to do, the theory that they consist of flights of minute satellites, the result be- comes one of the most surprising that can well be imagined. The explanation I would venture to offer of this strange phenomenon will, I fear, appear to many unduly speculative, if even it do not seem opposed to well-known physical laws. In an appendix to my treatise on Saturn, I have maintained the view that the moon has so thoroughly parted with its original internal heat that even the gases once subsisting on its surface have been transformed into the solid form. I was aware when THE PLANET SATURN IN JULY 1869. 257 I SO wrote, that at the time of full moon the hemisphere we see (or a part of that hemisphere) is subjected to a heat exceeding that of boiling water. An enormous amount of heat poured in this way upon the surface of a planet would be rendered latent in transmitting but a small portion of the solidified gases into the aerial form, and produce no effects observable to us on earth ; just as the full heat of a tropical summer’s day poured for hours on the peaks of the Himalayas, produces no change which the inhabitant of the valleys can perceive, on the snowy masses lying there. If this view were just, we should learn to look upon all the satellites throughout the solar system as in a somewhat similar state to that of our own moon ; and at first sight the members of the Saturnian rings would appear, on account of their extreme minuteness, to be of all others those in which the cold would be most intense. But then a circumstance comes to be considered which would have an effect the other way. It is a part of the theory of the motions of satellite- rings, that there would be continual collisions among the mem- bers. I have shown in full, in chapter v. of my treatise on Saturn, how these collisions would arise and how they would operate upon the figure of the ring-system. There would be a gradual increase of width, chiefly through the approach of the inner edge of the rings towards the planet ; and there would also be a tendency to the formation of new rings within those already formed. But the true significance of these changes is this, that the whole system must be continually undergoing a loss of vis viva. Every collision involves such a loss, and the increase in the width of the system is in a sense a measure of the amount of loss. But this increase of width, though indicat- ing, does not compensate for, the loss of vis viva. There is only one way in which the loss can be compensated, and that way is indicated in a passing manner, in a note at p. 126 of my treatise on Saturn. There must be a continual generation of heat corresponding exactly to the loss of vis viva. Now this heat must tend to render the condition of all the satellites of the system very different from that of one of the ordinary at- tendants upon a planet. For all must partake in the distribu- tion of this heat ; because it is absolutely impossible that any single satellite can have an orbit which, even for a few hours, can keep it free from collision with one or more of its fellows. Thus every satellite is kept warm, so to speak, by a process of continual friction, and no such process of refrigeration as I conceive to have taken place upon the moon, can come into operation upon the satellites forming Saturn’s rings. Nay, it may well be that the heat of these bodies is very much greater than the mean heat of our earth’s surface. For processes of collision fully equal to the generation of sucli heat might be in 258 POPDIAR SCIENCE REVIEW. operation without appreciably affecting the apparent width of the ring-system. And certainly the present appearance of the dark ring is such as to encourage the View that sufficiently rapid changes are in progress. It would follow from these views, that the spectrum of the ring’s light would exhibit variations corresponding to the various parts of the ring’s breadth. Of course, there are already well- marked gradations of light in the spectrum, because the light is different in different parts of the ring’s breadth. But the dark lines I have already spoken of as distinctive of the ring’s spec- trum, ought to be more distinctly seen in certain parts of the ring on another account. For there can be little doubt that the central parts of each ring are those at which collisions take place most frequently between the satellites ; and, therefore, if the cause I have been considering is really in operation, the dark lines ought to be seen best in those parts of the spectrum’s width which correspond to the central portions of the rings. The observation might be worth making, though it would be one of great difficulty and delicacy. Some recent researches by Professor Kirkwood, of Illinois, have supplied an interesting and sound proof of the real struc- ture of the rings. They are particularly interesting to myself, as affording an unexpected proof of a view I had put forward some time since which had seemed to some to be more imaginative than well-founded. In the preface to my treatise on Saturn, I had said that possibly we may yet detect in the Saturnian rings the indications of those processes by which the solar system had reached its present state. Now Professor Kirkwood’s re- searches tend directly to establish such a relation. He had shown that when the asteroids are arranged in the order of their mean distances certain well-marked gaps are observable, and that these gaps correspond to those mean distances which would give periods commensurable with the period of Jupiter. We know that when a planet has a period very nearly commensurable (according to some simple relation) with the period of a neighbouring planet, the two bodies disturb each other much more effectively than they would if there were no such relation. If one of the planets be much larger than the other, far the larger part of the disturbance falls upon the motions of the smaller planet. Saturn, for example, had long since been noticed as having his motions affected by a very remarkable inequality ; and the search for a cause resulted in the discovery that the peculiarity is due to the relation existing between the motions of Saturn and Jupiter, by which two revo- lutions of tlie former planet are accomplished in about the same time as five of the latter. The disturbance falls principally on Saturn, as being so much the smaller of the two bodies. And, THE PLANET SATURN IN JULY 1869. 259 as the asteroids are exceedingly minute when compared with Jupiter, it is evident that those members of the system which had periods commensurable with his would be very largely disturbed, and so come to have another period. Thus we can understand the fact that there should be no asteroids at those particular mean distances from the sun which correspond to the particular periods in question. But it is clear that if there were any possibility of doubting the fact that the asteroids form a zone of disconnected bodies, the circumstance established by Professor Kirkwood would prove that fact. If, then, we can trace in the Saturnian ring- system any signs of the action of similar processes, we shall have an independent and perfect proof that the rings are not continuous, but composed of discrete satellites. Now this is precisely what Professor Kirkwood has been able to do. He has shown that a small satellite revolving in the space between the outer and inner rings — that is, travelling around the black division — would have a period commensurable not merely with that of the neighbouring Saturnian satellite, Enceladus, but with those of all the four inner satellites. It remains absolutel}^ certain, therefore, that the ring is composed of bodies moving freely in definite orbits. And, further, those who agree with me in accepting the nebular hypothesis (or a modification of it) as truly representing the mode in which the solar system reached its present condition, will see in the law established by Professor Kirkwood the action of one of the processes which must have been most effective in the formation of our system. This paper would be incomplete if I did not refer to the- information which Mr. Browning, F.K.A.S., the optician, has- recently obtained respecting the variety of colour observable in the Saturnian system. I had never been able to recognise any well-marked signs of colour on Saturn with a four-inch achro- matic refractor.* But not only has Mr. Browning himself been able to detect a variety of tints with his large reflector, but I have seen a letter from an observer (using a similar but smaller instrument) who refers to the same tints. These tints are thus referred by Mr. Browning to the well-known colours of the paint-box : — The rings yellow-ochre, shaded with the same and sepia. The globe yellow-ochre and brown madder, orange and purple, shaded with sepia. The crape-ring, purple madder and sepia. The great division in the rings, sepia. The pole and the narrow belts, situated near to it on the globe, pale cobalt blue. * It must be remembered that small apertures are more favourable, as a rule, for the exhibition of colour than large ones. In the case of Saturn, perhaps, this rule should rather be, large apeHures and high powers.’’ 260 POrULAR SCIENCE REVIEW. These tints are the nearest I could find to represent those seen on the planet, but there is a muddiness about all terrestrial colours, when compared with the colour of the objects seen in the skies. These colours' could not be seen in their brilliancy and purity, unless we could dip our pencil in a rainbow, and transfer the prismatic tints to our paper * With reference to these interesting and graphic remarks, it must be pointed out that we might reasonably be disposed to refer phenomena so new and so remarkable to some peculiarity either of the telescope or of the observer’s vision, were it not that the observed blueness of the polar regions at once nega- tives such a supposition. I cannot but think the evidence thus afforded of the adaptability of reflectors to delicate chromatic studies singularly striking and convincing. It remains to be noticed that the shadow of the planet on the ring will become an interesting subject of observation during July and August. Observers should pay particular attention to the direction of those singular and as yet little understood peculi- arities of form which have been exhibited by this shadow. The contrast between the blackness of the shadow and the colour of the so-called black division between the rings, is also well worth noticing. If any doubt could remain respecting the constitu- tion of the rings, no argument could be more effectually used in favour of the satellite theory, than that drawn from the fact that the division between the rings is not vacant, but occupied by some entity or other which supplies a faint but readily de- tected light. I canot conceive what reasonable theory could be urged in explanation of the peculiarit}^, save that some minute bodies are travelling within this gap. "" From “ The Student ’’ for November 1868. PIsLte .XLVLU. 261 THE FERTILISATION OF SALVIA AND OF SOIHE OTHER FLOWERS. BY WILLIAM OGLE, M.D. Lectttree on Physiology at St. Geokge’s Hospital. [PLATES XLVIII. AND XLIX.] Mr. DARWIN has, in many places, and notably in his book on orchids, insisted on the dictum, ‘‘ Nature abhors perpe- tual self-fertilisation.” Even in hermaphrodite organisms there exists, he believes, invariably some contrivance which either entirely prevents self-fertilisation, or at any rate ensures a more or less frequent intercross. In this paper I wish to add some more facts to the many which Mr. Darwin has adduced in sup- port of this proposition. I think I shall be able to show, that in many species of salvia, and in some other plants, there are certain most ingenious contrivances, which hinder or impede self-fertilisation and ensure intercrosses between separate flowers. The salvia in which I first noted the phenomena which I am going to describe, is a tall handsome plant, which I take to be a cultivated variety of S. officinalis, A single flower of the na- tural size is pictured in fig. 1. The corolla is two or three times as long as the calyx, with a widely open mouth and dilated tube, which admits of the entrance of humble bees. These seem to be especially attracted by this flower, and on my visits to a piece of ground where the plant grew in profusion, I inva- riably found a large number of them buzzing about the blos- soms, settling on the tempting landing-place offered by the central lobe of the lower lip of the corolla, and diving into the recesses of the tube to enjoy the glandular secretion of the nec- tary at its base. There can, I imagine, he no doubt that the aromatic perfume of the whole plant and the glandular se- cretion of the fringe in the tube exist in order to promote the visits of bees to the flower. There are in this salvia, as in others, four stamens, of which, however, the two upper ones are rudimentaiy. The remaining two have a very peculiar structure. Each consists of a short 262 POPULAH SCIENCE REVIEW. stout filament, which is inserted into the mouth of the tube, as represented in fig. 2, and which thence runs backwards, so as to have its upper end completely hidden from view in the hood formed by the upper lip of the corolla. The short filament ter- minates in a connective which is developed to such an extent as to be actually longer than the filament itself, and at the two opposite ends of the connective are the two anther cells. The portion of the connective uniting the upper anther cell with the filament, is much longer than that portion which unites the filament to the lower cell. The upper anther cell is also itself much larger than the lower one, this latter being, in fact, almost sterile, and furnishing little or sometimes no pollen. It is not, however, so completely transformed into a barren structure as is the case in many other species of salvia, to be spoken of pre- sently. The upper cell, on the other hand, furnishes pollen in great abundance, and allows it to escape by dehiscing in the front longitudinally. The filament is attached to the connective externally by an excessively movable joint, so that a very slight pressure on either anther cell will cause the connective to turn on the filament with what the French would call a ‘^mouvement de bascule.” The joint is so strong that you may actually cause the connective to rotate four or five times in complete circles in the same direction on the filament before it is twisted off. The lower or sterile cells of the two anthers are adherent to each other, so that a slight pressure on one anther will produce rota- tion, not only in its own connective, but in both. This descrip- tion will be more intelligible on looking at fig. 3. In fig. 3 the stamens are represented as seen when looked at in front ; in fig. 4 they are seen from the side when at rest ; in fig. 5, as seen from the side when the anthers are made to rotate on the filaments. On looking at the front of the flower, the only parts of the anthers which are visible are the lower cells, with their portion of connective (fig. 6). These stick out into the gaping opening of the tube, projecting like an uvula into the throat. The rest of the anthers is hidden in the upper lip of the corolla, which forms a hood, closed more or less completely in front until the flower begins to wither. The lower anther cells project to such a distance in the mouth of the corolla as to render it quite im- possible for a bee to get at the nectary without pushing directly upon their upper surface. No sooner does the bee exercise this pressure than the connective rotates. The upper anther cells emerge from the hooded receptacle in wliich they are hidden, and are seen to perform a circular movement forwards and down- wards, until their dehiscent surfaces are brought into close contact witli the back of tlie bee, one anther cell rubbing it on either side. This movement may be artificially produced] by THE FERTILISATION OF SALVIA AND OTHER FLOWERS. 263 introducing a pencil into the mouth of the flower, but it is a far more interesting sight to watch it when brought about by the action of the bee. It can be seen with the greatest ease, and no one who has once seen it will doubt that the peculiar form and arrangement of the stamens is not an accidental and in- different one, but stands in direct connection with the visits of the bee to the nectary ; and that the curious modifications in the structure of the whole flower have occurred in order to ensure the adherence of the pollen to the back and sides of the bee (fig. 7). It will be noticed that the lower anther cells, those against which the head of the bee strikes, are sterile or nearly so. This is an instance of the apparent occasional economy of nature. It would be, as will be seen presently, of little or no use that the bee should have pollen on its head. None, therefore, or little, is produced by the cells against which the head impinges ; and the economy thus practised is very probably one of the conditions which favour the abundant production of pollen in the upper anther cells. In these it can be of use, and thus the material saved from the low^er cells is expended here to greater advantage.* It will also be noticed, as a further illustration of the accuracy of adaptation, that the upper portion of connective is very much longer than is the lower. In some other species of salvia this difference of length is much greater even than here. The result of this is, that the bee produces a very considerable rotation in the upper limb of the lever, notwithstanding that the direct motion produced by its own pressure on the lower limb is com- paratively slight. The shape of the corolla is also adapted to facilitate the motion in question or rather to increase its range. It will be noticed in fig. 2 that the tube bulges out just behind the barren anther cells. This allows of a greater displacement of the lower arm of the lever in a backward direction than would be possible were the bulging not present. It is easy to convince oneself, by inspection, that after the bee has struck the lower anther cells Avith its head, it penetrates still deeper, and that its back forces the cells into this retreat. It thus happens that, though the connective is not nearly so long in this species of salvia as in many others yet that the amount of motion produced in the * I refer, of course, to the law of halancement of growth, which was thus expressed by Goethe : — order to spend on one side. Nature is forced to economise on the other side.” The ment of haA’ing first propounded this law is claimed for Geofffoy St.-IIilaire, and also for Goethe. It had, how- ever, been most distinctly enunciated by Aristotle. For instance, cf. his trea- tise ^^De Partibus Animalium,” ii. 9 : tVjua r/)v avTt)v vTrepoxf)i’ fk ’roWoi'*; ToTTOvg adwarii dtav^i-uiv 4. Of the Greenland species 46, or exactly one-third, agree with those of the Miocene deposits of Europe. The determination of the age of the beds as Lower Miocene has accord- ingly been confirmed. Four of the species agree with those of Bovey Tracey, among them Sequoia CoutesicCj the commonest tree in the latter locality. In concluding the first part of his paper, the fiuthor ofiers a resume of the grounds on which the determinations of the species have been based. Seventeen species are represented by the leaves and organs of fructification among the Greenland specimens. Ten species are only represented by leaves in Greenland, but their organs of fructification occur elsewhere. Seventeen species, of those of which only leaves are found, exhibit, however, such marked characteristics, tliat there can be no doubt about their identification. Five cryptogams have been satisfiictorily recognised. Accordingly, though it must be allowed that the systematic position of many of the plants from North Greenland is as yet uncertain, yet the considerable number of abso- lutely identified species which can be produced enables us to form a clear idea of the Miocene flora of North Greenland. Subterranean Lava Tide«. — The idea of a regular tidal flow of fluid lava is SCIENTIFIC SUMMARY. 313 strongly opposed by Mr. G. P. Scrope, in a recent number of the Geologicol Magazine. After enumerating a variety of facts, he says, that such facts have brought him to the conviction that though there may be occasionally lateral flows of lava beneath the surface of a volcano, from an interior pool, through fissures opening outwards at a lower level — as in the tajopings of the lake of Kilauea, so frequently witnessed — yet, in general, lava solidifies so rapidly and readily from increase of pressure or diminution of temperature, that no very extensive accumulations of such matter in a fluid state are likely to exist even beneath an active volcano, still less below vaster areas of the earth’s crust, and that the apparent connection of one volcanic vent with others in its neighbourhood, or belonging to the same chain, is rather due to the lateral transmission or escape of heat than to the actual transfer- ence of liquid matter between one and the other. Many facts tend to show that ‘Gava,” the only fused rocky matter in nature with which we are acquainted, is, when it issues from the interior of the earth during volcanic eruptions, extremely viscous ; and though some currents are seen to How down an incline so low as 6° or 8° with a velocity of three or four miles an hour, others are so sluggish as to accumulate in bulky masses beside or over the orifice whence they are expelled. If,” says Mr. Scrope, “ it be suggested that in the depths of the volcano the fluidity of the lava is probably very much greater, owing to its higher temperature, this idea is, I think, incon- sistent with many well-known facts, such, for example, as the occasional efflux of liquid lava from the summit of Mauna Loa in Hawaii, while that in the crater of Kilauea at a level of 10,000 feet lower, and only sixteen miles distant, remains unaffected.” MECHANICAL SCIENCE. New Rifle. — After a long and laborious investigation, the Ordnance Select Committee have recommended the adoption by Government of the Martini- Henry rifle, in place of the Snider rifle now used. The former has only twenty-seven pieces in the breech against thirty-nine in the latter j the arrangement of the parts is stronger; the manipulation more simple, and the cost less. The Martini-Henry rifle of 0-45-inch bore, has a much lower trajectory than the 0-5-inch and 0-577-inch Snider, it is more accurate especially at long range, and the penetrating power of its bullet is greater. Liquid Fuel. — Captain Selwyn has published the results of further experi- ments on the use of liquid fuel. Although Captain Selwyn does not appear to maintain the exaggerated estimate of the evaporative duty of liquid fuel which he once entertained, he still seems to think that the whole theoretical heat of combustion may be utilised. So far as the experiments go, it has not yet been shown that in the ordinary conditions of practice a pound of liquid fuel will evaporate more than fifty per cent, more water than a pound of the best coal properly burnt. Some other applications of liquid fuel pos- sess much interest. Boiler-plate heating furnaces at "Woolwich and Chatham have been fitted with Messrs. Dorsett and Blyth’s apparatus, already de- 314 POPULAR SCIENCE REVIEW. scribed in these pages,"* and have been successfully worked with liquid fuel. In such a furnace the efficiency depends rather on the intensity of the heat produced than on its quantity, and it is quite possible that liquid fuel may be burnt with a much smaller proportion of air, and that a high and steady temperature may be the more easily and economically maintained than with coal. This result appears to have been attained at Woolwich, the furnace being worked at a less consumption of fuel, and the plates heated in a shorter time with oil than with coal. Steam Engine Terformance. — In the ordinary mode of comparing the duty of steam engines by determining tlie quantity of coal necessary to develope a given power, the efficiency of the boiler is not distinguished from the efficiency of the engine. Mr. B. W. Farey and Mr. Bryan Donkin have re- cently made some interesting experiments with an apparatus designed to measure directly the heat carried away in the condenser. Measuring at the same time the work developed by the engine, by means of indicator dia- grams, all the elements are ascertained, necessary for determining the efficiency of the engine independently of the boiler. The quantity of water passing through the condenser is measured by conducting it over a weir or notch. The temperatnre of the condensing water on entering the condenser and that of the mixture of injection water and condensed steam leaving the condenser, is ascertained by ordinary thermometers \ lastly, the work done in the cylinder is ascertained by indicator diagrams. Dividing the horse power developed in the cylinder, expressed in thermal units, by the quan- tity of heat imparted to the injection water in thermal units the quotient expresses nearly the efficiency of the steam. And since the efficiency of the steam in the same engine does not vary much for moderate variations of power, when the efficiency of the steam has once been ascertained the measurement of the volume and temperature of the injection water affords a new means of ascertaining the work done by the engine. Messrs. Farey and Donkin have therefore contrived photographic registering apparatus, by which the volume of flow and temperature of the injection water is con- tinuously recorded. The data so obtained being used either to determine the elliciency of the steam ; or, if the efficiency of the steam is known, to determine approximately the power of the engine. Mr. Herd on Iron- Clads. — Mr. E. J. Heed, the Chief Constructor of the Navy, has communicated to the Institute of Naval Architects a valuable exposition of his views on the advantages of short over long iron-clads, with an abstract of his paper previously presented to the Royal* Society. ^Ir. Reed believes that it is unwise to make an iron-clad very long, large, costly, and unhandy, in order to effect a comparatively small saving in engine power. Hence he has introduced into the navy vessels in which the length is only five and a half times the breadth, instead of being six and a half times as in earlier armour-plated vessels. The reason why the disadvan- tages of excessive length are more apparent in iron-clad than in other vessels is that, in them, a great part of the weight to be carried is in the armour, and is dependent on the form of the vessel. Any addition to the length leads to a corresponding increase in the area of the surface to be armoured Vol. viii. p. 03. SCIENTIFIC SUMMARY. 315 and in the unproductive weight to be carried. In the merchant-ship the load to he carried is nearly independent of the form, and any diminution of engine power required to drive the vessel, due to form, is pure gain. In the iron-clad, the diminution of engine power, by increasing the length and the fineness of the vessel’s lines, involves simultaneously an increase in the sur- face to be armoured and of the tonnage of the vessel. Mr. Eeed points out that in the only instance in which long and short iron-clads have been tried under precisely similar conditions, the six hours’ trial of the Minotaur ” (400 feet long) and the Bellerophon ” (300 feet long), when both vessels were working at 6,200 indicated horse power, the former made 14-165 knots, and the latter 14-053, the former having been a somewhat shorter time in the water, and having, consequently, a cleaner bottom. So that in this case, with the same engine power, the speed of the two ships was practically identical. The economy of cost of construction in the type of short ships introduced by Mr. Eeed is very considerable. liesistance of Armour-Plates. — Dr. Fairbairn has given, in a paper read before the Institute of Naval Architects, a full account of the experiments of the Iron Plate Committee, from 1861 to 1864, so far as they bear on the power of iron plates to resist projectiles, and on the qualities most desirable in armour casing. Joints of Pipes for Gas and Water Mains. — Mr. Barker has described to the Society of Engineers a new joint for pipes, designed to obviate the great loss from leakage with the joints in ordinary use. Mr. Barker uses spigot and faucet pipes, but he casts on them a coarse pitched screw thread. When the spigot is placed in the faucet, one turn serves to screw the pipes ! up to a bearing, and at the same time a layer of moist cement introduced ■ into a conical recess is compressed so as to form the joint. ' Palliser Bolts. — It is proposed to use the Palliser bolts, which have been I so successfully applied for armour-plating purposes, for the fish and fang I bolts of railway permanent way. The principle of the Palliser bolt has already been alluded to in these pages,* and there seems no reason why it I should not be as suitable for resisting the impacts to which railway fasten- I ings are subjected, as the concussion of proj ectiles. I j MEDICAL SCIENCES. j The Relation of the Osseous Medulla to the Blood. — The British Medical Journal, in abstracting a recent paper, by Herr Neumann, in the German 1 Centralhlatt, calls attention to the fact that Neumann’s startling theory that j the marrow developes blood-cells, has received confirmation by the observa- j tions of M. Bizzozero. Among other things, this observer says that the j condition of the marrow in the bones of frogs in winter, as compared with I summer, furnishes an important argument in favour of the theory that I marrow is a blood -gland. In winter, the white corpuscles in the blood of ; the frog are not half so numerous as they are in summer ; and in winter the * Vol. iii. p. 538. 316 POPULAR SCIENCE REVIEW. marrow consists almost entirely of fat-cells, whereas in summer it contains hardly anything but lymphoid cells. He examined the costal marrow and the spleen in five cases of death from typhus fever, and observed in both structures an enormous increase of cells containing blood-corpuscles. The Physiological Effects of Lightning. — Professor Pepper’s great induc- tion coil at the Polytechnic has afforded Dr. Richardson an opportunity of carrying out a number of extremely interesting experiments on the effects of powerful electric shocks on the animal body. In a lecture delivered at the Polytechnic, Dr. Richardson summarised the results of some of his researches, and of his summary of the effects of lightning shock the following is an abstract. 1. Absence of evidence of action of the heart : though it must be remembered that the heart-beat might continue, although it could not be heard. 2. Absence of reflex action : in batrachia, however, this did not always indicate death. 3. Diminution of the animal temperature in the cavities of the body. 4. Absence of colour in the semitransparent structures : this was not a reliable test. 5. General muscular rigidity was sufficient evidence of death ; but not local or partial rigidity, unless it affected the muscles essential to life, as the respiratory. 6. Coagulation of blood in the veins was a sure sign of death. If, on opening the largest vein that could-- be reached, the blood were found coagulated, there was no hope of restoring respiration. 7. Decomposition was the final proof of actual death. — Marks of various kinds had been described as being left on bodies struck by light- ning ; and the accounts of some of these had been regarded as chimerical or exaggerated. These marks were : 1, burns ; 2, impressions of metallic sub- stances j 3, ecchymoses ; 4, supposed impressions of such objects as trees or fences ; 5, loss of hair. — 1. Bui'ns were more likely to be severe when life was not destroyed than when the shock was fatal ; they varied in extent, from mere singeing to extensive cauterization. Pins and other metallic articles of dress often led to severe local injuries — the parts injured being those lying between the metallic points. — 2. Imp^'essions of Metallic Sub- stances. The occurrence of these had been doubted by Faraday and others j but Dr. Richardson had found, by experiment, that the impressions of orna- ments, &c., miglit be faintly struck on the surface of the body. The mark was a pure ecchymosis ; and for its production, resistance on the opposite side was neceasary. It was not a burn from heated metal j as, under favour- able conditions, a simple electric spark would produce it. — 3. Ecchymoses were sometimes found ; as was observed in the case of Professor Richmann of St. Petersburg, who was killed by an electric discharge in 1753, while performing experiments. — 4. Arborescent marks, wrongly supposed to be impressions of trees, t&c., were sometimes found. They were in reality, as was pointed out a hundred and ten years ago by Beccaria, the outlines of the superficial veins of tlie body. Dr. Richardson had succeeded in bringing out the outline of tlie veins in the ear of a rabbit, by means of the discharge from a Leyden jar. — 5. Loss of Hair was obsen ed in some cases where the nervous system was aflected. E.i'pcrimcnis with Ijiebig's Food for Children. — A\'e believe we were the first journal to call attention in this country to this valuable preparation. Indeed we were the first to do so, for it was in our pages that Baron Liebig himself described the substance as a soup for infants. Wo are, therefore, SCIENTIFIC SUMMARY. 317 interested to perceive that at a recent meeting of one of the continental scientific societies, Dr. Kjelherg related his experience of the use of Liebig’s food for infants as a remedy. Six cases of diarrhoea occurred in his Children’s Hospital among infants of from 1|^ to 2 years ; five of them had already been treated ^vith medicine without effect. A thin broth made from the food ” was given them as their only nourishment, and all medicine was discontinued. The motions at once assumed a better appearance. In one case, which had no previous treatment, the effect of the exclusive use of Liebig’s food was very striking. Dr. Kjelberg says that he had used the treatment in two cases of children, private patients, in whom not diarrhoea, but obstinate constipation was the malady. The children were still suckled, while the food was administered. The peristaltic function of the bowels rapidly became normal and regular. Dr. Kjelberg thinks that Liebig’s food possesses the capacity of regulating the activity of the intestinal canal. Opium-eating. — We do not vouch for the accuracy of the statement made in the New York Medical Necord that Mr. Horace Day (who is said to be the author of a recent American book, The Opium Habit ”) has eaten over fifty pounds of opium. What are the Actual ^Effects of Absinthe on the System. — Many of the memoirs in the Comptes-Rendus are more remarkable for the distinctness with which the conclusions they set forth are expressed, than for the sound evidence on which such conclusions are based. We won’t say that this applies to the following. But, as the question of the effect of absinthe is often asked, we shall lay the following conclusions of M. Magnan before our readers : — 1. The epileptic or epileptiform accidents in alcoholism — or, in other words, alcoholic epilepsy — are of a radically different nature, according as the alcoholism is acute or chronic. 2. In acute alcoholism the epilepsy is imder the complete influence of an external agent, of a poison (absinthe) which of itself alone causes the epileptic attack ; it is epilepsy by intoxica- tion.” 3. The alcoholic epileptics exhibit the ordinary features of simple alcoholic cases, and also superadded phenomena, among which the epileptic attack is dominant. 4. These two groups of symptoms (the alcoholic symptoms and alcoholic convulsions), united in the same subject, have a relation to the twofold nature of the poison (absinthe), whose elements are absinthe and alcohol. 5. In chronic alcoholism the epileptic or epileptiform accidents are under the direct control of organic modifications which take place in the patient. The excess of liquids, in gradually altering the tissues, renders them capable, under the influence of various causes, of producing by themselves convulsive epileptiform phenomena, accidents analogous to those that we see take place in other patients in certain cases of lesions of the nervous centres (general paralysis, tumours of the brain, &c.). {Comptes- Rendus, April 5.) An Anatomist decorated. — Professor Brunetti, the celebrated anatomist, of Padua, has been decorated with the orders of St. Anne of Bussia and St. Gregory the Great of Home. This last honour, says V Imparziale, has been conferred on him as a consequence of the illustrious astronomer. Father Secchi, having shown to the Pope some of his (Brunetti’s) anatomical pre- parations illustrative of his researches on the means of preserving animal structures. 318 POPULAR SCIENCE REVIEW. Chromic Acid in Therapeutics. — In the Brdletin General de la Therapeu- tique, Ur. E. Magitot recommends chromic acid as an application to various allectious of the buccal mucous membrane — such as all forms of stomatitis ; and particularly the different kinds of gingivitis, from that connected with dentition (as when, for example, it attends the eruption of a wisdom tooth), to ulcerative stomatitis. Aphtha3, and divers other ulcerations of the buccal mucous membrane, are also, he says, rapidly modified by this agent. But the afiection for which he specially recommends the acid is alveolo-dental osteo-periostitis.” METALLURGY, MINERALOGY, AND MINING. The Physical Properties of GadoUnite. — According to the researches of M. Des Cloizeaux, the mono-refracting crystals of this mineral (which is named after M. Gadolin, a Russian chemist) ought to be referred to the epidote. The percentage composition of the Gadolinite from Ytterby is, according to Dr. Berlin’s analysis, quoted by the author— Silica, 25-62 ; oxide of yttrium, 50-00 ; oxide of cerium, T OO; protoxide of iron, 14-44 j lime, 30'00 ; mag- nesia, 0-54 ; alumina, 0-48 ; potassa, 019 ; soda, 018. Total, 100-65. — Vide Comptes-Rendus, May 10. Aluminium a Bell-metal. — Some Belgian manufacturer has just had a bell cast of aluminium, and, we [^Scientific Opinion~\ are informed, with very good results. It is of course extremely light, so that, though large, it can be easily tolled. Its tone is said to be loud, and of excellent pitch. The Manufacture of Coppei'as. — The following is a brief statement of an improvement in the process for applying copperas to the purification of coal-gas, devised by Mr. P. Spence. “ My invention consists in the produc- tion of copperas from compounds of iron in a proto state by treatment with sulphuric acid. The substance I prefer is the slag of puddling-furnaces, commonly called tap cinder, or the slag which results from regulus during the process of smelting copper ores, but other proto compounds in a native state, or arising from manufactures, may be employed, of the former of which I give as examples the Cleveland and blackband ironstones. These substances having been ground, are treated in an ordinary manner with sulphuric acid in a suitable vessel, and the result is copperas in a dry powdery condition, applicable to the purification of gas from ammonia, or to other ordinary manufacturing purposes in which copperas is required. If it be desired to produce the usual copperas of commerce, it may bo obtained by dissolving the dry powdery mass in an ordinary manner, and then cryslal- li.sing it, as usually practised in such processes.” — Vide Mining Journal^ May 15. Utilination of Blast Furnace Slag. — The following method is now adopted in several iron works in Belgium : — The slag is allowed to run direct from the furnace into pits about eiglit or nine feet in diameter at the top, with sides sloping inwards towards the centre, where they are about three feet deep. The mass is left for eight or nine days to cool, when a hard, com- pact, crj'stalline stone is obtained which is quarried and used for building purposes, but chiefly for paving stones. They appear to wear exceedingly SCIENTIFIC SUMMARY. 319 well^ being quite equal to tbe grits and sandstones already so much used. — Vide The Artisan. Coal from Sea-ioced. — Some time since, says the Annales du Genie Civil, tbe practice was introduced of converting marine algce by calcination into an excellent coal superior to ordinary wood charcoal for filtering water, dis- infecting sinks, polishing glass and correcting the acidity and decolorising wines, — also for precipitating and decolorising vegetable alkaloids. Until recently no value was attributed to the marine algae — to-day they are an important article of commerce in several islands. The colours seen in tempering Steel. — An article in one of the American journals on the tempering of steel, states that the process is guided by the colour, and gives the following summary of the tints observed : — 1. Being put upon burning fuel, the steel gradually heated becomes tarnished, yellow, and straw-yellow. 2. The heat increasing, the colour deepens, and reaches a gold yellow, full yellow. 3. Afterwards, the steel takes several shades, rapidly following and blending with each other ; they are purple, pigeon’s throat, copper, brown yellow. 4. These shades become deeper until they become violet. 5. Afterwards they pass rapidly to indigo blue, full blue, dark blue. 6. This colour becomes weaker, and gives a sky-blue more or less pure. 7. The blue takes a greenish tint and produces shades which are grey and sea-green. 8. At last the steel reddens, and will no longer give distinct colours. The shades of these eight colours, which are called tem- pering colours, are perfectly distinct, very apparent, and easy to recognise ; but they take place only after hardening and on clean steel. The metal which has not been hardened will not show these colours so plainly j the shades are mingled, blended, and less in number. — Vide Van Nostrand's Engineering Magazine, No. III. Failure of a proposed Flan for Armour Plates. — Armour plates, made by coiling bars of iron as for Armstrong gun tubes, welding the coil by upset- ting, cutting the coil in two, and flattening out the halves into plates, have, says one of the metallurgical journals, proved a great failure, as the experts prophesied. The welds were found very defective. IIoiv to Weld Copper. — The difficulty of welding copper due to the for- mation of an infusible oxide, has been, says the Mining Journal, overcome by a device of Mr. P. Bust, Inspector of Salt Mines in Bavaria. The use of microcosmic salt on the surfaces to be united succeeded perfectly, but was too expensive ; he, therefore, substituted a mixture of one part of the salt with two parts of boracic acid, which answered the same purpose as the original compound, with the exception that the slag formed was not quite as fusible as before. This welding powder should be strewn on the surface of the copper at a red heat j the pieces should then be heated up to a full cherry-red or yellow heat, and brought immediatel}'- under the hammer, when they may be as readily welded as iron itself. For instance, it is possible to weld together a small rod of copper which has been broken j the ends should be bevelled, laid on one another, seized by a pair of tongs, and placed together with the latter in the fire and heated ; the welding powder should then be strewn on the ends, which, after a further heating, may be welded so soundly as to bend and stretch as if they had never been broken. Mr. Bust has welded strips of copper plate, and drawn them into a rod VOL. YIII. — NO. XXXII. Y 320 POPULAR SCIENCE REVIEW. without difficulty. To ensure success, the greatest care must be taken that no charcoal or other solid carbon comes into contact with the points to be welded, as otherwise phosphide of copper would be formed, which would cover the surface of the copper, and effectually prevent a weld. In this case it is only by careful treatment in an oxidising fire and plentiful appli- cation of the welding powder that the copper can again be welded. It is, therefore, advisable to heat the copper in a gas flame. As copper is a much softer metal than iron — it is much softer at the required heat than the latter at its welding heat — it must be carefully hammered with a very light hammer, or better, by a mallet, and so shaped as to resist the blows as far as possible. — Vide Mining Journal, May 15. The Minerals of the Breitenhach Meteorite. — The Proceedings of the Royal Society for May contain a report of Professor Maskelyne on this subject. This meteorite, which belongs to the rare class intermediate between meteoric irons or siderites and meteoric stones or aerolites (a class to which I applied some years since the term siderolites), was found in Breitenhach, in Bohemia. It is a spongy metallic mass, very similar to the siderolite of Bittersgriin, in Saxony, the hollows in the iron being filled by a mixture of crystalline minerals. These minerals seem to consist almost entirely of two 5 and the present notice deals with these two minerals. 1. One of them is of a pale green colour, crystallising in the prismatic system, and presenting at once the formula of an augitic mineral and a crystalline form nearly approximat- ing to that of olivine. 2. The other mineral is one of very great interest. It is, in short, silica crystallised as tridymite. In bulk it forms about a third part of the mixed crystalline mass. The crystals are very imperfect 5 but measurements in those zones accord with those of an hexagonal crystal. A section made for examination in the microscope showed two small crystals in which the axis happened to be normal to the section. Light traverses these crystals wfith equal brilliancy during the rotation of the crystal be- tween crossed Nicol prisms. That this was due to gyratory polarisation, and of a right-handed kind, was shown in the following manner : — A com- parative experiment was made with two sections of quartz of opposite qualities, and of the requisite thickness to give the sensitive tint” with crossed Nicols ; and below these were placed two thin sections of right and left gj'rating quartz, giving an orange tint. The two minute microscopic sections gave, on comparison of the colours in the centre of the field in each case, unmistakable evidence that the gyration was similar to that of ^‘right- handed” quartz. Tliere can be no doubt from these results, further details of which are to be laid before the society, that this mineral is silica in the form of its opaloid crystal, to w'hich Von Bath has given the name of Tridymite. Ik'tedion of Phosphorus in Cast Iron. — !M. Tanten, n French metallurgist, who has given mucli attention to this important problem, makes the follow- ing remarks: — It is w^ell known that very small quantities of phosphorus produce no sensible alteration in the quality of cast iron, whereas if the pro- portion exceeds a few thousnndth parts tlie iron is robbed of its most essential (jualities. It is very important, tlierefore, to a.scertaiii the exact amount of ])hosphorus present. Nearly all the methods in use for this pui^pose consist in treating the iron by means of oxidising agents, so as to cause the phos- SCIENTIFIC SUMMARY. 321 phorus to pass into the condition of phosphoric acid; which is precipitated in the state of a magnesian compound. Several causes of error exist in this treatment, for — 1. A part of the phosphorus escapes the action of the agents, and disengages itself in the form of an hydrogenous compound. 2. It is necessary to act upon very diluted solutions to prevent the ammo- niacal-magnesian phosphate mixing with the oxide of iron, in which case it is difficult to collect the small amount of phosphate deposited on the sides of the vessel in which the precipitate is made. 3. The arsenic which may he contained in the iron enters into the magnesian precipitate in the form of arseniate as insoluble as the phosphate. Creosote oil as a Source of Heat. — We have it on the authority of our contemporary, the Journal of the Society of Arts, that Mr. W. D. Dorsett has brought out a system by which not the creosote oil but its distilled vapour, which is more powerful, is made to do the work of coal in heating iron plates to the heat necessary for bending them for ships’ armour-plating and other similar purposes, where the advantages sought are a very high and at the same, time so equal a temperature as that, while producing the required amount of ductility in the material to be operated upon, it shall not be deteriorated in its fibrous tenacity. For some two or three months Mr. Dorsett has been experimenting with his patent fuel in Woolwich Dockyard, and so satisfactorily to the Admiralty authorities, that they have instituted tests at Chatham, with a view to the preparation of the armour- plating of the Sultan armour-plated ship now building in that dockyard. The advantages may thus be shortly summed up as compared with coal : — A greatly diminished cost and saving of time in producing the required heat of iron, as well as a saving of labour ,* an absence of refuse, and a surface altogether free from scale. As regards the effect of this new mode of heating upon the metal itself, one of the dockyard operatives declared, somewhat emphatically, that the commonest iron treated by it came out of the furnace as good as the best Low Moor. The apparatus is simple, and inexpensively applicable to existing coal-furnaces. It consists of a reservoir, from which the oil is pumped up as wanted into a receiver, where, by the application of heat, the vapour is generated, and this is passed through pipes into the furnace, and used as fuel in the ordinary way. MICEOSCOPY. The Microscopical Work of the Quarter. — The existence of the Monthly Microscopical Journal so stimulates histological inquiry that the brief space we are enabled to give to the subject does not admit of a thorough record. For the benefit of those who can specially devote their attention to this subject, we give the titles of the papers which have appeared in the last three numbers of the Monthly Microscopical Journal : — April. — Notes on the Scale-bearing Podurce. By S. J. Mclntyi’e, F.E.M.S. — On the Fibres of the Crystalline Lens of Petromyzonini. With a Note on the .^Esophagus of the Aye-Aye. By George Gul- liver, F.E.S. — Two New Forms of Selenite Stages. By Frederick Y 2 322 POPULAR SCIENCE REVIEW. Blanlvley, F.R.M.S. — Researclies on the Constitution and Development of the Ovarian Egg of the Sacculinge. By M. J. Gerhe. — On the Sim- ple Structure of Compound Leaves. By W. R. McNah, M.D., Edin. — On the Microscopical Structure of some Precious Stones. By H. C. Sorhy, F.R.S., &c. — On the Construction of Object-glasses for the Microscope. By F. H. Wenham. — On the Rhizopoda as embodying the Primordial Type of Animal Life. By G. C. Wallich, M.D., F.L.S., &c. — On the Structure of the Red Blood Corpuscle of Oviparous Verte- brata. By William S. Savory, F.R.S. — A Small Zoophyte Trough. By W. P. Marshall, President of the Birmingham Natural History and Microscopical Society. — On the Preparation of Rock Sections for Micro- scopic Examination. By David Forbes, F.R.S., &c. — On the Markings on the Pleurosigma angulatum and on the Lepisma saccharina. By J . B. Dancer, F.R.A.S. Mai/. — Notes on Zoosperms of Crustacea. By Alfred Sanders, M.R.C.S., F.R.M.S. — Protoplasm and Living Matter. By Dr. Lionel S. Beale, F.R.S., Fellow of the Royal College of Physicians, Physician to King’s College Hospital, and lately Professor of Physiology and of General and Morbid Anatomy in King’s College, London. — On some New Infusoria from the Victoria Docks. By Wm. S. Kent, F.R.M.S. — Professor Owen on Article VT., No. HI., of the ^ Monthly Micros- copical Jornmal.’ — On the Construction of Object-glasses for the Micro- scope. By F. II. Wenham. — Description of Parkeria and Loftusia, two Gigantic Types of Arenaceous Foraminifera. By Dr. Carpenter, V.P.R.S., and H. B. Brady, F.L.S. — The Microscope in Silkworm Cultivation. ByM. Cornalia. June. — On the Proboscis of the Blow Fly. By W. T. Suffolk, F.R.M.S. — Note on the Blood Vessel System of the Retina of the Hedgehog. By J. W. Hulke, F.R.S. — On Crystals Enclosed in Blowpipe Beads. By II. C. Sorhy, F.R.S., &c. — A New Process of Preparing Specimens of Filamentous Algre for the Microscope. By A. M. Edwards. — Action of Anaesthetics on the Blood Corpuscles. By J. H. McQuillen, M.D., D.D.S., Professor of Physiology in Philadelphia. — A New Uni- versal Mounting and Dissecting Microscope. By W. P. Marshall, President of the Birmingham Natural History and Microscopical Society. — On the Construction of Object-glasses for the Microscope. By F. II. Wenham. — On Free Swimming Amcebas. By J. G. Tatem, Esq. The Binocular Spectnim Mic7'oscope. — This instrument, which was de- scribed a few nights since at the Royal Society by Mr. Crookes, and which was favourably spoken of by Dr. Carpenter, is made by Mr. Charles Collins, of Great Titchfield Street, W. The principal features are the sub-stage and the box of prisms. The former carries a sliding-plate to hold the slit and apertures, a spring stop and screws for adjusting them, and a reversed object-gla.ss. The slit and this object-glass are about two inches apart, and if reflected light is pa-ssed along the axis of the instrument, the object-glass forms a very small image of the slit in front of it. A milled head moves the whole sub-stage, and screws bring the image of the slit to any part of SCIENTIFIC SUMMARY. 323 the field. Beneath the slit is an arrangement for holding an object of irre- gular surface or dense substance. The stage has a concentric movement, so as to permit the object to rotate, and enable the image of the slit to pass through it in any direction. The direct-vision prisms consist of three flint and two crown, fitted in a box screwed into the end of the microscope. By means of a pin they are thrown in or out of action. The object-glass screws on in front of the prism-box. By taking the illumination from the sky or a white cloud, Fraiiuhofer’s lines are visible, and by direct simlight they are seen in great perfection ; the dispersion is sufficient to cause the spectrum to cover the whole field, and the achromatism of the lenses being nearly per- fect, the lines from n to G- are practically in the same focus. A double- image prism near the slit enables two spectra to be seen, oppositely polarised, and the variations in the absorption lines are at once visible. A Nicol’s prism as polariser, and another as analyser, can be connected, and these enable the brilliant colours shown by some crystalline bodies, when seen by polarised light, to be examined. PHOTOGEAPHY. Cracking of Negatives. — The cracking of the thin film of collodion which forms the negative is a source of annoyance and loss to many photographers, and there are few artists of much experience who have been wholly exempt from it. A few weeks ago this subj ect was revived at a meeting of the London Photographic Society by a lady whose name is well and favour- ably known in connection with the artistic development of photography, Mrs. Julia Cameron, who had discovered that a large number of her best negatives had their films seriously damaged by means of a delicate net- work of cracks. This evil, although serious, is easily prevented and its effects equally easily cured. Dampness of the atmosphere is gene- rally understood to cause the reticulated crackings ; hence, to prevent the atmosphere from having any efiect of this kind, the negatives, when not in use, should be kept in packets separated from each other by means of one or more layers of blotting-paper. When thus packed and wrapped round with paper sized or varnished, so as to be comparatively waterproof, it may be safely assumed that the negatives will never crack in the manner described. A plate-box of the usual form is objectionable on account of each plate being exposed to the action of the atmosphere by which it is siuTounded. When a negative has already become cracked, a soft pad of cotton wool should be charged with some fine lamp-black, and rubbed all over its surface. The crackings are thus filled up so as to render their previous existence incapable of being detected. Whatever may be thought of the soundness of the principle of this remedial measure, there can be no doubt whatever as to its excellence in actual practice. The Morphine Process. — An American photographer, in experimenting with morphia as a preservative agent for dry plates, has found that by means of the following preparation, which keeps w’ell, plates may be prepared that will yield fine negatives for many months after they ai’e made. Mix toge- 324 POPULAR SCIENCE REVIEW. ther : — hot water, G oz. ; pulverised sugar of milk, ^ oz. ; tannin, 40 grs. ; tincture of opium, | drm. These are added to the water in the above order. The sugar of milk should he dissolved and allowed to stand half an hour before being filtered, after which the other ingredients are to be added. Photo- statistics. — At a recent meeting of the French Photographic Society, a suggestion was made concerning the desirability of organising plans for obtaining authentic photographic statistics, such as the quantity of silver and other chemicals consumed, the number of photographers in each country, the value of their productions, &c., &c. A Cloud Diajjhrapn. — From time to time suggestions have been made for effecting the uniform lighting of the negatives in a lateral direction, for it is a recognised fact that the intensity of the light on the centre of a photo- gi-aph is greater than that by which the margins are produced. This, how- ever, is scarcely noticeable except in the case of pictures containing a very wide angle. In a stop or diaphragm for a landscape lens it is desirable that a peculiar adjustment be made, so as to reduce the intensity of the light on the sky of the picture, and increase in a corresponding degree that required on the comparatively dark foreground. A very ingenious method of effect- ing this was proposed by the Rev. William Read, of Manchester, and consists in placing the diaphragm, not at a right angle to the axis of the lens as is usually done, but obliquely, and in such a manner as to transmit a much wider pencil of light from the foregi’ound of the scene to be photographed than from the sky. By this contrivance the bright sky is not overdone,” and represented as a flat white mass, as is so commonly the case. The tendency to darlmess of the foreground in the photograph is also provided against. The perfecting this idea has of late engaged the attention of opticians, and it is expected that before long an improved cloud-stop on this principle will be an article of commerce. Xeiv Photographic Societg. — A photographic society has been formed in Bristol, under the presidency of the Bishop of Gloucester and Bristol. There are many clever amateur and professional photographers who reside in Biistol and its vicinity; hence there is no reason why the society should not rapidly attain a high position. Neio Method of Preparing Printing Surfaces. — Mr. Davies, an Edinburgh amateur photographer, has completed some experiments, instituted by him with a view to render common papers sufficiently hard on the surface to bear being floated on tlie sensitising solution without absorbing it. As a conse- quence, I. ! is now able to produce brilliant photographs on such apparently unsuitable surfaces as those of brown wrapping paper, the backs of handbills, drawing-paper, canvas, <&c. Several good photographs, some executed on cartridge paper, have recently been exhibited at one of the London societies, as an illustration of what the process is capable of doing. Tlie method of preparing the paper is as follows : — From four to six grains of gelatine are soaked in an ounce of water for an hour, and are then dissolved by the ap- plication of heat. While still warm, add slowly, and with constant stirring, from four to five drachms of a solution of white lac. The strength of the lac solution should be six ounces of methylate spirits of wine to one ounce of either white or orange lac, according to the colour of the surface to which it is to be applied. Tlie mixture of the gelatine and solution of lac pro- SCIENTIFIC SUMMARY. 325 duces a creamy-looking emulsion^ in wliicli is dissolved four grains of cUoride of sodium, or a like equivalent of any other chloride that may he preferred. This solution, after being filtered, is applied to the paper hy means of a large flat camel’s hair brush, and when dry it is ready for being sensitised hy nitrate of silver in the usual way. New Flioto-enamel Process. — M. De Luey-Fossarieu, a Parisian artist, has j ust published a new method of producing vitrified, or enamel photographs. A plate of glass is coated with a sensitive solution composed of borax, white sugar, gum arabic, honey and bichromate of ammonia, dissolved in water. When dry, the plate is exposed to light, under a soft transparent position ; the development being effected by brushing on suitable pigments in very fine powder. This adheres to the surface inversely in proportion to the action of the light. The film, being transferred to the enamelled tablet, is vitrified in a suitable mufile. PHYSICS. Electric Phosphorescence in Parejied Gases. — In a recent communication to the French Academy (May 10), M. Le Roux states that these phenomena are not alone produced by the passage of the electric spark through gases, but can be caused by a process of induction. When, he says, a cog- wheel, highly electrified, is set in rapid motion close to a tube containing a rarefied gas, phosphorescent phenomena exhibit themselves. The Phosphorescence seen in Rarijied Gases after the Passage of the Electric Spark. — This subject, which is one of great interest, has been inquired into by M. Edouard Sarasin. Instead of a tube he uses a bell-glass for the vacuum. After describing the general arrangements, the author observes : — The gases experimented on in this apparatus were, first, oxygen and its compounds, and then other gases containing no oxygen. Oxygen, the author states, always gave a persistent luminosity after the interruption of the current. In order to see it, he says, it is necessary to close one’s eyes while the current is passing ; then, on opening the eyes when the current has ceased, one sees a sort of pale light along the track of the spark,” or rather that the spark had previously traversed. At low pressures, that is to say at 3 mm. and lower, this light fills the bell-glass. It is at a pressui’e of 2 mm. that the maximum of intensity and duration is produced. No other simple gas gives the same results. Hydrogen, nitrogen, chlorine, and iodine vapours give not the least trace of phosphorescence. The compound gases which contain no oxygen likewise give no luminosity of this kind. Thus ammonia, coal-gas, and hydrochloric acid gas, give none. And the same may, to a great extent, be said of atmospheric air, notwithstanding the oxygen that it contains. On the other hand, the compounds of oxygen all possess this property, more or less, and some of them in a very high degree. The substance which produces the most intense effect is sulphuric acid. In experimenting on the vapours of sulphuric acid, the author simply places under the bell-glass a large capsule filled with the concentrated Nordhausen acid. Then, when the air is exhausted, the vapour of the acid rises and 326 POPULAR SCIENCE REYIEW. diffuses itself throughout the space. Some of the experiments with this substance were of great interest. When nitrogen, air, nitrous oxide, carbonic acid, and carbonic oxide were used, the luminosity was in each case pro- duced; but when hydrogen was employed, not the slightest appreciable effect was obtained. M. Sarasin gives the following hypothetical explana- tion of these phenomena : — The nascent oxygen or ozone is diffused throughout the space. In this state it has a very strong tendency to com- bine with the elements in its presence, and in fact up to the time that the current ceases it recombines with them. This recombination of nascent oxygen or ozone, being effected with great energy, must be accompanied with a considerable degree of heat, and this in its turn produces the lumi- nosity to which the term phosphorescence is given. — Comptes-RenduSj April 12. Aneio Battery for Telegraphic purposes, but which may perhaps be gene- rally useful, has been invented by M. Guyot, and apparently is not unlike the ordinaiy Menotti sand battery. It consists of a porous earthen vessel filled with finely-powdered iron ore, in which is plunged a cylinder of gas-retort charcoal and an ordinary vessel filled with concentrated solution of common salt, in which is placed a slip of zinc. The only care required to keep such a battery in order is to keep the latter vessel always full of concentrated solution. Further the solution may be replaced by sand impregnated with it, or by salt in crystals, the humidity of the atmosphere being always suffi- cient to serve as a solvent. The Physics of the Gulf Stream. — M. Janies Croll, who has published some papers on this subject, speculates thus as to the stream as a heat-caiTying medium. The total quantity of water, he says, conveyed by this stream is probably equal to that of a stream 50 miles broad and 1,000 feet deep, fiowing at the rate of four miles an hour. And the mean temperature of the entire mass of moving waters is not under 05° at the moment of leaving the Gulf. I think we are warranted to conclude that the Gulf Stream, before it returns from its northern journey, is on an average cooled down to at least 40°, con- sequently it loses 25° of heat. Each cubic foot of water, therefore, in this case carries from the tropics for distribution upwards of 1,500 units of heats, or 1,158,000 foot-pounds. According to the above estimate of the size and velocity of the stream, 5,575,080,000,000 cubic feet of water are conveyed from the Gulf per hour, or 133,810,320,000,000 cubic feet daily. Conse- quently, the total quantity of heat tiansferred from the equatorial regions per day by the stream amounts to 154,959,300,000,000,000,000 foot-pounds. From observations made by Sir John Ilerschel and by M. Pouillet on the direct heat of the sun, it is found that were no heat absorbed by the atmo- sphere, about 83 foot-pounds per second would fall upon a square foot of surface placed at right angles to the sun’s rays. Mr. Meech estimates that tlie quantity of heat cut off by the atmosphere is equal to about 22 per cent, of the total amount received from the sun. M. Pouillet estimates the loss at 24 per cent. Taking the former estimate, G4’74 foot-pounds per second will therefore be the quantity of heat falling on a square foot of the earth’s surface when the sun is in the zenith. And were the sun to re- main stationarj' in the zenith for twelve hours, 2,790,708 foot-pounds would fall upon the surface. SCIENTIFIC SUMMAKY. 327 The Temperature of the Air^ and that of Trees and Forests. — In a paper sent in to the Frencli Academy on March 29, M. Becquerel gave an account of some curious inquiries recently conducted by him on this point. He stated that in severe cold in winter, when the temperature falls to 8°, 10°, and further below zero, it is colder in woods than outside them. M. Bec- querel the elder has taken this question up again, with the aid of observa- tions which he made in 1858 and 1859 with the electric thermometer on the temperature of the air in the north, compared to that of a tree of Om. 45 in diameter, to Om. 22 below the bark. In the month of July, at the time of the greatest heats, the temperature in the air was successively at 2940, 28*20, 26*95, &c. • whilst in the tree on the same days the register was 24*60, 25*90, 25*40, &c. ; the differences were equal to 4*80, 2*30, and 1*55, always diminishing. Once the temperature of the air, at the end of several days, reached 18*78 ; that of the tree was, on the contrary, higher, as follows : — 24*65, 23*50, 21*50. These results show that a certain time is necessary for the heat to penetrate the tree, but without attaining the maxi- mum temperature of the air, except in certain peculiar circumstances already set forth. The observations recorded further show that in summer the temperature of the air is in general^higher at nine o’clock at night than at nine o’clock in the morning, and even frequently higher than at three o’clock. This is a proof that the maxima only occur rather late in the evening. A new Oxyhydrogen Lamp. — Les Mondes (May 6) gives an account of some experiments which are given nightly at Paris in illustration of the qualities of a new lamp. The burner, which is arranged to burn either pure hydrogen gas or coal gas at any pressure from two millimetres up to several centimetres, is constructed in the following manner : — The oxygen issues from a central opening ; the hydrogen or coal gas issues from small tubular openings not unlike those met with in the Leslie gas-burner j but instead of being as in that burner almost vertical, they are in this instance bent so as to lay almost horizontal, and thus stand with the openings opposite to each other, while the oxygen is in the centre j the flame is directed against a piece of zircon-magnesia. We further notice a circular Argand burner without any magnesia cone, and so arranged as to have the combustion of the gas supported by oxygen gas instead of by air. A modi- fication of this burner, as regards the arrangement of the supply tubes, is made to serve for burning gas fed by oxygen, the burner being placed in strong glass globes so as to suit the purposes of lighting mines and for submarine lamps. Care has been taken by proper and suitable means to carry off the products of the combustion in each case in such manner as to insure the safe use of the apparatus. ZOOLOGY AND COMPAKATIVE ANATOMY. The Mole CricLet. — Those who are interested in this group will be glad to learn [that Mr. S. Scudder, the well-known American entomologist, has written a very valuable memoir on these insects. It is published by the 328 POPULAR SCIENCE REVIEW. press of the Essex Institute, from which has issued Dr. Packard’s excellent work noticed in our last number. A larva and beetle of theElater genus have, says the Aihenceum (June), been recently brought from Bahia and exhibited at the British Museum. The following description of them has been given. When seen in the da / ght it is somewhat like a meal-worm, but more tapering at each end and rather more than an inch long, of a pale yellow colour, with a small red head. There are ten beautiful bright golden and green luminous spots on each side of the body, edging the stigmata and differing in brilliancy as the animal respires, the head emitting a most brilliant ruby light, like the lamp of a railway locomotive. The insect often lies on its side, forming a ring of beautiful lamps, with the ruby head in the centre. ' When the animal crawls in the dark it looks like a double line of yellow lamps, as it were following the ruby light. The light is much more brilliant and intense than that of the glow-worm, but the individual spots are smaller. Natural History at the British Museum. — In the ^‘Report ” just presented to Parliament, Prof. Owen reports in general for the Departments of Natural History, progress in arranging and improving the exhibited collections. He complains, as before, of want of room ; the additions numbering 35,562. — Dr. Gray details for the Department of Zoology the acquisition of 24,144 specimens, of which 17,144 are Annulosa j the printing of catalogues of Diurnal Lepidoptera, by Mr. A. G. Butler ,* and of Heteropterous Hemiptera, Part HI., by Mr. F. Walker j also many important items of the additions. — The Department of Geology, under Mr. Waterhouse, has been employed in new arrangements. — The Department of Mineralogy, under Dr. Maskelyne, has acquired 1,036 specimens, including diamonds. Dr. Maskelyne has also added largely to the collection of meteorites, a subject in which he is now engaged in elaborate researches. Life on the deep-sea Bottom. — The Americans continue their important dredging enquiries in the Gulf Stream. A recent number of the Bulletin of the Museum of Comparative /joology (No. 7) gives the second series of reports of results. Mr. L. F. Pourtales, who supplies the record, states that the utmost depth reached with the dredge was 517 fathoms, or 3,102 feet, or over 1,000 feet beyond the late researches near Spitzbergen. The bottom has been divided into three regions, extending in zones around the Florida reefs : — 1. From the reef outwards four or five miles to the depth of 90 fathoms; 2. From 00 to 250 or 350 fathoms; 3. The bottom of the channel, which does not much exceed 500 fathoms. The first region is barren, and covered only by dead and broken shells, showing that the fauna of the reef itself does not extend seaward. The second is “ rich in animal forms,” and is particularly interesting to the geologist. It is a limestone, gradually increasing by the accumulation of the calcareous remains of Corals, * iOchinoderms, and Mollusks. These debris are consolidated by the tubes of Serpul.'p, the interstices filled up by Foraminiferae, and smoothed over by the Nullipores. It is supposed that this will eventually thicken until the water is shallow enough for tlio Astreans and Madrepores to begin their work of founding a new barrier similar to the existing reefs. This limestone is filled with recent fossils, furnished in great part by the animals now living on the bottom, but a few contribute by sinking after death from the higher regions SCIENTIFIC SUMMARY. 329 of the superincumbent water (teeth of fishes and shells of Pteropods), and others are brought by currents from littoral regions (bones of the Manatee, and fragments of littoral plants). All the branches of the animal kingdom, so far as their marine carnivorous orders are concerned, are abundantly represented in this region, but it is destitute of plants. The third region is sparsely inhabited by a few Mollusks, Kadiates, and Crustaceans, but the peculiar animals are the microscopical Globigerinje whose siliceous shells have covered the bottom of the channel with a thick deposit. The deep-sea animals of the second and third regions are of smaller size than allied forms of the littoral zone. The only exception is an Echinus, which is nearly of the average size, and an Actinia. The American Lepidoptera. — The American Entomological Society is now issuing in parts a list of Butterflies and Moths. The editors are Messrs. Grote and Robinson. American Grasshoppers have been equally well dealt with in a catalogue prepared by Mr. Samuel Scudder. The Vascular parts of the Retina of the Hedgehog. — The Proceedings of the Royal Society, May, contains a communication by Mr. J. W. Hulke, in con- tinuation of his former papers on the structure of the retina. The chief peculiarity, he says, is that only capillaries enter the retina. The vasa centralia pierce the optic nerve in the sclerotic canal, and, passing forwards through the lamina cribrosa, divide at the bottom of a relatively large and deep pit in the centre of the intraocular disc of the nerve, into a variable number of primary branches, from three to six. These primary divisions quickly sub- divide, furnishing many large arteries and veins, which, radiating on all sides from the nerve- entrance towards the ora retinae, appear to the observer’s unaided eye as strongly projecting ridges upon the inner surface of the retina. When vertical sections parallel to and across the direction of these ridges are examined with a quarter-inch objective, it is immediately perceived that the arteries and veins lie, throughout their entire course, upon the inner surface of the membrana limitans interna retinae, between this and the membrana hyaloidea of the vitreous humour, and that only capillaries penetrate the retina itself. The development of the Zoosperms of Fishes forms the subject of a paper published in the Bulletin of the Academy of Sciences of St. Petersburg, by M. OwsiannikofF, whose researches on the zoosperms of the salmon and other fishes lead him to conclusions quite opposed to those of Kolliker. The cells which develop the zoosperms may, he says, sometimes be seen to con- tain from ten to fifteen secondary cells within them, and these are the young spermatozoa. The nucleus of the cell becomes the head, and the protoplasm which surrounds it forms the tail. The adult spermatozoon has a head like an ace of hearts,” pointed in front and broad behind. It consists of two lateral parts, which are separated by a superficial groove. Immediately behind the head there is a thickening of the tail, which however has no special feature. The zoosperm does not move along by jerks, but by a dis- tinct undulating motion. When water is added to the seminal fluid the zoosperms move about briskly, but when much is added the tails disappear. This, the author says, is due to a retraction of the tail towards the head, and a coiling of the former round the latter. 330 POPULAK SCIENCE KEYIEW. The teeth of Rotif era. — The Rev. Lord Sidney Godolphin Osborne made a communication on this subject to the Literary and Philosophical Society of Manchester at its meeting on April 6. The dental organ, he says, con- sists primarily of two slightly arcuate jaws, broad at their upper extremi- ties and narrow and pointed at their lower ones. Elastic ligaments bind these together at each end. The front or convex margin of each jaw is crenulated, the projections corresponding with the transverse parallel ridges usuall}^ regarded as the teeth of the animal. These jaws form the two lips of a sac, the lateral parts of which consist of a separate tissue, which over- laps each jaw at its anterior margin, hooked on, as it were, to the crenulations and thrown by them into permanent parallel corrugations. Each of these corrugated organs passes first outwards and then downwards and backwards, where they are bound together by another broad membrane, which completes the sac posteriorly. The food enters this sac by a passage from the oesopha- gus, at its superior extremity, is crushed between the two jaws, and then passes out again by a similar orifice at its opposite or lower end to enter the stomach. Of these tissues the jaws are the hardest, and are capable of being dissected out, as Lord S. G. Osborne has succeeded in doing. The lateral coiTugated organs have a concavo-convex form, which they appear capable of retaining after dissection 5 they appear less dense than the jaws, but more so than the membranous tissues of the gizzard, to which they are united. The central corrugations are always the largest. The Varieties of Dogs. — Dr. John Edward Gray has written a paper on the varieties of dogs in the Annals of Natural History. In reference to that kind of variation, which he thinks ought to be looked upon as abnor- mality, the author points out the following four types : — 1. The short and more or less bandy legs of the turnspit and lurchers, which are common to terriers and spaniels. 2. The more or less imperfect development of the upper jaw, found in the bull-dog, pug-dog, and different breeds of spaniels. 3. The great development of the ball of the eyes, so as to become too large for the orbit and exceedingly prominent and liable to accident, found in some breeds of spaniels and terriers. 4. The more or less complete want of hair, which is generally accompanied by a more or less complete want or great imperfection in the development and rooting of the teeth, showing the relation between these two organic productions. The Conformation of the Negro Cranium. — At the meeting of the Physical Society of Edinburgh, on April 7, a paper was communicated by Dr. J. S. Smith and Professor Turner, on eight negro crania, recently sent from Old Calabar. Four of tlie skulls were those of males and four females. They were the crania of slaves of the Calabar negroes, and were probably of the Iboe tribe, having been brought from the delta of the mighty Niger or (^uorra. These negroes have been described as being among the most degraded of the negro race. The skulls, however, showed no such appear- ance of degra^lation, and one of the male skulls had an internal capacity or brain bulk of 1>.‘» cubic inches. The crania also exhibited a much greater variety of size than was to have been expected in a rude negro people. Mr. Ilobb considers that the degraded state of the delta negi'oes has been much exaggerated. He has lived among them, and states that they are simply what paganism makes them, but their nature is similar to our own, and they SCIENTIFIC SUMMARY. 331 can be elevated to a biglier platform. Minute details were given of tbeir anatomical character and measurements, and the gronp of crania are to be added to the valuable collections of the Anatomical Museum of the University. The Atlantic Sea-bottom. — On June 6, the Porcupine, then in charge of Mr. J. Gwyn Jeffreys, put into Galway Harbour, and news was received of some of the results. These are briefly stated in a note in a weekly contem- porary. The weather had been fine, and dredgings had been made at depths from 80 to 808 fathoms. Soundings, too, have been taken in places where previous soundings were few. The 808 fathom dredging, which took 1,200 fathoms of line, brought up two hundredweight of Atlantic mud. The winding in ” of this find occupied an hour, the donkey-engine doing its work to full satisfaction. In a haul at 110 fathoms 408 large specimens of Echinus Norvegicus, and a living mollusk, with eyes, were brought up. But in addition to natural history, the expedition has demonstrated that a new kind of thermometer for indicating the temperature at any depth gives satis- factory results. If this thermometer is trustworthy, then all previous ther- mometers used in deep-sea soundings are wrong, for at the 808 fathoms depth it showed four degrees lower than the thermometer usually employed, and the same at 723 fathoms. And further, Mr. W. L. Carpenter, who is with the expedition, writes concerning the experiments on water taken at different depths, that the bottom water does not appear to differ from surface water in the quantity of contained gases, nor in specific gravity ; the latter at 60° F. being always 1-0278. But the proportions of oxygen to carbonic acid and nitrogen differ greatly, for ^bottom water contains from two to three times more carbonic acid than surface water. And as regards the tests for organic matter in the water, there is an almost total absence of decomposing organic matter ; but of matter in a condition ready to decompose there is a nearly constant quantity whether at bottom or surface. The Organ-pipe Coral. — Dr. Perceval Wright, Professor of Botany in Trinity College, Dublin, states as the result of his observations on this Coelenterate that the details given in Kolliker’s leones are in some respects incorrect. — Annals of Nat. Hist, May. The British Nemerteans. — The structure and arrangement of these animals have been stated in a paper read before the Koyal Society of Edinburgh, but only published in abstract in its Proceedings. The anatomy is minutely gone into, and forty new species are described. The Hanger of Microscopic Methods.'^ — M. Bobinski, in a memoir published in the Comptes-Rendus for April, calls attention to the errors in interpreting structure caused by using reagents. He alleges that the lym- phatics which Herr Eecklinghausen has discovered in the epithelium are mostly the result (artificial) of the use of nitrate of silver, which stains the outside of the cells more than the inside and thus leads to the notion of the existence of a number of communicating canals which are really not present at all. A nexo Siliceous Sponge which was taken at Santa Cruz, and which has been examined by Dr. Leray, an American naturalist, is described at con- siderable length in the Monthly Microscopical Journal for June. The genus Pherojiema has been founded for its reception, and it is said to resemble 332 POPULAR SCIENCE REVIEW. Ilyalonema. The following details are given. The body of the sponge is oblong ovoidal, with the narrower end upward, and with one side more prominent than the other. The lower extremity is rather cylindroid and rounded truncate. The upper extremity is conical, with a truncate apex presenting a large circular orifice. This is about four lines in diameter, and is the exit of a canal which descends in the axis of the sponge for almost half its depth, and then appears to divide into several branches. The sides of the sponge form thick dense walls to the cylindrical canal, which is of uniform diameter before its division. In its present condition the sponge is of a light-brown hue. Its surface exhibits an intricate inter- lacement of stellate, siliceous spiculse, including a tissue of finer spiculae of the same character, the whole associated by the dried remains of the softer sponge tissues. More or less fine sand, especially at the lower end of the sponge, appears to be introduced as an element of structure. From the lower end of the sponge there projects a number of distinct or separate tufts of siliceous spiculse, looking like tufts of blonde human hair. In the specimen there are fifteen tufts projecting around two-thirds of the ex- tremity of the sponge, but the remaining third of the extremity of the latter exhibits about ten orifices, from which as many additional tufts appear to have been extracted. Length of the body of the sponge inches ; diameter at middle 22 lines, at lower end 15 and 17 lines, at upper end 8 lines. Length of tufts of spiculae 2 inches. The Mammalia of North-West America. — Some notes on these were recently furnished in a paper read by Mr. Robert Brown before one of the Scottish societies. The author gave an account, illustrated by maps, of the different distinct faunas into which he divided the extensive territory of North-West America, and detailed the various genera and species be- longing to each. Special reference was made to species believed to be new. Mr. Brown gave many curious and interesting details of his own experiences and adventures in the wilder districts of that comparatively little known part of the world. The paper was, we believe, one of a series which Mr. Jlrown is preparing on the zoology and botany of North-West America. The Chair of Physiology at the Poyal Institution. — The Fullerian Professor- sliip, which was lately resigned by Professor Huxley, has been given to Dr. Michael Foster. Comparative Psychology is the title of the new section to be formed in the Ktlinological Society. The Desiccation of Rotifer's. — The Proceedings of the Literary and Philo- sophical Society contain a report by Professor Williamson on some observa- tions on this questionable phenomenon by Lord Osborne. Professor William- son exliibited some small glass tanks or Rotiferous aquaria, some of which Imd been prepared by Lord S. G. Osborne, which had been dried up again and again. One of tliese, in a dry state as it had been for five months, was moistened by the addition of a little water, and in five minutes the animals were in full activity, looking thin and hungry, but perfectly vigorous. The experiments of Lord S. G. Osborne confirm the statements of Spallan- zani, that these Rotifers may be dried up for years without vitality being destroyed. 'J’anks for the preservation and examination of these objects are reaflily made by joining two ordinar}' microscopic glasses on three sides by means of electric cement, and then stocked by the introduction of a little SCIENTIFIC SUMMARY. 333 Rotiferous dust. In such tanks they multiply rapidly, the occasional addition of a few drops of water to counteract evaporation being all that is needed for their preservation. Function f the Contractile Vesicle in Infusoria. — In a paper on Stentorj in the last Journal of Anatomy, Dr. Moxon brings forward some new arguments on this point. He denies that such organisms, from their small size, require a heart. The Frohoscis of the Blowfly. — The Monthly Microscopical Journal for June contains four very handsome plates, illustrating this very peculiar organ. Microscopists will do well to refer to them. Free-swimming Amoehce. — The above number also contains an account by Mr. J. G. Tatem of certain curious tailed swimming amoebae. A new Genus of Salamanders has been found by Professor Cope (U.S.) in a number of specimens brought from Mexico. It dilfers from Sperlerpes, in having the parietal and palatine bones unossified, and the inner nares open- ing into the orbits. The phenygoid teeth are in one patch. Toes, four on the front feet and five on the hind, rudimentary. Th» tail is as long as the head and body together. The total length is only two inches. It has a pale dorsal band and black sides. A female specimen contained eggs one line in diameter. He has called the species, which is a new generic type, Thorius pennatrihus. Origin of the second Cervical Vertebra. — We learn from the American Na- turalist (June) that a very important memoir on this subject has been pub- lished in a recent number of the Proceedings of the Swedish Academy, by Professor Kinberg. This origin he refers to the fusion of two vertebrae to- gether. In mammalia, generally, says Dr. Lutken, who reports upon it, the odontoid process is separated, during a longer or shorter period, from the true corpus epistrophcei by two intervertebral epiphyses in the same manner as in all other ordinary distinct vertebrae ; the odontoid process has parts answer- ing to the arms, which are, however, not developed into true arches, but analogous to that of certain caudal vertebrae ; the epistrophaeus has of course two corpora fused together like the sacral vertebrae, and consequently draws its origin from the connection of two primordial vertebrae. The Zoological Society has been doing excellent work during the quarter. It would be impossible, with the space at our disposal, to give even a list of the papers read. We may, however, refer to one of great importance to ^ comparative anatomists. It was upon the homologies of the bones of the internal ear, by Professor Huxley. j The Chair of Comparative Anatomy in the College of Surgeons. — Scientific I Opinion announces that Professor Huxley has resigned the chair, and that I Mr. W. H. Flower, F.R.S., is likely to succeed him. We regret Professor Huxley’s resignation, but at the same time congratulate the Council of the College on its selection of Mr. Flower for the Hunterian chair. I The Muscles of Invertebrate Animals. — On this subject a very elaborate I paper appears in the last number of Max Schidtzds Archiv fur Mihroskopisclie 1 A natomie, by Herr Schwalbe. The author goes through several types, be- j| ginning with the Actinia, and ending with Echinoderms and Gasteropods. jj Two handsome folding plates illustrate the memoir, and represent the mus- cular fibres as prepared with chromic acid, bichromate of potash, and osmic acid, and seen with a No. 10 Hartnack’s immersion lens. The fibres of some 334 rorULAR SCIENCE RE7IEW. of the annelids (like Nereis) are peculiar in possessing a number of lateral processes. In others the sarcolemina is indicated, though it may of course be asked in how far it is a post-mortem or artificial structure, or how far it is represented by the connective tissue which unites the muscular fibres together. Cohesion of the. Blood- Coi'puscles. — As to this singular phenomenon, Professor Norris, of Birmingham, gives the following account in a paper quite recently communicated to the Eoyal Society. My idea of the blood - corpuscle is that its contents are something essentially different, so far as cohesive attraction is concerned, from the liquor sanguinis, that is to say, not readily miscible with liquor sanguinis. This is of course self-evident, if, according to some modem views, we regard the corpuscles as tiny lumps of a uniformly viscous matter,” inasmuch as such matter must be insoluble in, and immiscible with, the liquor sanguinis. The explanation is equally easy, if we accept the old and, I believe, the true view of the vesicular character of these bodies, as we have only to assume that the envelope is so saturated with the corpuscular contefits as practically to act as such contents would them- selves act, i.e. to exhibit a greater cohesive attraction for their own particles than for those of the contiguous liquid. The cohesive power of the blood- corpuscles varies with varying conditions of the liquor sanguinis, and this is doubtless due to the law of osmosis; for we can readily imagine that when the oxosmotic tendency was in excess the corpuscles would become more adhesive, and, on the contrary, when theendosmotic current prevailed, less so. In any case the increased cohesiveness will be due to the increased extrusion upon the surface of the corpuscular contents. All, then, that is required in the case of tlie blood-corpuscles is a difference between their liquid contents and the plasma in which they are submerged. That this difierence is not so great as between the liquids used in these experiments is probable, but it must also be remembered that the attraction is not so powerful. The power required to attach the blood-corpuscles together is, on account of their exceeding minuteness, extremely small, as they are thus so much more removed from the influence of gravitation, and brought under that of mole- cular attraction.” The Colour ituj Matter of the Feathers of the Turaco. — This substance, which has been especially examined by Professor Church, is thus described by liim in the Proceedings of the Royal Society. It is a remarkable red pigment, extracted from four species of Turaco, or plantain-eater ; it occurs in about fifteen of the primary and secondary pinion feathers of the birds in question, and may be extracted by a dilute alkaline solution, and reprecipitated with- out change by an acid. It is distinguished from all other natural pigments, yet isolated by the presence of fi-0 per cent, of copper, which cannot be re- moved without the destruction of the colouring-matter itself. The spectrum of turacine sliows two black absorption-bands, similar to those of scarlet cruorine ; turacine, however, differs from cruorine in many particulars. It exhibits great constancy of composition, even when derived from different genera and sjwcies of plantain-eater ; as, for example, the Musophaga viola- cca, the Corythaiv alho-cristata^ and the C. poiphyreolopha. The Chair of Physiology at Bartholomew’s Hospital, lately vacated by Mr. W. S. Savory, P.K.S., has been given to Mr. Morrant Baker. 1 335 EXPEEIMENTAL ILLUSTEATIONS OF THE MODES OF DETEEMININO THE COMPOSITION OF THE SUN AND OTHEE HEAVENLY BODIES BY THE SPECTEUM. A Lectuee delivered to the Working Mex of Exeter, August 21, 1869. By WM. ALLEN MILLEE, M.D., D.C.L., V.P.R.S. [PLATE L.] ONE of the most important features of the age in wliich we live is the rapid manner in which man’s knowledge of the powers and properties of the different substances around him is being extended. We behold, on all sides, an extraordinary growth of what is called physical science^ and we witness every- where the increasing command which this increased knowledge gives to man over the materials of which this globe consists. I shall devote the time which we are to spend together this evening to an illustration of some of the modes in which this mastery of mind over matter is to be obtained ; and in this review shall draw my examples mainly from the striking achievements recently performed in the application of optics to chemistry, usually described under the term of spectrum analysis. Marvellous as are many of the revelations of science, it is to be noted that the methods of their discovery may generally be resolved into the application of ordinary observation to the objects to be examined. The distinction between ordinary and scientific observation is, indeed, merely in the degree of its accuracy. The man of science is perpetually contriving means to render his observations strictly accurate, and to reduce them, whenever it is practicable, to a form in which their results may be represented by weight or by measure. To take a simple instance : There is, perhaps, no great diffi- culty, even to those unfamiliar with science, in believing that sound is produced by the vibratory motions of the sounding body transmitted through the air to the ear ; since when a harp- string is suddenly stretched, or the cord of a piano is struck, a tremulous motion of the string is seen to accompany the sound thus produced ; and as the motion • becomes less visible the sound gradually dies away. It is not difficult to render these VOL. VIII. — KO. XXXIII. Z 336 POPULAR SCIENCE REVIEW. motions distinctly visible to a large audience, as I intend pre- sently to show. What, now, is the exact distinction between a mere noise and a musical note — between harmony and discord ? A noise consists of the recurrence of sounding vibrations at irregular intervals ; whilst every musical note is produced by its own particular number of vibrations, which recur at perfectly equal intervals. Several contrivances exist, by means of which the number of these vibrations, which occur in a second of time, can be counted. It has been thus ascertained that the higher or shriller the note, the more frequent are the motions by which it is produced. A simple expedient will enable us to show the number of vibrations of a note — say the treble C of the piano, and to prove that this note is due to twice as many vibrations in a second as are necessary to form the middle C, or the octave immediately below it. Here are two tuning-forks, one of which, when caused to vibrate, emits a note which is an octave higher than the other. Attached to one of the prongs of each fork is a needle which partakes of the motions of the prong. If a piece of smoked glass be drawn across the points of the needles when the forks are not sounding, the soot will be scratched off the surface of the glass in the form of two straight lines, the image of which may be thrown upon the screen by means of a strong light. But if the tuning-forks be made to sound by drawing a violin bow across them, a second piece of smoked glass will then show not two straight, but two zigzag lines ; and the line produced by the shriller note will exhibit just twice as many notches as that caused by the other fork. In a similar manner, it might be shown that the intermediate notes are produced by vibra- tions of intermediate frequency, a definite number being required for each note, as may be seen in the table, which exhibits an octave of the musical scale. Batio of tue Sounds of the Musical Scale. c 1 1) E E G A B C 0 H 0 n 4 3 3 5 15 9 2 3 8J Vibrations por Second. Intervals. I) ]•: y o A i3 c 2.5(5 288 320 3411 384 420| . 480 512 DE. miller’s EXETER LECTURE. 337 The curves produced by two notes sounded at the same moment may fit into each other at certain definite intervals. In such a case we have a harmonious combination; whereas, when the curves do not so fit, a discordant combination of sounds is the result. The annexed woodcut exhibits the curves produced by the notes of a common chord, the upper and lower curves representing those of the octave. The vibrations of a tuning- fork, or other sounding body, are transmitted to the ear through the air, which is thrown also into wavelike movements, the waves of sound being longer in the lower, and shorter in the shriller notes. In the treble C of the piano, which is produced by 512 vibrations per second, the waves that it occasions in the air are 2ft. long ; while in the C of the octave below, the number of vibrations is 256, or just half, and the length of the aerial wave is 4ft., or twice as great. The effects produced by vibration are not limited to those of sound. The still more remarkable phenomena of light and heat are connected with movements of this kind of intense rapidity, the frequency of which is so great as almost to baffle belief, from 35,000 to 70,000 such waves being contained in the space of a single inch in the case of light. It has been concluded from experiments, into a description of which time does not permit us to enter, that in all substances which give out light of their own — such as a piece of lime intensely heated in a jet of burning gas, or a rod of charcoal glowing in the extreme heat produced by a current of elec- tricity excited in a powerful voltaic battery, the particles of the solid are in a state of inconceivably rapid vibrati9n, and that these vibrations are transmitted to the eye by means of some infinitely subtle medium, termed the ether, which fills all space and the interstices of matter, and which, though not light itself, when thrown into vibration by a luminous object, excites in our eyes the sensation of light; just as the air, though not itself sound, yet, when thrown into vibration by a sounding body, excites in our ears the sensation of sound. I will now, by means of the voltaic battery, ignite a piece of charcoal very intensely. The light thus produced will occasion a series of intensely rapid vibrations in the portion of the ether contained in this room, and these will pass off in straight lines in 338 POPULAR SCIENCK REVIEW. all directions from the white-hot charcoal. If the charcoal be enclosed in a dark lantern, I can allow a portion only of its light to escape into the room, and can direct it at pleasure into any part by using a small mirror or flat polished surface. The opening by which the light escapes is, in this instance, a narrow vertical slit. You will observe the light is of a pure white. I propose now to show you another property of light, and to prove that white light consists of a mixture of several different colours. If the slice of light which issues from the lamp be allowed to fall upon a clear plate of glass with flat faces parallel to each other, the light will pass through the glass without undergoing any apparent change either in its colour or its direction ; but if it be allow^ed to fall upon one of the faces of a piece of glass cut into the form of a triangular bar or prism, we shall have a very different result. The light will be abruptly altered in its direction as it passes through the glass ; it will be refracted, as it is said : and now the beam of light, instead of falling upon the screen as a slice of white light, will be spread out into a ribbon of gorgeous tints, the brillianji hues of which will graduate insensibly from red into violet. This is repre- sented in fig. 2 of the Plate. The red end of the beam of light which is least altered from its original direction is said to be the least refrangible ; whilst the violet, which has experienced the greatest change, is said to possess the greatest amount of refrangibility. As this word “ refrangibility ” is one which I shall often have to use, it is necessary that you should dis- tinctly understand what it means — viz. the degree to which any ray is suddenly bent from its original direction by the action of the prism. Such a coloured image constitutes what Sir Isaac Newton called the prismatic spectrum. He varied this experiment in a great number of ways, and concluded that white light consists of a mixture of various colours, like those of the rainbow. By recombining these colours, the original white light is repro- duced. This may be done by sending it through a second prism placed in tlie opposite direction to the first. The action of the prism* which we have just examined is to open out the colours of which the white light consists into a fan of coloured light; so that, instead of perceiving a single white image of the slit, a series of images is obtained of every shade of colour. Koc'h image possesses its own special degree of refrangibility, and its characteristic tint; whilst each overlaps its neighbour on either side, so that the whole forms a continuous and beautiful blending of harmonious hues, commencing with red and ending in the violet. What the pitch of a note is in sound, such is colour in light. The undulations of the ether are longest and slowest in the red, and sliortest and most rapid in the violet. Dll. MILLED S EXETED LECTUDE. 339 with all degrees of intermediate frequency between. We may say that red is the bass, and violet the treble of colours. Few things in the progress of science are more remarkable than the manner in which discoveries in one branch of enquiry often prove of the greatest importance to the advancement of other branches of knowledge, with which they appear, at first, to have no connection. A striking instance of this kind occurs in the manner in which optical science has aided the studies of the chemist. By means of chemical analysis, it has been dis- covered that the various substances which are found upon the earth may be separated into a comparatively small number of bodies, out of which no other kind of matter may be separated. Out of sulphur, for example, nothing but sulphur can be obtained. These the chemist terms elements, and out of these all the different substances with which we are familiar are formed. For instance, the air we breathe is composed mainly of a mixture of two such elementary bodies — viz. the gases oxygen and nitrogen; water consists of oxygen chemically united with the gaseous element hydrogen ; and among the elements are fhe various metals — gold, silver, iron, copper, magnesium, sodium, and so on. These different substances the chemist distinguishes from one another by means of certain chemical tests. For instance, I may, by the addition of ammonia to a certain solution, find copper by the beautiful blue tinge pro- duced. In like manner, I may, by the white cloud occasioned on adding common salt to a second vessel, ascertain the presence of silver ; while in a third, the presence of iron is not less cer- tainly revealed by the red colour produced on adding potassic sulphocyanide. Within the last few years optics has come to the aid of chemistry in a manner which I must now endeavour to explain. We have seen that this spectrum of glowing charcoal is con- tinuous from end to end. Provided that the ignited material be a solid, its chemical nature has no influence upon the colour of the light which it emits. Whether, for example, the heated body consist of lime, magnesia, flint, cla}^, charcoal, iron, or platinum, so long as the substance is in the solid form a con- tinuous spectrum is obtained, containing rays of every degree of refrangibility, and of every colour, from the deepest red to the extreme violet. The spectrum of an ignited cloud of solid par- ticles, such as that produced by soot or any solid suspended matter, such as phosphoric anhydride when phosphorus is burned in oxygen gas, is also continuous. The same continuous spectrum is also produced by a white-hot liquid, such as melted copper or cast iron, and no difference dependent upon the chemical nature of the substance can be perceived in any of these cases. Such spectra, therefore, teach us nothing of the 340 r OCULAR SCIENCE REVIEW. chemical composition of the bodies by which they are pro- duced. But the case is very different when the spectrum of a gaseous body is examined. Then we have an interrupted spectrum, composed of bright lines of light of certain colours only, with intervals between them more or less completely dark. When- ever an interrupted spectrum composed of bright lines is seen, we infer that we are dealing with the spectrum of a transparent gaseous body in a state of intense glowing heat. Each gas or vapour emits light of a particular kind, which is collected into a line or group of lines peculiar to itself. If the position of these lines be accurately measured, it is found that the same sub- stance always gives rise to lines which occur invariably, exactly in the same part of the spectrum. Hence these lines may be made use of as tests of the particular substance by which they are produced. I showed you, just now, chemical tests of silver, copper, and iron. Now let us look at the optical tests, which are not less certain. Silver, for example, when heated suffi- ciently to distil it in vapour, emits a brilliant green light, which is mainly concentrated into two intense green bands, fig. 3, the other part of the spectrum being produced by the charcoal on which the silver rests. Copper also emits a green light, but this is seen to consist of a more complex system of bright bands, fig. 4. Iron, when volatilised at a still higher heat, in like manner gives a light with a system of bands still more complicated and nume- rous. Magnesium likewise furnishes an intense green band, which is really composed of three, so closely approaching each other as to appear on the screen but one. Each metal and each chemical element has in fact its own special set of bands. Each, when converted into vapour, vibrates in a definite way, pro- ducing a special set of luminous vibrations of fixed frequency, just as when a particular tuning-fork is struck, it occasions a series of waves of sound which occur with the particular fre- quency characteristic of its peculiar musical note. If, there- fore, we can determine with accuracy the position and number of lines in the spectrum of each chemical element, we can at once recognise its presence whenever we see its light, by simply measuring the position of these lines. Why, then, does a substance, when in the solid or the liquid form, not produce a spectrum like that which it furnishes in the gaseous state ? liodies, when in a solid or liquid form, are tied together l)y the attraction of their particles, and consequently their vibrations appear to be those of the mass, not those ot their constituent atoms ; whereas, in the state of gas or vapour, their constituent particles are widely separated from each other, and each is free to move independently of the rest. You will now easily perceive that this optical method of ana- DE. MILLEk’s EXETEE LEdTtJRil. 341 lysis enlarges the field of our enquiries to an extent which is really incalculable. Not merely can we, by looking through a prism into fiame in the midst of this room, ascertain that silver or iron, or both, are there. If I were to carry my apparatus to the top of Haldon Hill whilst you remained below, you would still be able to recognise the metal, be it what it might, which I was distilling in the voltaic arc. Nay, more, look into a furnace at any distance that you please through a prism, you may inter- pret the chemical changes that are occurring within its flame ; and the same method of observation may be extended to the outburst of a volcano, or beyond the limits of the earth, to the light of the sun, to the faint beams of the stars, and to the almost imperceptible haze of the nebulse studded here and there through the boundless fields of space. Do not, however, suppose that the foregoing observations comprise all that is needful to enable you to interpret all these wonders. Up to the present time I have shown you two kinds of spectra, viz., 1. the continuous spectrum, characteristic of the light of a glowing solid, or liquid, or cloud consisting of glow- ing solid particles (see Plate L., fig. 2), and 2. the irderruptecl spectrum, composed of ‘the bright lines which distinguish the spectra of glowing gases or transparent vapours (fig. 3). 3. Besides these there is a third kind of spectrum more remarkable than either, consisting of a luminous coloured band crossed by black lines^ shown in fig. 1. If an intensely luminous solid be viewed through a gas less intensely heated a very singular result is obtained. The spectrum of the gas is seen, as well as that of the solid behind it ; but the gaseous spectrum is reversed, that is to say, the lines of which it is formed, instead of being bright, are blacky as is shown in the lower half of fig. 9 ; while in the upper half the bright lines of sodium are seen occupying exactly the same position as that occupied by the dark lines Fig. 9, below, the lower part showing the appearance of a compound spectrum, formed by a luminous solid, in front of which is an atmosphere of sodium vapours. These effects you will see may be imitated experimentally, and the result may be shown on the screen. How are these black lines produced by thus adding light to light? Instances are not wanting in which sound added to 342 rorULAR SCIENCE REVIEW. ■ soiiiul produces silence, the waves interfering and neutralising ’ each other. But the disappearance of light in these black lines is not due to this cause. In the case of these black lines it arises from the circumstance that a body which is emitting light consisting of vibrations of a definite degree of fre- (jiiency, can absorb those portions of the light of other bodies which possess a corresponding rate of vibration, and can then radiate it forth anew in all directions ; much in the same way as a tuning-fork produces a resonance when held opposite the mouth of a box holding a column of air of such length as to vibrate in unison with itself, though it produces no such reso- nance when held opposite a box of different length which does not vibrate in harmony with it. The air in the resounding box first absorbs and then gives forth the vibrations of the fork with which it corresponds. In the case of sodium, for instance, the vapour of this metal absorbs the light of that particular portion of the spectrum of the body behind it, which corresponds with it in its rate of- vibration, and it allows all the rest of the light behind to pass on unaffected. If the sodium vapour is at a considerably lower temperature than the body behind, the absorbed rays will elevate the tem- perature of the metallic vapour somewhat, and will cause the sodium to give out a light which is a little greater than that line to the sodium alone ; but it is considerably less than that which v/ould be produced by the continuous spectrum of the body behind it, and the result is that when the combined image of the two spectra is thrown upon the screen we obtain what appejirs to us as a black line : but it really is .a line of low illu- minating power, which, being contrasted with the intense light of the spectrum on either side, produces upon our eyes the impression of a black line. If the sodium be raised in temperature until it acquires the same degree as that of the body behind it, the light which falls upon the sodium flame will still be absorbed as before; but now, as the intensity of the sodium light is ecpial to that of the spec- trum behind it, no sensible effect will be produced upon the screen. But if, on the other liand, the sodium flame be still liotter than the body behind it, it will be more intensely lumi- nous, and instead of a black line we shall have a bright line crossing the spectrum at this point. The vapour of sodium, according to its temperature, may tlierefore give rise to three different effects. 1. It may produce a black line, when the temperature of the sodium is low. 2. It may j)roduce no sensible effect, in which case the temperature and the light of tlic sodium arc cf[ual to those of the body behind it. 3. It may produce a bright line, but in this case the Dl?. - miller’s EXETER LECTURE. 343 temperature of the sodium and its light must be considerably higher than those of the glowing body behind it. What is true of the vapour of sodium is true also of other vapours. The light of the sun affords us a remarkable instance of a case in which the first condition is realised. The spectrum of the sun’s light is not continuous, but is crossed by a multitude of fine black lines, a few of which are represented in fig. 1 on the Plate. These lines, you will observe, vary in number, in blackness, and in definiteness in different parts of the spectrum. A facsimile of the lines in the neighbourhood of the line marked Gr as photographed by Mr. Rutherfurd, is shown in fig. 10, upon a scale eight times larger than the spectra shown in the coloured plate. Fig. 10. The fact of the existence of these lines was first noticed between sixty and seventy years ago, by Dr. Wollaston, and anyone may easily observe a few of the principal lines by pro- ceeding as he did ; placing himself in a darkened room, allow- ing a beam of daylight to come in through a chink of about a twentieth of an inch wide, like that formed by the edge of a nearly closed door, and then at a distance of 10ft. or 12ft. view- ing this line of light through a glass prism held close to tlie eye, with its edge parallel to the line of light. Little, however, was it imagined when these lines were first seen that in them lay the means of ascertaining the chemical components of the sun. Many among you, from what I have already said, will, however, see how this knowledge is obtainable. The sun itself is not a mere globe of glowing iron. It con- sists of a central, intensely heated nucleus, above which is an atmosphere filled apparently with white-hot solid particles dis- tributed in the form of vast clouds over the whole surface, and outside this powerfully luminous atmosphere is another less heated gaseous stratum containing the vapours of a variet}^ of bodies, most of them metallic in their nature. The black lines which we see in the solar spectrum are the effects produced b}’^ these cooler but still intensely heated metallic vapours, upon the light emitted by the cloud -like luminous surface of the sun. How are we to learn what the bodies are in the sun by which these black lines are formed ? The first thing to be done is to measure their position accurately, and to make a map of them. 344 t»OPULAR SCIENCE REVIEW* Fraunhofer, a working optician, of Munich, was the first person who attempted this, and they have been called Fraunhofer’s lines. In order to do this, he viewed the sun’s light through a prism placed in the focus of a small telescope provided with micro- meter screws for measurement, and he mapped upwards of 600 of them, and indicated the most conspicuous by the letters of the alphabet. Still, this does not explain the meaning of the particular lines. The map itself needs interpretation. For this explana- tion, and for the mode of experiment required, we are indebted to Professor Kirchhoff. The figure shows a diagram of this ar- rangement in plan. If we take two wires of any metal, such, for instance, as magnesium, and by means of a strong heat, such as that of the electric spark, convert a portion of the metal into a luminous gas, and place the spark-giver at m opposite the slit 0 of Fraunhofer’s apparatus, which, in its present improved form. is called a spectroscope, we shall see the bright lines characteristic of magnesium. Suppose that over one-half of the slit o of the spectroscope a small reflector r is placed, as is shown by a front view and on a larger scale in fig. 12, and that by means of this reflector a beam of the sun’s light s, fig. 11, is reflected into the tube, then transmitted first through the lens I, then through the prism p, and afterwards through the telescope t, into the eye of the observer, and at the same time the electric sparks are made to pass between the magnesium wires : two spectra will then be seen, one over the other, edge to edge, just as is represented in fig. 9. By thus comparing the spectra of the different elementary liodies with that of the sun, not only was magnesium found to be present, intismuch as the bright lines of magnesium coincide with certain dark lines in the solar spectrum, but sodium, iron, calcium, hydrogen, and eleven other elements — sixteen in all. i)K. MILLEE^S EXETER LECTURE. 345 as enumerated in the following table, are present in the atmo- sphere of the sun, viz. : Aluminum, barium, cadmium, calcium, chromium, cobalt, copper, hydrogen, iron, magnesium, manga- nese, nickel, sodium, strontium, titanium, zinc. By concentrating the light of the brightest fixed stars with a powerful telescope, a point of light of sufficient intensity may be obtained to enable its spectrum to be examined. It is neces- sary first to open oiit this point into a narrow line of light ; and this is effected by the use of a cylindrical lens, which spreads the light out in one plane only. The telescope must be made to follow exactly the apparent motion of the star in the heavens ; and in the telescope, exactly at the focus of the object-glass, a narrow slit, not wider than a fine hair, is placed. The light of the star must be kept perfectly steady on this slit, and then be examined through a small spectroscope, which is attached to the telescope and follows its movements. A special apparatus is also connected with the instrument for producing sparks from the particular metals which it is desired to compare with the lines in the star spectrum.* The diagram to which I now call your attention represents the star spectroscope employed by Mr. Huggins and myself in these difficult and fatiguing observa- tions. Only the brighter stars have as yet been examined; eight or ten pretty fully, others less perfectly. It is, of course, impossible to render such observations visible to more than one person at a time, and then only under particularly favourable Fig. 13. circumstances, and when the star is in a suitable position in the heavens. I have, however, here some photographs of careful * A figure and detailed description of this iustrunient was given in tli April number of this Revimo, p. 142, fig. 7, Plate XLII. 346 rOrULAR SCIENCE REVIEW. drawings which will give the appearance of two or three such stars. Each star has a different series of lines in its spectrum ; but each is found to contain several of the chemical elements which are met with upon the earth. Fig. 13 represents the spectrum of the bright star Aldebaran, in the constellation Taurus ; tig. 14 that of Betelgeus, the bright star in the shoulder of Orion, and fig. 7 on the Plate that of Sirius, the most brilliant of the stars visible to us in this country. Many of the metals found in these stars are of comparatively rare occurrence, while others are abundant. For instance, in Aide- baran, sodium, magnesium, calcium, iron, bismuth, hydrogen, tellurium, antimony, mercury ; in Betelgeus, sodium, magne- sium, calcium, iron, bismuth, thallium ; in Sirius, sodium, magnesium, hydrogen, and iron. Several of the substances found in these stars appear to be absent from our sun. The fixed stars vary in colour, and they each have their own peculiar spectrum, yet they are formed upon a plan which these observations show is analogous to that of our sun, viz., an intensely heated nucleus or kernel surrounded by a less hot, but still prodigiously heated atmosphere, containing various metallic and other vapours, many of which are identical with the ele- ments which occur in the earth. In the spectra, both of the sun and of the fixed stars, there are, however, numerous lines which we have not as yet been able to refer to their constituent mate- rials. This arises, probably, in a great measure from our im- perfect acquaintance with the spectra of the elements at present known. It arises in part also from our ignorance of some of the elements which compose our earth itself. Within the last eight years no fewer than four elementary bodies, viz., caesium, rubi- dium, thallium, and indium have been discovered by the special character of their spectra. Thallium, for instance, produces a magnificent green line unlike that of any other element, shown at Plate L., fig. 5. Indium shows two remarkable bands in the blue, fig. 6. Another reason why we have not yet interpreted all these lines is, probably, that many of them are the results of com- pounds formed in the outer and less heated part of the sun’s atmosjdierc, wliere ordinary chemical attraction again exerts itself. In the intense focus of the nucleus of the sun the heat is so fierce that all chemical combinations are destroyed, and the elements occur in a state of mixture with each other, as they do in the intense heat of the voltaic arc. Hut the revelations of the spectroscope do not end here. From time to time stars blaze forth in the heavens with great brilliancy, and then as s[)oedily fade and dwindle awa}% Mar- vellous changes are seen in such civses to be going on. In DR. miller’s EXETER LECTURE. 347 May 1866 a star suddenly burst forth in the constellation of the northern crown. On examining its spectrum, a wonderful condition of things was rendered visible, which will be made intelligible by examining a representation of the spectrum of this star — T coronse, as it is called — Plate L., fig. 8. This star exhibits three different spectra ; two of them resemble the spectra of the stars in general, consisting, that is, of the con- tinuous spectrum of the nucleus, crossed by the spectrum of dark lines produced by the gaseous bodies contained in its outer atmosphere. But in addition to these is another spectrum, composed of four or, perhaps, five bright lines. This is the spectrum of a gaseous body in a state of intense incandescence, or glowing heat ; and the position at c and f of the principal bright lines shows that one of the luminous gases is hydrogen. The great brightness of these lines shows, too, that the gas is hotter than the body of the star itself. These facts, taken in con- nection with the suddenness of the outburst of light, and its very rapid decline in brightness (from the second magnitude to the eighth magnitude in twelve days), that is to say, from a bright star to one invisible without the aid of the telescope, suggests the startling probability that the star had become sud- denly enwrapt in the flame of hydrogen which was burning around the star and combining with some other element. As the hydrogen gradually became exhausted, the flames dimi- nished in intensity, and the brightness of the star declined in a corresponding proportion. I must yet mention one more of the class of objects which occur in the heavens, still more enigmatical than any which I have at present described, and upon the nature of which spec- trum observations have thrown an unexpected amount of information ; I mean the nebulce. When the eye is aided by a telescope of moderate power, a large number of faintly luminous patches and spots are distinguished in the sky, which differ entirely in appearance from the defined brilliant points of light formed by the stars. Many of these singular objects, when viewed by the most powerful telescopes, still resemble mere shining clouds. These objects have been a standing puzzle to astronomers, and the interest connected with their nature has been increased by the suggestion of Sir W. Herschel, that they were possibly portions of the original material out of w^hicli existing suns and stars have been formed, and that probably in these nebulae we may actually watch some of the stages through which suns and planets pass before they take their final shape. Spectrum analysis, if it could be applied to these excessively faint objects, would immediately show wdiether they had a con- stitution like that of ordinary stars or not. Certain of these bodies when thus examined give no continuous spectrum, but 348 POPULAR SCIENCE REVIEW. one consisting of bright lines only. Fig. 15 is copied from a drawing by Lord Eosse of a nebula, afterwards examined by !Mr. Huggins, and a representation of the spectrum which he observed, and which proves that this particular nebula consists of glowing gas without any central solid or liquid nucleus. About twenty out of sixty nebulae examined by Mr. Hug- gins formed spectra composed of bright lines only. Of the rest, most give a faint con- tinuous spectrum, as though these were really in a more advanced stage of condensa- tion than the gaseous nebulae. In all these spectra a bright line coincident with one of the ’ bright lines of nitrogen occurs, so that they appear all to have a common character, and contain the same elementary substance. In a few of the brighter nebulae, three or even four lines have been observed, as in the instance figured above ; but the position of each of tliese lines is in all cases the same, when compared with the spectra of other nebulae. The position of the third line coin- cides with that of the most prominent line in the spectrum of hydrogen, so that there can be little doubt that the elementary gases, hydrogen and nitrogen, in a state of high ignition, are the chief components of these remarkable bodies. And now let us endeavour to form some notion of the dis- tances of these bodies, of which the constitution and chemical nature have thus in part been made known to us. The diameter of the earth on which we live is nearly 8,000 miles, and the moon is at about thirty times this distance from us, while the sun is 380 times as hir off as the moon. How can we in any way picture to ourselves these immense distances? Suppose that the sun were represented by a globe 2 ft. in dia- meter, the earth would then be of the size of a pea, and it would be placed at a distance of 215 ft. from it, or about twice as far off as I am from the wall of this room in front of me ; and the moon would be of the size of a mustard seed placed 7 in. from the pea, which represents the earth ; whilst Neptune, the most distant of the planets, would be of the size of a large plum, and would l)C placed at a mile and a quarter from the 2 ft. globe supposed to represent the sun. Well, Sirius, the brightest of the fixed stars, if measured by this scale, would be 40,000 miles away from us, or at a distance five times as great as that which now separates us in a straight Fig. 15. DE. millee’s exetee lectuee. 349 line from New Zealand. There is no doubt that many of the minute telescopic stars are several hundred times as distant from us as Sirius. Astronomical observations upon the eclipses of Jupiter’s satellites have shown that it requires rather more than eight minutes for the light of the sun to reach the earth ; it would take not less than twenty-three years for the light of Sirius to traverse the distance between that star and the earth if it travelled at the same rate. And of the distances of the nebulae we have no means of forming any calculation. How amazing the thought that throughout the whole of this unbounded range of space matter is to be found of the same kind ! Aggregated into masses which, though differing from one another in composition, like the various veins of ore which occur in mines upon the surface of our globe ; }^et all are evi- dently of common origin, all obey the same laws, and all possess a chemical nature similar in kind. Surely one is tempted to think, if the discovery of such marvels, if the measurement of such distances, the estimate of the mass and the magnitude, the calculation of the velocity of these bodies in space, and the determination of their chemical composition at distances the accurate conception of which transcends even the ability of imagination ; if these, I say, be not beyond the power of man, it may well be supposed that there is no limit to the discoveries which are within his reach. In one sense this is true. The visible works of God are laid open to our investigation to an extent which is really unlimited ; and one of the noblest occupations in which man can be engaged is in thus tracing the footprints of his Creator, and in discover- ing the laws which He has imposed upon matter, and by which suns and systems are controlled. But if there be a spiritual as well as a material universe, we must not the less have our material upon which to work, before we can attempt its investi- gation. It is just for the purpose of supplying this material, and of instructing us in this most important of all knowledge, that the Bible professes to have been given, since it is a know- ledge which we might for ever seek in vain, in meditating on the works of creation, however successful in unveiling its secrets by scientific investigation. While, then, we explore in admiration and delight the won- ders of nature, as they are commonly termed, or the works of Him who is the author of nature, as they truly are, let none of us forget with equal diligence to study that volume which alone can reveal to us the spiritual, the unseen, and the eternal — a study which, to be effectual, must be approached in the spirit of prayer for the guidance which is promised to everyone who asks in the belief that so asking he shall receivei 350 POPULAR SCIENCE' REVIEW. WHAT IS BATHYBIUS? By Brofessor W. C. WILLIAMSON, F.R.S, DURING- each successive year the Protozoa prove to be of increasino- importauce to the physiologist. In no other class of matured animals can the protoplasm, of which we have recently heard so much, be studied to such advantage. Con- stituting the lowest known manifestation of both animal and vegetable life, it seems to bring us very near to the boundary between the organic and the inorganic worlds. It exhibits the simplest phenomena of life under the least complex of conditions ; hence it has recently been appealed to b}^ one of the most philo- sophical of living zoologists as capable of throwing light upon the most recondite of biological problems. Without accepting all, or even the chief of the conclusions at which Professor Huxley has arrived from his study of protoplasm, he must be deemed right in the importance which he assigns to it. Whether seen as the gelatinous sarcode of the Protozoa, occupying the base of the animal kingdom, or as the yolk-material out of which the embryo of the highest vertebrate is formed; — whether we observe its plastic mass in the primordial germ of a ProtococQUS or of a Volvox, or as it appears in the leaf-bud of an oak, it everywhere brings before us the first stage in acts of organi- sation in which it is the chief, if not the only actor. Neverthe- less, I am unable to see that our study of protoplasm has })rought us nearer than before to a knowledge of the origin of that mysterious force which converts inorganic into organised material. There yet remains to be bridged over that un- fathomed gulf which separates death from life — the most complex effects of inorganic forces from the simplest of vital phenomena. We can trace the action and development of protoplasm through successive generations of organisms, but, like the spot where the rainbow touches the ground, its mysterious origin recedes as we advance, and a weary chase leaves us no nearer our object than when we commenced its pursuit. We increase our information respecting the conditions of its existence, but not of its origin ; WHAT IS BATHYBIUS? 351 and I believe that from the nature of the problem this ignorance will continue. We are asked, wherein does the so-called vital force differ from other physical forces ? Oxygen and hydrogen combine to form water; if you admit vitality, why not require a principle of sequosity to explain this combination and its resultant phenomena? What better philosophical status,” asks Prof. Huxley, has vitality than SBquosity ? ” I reply, we require the admission of no new force to explain the combination of gases in the formation of water. The phenomena occur in accordance with known laws of affinity. The synthetical experiment is but one of a vast series of similar experiments, in each of which we can combine separate elements with absolute certainty that the resultants will be identical with, and fulfil all the functions of, the same products when formed in nature’s laboratory. But the case is different when we turn to living organisms. We may know the proportions of oxygen, hydrogen, carbon, and nitrogen, existing in any form of proto- plasm, and we may even succeed in forcing those elements into an artificial combination having the same proportions, but in no single instance have we been able to endow such a combination with the powers of life. The resultant is not protoplasm. It does not live. It performs none of the vital functions. ‘‘ Certain con- ditions ” are wanting, and, so far as experiment has hitherto gone, the laboratory has proved unable to supply those conditions. Some force ” is required which is not under the control of the ablest physicist, and which differs in kind as well as in degree from those with whose operations he is familiar. We infer this, because all the functions of the resultant of nature’s organic synthesis are different from those of all artificial products. It is this lacking force which we indicate under the name of vital ; and so long as experimental philosophers fail to make their artificial combinations do what it does, I claim to be as philo- sophical, and to be acting in as truly a scientific spirit, when I recognise its existence as when I speak of a magnetic force or of a force of gravitation. Professor Huxley asks, “What justification is there, then, for the assumption of the existence in the living matter of a some- thing which has no representative or correlation in the not living matter which gave rise to it ? ” Surely the question, thus put, involves a fallacy. Professor Huxley admits that to produce the results referred to the introduction of a new element is needed. The not living matter requires the aid and instrumentality of matter that is living, and it is precisely this necessity which leads me to conclude that the living matter does contain something wanting to the “ not living matter.” The living organism increases, multiplies, and reproduces itself through a power that is inherent, whereas a crystal can only do so VOL. Vlll. — TS’O. XXXIII. A A 352 POPULAR SCIENCE REVIEW. through powers external to itself ; whatever it may be, the vital power is always derived; no known combination of inorganic elements or dead forces could have created it. Except in a few obscure cases, too ill-understood to be made the basis of a grave argument, protoplasm can always be traced, directl}^ or indirectly, to some pre-existing form of protoplasm. We nowhere discover any power which, without the intervention of some already living agent, can convert inorganic matter into living matter. If we could even trace back the history of protoplasm, until we reached one of Mr. Darwin’s primseval germs, our philosophy would still leave the first of these living azotised combinations un- accounted for. Since, then, scientific experience affords no proof that life is nothing more than a function of material com- binations, acted upon by physical forces, we are justified in the recognition of a vital principle, emanating primarily from a living Creator, but which, once created, appears capable of self- perpetuation to the end of time. If, having recognised the importance of the study of protoplasm amongst the lower animals, we commence its pursuit, we soon dis- cover the difficulties which surround it, especially when we discover the apparent inadequacy of the causes to the effects produced. We see a granular jelly evolving endlessly varied forms of grace and beauty ; at one time using silica as its raw material, at another carbonate of lime. Here it glues together grains of sand, there it develops a new sand-like compound, the very nature of which has yet to be discovered. In one form it produces the horny network of a sponge — in another the ethereal tracery of an Euplectella. The colours of its products are almost as varied as their material forms. We seek the cause of all this rich diversity — but we seek in vain. We see the almost motionless granular jelly investing the objects of beauty which it has constructed, but it affords us no indication of the secret of its wondrous power. We hail every new fact tending to throw light upon a history wliich is as obscure as it is marvellous. Hence the importance attached to Prof. Huxley’s discovery of the vast masses of sub- marine protoplasm, to which he has given the name of Bathybius. When, in 1857, Capt. Dayman, of H.M.S. Cyclops, returned from Ids exploration of the bed of the Atlantic, some of his specimens of “ soundings ” were placed in the hands of Prof. Huxley for examination. The explorers had already noticed the singular stickiness of the mud brought up by the lead, and Prof. Huxley soon found that this viscid condition arose from the diffusion through it of abundance of sarcode or protoplasm of a protozoic nature. The mud, like much of what constitutes the bed of the Atlantic, consisted chiefly of accumulated shells of Globbigerna biilloides — themselves the skeletons of a protozoic sarcode. The Bathybius occurred in minute patches of gelatinous protoplasm, WHAT IS BATHYBIUS ? 353 Usually of irregular shape, but occasionally assuming roundish forms. It consisted of a transparent jelly containing innumer- able, very minute, granules, many of which Prof. Huxley found to be equally soluble in dilute acetic acid and in strong solutions of the caustic alkalies ; but, in addition, there occurred some remarkable bodies to which great interest is attached. In the first instance Prof. Huxley noticed, adherent to the protoplasm, and occasionally embedded in it, numerous minute rounded bodies, soluble in acids, and to which he gave the name of Coccoliths. Still later, in addition to these Coccoliths, Dr. Wallich discovered, associated with the Bathybius, some larger spherical bodies of more complex organisation, which he designated Coccospheres. Yet more recently Prof. Huxley has re-examined his specimens under higher powers, and found his Coccoliths were of two classes — to which he now gives the re- spective names of Discolithus and Cyatholithus. The Discolithi he describes as oval discoidal bodies, with a thick strongly re- fracting rim, and a thinner central portion, the greater part of which is occupied by a slightly opaque, as it were, cloud-patch. The contour of this patch corresponds with that of the inner edge of the rim, from which it is separated by a transparent zone. In general the Discoliths are slightly convex on one side, slightly concave on the other, and the rim is raised into a prominent ridge on the more convex side.”* These objects usually range from -4 oVo 5"oVo their longest diameter. The Cyatholiths are like minute shirt-studs. They are stated to have ^^an oval contour, convex upon one face, and flat or concave upon the other. Left to themselves, they lie upon one or other of these faces, and in that aspect appear to be composed of two concentric zones surrounding a central corpuscule.” A lateral view of any of these bodies shows that it is by no means the concentrically laminated concretion it at first appears to be, but that it has a very singular and, so far as I know, unique structure. Supposing it to rest upon its lower surface, it consists of a lower plate, shaped like a deep saucer or watchglass; of an upper plate, which is sometimes flat, sometimes more or less watchglass-shaped ; of the oval, thick- walled, flattened corpuscule, which connects the centres of these two plates ; and of an intermediate substance, which is closely connected with the under surface of the upper plate, or more or less fills up the interval between the two plates, and often has a coarsely granular margin. The upper plate alwa}\s has a less diameter than the lower, and is not wider than the intermediate * On some Organisms from great Depths in the North Atlantic Ocean. • Quarteiiy Journal of Mici'oscopical Science^ Oct. 1868, p. 206. A A 2 354 POPULAR SCIENCE REVIEW. substance.” * These Cyatholithi are further stated to vary in size from -goVo "soVo diameter. The coccospheres are described by the same distinguished observer as ‘‘of two types — the one compact and the other loose in texture. The largest of the former type which I have met with measured about Y3V0 diameter. They are hollow, irregu- larly flattened spheroids, with a thick transparent wall, which sometimes appears laminated. In this wall a number of oval bodies, very much like the ‘ corpuscules’ of the Cyatholiths, are set, and each of these answers to one of the flattened facets of the spheroidal wall. The corpuscules, which are about an inch long, are placed at tolerably equal distances, and each is surrounded by a contour-line of corresponding form.” “ Coccospheres of the compact type of voVo diameter occur under two forms, being sometimes mere reduc- tions of that just described, while, in other cases, the corpus- cules are round, and not more than half to a third as big, though their number does not seem to be greater. In still smaller coccospheres, the corpuscules and the contour-lines become less and less distinct and more minute, until, in the smallest which I have observed, and which is only 45-Vo inch in diameter, they are hardly visible.” “ The coccospheres of the loose type of structure run from the same minuteness up to nearly double the size of the largest of the compact type, viz., yA-o of an inch in diameter. The largest (of which I have seen only one specimen) is obviously made up of bodies resembling Cyatholiths of the largest size in all particulars except the absence of the granular zone, of which there is no trace. I could not clearly ascertain how they were held together, but a slight pressure suffices to separate them.” f The relations subsisting between these Coccospheres on the one hand, and the Cyatholiths on the other, are very obscure ; but Professor Huxley deems it probable that some close affinity does exist; but whether the Coccospheres have been formed from a coalescence of Cyatholiths, whether the Cyatholiths have resulted from the breaking up of the Coccospheres, or whether the Coccospheres are altogether independent structures, yet remains to be decided. There appears, however, no reason to doubt that Coccoliths, Coccospheres, and Cyatholiths, equally belong to Pathybius, as the skeleton of a sponge, or the shell of a Foraminifer belong to their respective protoplasmic sarcodes. Since I'rofessor Huxley completed the observations to which I have referred, Hr. Carpenter and Professor Wyville Thomp- • On some Organisms from great Depths in the North Atlantic Ocean. Quarterly Jourtial of Microscopical ikicTice, Oct. 1808, p. 207. t Idem., p. 200. WHAT IS BATHYBIUS? 355 son have conducted a very important series of deep-sea dredg- ings off the north coasts of Scotland, and in the neighbourhood of the Faroe Islands. In Captain Dayman’s dredging opera- tions the viscid mud was found between the fifteenth and forty- fifth degrees of W. longitude. Those of Drs. Carpenter and Thompson were carried on much further eastward ; but in the latter instance the same deposit was found over a range of at least 200 miles, throughout which the dredge came up from time to time filled with Globigerina-mud and saturated with Bathybium, with its associated Coccoliths and Coccospheres. The Globigerina deposit exists in a similar manner in many and distant parts of the ocean, in both hemispheres ; and it is more than pro- bable that when the remote localities are subjected to the same examination as our northern seas have recently undergone, Bathybius will be found in them also. Its low organisation renders it probable that it will be found to be like its com- panion Globigerina, a thorough cosmopolite. On this point Dr. Carpenter suggests that the range of these objects is regulated by temperature rather than by locality. It was already known that many deep-sea localities existed, in which the Grlobigerina- mud did not occur; and it had even been suggested that its range was limited to that of the warm Gulf-stream. Dr. Car- penter confirms this general conclusion, and points out that its prevalence is connected with a bottom temperature of 45°, which in our northern latitudes can only be attributed to the Gulf-stream. Bathybius yet requires to be considered in two other impor- tant relationships — the one geological and the other zoological. Chalk, examined microscopically, has long been known to abound in minute ovate organisms, known as crystalloids, asso- ciated with the Globigerinse and Textillarise, of which chalk mainly consists. I recognised the organic origin of these bodies in 1847, and figured one of them very imperfectly, viewed as an opaque object, in my memoir On some of the Microscopic Objects found in the Mud of the Levant;”'^ but, ignorant of Coccoliths, I concluded that they belonged to some minute form of Oolina or Lagena. More recently Mr. Sorby has subjected these bodies to a much more careful examination, and both he and Dr. Wallich have identified them with Professor Huxley’s Coccoliths. It now appears that both Coccoliths, Cyatholiths, and Coccospheres, occur fossilised in the chalk, establishing, in a remarkable manner, the close resemblance of the conditions under which the chalk-beds were formed and those existing along the tract of the Gulf-stream at the present da3^ Dr. Carpenter goes even further than this, and regards it as highly probable that the deposit of Globigerina-mud has been * Trans. Phil. Soc., Manchester,” vol. viii. fig, 71. 356 POPULAR SCIENCE REVIEW. going on over some part or other of the North Atlantic sea-bed, from the Cretaceous epoch to the present time (as there is much reason to think that it did elsewhere in anterior geological periods), this mud being not merely a chalk formation, but a continuation of the chalk formation ; so that we may he said to he still living in the cretaceous epochJ’^ * With the earlier part of the preceding paragraph I partly agree, but from its concluding sentence I must dissent. Chalk chiefly consists of an accumulation of Grlobigerina cretacea, associated in cdmost equal proportions with a minute Textil- laria and with Coccoliths. The fossil Grlobigerina is probably but a mere variety of the recent Gr. bulloides ; hence, so far as it is concerned, ancient and modern deposits may have been con- tinuous. But in none of the modern Grlobigerina beds which I have examined have I found anything resembling the fossil Cre- taceous Textillaria, the disappearance of which requires to be accounted for. What I believe to be the same species occurs abundantly, amongst other modern types of Foraminifera, in the recent sandy deposit underlying Boston in Lincolnshire, but 1 never succeeded in discovering it living in the sea. From some unknown cause it has disappeared. On the other hand, our modern deposits abound in Diatoms and Eadiolarige, of which no trace appears in the true Cretaceous beds. That in the depth of the Atlantic Cretaceous and modern deposits may be conformably and continuously superimposed is not impossible, but con- formable continuity of series does not constitute identity of age or of formation. In the Speeton clay of the Yorkshire coast we have, in the same blue deposit, a transition from the Oolites to the Cretaceous beds. The deposits have continued to accumu- late without physical change from the one age to the other, but the fomiations to which the upper and lower portions of this clay Ijelong are distinct, and represent distinct epochs. Dr. Carpenter is disposed to conclude that the higher forms of the Atlantic and Cretaceous fauna) will prove to be nearly identical ; but I doubt this, and we must not repeat the blunder of Ehrenberg, in the case of the tertiary beds of the IMediterranean coasts, which he regarded as Cretaceous, because he found that they abounded in Cretaceous types of Foraminifera, overlooking the wide ditfer- ences presented by the higher organisations of the two forma- tions. So in tlie instance under consideration. Owing to the low vitality of the Protozoa, some of them have survived the clianges which time has wrought in the higher groups of animals. The recent Globigerinm and Bathybia are probably descendants from tliose which lived during the Cretaceous period, Imt tlieir companions are not the same. The abundant Textillaria* are replaced by Diatoms and Badiolaria). Instead of • Proceedings of the Royal Society,” vol. xvii. p. 192, WHAT IS BATHYBIUS? 357 Marsupites we have the Ehizocrinus. The Ananchytes and Galerites are represented by Cidarites and Spatangi; amongst star-fishes Tosia (Goniaster) has given place to Ophiocoma. For the chambered Cephalopods we have the modern cuttle-fishes, whilst the Saurians and Ganoid fishes of the Cretaceous age have left no descendants in these Atlantic depths, their places being taken, in all probability, by the more familiar and much more useful codfish. The zoological affinities of Bathybius are not very difficult to understand, though the young student is apt to become bewil- dered by the growing number of classifications of the Protozoa that are being offered for his acceptance, and the multitude of new terms with which, in consequence of these new classifications, our journals have become loaded. The last of these arrange- ments is that of Hackel, who has separated the Protozoa, under the name of Protista, equally from plants on the one hand and from animals on the other. He regards them as the common starting-point from which, in accordance with Darwinian ideas, both plants and animals have derived their origin. Without necessarily accepting this creation of a third organic kingdom, we may beneficially recognise Hackel’s division of the Amseban section of the Protozoa into two groups, viz., the Monera and the Protoplasta ; the former comprehending those Amaebae which exhibit an uniform granular sarcode without any trace of or differentiation into special organs, and the latter including those types in which we have such special structures in the form of contractile vesicles, nuclei, or other differentiated appendages. So far as the structure of the sarcode is concerned, Bathybius is apparently a true Moner, and such its discoverer considers it to be. At the same time, the existence in connection with it of Coccoliths and Cyatholiths indicates the necessity for separating it from Hackel’s other Monera, which have no such special- appendages. But the time has not arrived for determining the absolute relations of these objects. New types, as Hackel him- self admits, are being discovered, rendering modifications of his groups necessary. Meanwhile there can be no question that Bathybius is the lowest of those known Protozoa, which, like the Foraminifera, secrete calcareous elements. Eemembering the extent to which the sarcode is diffused through the mud of the Atlantic, there appears much that is suggestive and im- portant in the observation of Dr. Carpenter, that, had its power of secreting a calcareous framework been somewhat increased, so that instead of detached structures in the form of Coccoliths, &c., it had produced a continuous calcareous mass, it would have given us a living prototype of the Laurentian Eozoon. The discovery of this widely and continuously diffused Bathybius strongly sustains Dr. Carpenter in his conviction of the animal origin of that primseval structure. 358 ARE THERE ANY FIXED STARS? r»Y RICHARD A. PROCTOR, B.A., F.R.A.S., Author of Saturn and its System,” ^^Halfhours with the Stars,” &c. &c. [PLATE LI.] DURINGt the last few years astronomers have been attacking questions which seem, at first sight, far beyond the range of the human intellect, or of the instrumental appliances which human ingenuity can devise. A marked contrast, indeed, is to be distinguished between the inquiries which have been made within the last decade and the most valuable discoveries of all previous times. Not one of the results which had rewarded the labours of scientific men up to the middle of the present century would have seemed incredible to Francis Bacon had it been predicted to him ; nay, there is scarcely one of them which is not more or less distinctly shadowed forth in that strange and little-read work of his, the “ Sylva Sylvanum.” But even he, daring as were his conceptions and hopeful as were his views of the powers of that method of research which he incul- *cated, would probably have smiled with contempt had the idea of analysing the sun or the fixed stars been mooted in his presence. The Frenchman who lately brought before the Im- perial Academy at Paris the absurd proposition that our astro- nomers and physicists should make signals to the inhabitants of Mars and Jupiter scarcely appears a greater dreamer to us than any one would have appeared to Bacon who put forward a notion seemingly so preposterous. At first sight it may seem to many that the subject I have now chiefly to deal with — the determination, namely, by ourastro- noiners, of the motions of recess or approach which the fixed stars may possess — does not belong to the category of those researches which appear altogether hopeles.' small indeed, compared with the wave-lengths ; but this range, however small, must have a definite value at any given distance from the source, and the total amount of motion in any spherical surface round the source of light would have a definite and constant value. But to suppose a definite amount of oscillation in an in- finite number of such spheres is to suppose that an infinite effect can accrue from a finite cause. ARE THERE ANY FIXED STARS? 363 The simplest illustration we have of wave-motion is in the material waves which traverse the surface of water. Now here, be it noticed, we must not think of such waves as roll in upon the shores of the sea, but of the true waves which traverse the surface of open seas. In such waves there is not as there appears to be a rapid transmission of matter, but a simple os- cillation of the particles of the water. Suppose there are long rollers sweeping over the face of the ocean. Then we should call the distance from the crest of one roller to the crest of another the wave-length ; the difference of altitude between the crests of the rollers and the bottom of the “ trough ” between them would be the wave-height, or wave-amplitude as it is sometimes termed; and the rate at which the rollers travel would be the velocity of transmission, I mention these points, so tha.t in dealing with other waves which we are unable to recognise as visible entities, the significance of the terms we shall have to make use of may be understood by a reference to the familiar relations of the ocean-rollers. Now, suppose we wish to determine the wave-length of a roll- ing sea, what are the methods which would suggest themselves ? If we could measure a line extending from crest to crest at any moment, we should, of course, know the wave-length ; but fail- ing (as might well happen) such a means as this, it is obvious that our resource must be to determine first the velocity of the waves, and secondl}^ the number which pass in a given time. Suppose the first point gained (say by noticing the time which a particular roller occupies in travelling between two ships a mile apart), and, for convenience of illustration, let us imagine that the ascertained velocity of the rollers is 500 yards per minute. Now, suppose that an observer, counting the waves which pass the side of his ship, notices that 10 pass each minute. Then he knows at once that in that time the first which passed has travelled to a distance of 500 yards; and as all the 10 are dis- tributed over that distance, each must be 50 yards in length, if the ship has not moved in the interval. But if the ship has moved, there is a difference. For supposing the ship to have moved in the same direction as the waves, and at the rate of 100 yards per minute, then the crest of the first wave is only 400 yards off instead of 500, and the wave-length is but 40 yards. In other words, the true length is less by 10 yards than the length which would be arrived at on the supposition that the ship is at rest. On the contrary, if the ship is moving at the same rate against the waves, the true distance of the first wave-crest is 600 yards, the true wave-length 60 yards ; and the effect of the ship’s motion is to cause an apparent increase of 10 yards in the wave-lengths. 364 rorULAR SCIENCE REVIEW. And clearly, if we could only conceive such a state of things as that the ship should be really at rest and the whole mass of the rolling sea bodily transferred under the ship, we should get a similar result. If the transference were in the direction of the wave-motion (which would correspond to a motion of the ship against the direction of the waves), the result would be an under-estimate of the wave-lengths ; while in the reverse case the wave-lengths would be over-estimated. Now let us consider the case of sound-waves. These are somewhat less familiar to us (so far as our ordinary modes of perception are concerned); but, inasmuch as we can more readily make experiments on them than on light- waves (owing to the enormous velocity with which the latter travel), they will serve to give a convenient illustration of the property we are to deal with. Let fig. 2 represent a series of sound-waves generated by the vibrations of the tuning-fork A. When the right-hand prong is at a (the limit of a vibration), a is a place of aerial condensa- tion; the next such place is at b {ah being the wave-length corresponding to the vibrations of the tuning-fork), the next at c, the next at c?, and so on. The ivave-amplitude does not con- cern us, but I may mention in passing that it is measured by the amount of the aerial condensation at a, h, c, cl, &c. The tone of the sound depends on the wave-length cib, and a given tuning-fork will cause aerial waves of a particular length (that is, will give out its proper tone), if it be at rest But now suppose that the tuning-fork is being moved, and that with a velocity bearing an appreciable relation to the velocity with which sound travels. It will readily be seen that the tone now produced by the tuning-fork will be different from what may be termed its natural tone. Thus suppose that during the interval which sound would occupy in travelling from a to b, the tuning-fork has been moved so that the prong a is at a\ During the interval the prong has made one complete vibration, and a' is now therefore a region of condensation instead of a ; b is, of course, a region of condensation, just as it would have been if the fork had been at rest. Hence the wave-length has been reduced to cc'b ; and as all the waves proceeding from the neighbourhood of the vibrating fork are similarly affected, there results a series of waves, pf, fg, gh, &c., as in fig. 3. On the other hand, if the fork had been moved in the oppo- site direction, there would have resulted the series of waves kl, Ira, ran, &c., represented in fig. 4. In the former case the tone of the resulting sound would have been more acute, in the latter it would have been more jriaLe ±il. E- — s Eig 5 SydjrogeTv at AimoSt fyrtssvure So lor Spectrum, Une.F Spectrum, of Sirius Uydro^eTi in, Hdcuzvm, tahe Fi^.6. 01b sf/rved Proper Mot] ol^s of stars in Mrs a Major & nei^PPourliood 'TKe.feai}ieredy arrow inSlfxuxies Out dire.ctiort ouicL ajrioixrct of rrwticn -which, ihje. sa:n,’s esiirnatedy proper moiixon, shouZoL- give to fitocrs in ihe. above riccLghhcnxTl'ioooly out Oce estcniMteoL rneoun, uiLstxx^hce of the 2 mxxgwbtuud,e sixx.rs ARE THERE ANY FIXED STARS ? 365 grave, than the natural tone of the fork.'^ And a little con- sideration will show, that if, instead of the fork being moved, the ear were brought rapidly towards or from the vibrating fork, similar effects would follow — a rapid approach rendering the sound more acute, a rapid retreat rendering the sound more grave. It is absolutely necessary, here, that the velocity either of the fork or of the ear should bear an appreciable proportion to the velocity of sound. In other words, aa' or aa" must bear an appreciable ratio to ah. This is obvious, since what is wanted is, that ef or kl should differ appreciably from ah. Now, if we only suppose the vibrating end a of the fork to be a particle whose vibrations are generating light of a par- ticular wave-length — that is, of a particular colour^ we see that the reasoning we have applied to sound-waves must be equally true of these light- waves. If the source of light be approaching us, through its own motion, or ours, or both, the waves will seem- ingly be shortened ; and if the source of light be receding, the waves will be lengthened. In other words, there will be in either case a change of colour — the change being towards the blue end of the chromatic scale in the former case, and towards the red end in the latter. But here, as in the case of sound, the condition has to be ful- filled, that the velocity of approach or recess shall bear an appreciable proportion to the velocity with which the waves travel ; that is, to the velocity of light. Now, light travels at the rate of about 185,000 miles per second; and it seems hardly conceivable that any material movements in the universe should bear an appreciable relation to so enormous a velocity as this. We could not hope, then, that any luminous object in the universe should indicate by a change of colour a change in the direction of its motion. But this is not the only nor the principal difficulty in the application of such a mode of estimating motion. Doppler, who was, I believe^ the first to suggest that the colours of the stars may serve to indicate whether these bodies are approach- ing us or receding from us, omitted to notice a circumstance which rendered his whole argument nugatory : — In the case illustrated by figs. 2, 3, and 4, we dealt with the affections of only a single wave-length. If all stars sent us ^ light-rays having a definite wave-length, then what we have * Professor Tyndall has remarked that when a train rushes rapidly past a station a change in the tone of the whistle may he noticed by a person on the platform, the sound being more acute as the train approaches than after it has passed the station. 366 POPULAR SCIENCE REVIEW. described would happen ; and if our perception of colour were but sufficiently delicate, we could tell whether a star were moving from or towards us by the colour of its light. But this supposition implies that a star’s colour should be mono- chromatic ; and we know that the light from the stars consists of a combination of all the prismatic colours. But again, if the spectrum had definite extremities, and if no action of any sort took place beyond those extremities, then something like what Doppler conceived would take place. For then the light-waves of all lengths would be affected by a star’s motion ; so that if a star were approaching us, all the waves would be shortened, and a part of the red end of the spectrum would suffer extinction, while in the reverse case the blue end of the spectrum would be shortened. We know, however, that beyond the visible ends of the spectrum, waves too long and too short to affect the eye as light-waves are really in existence. Thus instead of the red end or the blue end suffering, in the cases imagined above, all that would happen would be that the heat-waves beyond the red end or the chemical rays be^mnd the blue end would become light- waves, replacing the red or blue end of the spectrum, as the case might be. But these considerations, while showing that nothing can be hoped for from Doppler’s suggested consideration of star-colours, show that a much more delicate and satisfactory test can be applied. We see that the whole spectrum is shifted bodily. ThereforG all its lines, whether dark or bright, must he shifted U'iih it. This is a motion we may ho'pe to estimate, because we can bring into comparison with any line in the shifted spectrum the corresponding line belonging to some terrestrial element. We have, in fact, a test of the most extreme delicacy ; and were it not that the most rapid stellar motions can produce but the minutest change in the position of the star’s spectrum, we might read off the stellar motions of recess or approach as readily as we can determine the general character of the star’s light by the same mode of analysis. But when it is remembered that the velocity of light is about 1 85,000 miles per second, we see that a star must be moving with enormous velocity that its spectrum may exhibit any appreciable change of position. Our sun is supposed to be tra- velling at the rate of about 5 miles per second, and we have reason to believe, from some researches of Mr. Stone’s, that the average motions of the stars may be about one-third greater, — say about 7 miles per second. Now, it has been estimated by ' Mr. J. Clark Maxwell that a velocity equal to that of the earth in her orbit, that is, rather more than 18 miles per second, would shift the sodium line i), through a space equal to about the tenth part of that which separates i), from Ug, these lines AEE THEBE ANY FIXED STABS? 367 forming what is commonly called the double line D of sodium. An idea, therefore, may be formed of the difficulty of estimating the stellar motions of recess or approach, unless in those excep- tional cases where the star’s real motion is much greater than the above-mentioned average. Of course, the whole question is one of the dispersive power of the spectroscope ; and inasmuch as a telescope of large aper- ture will permit us to use a higher dispersive power than we could apply to a smaller instrument, the size of our telescopes enters into this as into so many other questions of astronomical interest. To secure the greatest dispersive power possible, without inconvenience, Mr. Huggins used the form of spectroscope exhibited in fig. 7, Plate XLIII. of my paper on the spectro- scope, in the “Populab Science Eeview” for April last. The reader is referred to that paper for a description of the qualities of this arrangement. The star selected for the first application of the new method of research was Sirius, on account of its great brilliancy. It was necessary to consider some one recognised line of his spec- trum, and the line corresponding to the solar line P (the blue- green hydrogen-line) was the one selected. Fig. 5 shows the result of the experiment. The two upper spectra are not directly concerned in the method applied ; but it is well to notice the perfect coincidence in position between the sharp dark line in the solar spectrum and the middle of the diffused line obtained from hydrogen at ordinary atmospheric pressure. Any want of coincidence here would have thrown doubt on the result of the experiment. The hydrogen-line, actually compared with the dark and somewhat diffused F-line of the spectrum of Sirius, was obtained from hydrogen in the so-called vacuum-tube. Mr. Huggins made it fall side by side with the diffused dark line F in the spectrum of Sirius, and in some experiments he brought the bright line upon the Sirius-line. It will be seen from fig. 5 that the bright line fell sensibly away from the middle of the dark line. It became obvious from this that Sirius has a motion in the direction of the line of sight, and since the dark line was shifted towards the red end of the spectrum, it followed that the motion was one of recession. From a careful measurement of the discordance between the two lower spectra of fig. 5, Mr. Huggins calculated that at the epoch of the observation Sirius was moving from the earth at the rate of 41*4 miles per second. But a part of this motion was due to the earth’s motion in her orbit, and having made due reduction on account of this consideration, IMr. Huggins found that there remained a motion of recession from VOL. VIII. — NO. XXXIII. B B 368 fOPULAH SCIENCE EEVIE^. the sun of 29*4 miles per second. Lastly, he considered the effect to be ascribed to the sun’s motion, which is directed to- wards a point almost exactly opposite Sirius. If Otto Struve’s estimate of the solar velocity is correct, then the motion of Sirius in the galaxy is reduced to somewhat less than 25 miles per second ! Interesting as this result is, the fact that the power of the new mode of research has been established is yet more so ; for there is nothing to prevent the method from being applied in turn to all the lucid stars ; nay even, with suitable instrumental power, to the telescopic orbs. The results obtained from such re- searches cannot fail to be of the utmost value. I take myself a special interest in the new method of re- search, because I hope to find its results confirmatory and elucidatory of certain peculiarities in the stellar motions which I have recently been led to notice. On mapping the proper motions of about 1500 stars in the manner indicated in fig. 6, I have found in many parts of the heavens distinct traces of star- drift ; that is, of the systematic motion of groups and sets of stars in particular directions. A singular instance of this is found among the bright stars of Ursa Major, five of which are moving (as shown within the oval, 5, in fig. 6) in the same direction, and with the same velocity. Two other stars near ^ are also moving in the same manner. One cannot doubt that these stars are associated in some way, and so form a system ; especially when it is noticed that the stars are moving in a direction almost directly opposed to that due to the sun’s motion in space. Scarcely less remarkable is the community of motion observed within the oval a. And it will be noticed that among the remaining stars of the map there is a com- munity of motion either inter se, or with the stars included within the ovals. It will be a matter of extreme interest to determine by Mr. Huggins’s method whether the stars which thus seem to form drifting systems have a community of motion of recess or of approach. Should this be the case, no doubt could possibly remain that the stars form sets or groups, and that there is no approach to that generally equable distribution described in our popular treatises of astronomy. 369 KENT’S HOLE. By W. BOYD DAWKINS, M.A., FJl.S. The systematic exploration of Kent’s Hole, under the auspices of the British Association, has been carried on since the year 1865, and is likely to prove a 'piece de resistance for a very long time to come. Up to the present time it has yielded upwards of fifty thousand bones, and a large number of other objects of interest ; it has also afforded evidence of extremely high value as to the enormous antiquity of the human race. It has, how- ever, fared badly in the sporadic fashion in which it has been laid before the public, the only authentic accounts being the reports of progress furnished by the Kent’s Hole Committee, from which it is almost impossible to gather an adequate idea of the cave and its wonderful contents. It would indeed almost seem as if the exploration were attended by a fatality that forbids the public from acquiring any exact knowledge until a great deal of the interest is lost, for the admirable investigations of Mr. McEnery, begun in 1824, were not published until 1859, and even then in a very disconnected fashion. To supply this need as far as may be, by adding the information in the Eeports to that contained in the notes above alluded to, and thus to con- struct a connected story, is the object of the following outlines. Kent’s Hole has been known from time immemorial, but until the year 1824 it was not rifled of any of its treasures, when it was visited by Mr. Northmore for the purpose of ascer- taining whether it were or were not a Mithratic cavern ; for the Druidical priesthood, like their Egyptian, Chaldean, and Brah- minical brethren, worshipped, in such cavernous recesses, whether artificial or natural, the Solar Grod.”"^ He expressly states also that he wished to discover organic remains, for the excitement consequent on Dr. Buckland’s discoveries in Kirkdale and other * Cavern Besearclies,” by tlie Bcv. J. HcEiicry, Edited by E. Vivian, 1859. B B 2 3/0 fOrULiR SClE^^CE RETIEW. caves was then at its height, and the Eeliquiae Diluvianse was known better in this country than the great work of the im- mortal Cuvier. Fortunately his enthusiasm was rewarded by tbe attainment of both objects ; for, besides the discovery of “ the baptismal lake of pellucid water, the creeping path of stone, the mystic gate of obstacle, the oven mouth, which satisfied him that the cave had been the Temple of Belus, he broke til rough the stalagmite covering of the floor, and found remains of the hyo3na, fox, and other animals ; to him, therefore, Mr. Pengelly rightly assigns the credit of the first discovery of the fossil mammalia. From this time there was no printed record of the explorations, that were conducted by many people, that is of any importance, until the year 1840, when Mr. Godwin Austen published his opinion that hyaenas had dwelt in the cave, and that flint implements occur in Kent’s Cave under pre- cisely the same conditions as the bones of all the other animals.” The value, he goes on to say, of such a statement must rest on the care with which a collector may have explored ; I must therefore state that my own researches were constantly con- ducted in parts of the cave which had never been disturbed, and in every instance the bones were procured from beneath a thick covering of stalagmite ; so far, then, the bones and works of man must have been introduced into the cave before the floor- ing of the stalagmite had been formed.”* In 1 847, and again in 18d6, ]\Ir. Vivian corroborated the truth of Mr. Austen’s obser- vations. Three years afterwards he published JNIr. McEnery’s manuscript, written in 1834, and which doubtless furnished the clue to all the investigators from the time it was written. Had Mr. IMcEnery’s intention - of publishing a memoir of Kent’s Hole been carried out immediately after its exploration, we should certainly not have been obliged to wait until the year 1857 for the discoveries of i\I. Boucher de Perthes in the valley of the Somme to prove the high antiquity of man, and archaeology as a science would have ranked as high as palaeontology. Such is tlie brief epitome of the literature of the cave. Mr. McEnery’s famous collection was, at his death, scattered almost literally to the four winds, but the lion’s share found its way to the British INIuseum, wl)ere, together with his unpublished plates, drawn by the most eminent artist of that day, Mr. Scharf, they form the basis of IVofessor Owen’s list of animals published in 1846. f We will now pass on to the consideration of the contents of the cave, beginning with the most modern, and thus reversing the usual geological order. The cave itself consists of two • “ Literature of Kent's Cavern, Torquay,” by W, Pengelly, F.ll.S. l)evon.««liire Association, 1868. t JJritish Posail Mainniah,” 8vc. 1846. Kent’s hole. 371 parallel series of cliambers and galleries, an eastern and a western, which penetrate the Devonian limestone in the line of the joints. It has a northern and a southern entrance, which occupy very nearly the same level on the low cliff on the eastern side of the hill; the latter are about fifty feet apart, from a hundred and eighty to a hundred and ninety feet above the level of mean tide, and about seventy feet above the bottom of the valley immediately adjacent.”* The largest chamber of the eastern series is sixty-two feet from east to west, and fifty-three from north to south. The contents of the cave may be divided into three great divisions : the pre-historic, which is represented by a layer above the stalagmite, but which in some places is covered with a thin stalagmitic crust ; that which lies under- neath the solid and continuous stalagmite ; and lastly, that which belongs to an epoch when an older stalagmitic crust was formed, which has been for the most part destroyed, but which is still represented by enormous detached blocks. In the first of these Mr. McEnery found fragments of pottery, calcined bones, charcoal and ashes, and arrow-heads of flint and chert. The pottery is of the rudest description, made of coarse gritty earth, not turned on a lathe, ornamented by zigzag indentations similar to those found on the urns in the barrows of Wiltshire and in the cave of Kuhlock ; along with them were round slabs of roofing slate of a plate-like form, some crushed, others entire, which probably served for the covers of the cinerary urns, indi- cated by the fragments of pottery. Near the entrance he found articles of bone of three sorts, some of an inch long and pointed at one end, or arrowheads ; others about three inches long, rounded, slender, and likewise pointed.” They may have been either bodkins, or pins for fastening the garments of a savage race. The shaggy wolfish skin he wore Pinned by a polished bone before. The third article does not seem quite so easy to explain ; it is of a different shape, quite flat, broad at one end, pointed at the other the former retaining the truncated form of a comb which has lost its teeth. ‘^Nearer the mouth were collected a good number of shells of the mussel, limpet, and oyster, with a palate of the scams” (now in the Oxford Museum). In the same passage there was a stone hatchet or celt of syenite. As we advanced towards the second mouth on the same level were found, though sparingly, pieces of pottery and round pieces of blue slate, about an inch and a half in diameter, and about a quarter thick.” There were also several round pieces of sandstone grit, about the form and size of a dollar, but thicker * “ Report of the British Association,” 18G7, p. 24. 372 rorOLAR SCIENCE REYIEW. and rounded at the edge, and in the centre pierced «with a hole, by means of which they seem to have been strung to- gether like beads. Clusters of small pipes or icicles of spar, such as depended from the roof at our first visit, we saw collected here in heaps buried in the mud. Similar collections we had occasion to observe, accompanied by charcoal, throughout the entire range of the cavern, sometimes in pits excavated in the stalagmite. Copper ore ‘^w^as picked up in the same deposit — a lump much oxydised, which the late Mr. Phillips analysed, ^vas found to be virgin ore.”^ By the term virgin ore it is very possible that native copper may be implied, which occurs not only in Cornwall, but also in Ireland and Scotland. It is worthy of remark that native copper has been worked by the Indians on the shores of Lake Superior from time immemorial, and that a few copper imple- ments have been found both in Ireland and Scandinavia. There was also evidence of the cave having been penetrated l)y iron-using folk ; in an interesting little grotto formed by the bending over a flag of stalagmite into an arch elevated only two or three feet above the level of the floor. Its mouth was closed with blackish mould, in digging which in quest of pottery we broke into a circular cell ” of small dimensions, with its “ floor covered by stalagmite, in the surface of which were in- serted large shells with the cup uppermost, as if placed to collect the droppings. The entire skeleton of an animal resembling a badger, and portions of the upper jaw of a hog, with one of its tusks indicating great magnitude, were scattered over the earth, and in the midst of all a barbed spear of iron. These relics were severally invested with a crust of stalagmite like the speci- mens from the Grerman and English dropping-wells, and reposed with their under surface inlaid in the floor. Many of the bones, when stripped of their spar, were found discoloured, as if by smoke; pieces of charcoal indicated the remains of a fire.” i\Ir. McEnery did not find any implements of bronze, but his omission has been supplied by the explorations of the Kent’s Hole Committee in 1865, in which a bronze ‘^fibula, the bowl and part of tlie stem of a spoon, a spear liead, a fragment of a socketed celt, two or three rings, one coil of a helical spring, a pill ” nearly four inches long, and an object “ resembling a horse- shoe in form, but not more than an inch long,” were also found. There is therefore evidence that the black superficial layer be- longs, not merely to the neolithic, Imt also to the bronze and tlie iron ages, and from the occurrence of Koman pottery it may in part be referred to a time not more remote than the Koman occupation. This association of objects belonging to widely • McIOncry, ^^Cavc liesearclies,” pp. 14. 15, 10, Kent’s hole. 373 different periods is just what we might expect when we consider that caves have been used for places of habitation from the remotest times to the present day. But Kent’s Hole had also been used as a place of sepulture, for Mr. McEnery discovered a skeleton lying at full length in it, as well as fragments of burnt human bones, which probably indicated the habit of cremation. In one spot the traces of occupation overlay a burial-place. Fragments of pottery, both plain and ornamented, writes Mr. McEnery, lay strewed about in abundance, in a black layer, containing quantities of marine and land shells, such as patella, limpet, ostrea, turbo, pinna, helix, solen, &c., as well as bones of stag, fox, rabbit, and small ro- dents. Among the animal remains were some curiously fashioned by art, being sharpened at one end for piercing. “ A large rock now lay between us and the next stratum. On lifting it over a still more startling discovery was displayed : — pottery, charcoal, human teeth and bones, flint relics, copper ornaments and mountings of tin ; two lumps of virgin copper ore were pressed together into a cake, on a large flat stone, against which they had been violently crushed by the superposition of the rock which we had just removed. We collected on this spot the remains of two sepulchral' vessels ; one was a plain urn slightly indented, coarse and sunbaked, with its walls about half-an-inch thick ; it most probably contained the ashes which were spilt about, and which enveloped two black spear heads. The other frag- ments were thinner and highly ornamented, answering in every respect to those small figured vases found in the barrows, and designated by Sir Eichard Hoar drinking-cups. The pieces of both vessels were scattered at a short distance from each other on the flag, and were evidently connected with the human bones, flint relics, and other substances just described as grouped to- gether ; the whole forming a distinct interment.” So far as I know this is the only case on record of the occurrence of tin in an interment of this kind. It is a most unfortunate thing that the prehistoric remains found by this indefatigable explorer, have been so scattered that it is almost impossible to trace them, or to find with absolute certainty any exact specimen which he describes. In the Oxford Museum there are bones from this black layer, which prove that the prehistoric folk who lived in the cave, or who used it for purposes of sepulture, fed upon the small Celtic short-horned ox, the Bos longifrons, an animal which cannot boast of higher antiquity than the modern alluvia and peat bogs, and which was most probably introduced into Europe during the neolithic age. In the Swiss phalbauten of the later period, it is found along with the horse, dog, and goat. It probabl}^ accompanied a nomad race from some area to the east and south from Central Asia. 374 POPULAR SCIENCE REVIEW. It occurs universally throughout Fi-ance, Grermany, Britain, and Italy, and may be taken as the characteristic animal of the pre- historic epoch. In Gaul and Britain it supplied the Koman les:ionaries with beef. In addition to many objects similar in their nature to those which have been described, amber beads, spindle whorls, a frag- ment of polished flint celt, and a portion of a cake of smelted copper, have been discovered by the Kent’s Hole Committee in the prehistoric layer. We now pass on to a brief account of the underlying deposit, which furnished to Mr. McEnery and to all subsequent explorers so rich a harvest. Immediately under the black superficial bed is a layer of stalagmite of varying thickness, which forms an adamantine pavement over the earth, large blocks of stone, and the remains of the postglacial animals. In one part, above a spot w'hence Mr. McEnery obtained flint implements, it was 2 ft. thick; in another it was no less than 12ft. The red earth is that which is usually found in caverns, and has been carried in by the percolation of water through the rock. The large angular IdIocIvS which it contains consist of Devonian limestone detached from the roof, and of an ancient crystalline stalagmite, to which we shall revert towards the conclusion of this essay. The small rounded pebbles of granite and other foreign materials have been washed in by the flow of -water from some bed of gravel in the neighbourhood. The remains of the animals are, more or less, gnawed and scored by teeth like those found in Wookey and Kirkdale. They prove that the cave was inhabited by hyamas, and that the animals to which they belonged fell a prey to those destructive carnivores. The remains in the cave belong to the following species : — Bhinoloplius femim oqiiiniim Sorex vulgaiis Ursus arctos Tarsus speliieus Ursus ferox Meles taxus Mustcla erminoa JjUtra vuljraris (!/’anis vulpus Cnnis lupus 1 1 vicna spoljca I’Vlis leo M ach ai rod us 1 a ti d ( t.s (’ervus nie^'’acoro8 Cervus tarandus Ccrvus elaplius Bos primig-enius Bison priscus Siis scrofa Equus caballus Bliinoceros ticliorli’nus Ehqdins priniigeiiius Lepus cuniculus Lop us tiniidus Lagomys spcl?Gus Arvicola pratensis Arvicola ngrcstis Arvicola anipliibidus Castor fiber 31 us musculus To this list must be added Homo j^cdcvolithicus, as he inny Kent’s hole. 375 be called, for his implements of chert and flint have been found wherever the stalagmite has been broken through, in intimate association with the bones and teeth of the other animals. To pass over the implements found by Mr. McEnery, Mr. Grodwin Austen, and others, those discovered by the Kent’s Hole Com- mittee, up to the year 1867, amount to over 700. They are divisible into three classes — mere flakes, lanceolate imple- ments pointed at one end and truncated at the other, and oval implements, convex on both sides and worked to an edge all round the margin.” * The largest specimen of the first class is nearly five inches long ; they all belong to the types found in such abundance by Messrs. Lartet and Christy, in the Keindeer caves of the Dordogne. Near the entrance, indeed, a black layer occurred, underneath the stalagmite, that was perfectly crammed with ashes and the relics of feasts, which furnished no less than 366 implements. A bone piercer also, and a harpoon, were found associated with the remains of rhinoceros, hyaena, and the other cave mammals. Three other bone implements have also been met with — a portion of a highly-finished harpoon, with barbs on either side of the axis, a bone pin, and a bone needle. In fine, the human implements in Kent’s Hole, whether they be chert, flint, or bone, so strongly resemble those found in the Keindeer caves of the Dordogne, both in form and workmanship, that there can be little doubt of their having belonged to savage tribes of precisely the same habits, who lived on the chase, and eked out their miserable lives by fishing. One of the most remarkable facts, brought to light by Mr. McEnery, is the former presence of the sabre-toothed tiger in the cave. Its characteristic canines were found associated with thousands of the teeth of the horse and the hysena, in a spot fat with the sinews and marrow of more wild beasts than would have peopled all the menageries in the world.” Kent’s Hole is the only place where this fell carnivore is found along with the remains of the mammoth, reindeer, and other characteristic postglacial mammals. It belongs to an archaic type which sprang into existence during the Miocene times in France, Germany, and Switzerland, that preyed upon the Hipparion and Antelope on the plains of Marathon and on the Indian flanks of the Himalayahs — to a type that coexisted with Elephas ineri- dionalis and Mastodon, during the Pliocene times in France, Germany, Britain, and Italy, and in South America preyed on the gigantic Sloths and peculiar Horses of the Brazilian caves. We have already mentioned the large masses of stalagmite which occur in the cave earth ; they prove indisputably that there was a stalagmite floor in the cave before the introduction Keport, 18G6, p. 8. 37G rorULAR SCIENCE REVIEW. of the earth, and long before the formation of the present sta- lagmite pavement. They are remarkable for their hard crys- talline structure, and in one or two cases they have yielded fragments of very dense mineralised bone. In a portion of the cave, called the gallery, there is evidence of the undisturbed portion of the crust, in “ a ceiling” or uppermost floor, that extended from wall to wall, ‘^without further support than that furnished by its own inherent cohesion. Above it there is in the limestone rock a considerable alcove. This branch of the cavern, therefore, is divided into three stories or flats— that below the floor occupied with cave earth, that between the floor and ceiling entirely unoccupied, and that above the ceiling also without deposit of any kind.” From its being stained with cave earth, as well as from its position, the ceiling at the time of its deposition must have been supported by a layer of cave earth, and therefore the inference becomes necessary that, while it was being formed, the cave must have been fllled up to its level. It would, indeed, be as impossible for a solid calcareous sheet to be formed in mid air as it would be for a sheet of ice to be formed without resting on the water. From some cause or other this ancient stalagmite has been in part broken up, and the materials by which it has been supported have disappeared. That, however, even prior to its formation, animals dwelt in the cave, is proved by the bones which are imbedded in the large fallen masses. Moreover, there is reason to believe that certain fragments of bone and splinters of teeth, remarkable for their mineralisation, that have been found in the earth now occupying the cavern, were derived from this more ancient deposit ; for they differ essentially from the remains with which they are now associated, being heavier and of a more crystalline struc- ture. Some splinters have assumed the fracture of green-sand chert. So hard, indeed, was one of the canines of bear, that it has been splintered by the hand of man into the form of a flint- flake, and has evidently been used for a cutting purpose. Its fracture proves that it was mineralised before it was splintered; and as it was found in the present cave earth, it must have been fashioned while the cave was being inhabited by palaeolithic man, prior to the accumulation of the earth. For these reasons the evidence in favour of these denser remains having belonged to the deposit wliich once supported the ancient floor seems to me incontrovertible. This view opens up an entirely new field fnr investigation as to the discovery of the sabre-toothed tiger, for it is very possible that this pliocene mammal may really belong to the older cave earth, and not to the more modern, in wliich the remains of the jiostglacial mammoth, woolly rhino- “ Tlritibh Association Reports,” 1800, pp. 45. Kent’s hole. 377 ceros, and the like, occur. But whether it be true or not, it adds a tenfold interest to the exploration of the cave, because there may be still left, in some nook or corner, masses of the older breccia, containing forms of life that had passed away before the post-glacial invaders from the north had arrived in western Europe. From this brief sketch it will be seen that the contents of Kent’s Hole are divisible into three distinct groups, each of which is separated from the others by a blank of indefinite length, not to be summed up in years. At the top there is the prehistoric series, below that the postglacial cave earth series ; and, lastly, imbedded in the latter, are ossiferous masses of sta- lagmite which belong to a much more ancient order of things, and which chanced to have been left by those causes by which the ancient cave earth was removed. Whatever those causes were — and they must have been aqueous — they did not affect Kent’s Hole alone, but also the neighbouring cavern of Brix- ham, and in precisely the same way. 378 rorULAR SCIENCE REVIEW. THE LINGERINa ADMIRERS OF PHRENOLOGY. By Professor CLELAND. [PLATE LIE] TO slay those that are already" slain may be excellent sport to employ the courage of a Falstaff, but the reader perusing the title of tliis article may perhaps be disposed to ask why the pages of this review should be occupied with the discussion of so dead a doctrine as Phrenology. The answer is, that although phrenology never had much countenance from scientific men, and has long since been banished by them, with one consent, to the limbo of exploded chimeras, yet among educated men and women not physiologists, and not pretending to know anything .about anatomy, it still holds its ground wonderfully, and counts considerable numbers of people who believe in its miraculous skull maps ; while, beside these, there is a far more numerous class of persons, including, imdeniabl}?-, a certain proportion of scientific men, who, admitting that the minute division of the cranial vault into organs is untenable, yet profess belief in a larger mapping, and have no hesitation in relegating the reason- ing faculties exclusively to the forehead, and the moral senti- ments and volitionary powers to other parts of the brain-pan. This state of matter does not exist without a sufficient reason to account for it. Long before the time of Gall and Spurzheim, men were in the habit, sometimes consciousl}^, and much more frequently half unconsciousl}^ of gauging the intelligence and moral qualities of their neighbours by their personal appearance generally, and more particularly of estimating them according to crude impressions derived from the shapes of their heads. Tliey judged rightly enough that there was some connection })ctween brain and mind. Much of the evidence that the brain is the organ of the mind is so palpable that it could not remain long hid. The effects of injuries and diseases of the brain in disturbing tlie intelligence, its larger size in the higher than in the lower classes of animals, and more especially its distinctively great development in man : these circumstances, together with the indubitable frcf|uency of finely proportioned lieads among THE LINGERINa ADMIRERS OF PHRENOLOGY. 3)9 persons of distinguished talent, and the tendency of the eye to dwell on clumsy or forbidding proportions, when occurring in persons brought under notice as stupid or depraved, all seemed, though vaguely, to point out that a scrutiny of the amount of the brain and shape of the cranium was likely to afford an index of the strength and qualities of the mind. Gall propounded his theory that different portions of the brain were the organs of different mental faculties, and that according to the size of those different parts of the brain, so the mental qualities varied ; and making continual observations on the heads and characters of those with whom he came in contact, he covered the surface of the cranial vault with a map, which at once professed to indicate the correct analysis of the mental faculties, and to assign to each of these its proper habitation. The psychological difl&culties of their pursuit do not seem to have weighed heavily on either Gall or his followers ; and as for the exceedingly great obstacles in the way of estimating the proportions of even large masses of the brain by observation of the surface of the skull, not only did the phrenologists strangely ignore them, but we are con- strained to say that even anatomists have been very slow to appreciate them. Phrenology, however, supplied a want which the public felt, seeming to furnish an answer to questions which were continually obtruded before them, and giving precision to the notions founded on fact which had previously possessed their minds: this, we believe, is the principal reason why phrenology became so popular as it did, and v/hy it is not yet eradicated from the public mind. Probably scientific men, in dealing with phrenology, have been too much in the habit of contenting themselves with merely pointing out that the system is certainly a blunder ; and their hearers have gone away impressed with the conviction that it is impossible for the uninitiated to argue with experts, yet saying in their hearts that they are sure there is a mistake somewhere, and unwilling to part with all their beautiful theories and get nothing in exchange. Iconoclasm is not popular : when an image is thrown down it is well that its destruction should make way for a flood of light sufficient to satisfy the eye in its stead. This is an achievement not easy to accomplish, but, actuated with the laudable motive of attempting it, the writer will try, not only to reiterate the reasons why phrenology cannot possibly be true, but to give some idea of what is positively known re- garding the brain and its functions, and to point out in what direction speculation may be still legitimately indulged. Let us begin at the beginning, and try and form some general notion of what the brain is as it is known to the anatomist, before we dogmatise about the functions of the parts which happen to come in contact with the upper and lateral walls of the skull. 380 POPULAR SCIENCE REVIEW. If a chick be examined in a hen’s egg which has been allowed to hatch for twelve hours, or if the embryo of any vertebrate animal be examined at a similarly early period, it will be seen to exhibit a long open furrow, the walls of which are the first portions of the animal to be formed. The most superficial layer of sub- stance entering into the construction of this furrow may be described as a long ribbon, consisting of two symmetrical parts separated by a longitudinal groove : this is the embryo brain and spinal cord, constituting one continuous structure, the cerebro- spinal axis. The parts which support the ribbon form in like manner the cranium and the spinal canal, primarily undistin- guishable one from the other. The edges of the furrow rise up and become united, so that the open furrow is converted into a closed cylinder ; and similarly the ribbon within it has its lateral edges brought together, so that the brain and spinal cord, at an early period of their development, form one continuous tube. The walls of the tube so formed become ultimately much thickened and exhibit two kinds of texture, which, from their colour, are distinguished as the grey and the white. In the case of so much of the tube as lies in the spinal canal and is afterwards termed spinal cord, the development proceeds very regularly; white matter is deposited on the outer wall of the cylinder, and gre}^ matter on the inner wall, until it appears solid. A minute canal, however, the central canal of the spinal cord, con- tinues to traverse its whole extent throughout life, and is the re- mains of the original hollow of the tube. Towards the lower part of the cord in birds there is even a space called the sinus rhom- boidalis, where the cylinder is never completed, and the central canal is open on the dorsal aspect. Now, however different the brain may be in the adult condition from the spinal cord, it is extremely interesting to note that it is the anterior portion of the same cylinder, but that the cylinder undergoes some bend- ings, its walls are greatly thickened in some places and imperfect in others, and the continuation of the central canal is in some places greatly dilated, and in others contracted. As respects texture, there is much in common between the brain and spinal cord. They are similar in appearance, and both consist of true nerve tissues, with a fine reticulum of sup- ])orting substance in which those more important elements are imbedded. The proper nerve tissues are two in number, nerve fibres and nerve corpuscles : the nerve fibres are long threads which have the property of transmitting along their course a certain change of condition which constitutes nervous influence, and which, it may l)e mentioned, is a purely physical action, not electrical, hut involving in its operation electrical changes. Nerve fibres transmit this iiifluerjce, hut have no power of originating, directing, or modifying it : they are simply con- THE LINOERINa ADMIRERS OF PHRENOLOGY. 381 ductors, and such nerve fibres are the essential elements in all the nerves throughout the body. Nerve corpuscles are bodies of which it is only necessary to say that they present a variable number of poles or branches, and there is no reasonable doubt that those poles are in direct continuity with nerve fibres. According to circumstances little understood, these corpuscles have the property of modifying impressions of nervous influence, and of directing them into different channels with which their poles communicate. Now the white substance of the brain and spinal cord contains only nerve fibres without any nerve cor- puscles, these latter being found exclusively in the grey sub- stance. It is quite plain, therefore, and universally recognised, that the white substance is only useful as containing channels of communication between different parts of the grey, and also between grey substance and the muscles and sensitive parts throughout the body. But even grey substance is not always or even generally capable of being affected directly by the consciousness; and in the case of the spinal cord, it is very certain that consciousness resides in no part of it, either white or grey. The spinal cord is the centre with which are connected the nerves of the muscles and integuments of the greater part of the body, and in the ordinary actions of the body what usually happens is this, that impressions made by the contact of external objects on the terminations of sensory nerves in the integument are transmitted by them to the nerve corpuscles of the cord, and, through series of these, conducted to the parts of the brain which are in immediate connection with consciousness ; while also, when the mind wills certain movements of the body, the stimulus proceeds from those parts of the brain, and, by some altogether unknown mechanism, is ultimately so distributed that there extend from the grey matter of the cord impressions along the nerves so adjusted as to produce precisely that amount of contraction of muscles, of whose existence the mind is utterly ignorant, which is necessary to effect the required result. But it is always the same kind of stimulus, the nervous influence, wherever it issues from, which acts upon the cord. Thus, for example, when the cord near its upper part is severed from the brain by an injury, there is loss of all sensation and voluntary motion in the parts supplied by it below the place of lesion, the consciousness being no longer in communication with those parts ; but irritation of the integument still sends a current as before to the spinal cord, and this being distributed by the cor- puscles of the grey matter, and descending again by the motor nerves, causes involuntary contraction of muscles. This is pro- bably the simplest possible example of the phenomenon termed by physiologists reiSex nervous action. We have ventured on this extremely cursory and general 382 POPULAR SCIENCE REVIEW. survey of the spinal cord, the simplest portion of the cerebro- spinal axis, in order that the general reader may form some conception of the kind of mechanism which extends through the more obscure and intricate portion, the brain. To explain fully the extremely complex structure of the brain would require much greater detail than is allowable in an article like this, but a general idea of the most important facts will best be arrived at by pursuing the account of its early development, which we have already begun. The cylinder which we have traced in the embryo, so far as the spinal cord is concerned, is, immediately on its closure, expanded in its cranial part into a series of three primordial vesicles, and immediately afterwards two little hollow buds, called the hemisphere vesicles, project laterally from the fore- most of the series. Without tracing the history of the primordial vesicles, it is sufficient for our present purpose to point out that the cerebellum is originally a part of the hindermost, projecting upwards as a hollow pouch, and that it is quite certain, from experiments on the lower animals, that no consciousness what- ever resides in any of the parts developed from that vesicle ; also it is equally certain that not more than the very feeblest consciousness resides in those parts into which the walls of the two other primordial vesicles are developed. These parts are devoted to the carrying on of obscure functions connected with the sensibility and movements of the body strictly com- parable with the functions of the spinal cord, and entirely of a j)hysical description ; the organs of the mental faculties are the developed hemisphere vesicles, and these only. The hemisphere vesicles rapidly enlarge and extend backwards over and around the other parts of the brain, so as to reach to the cerebellum behind, come in contact with the whole roof and sides of the skull and a hirge part of its floor, and press one against the other in the middle line of the whole length of the skull for an average depth of a couple of inches; and early in embryonic life they are already much the most bulky parts of the brain. 'I'he grey matter which lines the whole length of the cerebro- spinal cylinder fails to be developed in the hemisphere vesicles, except at one part placed at the neck of the vesicle, and called by anatomists the corpus striatum, but of which we know nothing in respect of function, and can only note that it is traversed by the whole mass of fibres joining the hemisphere vesicles with the cord and cerebellum. The whole of the rest of the hemi- sfdiere vesicle, or, as it is termed, the cerebral hemisphere, consists of an enormous mass of white matter, with a superadded layer of grey matter on the outside. The cerebellum has the same peculiarity of having its grey matter on the surface, and it is curious to note that both the grey matter on the cerebellum THE LIN^ERINa ADMIRERS OF PHRENOLOGY. 383 and that on the cerebrum, while differing one from the other in minute structure, differ still more from the grey matter which is foimd elsewhere, and the function of which is, as we have seen, in a general way, well understood. Also the cerebellum and cerebral hemispheres resemble each other in being thrown into numerous elevations and depressions, in order to expose a larger extent to the vascular membrane on their surface, which sends its minute branches into them. These circumstances might plead a little for the doctrine that the cerebellum is conuected with a psychical faculty, whatever that might be, but its totally different source of origin is clearly opposed to such a notion ; and we are not left merely to speculate on the subject, for both disease in the human subject and experiment on animals teach us that when the cerebellum is destroyed, the power of combining movements so as to regulate and guide them is lost, the limbs being still capable of being moved, but walking and handling being impossible. Thus it is certain that the function of the cerebellum is totally different from what the phrenologists hold it to be. Examining the cerebral hemispheres in different animals, and proceeding from the lower to the higher forms, a progress in development is found, similar to the progress made in em- bryonic life. Thus in fishes they are represented by very small parts in the fore part of the brain; in birds they have not extended sufficiently backwards to be in contact with the cere- bellum, and their bulk is due almost entirely to the corpora striata ; in rodent animals their surface is smooth ; and, as one passes to the higher groups of mammals, more and more com- plicated convolutions of the surface are met with ; while in man by far the greatest complexity is found. Whatever the particular cerebral changes may be which accompany and are necessary for thought, there can be no question that they occur in the grey matter, and that the white matter is only useful by bringing the different parts of the grey matter into communication one with another, an end which it accomplishes very thoroughly by its complicated commissures and countless bundles of fibres taking all directions. Judging, then, from comparative anatomy, and even on phrenological principles, one would expect that, among men, the greater the amount of grey matter of a given quality, the more effec- tive would the hemisphere be for the exercise of the mental faculties ; and this, there is good reason to consider, is to some extent actually the case. But the quantity of grey matter varies according to other circumstances besides the size of the skull. The vertical depth at any one spot, from the surface of the grey matter down to the white, differs in different brains ; and what is probably more important is, that the complication of the yoT , VIII. — NO. XXXIII. c c 3.84 POPULAR SCIENCE REVIEW. convolutions varies greatly. Complex convolutions are probably more important than the thickness of the sheet of grey matter, because it is obvious that not only quantity but activity of texture will be an advantage ; and complexity of convolutions involves increased surface of vascular membrane, sending its blood-vessels into the grey matter, and furnishing its elements with the means of activity. In harmony with this supposition, the simplest condition of the convolutions has been found in the brains of the lowest races of humanity, and Wagner’s comparisons of the brains of various persons of ability with others from persons of supposed limited intelligence show more complicated convolutions in the former than the latter, although at the same time exhibiting apparent exceptions to that rule. It may be noticed in this connection, that if two skulls of the same cranial capacity be one long and narrow and the other short and broad, the long and narrow one is that which has the greatest amount of surface, and is therefore most favourable for a large propor- tion of grey matter ; so that, ceteris paribus, the long skull has probably an advantage over the broad skull ; while, on the other hand, there is no doubt that, with a given model of skull to start from, the tendency of expanding hemispheres is rather to increase the breadth than the length. Turning now to the fundamental doctrine of phrenology, that different parts of the cerebral hemisphere are the organs of different mental faculties, we feel assured that no physiologist will hesitate in giving it a distinct and emphatic denial. It is true that the convolutions of the hemispheres are so constant that they are named ; but the existence of the convolutions is not for the sake of dividing the hemispheres into parts, and does not do so, but only affords, as has been said, facility for vascular supply ; and, at all events, the convolutions have not the smallest correspondence with the phrenological organs which cross them, cut them up, and combine them in the most regard- less fashion. But the fatal objection to the doctrine of different functions in different parts is to be found in the teachings of experiment and pathology. An animal will bear to have its cerebral hemi- spheres gradually sliced away; and the slicing may be done in any direction witli the same result, namely, gradually increas- ing stupidity, but witli no change of character according as one or other phrenological organ is removed. 80 .also, persons have often recovered from wmunds from whicli portions of the brain liave protruded and been ampu- taterown. All these features are of importance in deter- mining the species to wliich an agaric belongs. The mishaps wliich accompany the eating of fungi, when they occur, may be tnveed to a negligence in regarding these particulars, especially the presence of the ring and the colour of the gills. Tlie wliole substance of tlie mushroom is cellular. If, as 5:he anatomy of a musheoom. 393 chemists tell us, more than ninety per cent, of a mushroom is water, the walls of the cells must be delicate and communicate freely. We know that fungoid growth is proverbially rapid. To obtain a tolerably accurate idea of the structure of the tissue of an agaric, it is advisable to slice off with a razor a thin longi- tudinal section from the centre of the stem. Such a slice will exhibit delicate tubular cells, the general direction of which is lengthwise, with lateral branches, the whole interlacing so inti- mately that it is difficult to trace any individual thread very far in its course (fig. 8). Another slice, taken in a similar manner transversely across the stem, will exhibit a much more porous character from the cut ends of the tubes being presented to the eye, mixed with branches or lateral cells. It will be evident that the structure is less compact as it approaches the centre of the stem, which in many species is hollow. Another section, taken in either direction from the pileus, shows that although the same type of structure prevails the cell walls are even more delicate, and it is more difficult to trace the course of the cells. There is a less distinct longitudinal direction, less pronounced fibrous character, and greater uniformity in density. Finally, a section across the gills (as at fig. 13) will show with a lens their relation to the pileus, but if a slice be taken from the cut face of one of the gills, a delicate, but by no means impossible operation, the central portion will be seen to be precisely the same kind of structure as the pileus, and indeed to be an extension of the pileus in plates, with the special cells of the hymenium growing from them on each surface (fig. 14). It may be observed here, that in order to the successful manipula- tion of fungi of this class, so as to obtain thin and satisfactory sections, it is essential that the agaric should be freshly gathered and cut while still firm, and before it has parted with any of its water. This caution is especially necessary if the weather is mild and dry. A glance at the surface of the gills of almost any agaric will furnish the reason why they are nearly the same distance apart near the stem and near the circumference. Of course, if there were only one series of plates radiating from the stem, they would increase the distance between each other in proportion to their distance from the stem. This is obviated by a second, and a third, and even a fourth series, each shorter than the other, extending from the margin of the pileus inwards between the longer gills, so that the distance between gill and gill is nearly uniform over the whole of the under surface of the pileus. The arrangement is similar to the diagram given in the plate (fig. 4). The hymenium is the spore-bearing surface. In puff-balls the hymenium is enclosed within the peridium, or external en- velope, but in the mushroom it is exposed or naked, and spread 394 POPULAR SCIENCE REVIEW. over the gills. Those plates which grow side by side, radiating from the stem, on the under surface of the pileus, or cap, of a musliroom are covered on all sides with a delicate membrane upon which the reproductive organs are developed. This is the hymenium of the mushroom. If it were possible to remove this membrane in one entire piece and spread it out flat, it would cover a very large surface, for it is plaited or folded like a lady’s fan over the whole of the gill-plates or lamellse of the fungus. It is this surface which is at first creamy, then pink, and ulti- mately purplish-brown, the colour being communicated by the myriads of spores produced upon it. If the stem of a mushroom be cut off close to the gills, and the cap laid upon a sheet of white paper, with the gills downwards towards the paper, and left there for a few hours, when removed a number of dark radiating lines will be deposited on the paper, each line corre- sponding with one of the gills. These lines are made up of spores which have fallen from the hymenium ; if placed under a microscope their true character will be at once evident. Kemove a fragment of the thin membrane carefully from one of the gills and place it on a slip of glass, then examine it with the microscope. The whole surface will be seen studded with spores (fig. 7). The first peculiarity which will be observed is that these spores are almost uniformly ingroups of four together. The next feature to be observed is that each spore is borne upon a short slender stalk ; finally, that four of these stalks proceed from the apex of a thicker projection from the liymenium, such projection being therefore the bearer of four sterigmata, or little stalks, each surmounted by its spore. Take one of the gills and place it flat on a slip of glass, and then examine the free margin of the gill, so as to obtain a view of the projections from its surface sideways: and by this arrangement the observer will discover on the hymenium two kinds of projections — one, the 6asicZia, already alluded to, bear- ing spores; the other, cysiidia, larger projections, without spores. These two kinds of bodies which are produced on the hymenium of most, if not all, the agarics, demand a still closer investiga- tion. Before doing so it would be well to cut through the centre of one of the gills with a sharp razor, and from the cut surface to slice off a thin transverse section of the gill. By this process we shall discover that the cellular tissue of the pileus passes down the centre of the gills, that the cells are directed outwards towards the hymenium, that short cells intervene near tlie surface, and upon these compressed spherical cells the pro- jections, or h(LHulia and qintldia, are produced (fig. 14). There is no disjunction of the hymenium and the cellular structure of the hyineno|)horc, but the former is a continuation of the latter. To speak or write of the hymenium, therefore, as a distinct THE ANATOMY OF A MUSHROOM. 395 membrane is scarcely accurate, since it is composed of the apical cells of the threads which together constitute the hymenophore. It might be possible to isolate a thread from the m}^celium, to trace it up the stem, through the pileus, down one of the gills to the surface, and there to support one of the basidia, with its four spores. During the course of such a thread the cells would be modified, sometimes elongated, sometimes shortened, and at length when reaching the hymenium, in some species, spherical, continually giving off lateral branches, and interlacing with the neighbouring threads, but maintaining a continuity through the whole structure, so that typically the whole mushroom may be regarded as a congeries of branched threads, bearing spores at their tips, consolidated together into one individual. Basidia, or formative cells, are usually expanded upwards, so as to have more or less of a clavate form, surmounted by four slender points or tubular processes, each supporting a spore, (fig. 5 6). The contents of these cells are granular, mixed ap- parently with oleaginous particles, which communicate through the slender tubes of the sporophores, or sterigmata, with the in- terior of the spores. Corda states that although only one spore is produced at a time on each sporophore, when this falls away others are produced in succession, for a limited period. On this point we have no additional evidence. As the spores approach matu- rity the connection between their contents and the contents of the basidia diminish and ultimately cease. When the basidium which bears mature spores is still well charged with granular matter, it may be presumed that the production of a second or third series of spores is quite possible. Basidia which are wholly exhausted of their granular contents, and become hyaline, may often be observed. Seynes*^ observes on this subject, If we could assure ourselves that amongst the tetrasporous basidia there are but two generations, each of four spores, that would show another affinity with the theca3 of the Ascomycetes, which produce, for the most part, eight spores.” Cystidia are usually larger than basidia, varying in size and form in different species. They present the appearance of large sterile cells, attenuated upwards, sometimes into a slender neck (fig. 5 c). Corda was of opinion that these were male organs, and gave them the name oipollenaire. Hoffmann f has also described both these organs under the names of jpollinaria and speiinatia ; but he does not appear to recognise in them the sexual elements which those names would indicate, whilst Seynes recognises * “ Essai (Time Flore mycologiqiie de la nigion de Montpellier et du Gard,” par J. de Seynes. Paris, 1863. t Die Pollinarien iind Spermatien von AgaHcus in Botanisclie Zeitimg,” 29 Febr., 7 Mar. 1856. 396 POPULAU SCIENCE REVIEW. them, and suggests that the cystidia are only organs returned to vegetative functions by a sort of hypertrophy of the basidia.” This view is supported by the fact that in the section Pluteus the cystidia are surmounted by short horns resembling sterig- mata. Hoffmann has also indicated the passage of cystidia into basidia Zeit 1856, pp. 139). All the evidence seems to be in favour of regarding the cystidia as barren conditions of hasidia. There are in the hymenium-a third kind of elongated cells, called by Corda* “basilary cells,” and by Hoffmann “sterile cells,” which are either equal in size or smaller than the basidia, with which also their structure agrees, excepting in the deve- lopment of sterigmata (fig. 5 a). These are the “proper cells of the hymenium ” of Leveille, and are simply the terminal cells of the gill structure — cells which, under vigorous conditions, might be developed into basidia, but which are commonly arrested in their development. As suggested by Seynes the hymenium seems to be reduced to great simplicity : “ one sole and selfsame organ is the basis of it ; according as it experiences an arrest of development, as it grows and fructifies, or as it becomes hypertrophied, it gives us a ^araphyse, a basidium, or a cystidium, in other terms, atrophied basidium, normal l)asidium, hypertrophied basidium : these are the three elements which form the hymenium.” The presence of male organs, or antheridia, or anything analogous thereto in the mushroom, and in fungi of the mush- room type, has yet to be demonstrated. Hitherto all efforts to discover them appear to have failed. The only reproductive organs, therefore, with which we have to deal are the spores. Tliese are sometimes called basidiospores, because they are borne at the summit of the cells termed basidia. It has been noticed already that they are tetrasporous, that is, they are produced in groups of four to each basidium. The spores are at first colour- less, in some species they remain so, in others they pass to some shade of brown. The variety of tint, form, and size of the spores of agarics is so great that it would be difficult to enume- rate. Anyone desirous of studying them can do so with little trouble by placing the pileus of fresh specimens, gills down- wards, on slips of glass, and protecting the spores so obtained l)y tliin covers, in the usual way. The spore envelope is con- sidered to be composed of two membranes — the external, or more tenacious, l)eing the exosporium, and the internal, more delicate, the endosponum. It is always the external membrane which is coloured. The spore contents are the same as those of • “leones Fiingonim hucusqne cognitonim.” Tomus iii., p. 41. Pragee, 1839. THE ANATOMY OF A MUSHROOM, 397 the basidia, and pass from the latter to the former through the slender tubular sterigmata during the growth of the spore. At first the apices of the sterigmata swell and assume the form of small, round tubercles. For a long time the spherical shape is maintained, but at length the form peculiar to the species, whether ovoid, elliptical, angular, or cylindrical, is established, and in some kinds the surface is covered with asperities, whilst in the majority it is smooth (fig. 9). When the spores are mature their colour is comparatively constant in the same species. So much is this the case that the colour of the spores is employed to divide the different species of agarics into five groups or series. In one of these the spores are colourless, or white when seen in a mass. In another they are salmon-coloured. In a third series they are rusty, tawny, or brownish. In a fourth — to which the common mushroom, and the meadow mushroom {Agavicus arvensis) belong — the spores are of a brownish-purple or brown. And in the fifth series they are black, or nearly so. The spores being matured fall from the basidia upon the ground beneath the pileus. So profuse are the spores in some species, that, espe- cially when white, they seem wholly to cover the surface imme- diately beneath. That very common species {Agaricus melleus), which grows in large tufts on old stumps, is a familiar example of the profusion of spores which may be evolved from a single fungus. In this instance the ground, or any intervening object, is rendered as white as if sprinkled with flour or powdered lime. The most obscure period in the life history of an agaric, and some other fungi, is that which intervenes between the mature spore and the young plant. We see the spores fall to the ground in profusion : from myriads of spores perhaps the same spot does not the next season supply us with a single fungus. We collect the spores of species after species, and try by all known processes to force them to germinate, but it is fruitless. Their behaviour is, to all appearance, that of unfertilised ova, of unimpregnated germs. What are the conditions which agarics require in order to render their spores fertile? We know something of one species, and of one only ; but even that is accidental, and we cannot give a logical reason. The great difficulty in the way of cultivating other esculent species is that of ascertaining the requisite conditions for the germination of the spores. Here is a good field for investigation and experi- ment, and there is no doubt that if persevered in such efforts would produce results calculated to bring us nearer to the com- prehension of this mystery, which is at present wholly a mystery, such as involves no other members of the vegetable kingdom. It is possible that spermatia may yet be traced where they are 398 rorULA.ll SCIENCE REVIEW. now least suspected. No one was prepared to expect zoospores in the conidia of white rusts (Gysto]pus\ or in the oospores of the parasitic moulds {Peronospora) until De Bary’s investiga- tions set the matter at rest. Such a complex method prevails in some fungi, as in Bunt {Tilletia caries) an alternation of generations, that we may even suppose that it is not more simple in agarics. Curious instances of conjugation have also been discovered, as by De Bary^' and Tulasne,f bringing the mode of development more into harmony with what has been observed in the lower alga3. Something analogous to this is detailed by Professor Karsten,:}: as having been observed by him to take place on the mycelium of the common mushroom and Acjaricus vac/inatus. He says, “ In Agaricus cccmpestris, by gradually going back from the forms recognisable with cer- tainty as the youngest states of the cap to smaller ones, I found an organ which, from its peculiar form and texture, I could not but regard as the first commencement of the fruit. This was an oval, almost egg-shaped, simple cell, standing upon a short peduncle of the thickness of the mycelium, and of from three to four times the diameter ^ of this, filled with albuminous matter and overgrown by filaments of the mycelium, which w'ere at first single, but by continually increasing in number, at last form a thick rind {peridium, velum) over the central ovicell, which, in the meantime, increases in size.” In Agaricus vaginatus he found similar bodies (fig. 12), and beside them cylindrical cells springing from the mycelium. In one instance this cylindrical filament consisted of two cells, the upper of which contained a turbid fluid. This upper portion was in contact with the oval cell, so that it seemed to be pressed into the latter, and amalgamated with it at the point of contact (fig. 11). Karsten names these stalked ovoid cells archegonia, and concludes that the conjugation of these two bodies, the cylin- drical with the ovoid, is a fecundative process, similar to what he had described as taking place in a lichen {Coenogonium). At present these observations have not been confirmed, and it would ]je idle to speculate upon their value, or to accept them as an elucidation of the m}^stery of germination. If we admit Karsten’s theory, it has still to be shown w^hat are the condi- tions under which these two forms of cells are produced. The germination of the spore and growth of mycelium is the • “ Annalefl des ScionCG.s naturelles.” Surio V: Botaniqiio. Vol. v. p. 343, ann. Morphologio und Physiologie der Pilze etc.” Leipsic, 1806, t Note sur lea Pheiiomfenea de Copulation que pr^sentent quelquea cham- pignona. Ann. dea Sc. nat.” S^rieV: Botanique. Vol. v. p. 211. ISGO. t “ BotaniacheL'ntersuchungen,” 1860, pp. 100-109. Trnnalatedin ^^Ann, and Mag. of Natural History,” Series iii. vol. xix. p. 73. 1807. THE ANAT03IY OF A MLSH1103M. 399 subject which requires elucidation, and when we have ascer- tained the mode of growing agarics of any species, ad libitum^ from the spores, it Avill be comparatively easy to determine whether a kind of prothallus is formed on which germ and sperm cells are developed, cis in some other cryptogams, or whether the plant at once rises from the mycelium witliout any such intervention. EXPLANATION OF PLATE. Fig. 1. A^oimg mushrooma (Agaricus campe.tri^ springing from the mjcelium or spawn. „ 2. Longitudinal section of young mushroom with indication of future gills. 3. Longitudinal section of mushroom in a more advanced condition. „ 4. Diagramatic shetch of portion of the hymenium of mushroom, showing arrangement of the gills. „ 5. Fragment of hymenium of an agaric ( GoinpJiidius'), showing a sterile cells, h hasidia, c cystidium, magnilied highly. „ 0. Longitudinal section of mature mushroom (Agaricus campcstris), a mycelium, h stem, c veil or ring, cl pileus or cap, e gills, covered with the hymenium. „ 7. Portion of hymenium of meadow mushroom (Agaricus arvcnsis), seen Irom above, with the spores in situ, magnified. „ 8. Portion of stem of mushroom, highly magnified. „ 9. Spores of mushroom (Agaricus campestris) , more highly magnified. „ 10. Transverse section of stem of Agaricus campestris with its pale, pith-like centre. „ 11. Archegonium and cylindrical branch-cell from Agaricus vaginatus, highly magnified. After Karsten. „ 12. Two naked archegonia from the same agaric, highly magnified. After Karsten. „ 13. Transverse section of gills of mushroom. ,, 14. Transverse section of gill of mushroom (Agaricus ca^npestris), showing arrangement of hymenium with its hasidia and spores, and central cell-structure descending from the pileus, highly magnified. D D VOL. VIII, — XO. XXXIII, 400 rorULAR SCIENCE REVIEW. THE CHEMISTRY OF A COMET. TvEcturek ox ^’atural Piiilosophy in Charing Cross Hospital. MI ERE are few facts in modern science more marvellous than that of the application of certain optical properties of gases to the determination of the materials of the sun and' fixed stars. But perhaps the application by Professor Tyndall of some chemico-optical phenomena to the elucidation of the nature of cometary matter is no less remarkable. In the belief that the experiments and speculations of our distinguished physicist on this subject are as yet but imperfectly known, we propose to give some account of them in the following The reasons which require us to regard the cause of cometary phenomena to be a material substance are two. In the first placo, a comet pursues a path the direction of which has been proved to be such as would result from the attractions of the sun and planets for a mass having a certain momentum. .Secondly, the light of a comet has been shown to be reflected light received from the sun, inasmuch as that it is ‘polarised light, and that it weakens or intensities as it respectively removes from or advances towards the sun ; for the light of a self-luminous body is never found to be polarised, and it does not alter in intensity or brightne.ss arge Stytated Fos- sorial Crickets.” By Samuel H. Scudder. Salem. 1809. “ The I^epidopterist’s Huide.” By II. Huard Knnggs, M.D., F.Ii.tS. Lon- don : Van Vcorst. 1809, KEVIEWS. 415 with the stages of insect development, and thus we have four different sec- tions in the work, corresponding respectively to the egg, larva, chrysalis, and imago. Under these heads there is nothing left untold which could he said ; and as Dr. Knaggs is not a compiler, but simply an entomologist who writes his experiences, everything he says is worthy of attention. In this little volume the butterfly hunter will find all his difficulties smoothed over ; and if he wishes to know how, where, when to observe, capture, rear, hatch, preserve, and feed insects, he can have no better guide than Dr. Knaggs. IRON BRIDGES.* The feature which characterises the architecture of the present age is the extensive employment of iron in nearly all structures. It has com- pletely taken the place of timber, and with the best results, and in many cases is used as a substitute for stone and brick. But the use of iron has in- volved the necessity for skilled calculation of its strength, its power to resist strains, its elasticity, and so forth, such as the older architects never dreamed of. It is of the utmost moment that these points should be thoroughly understood, and it is satisfactory to find that so excellent an authority as Mr. Unwin has published a clear and tolerably simple book for the use of mechanical engineers who have to deal with iron structures. It is one of the characters of this work that it explains the graphic method — now so general in other branches of science — for the determination of data for estimating the pressure and oscillation of iron structures, such as bridges. SCIENTIFIC AGRICULTURE.! The first volume of this work, published a couple of years ago, was chiefly if not wholly written by the principal of the Cirencester Agricultural College. The present volume comprises a series of essays, some scientific and some politico-economical, and by various writers. Among the more im- portant chapters are those on experiments on wheat, grass, and barley, by Professor Wrightson,on the absorptive powers of soils by Mr. R. Warington, and on the distribution of tribasic phosphate of lim^, by Professor Thistleton Dyer. * « Wrought-iron Bridges and Roofs. Lectures delivered at the Royal Engineer Establishment, Chatham.” By W. Cawthorne Unwin, B. Sc. London : Spon, 1869. t Practice with Science,” vol. ii. Longmans. 1869. vcL. Ti:i. - E E 416 POPULAR SCIENCE REVIEW. ASTRONOMICAL TABLES.* GENEILAL SIIORTREDE’S tables enable the seaman to find the azimuth at sea by means of the hour augle^ in all navigable latitudes at every two degrees of declination between the limits of the zodiac, whenever any of the heavenly bodies is observed at a. convenient distance from the zenith. Navigators will find these tables economise time materially. Astronomers will also, we think, find them useful. The author of “ How to Keep the Clock Right ” shows us the disadvantages of the sextant method and the expense of good transit instruments, and lastly the errors of the “meridian lines,” “dipleidoscopes,” &c., due to the sun’s action on the pillars, «S:c., to which they are attached. He then describes his own metliod by observations of the fixed stars, and gives an account of a pillar which is not likely to be affected by the sun. Amateur astronomers will be interested in trying the experiment. THE FERTILIZATION OF ORCHHDS.t This is a reprint of a most impoi-tant paper published by Mr. Darwin in the Annals of Natural History for last month (September). The paper is a translation of a series of notes prepared by Mr. Darwin for a French edition of his work on the Fertilization of Orchids. It contains, on the one hand, coiTections of some serious errors into which the author had fallen, and, on the other hand, confirmations of many of his statements. It also contains new facts of interest from the author’s observations, and those of other observers. We have not space to abstract the paper, having only received it a few days before “ going to press,” but we heartily commend it to the attention of all philosophic botanists. Natural History Transactions of Northumberland and Durham. Part I. Vol. HI. Here is a thick honest-looking 8vo. volume, in close tjy)e, and with first- cla.s8 plates. It indicates part of a year’s work done up in the North, and it is, like all its predecessors, full of able memoirs, which take equal rank with those of the Linnean and other societies. The Rev. R. F. Wheeler contributes the opening and the final papere, the one being a long report of the meteorology of 18G7, and the other a similar record for 18G8. The three most valuable articles are those (two) by Messrs. Hancock and ♦ “Azimuth and Hour Angle for Latitude and Declination.” By Major- General Hhortrede, F.R.A.8. London : Strahan, 18GG. “ Howto Keep the Clock Right by obser\'ations of tlie Fixed Stars with a small fixed Telescope.” By T. Warner. Williams and Norgate : 1861). t “ Notes on the Fertilization of Orchids.” By Charles Darwin, M.A., F.It.S. Reprinted from the “Annals of Natural History,” September, 1869. EEYIEWS. 417 Atthey, on various species of Ctenodus, and also on tlie remains of reptiles and fishes from the shales of the Northumberland coal field, and a paper by Mr. G. S. Brady, on the Crustacean fauna of the salt marshes of Northum- berland and Durham. These are all lengthy memoirs, of great value as con- tributions to science. Geological Fragments. By John Bolton. London : Whittaker. 18G9. A not uninteresting sketch of rambles among the rocks of Furness and Cartmel, displaying careful observation of local geology devoid of any feature of originality, and containing a few very rough sketches of Actino- crinis. It is a sort of book never much read, and out of which publishers seldom realise fortunes. The True Theory of the Barth. By Research. Edinburgh: Bell and Bradfute. This work reminds us of a class whose authors delight so in quoting Scripture that we at once call to mind that elderly lady who re- ceived so much consolation from the constant repetition of the word Meso- potamia. It is a book utterly beyond our province. We can’t understand it, and if we did we couldn’t review it in these pages. A nev) Instantaneous wet Collodion Process. By Thomas Sutton, B.A. London : Green, 1869. The author, who was formerly lecturer at King’s College, describes a new process deserving the attention of photographers. The principle on which it depends consists in banishing free acid altogether from the process. The collodion used is neutral, the nitrate bath is neutral, and the sensitive film and the development are alkaline. Abolition of Patents. Longmans, 1869. This is a reprint of the principal speeches made during the past six months on this subject. Facts concerning the Sun is a reprint from the Riverside Magazine (Ameri- can) for August. Its illustrations are somewhat sensational, and relate to the August eclipse seen in America. r: K 2 418 SCIENTIFIC SUMMARY. ASTRONOMY. ^HE Eclipse of August 7. — The successful obseryation of this great total eclipse by the American astronomers is undoubtedly the most important astronomical event of the past quarter. The study of solar’physics has re- cently made such rapid progress, and facts of such importance have come to light, that greater attention is attracted towards eclipse-observations than at any former epoch. The circumstances of the [recent] eclipse were of the most favourable character. The moon’s shadow traversed the United States along a course which brought the line of central eclipse close by many of the most important observatories. Then the weather was all that could be desired, so that not one of the observing parties, so far as is yet known, lost any part of the totality. Again, the peculiarities on which the darkness during totality depends were all, it would seem,7n favour of the observers. Few circumstances are more perplexing than the different degrees of dark- ness observed during total eclipses of the sun. In India, during the great eclipse of last year, though the sun was hidden Tor nearly seven minutes, the darkness was by no means striking; whereas in America this year, although the totality lasted scarcely four minutes, the obscuration was very remarkable indeed. The discovery by Professor Winlock that the spectrum of a prominence which was visible during the eclipse contained no less than eleven bright lines, is perhaps the most interesting result of the eclipse ob- servations. It shows that whatever the prominences may be, they are not simple hydrogen flames. It is to be hoped that our spectroscopists may be able to detect these lines, and so to learn what substances are present in the va.«t tongues of flame which spring from the solar photosphere. Search for lutra-Mei'curial Planets. — The observers of the eclipse of August 7 searched in the sun’s neighbourhood for the planet Vulcan which Ix?scarbault is supposed to have discovered. If such a planet as this really exist in the sun’s neighbourhood, it should be a very conspicuous object during a total eclipse (unless, of course, it happened to be in or near either of its conjunctions). The extreme brilliancy of its illumination would more than make up for its great distance, even a.ssuming it to be in that part of its orbit where it would be further from us than Mercury or Venus at their elongations. No sign of Vulcan or of any of its suppo8ed[fellow-planets was detected during the recent eclipse, however ; andj thus for the present the theory that there are planets within the orbit of Mercury remains in abevance. SCIENTIFIC SUMMARY. 419 Heat from the Moon, — Few questions have been discussed more closely than that of the heat we derive from the moon. As the moon sends us much light, it seemed likely that she sends us also much heat. But the major part of the heat sent towards the earth being what is called obscure heat, it remained doubtful whether our atmosphere may not wholly or all but wholly intercept the lunar heat- rays. All the experiments made by Be Saussure, Melloni, and others, seemed to suggest this view. Recently, however, the powers of the Rosse telescope have been applied to the search for lunar heat,. The moon’s heat-rays were collected on the face of a deli- cate thermopile, and the indications of the instrument pointed conclusively to the presence of heat. The experiment was so carefully conducted that no further doubt can exist as to the fact that we receive a certain supply of heat from the moon. Lord Rosse compared the heat thus received with heat derived from certain terrestrial sources ; and he came to the conclusion that the heat of the moon’s surface cannot be much less than 500° Fahren- heit. When we remember that the surface of the moon is exposed for fourteen days in succession to the sun’s action, and that there is no atmo- sphere to partially ward off the solar rays, we can understand that intense heat should prevail on the moon’s surface ; and Sir J. Herschel long since pointed out that we cannot ascribe to the moon’s surface at the time of full moon a less heat than that of boiling water. Hr. TyndalVs Theory of Comets. — Dr. Tyndall has given a full account of his views respecting comets. He supposes the atmosphere of a comet to extend to an enormous distance on every side of the head, and that the in- terception of the solar heat-rays by the head leads to the prevalence of the actinic rays in the part screened by the head. Thus there results the formation of the same sort of cloud — an actinic cloud, he calls it — which is formed in Dr. Tyndall’s well-known experiments. As the formation of this cloud-tail is not instantaneous, but may proceed with any degree of velocity (according to the structure of the cometic atmosphere), and as the destruc- tion of the old cloud-tails when they come into the presence of the solar heat-rays, may also proceed with any degree of velocity, the curved appear- ance of comets’ tails is satisfactorily accounted for. Dr. Tyndall’s theory is not without difficulties, however; and, as Mr. Huggins has remarked of Benedict Prevot’s somewhat similar theory, it is ‘‘ obviously inconsistent with the observed appearances and forms of the tails, and especially with the rays which are frequently projected in a direction different from that of the tail, with the absence of tail immediately behind the head, and with the different degrees of brightness of the sides of the tail.” Photographs of the Approaching Transit of Venus. — We have already mentioned that De la Rue advocates the application of photography to the transits of J874 and 1882. Major Tennant has made several important suggestions as to this mode of utilising the transit. It would obviously be an immense advantage if the difficulties of ordinary observation of Venus in transit could be got over by photographic skill. It may be found that we are to look to photogriiphy for tlie best determination of the fundamental element of astronomy — the sun’s distance. Many points of difficulty seem to be mastered in theory by the application of photography. We know that Halley’s method of utilising a transit substitutes a time-measurement of t 420 rorULAll SCIENCE EEYIEW. chord traversed by Venus for the determination — not of the real length of that chord — but of the greatest approach of Venus to the sun’s centre. And the reason for the change is obvious. If an observer were sent out to de- termine how near Venus approached the sun’s centre, as seen from a northern or southern station, he would be subject to a number of difficulties. In fact, a very slight consideration of the subject shows that the micrometrical determination of the distance would be practically valueless. But the photographer can at once secure a picture of the sun with Venus on his disc at the moment of estimated nearest approach, besides several photographs taken (at short intervals) before and after that moment, and the examina- tion of these photographs afterwards by an astronomer in his study, with the simple appliances of dividers and protractors, will tell everything that could be learned from trustworthy micrometrical measurements, were such measurements possible. There are, however, it must be admitted, difficulties of some importance in the application of this method. The optical considerations involved are of themselves sufficient to render the interpretation of the photographs a matter of considerable complexity. And then, again, the distortion result- ing from the shiinkage of the collodion film may be much more considerable under the special circumstances of such photographic work as we are con- sidering than under any of the ordinary processes. As Major Tennant remarks, the probable value of photographic records of the transit is very great, but evidence has still to be adduced on the subject before the method can be unreservedly trusted. It may be remarked tliat if it is intended to apply photography to the approaching transit, the places best suited for the purpose would be different from those available for either Halley’s method or Delisle’s. We know that for the former method places must be chosen where the whole transit is visible, and where, subject to this condition, the displacement of Venus’s chord of transit may be greatest either northwards or southwards. For the photographic method, the latter point alone need be attended to, and the complication, arising from the necessity of considering the earth’s rotation, is for the most part got rid of. Delisle’s method really involves the deter- mination of Venus’s displacement at right angles to the sun’s limb at ingress or egress, this displacement being due to the separation of the observers who observe either (i) accelerated and retarded ingress, or (ii) accelerated and retarded egress. Now nothing would be gained by placing photographic stations near those regions suitable for the application of Delisle’s method, becau.se tlie very object of Delislo’s metliod is the securing of non-simul- taneous observution.s, wliile the perfection of the pliotographic method con- sists in tlie comparison of simultaneous observations made in oppo.site parts of the earth’s surface. Mr. JliniT A JCkmcjits of the Transit of Venus in 1874. — Some surprise was cxicasioned by tlie circumstance tliat ^I. I’uiseux liad deduced different re- sults than Mr. Hind from Loverrier’.s tables of the sun and Venus. INlr. Hind, having little faith in the efficacy of a re-exuinination of his own cal- culation.‘< by him.self, placed the matter in the hands of Mr. Plummer, the ai' distant at Mr. Bishop’s observatory, a very able and acute computer. The results of Mr. I’lmnmer's calculations accord so closely with those already SCIENTIFIC SUMMAEY. 421 published by Mr. Hind as to leave no doubt that M. Puiseux has fallen into some error in the course of his calculations. Mr. Hind’s elements for external and internal contact at ingress differ only 14 s. and 27 s. respectively from Mr. Plummer’s values ; while the elements for external and internal contact at egress differ onl}^ 3 s. and 1 s. respectively. As Mr. Plind remarks, these differences for such a phenomenon are insignificant ; the possible errors of any predictions of the times of contact must be very much larger.” The result is fortunate for those astronomers who had taken Mr. Hind’s elements as the foundation for inquiries into the circumstances of the approaching transits; though very little doubt was felt that the difference between Mr. Hind and M. Puiseux would be settled as it has been. Maps of the Transit of Venus in 1874. — Mr. Proctor’s maps of the transit are published in the recently issued number of the monthly notices. He claims for them that they indicate in a trustworthy manner all the circum- stances of the coming transit. They were constructed,” he remarks, with every precaution to insure accuracy. The intersection of longitude- lines and latitude parallels to every 10° were separately constructed for by a double process, and in all critical cases further tests were applied. In all, the construction of the maps involved upwards of 3,000 measurements.” Mr. Proctor may congratulate himself that he had selected Mr. Hind’s ele- ments of the transit on which to base his constructions in preference to M. Puiseux’s ; for had he selected the latter the greater part of his work would have been thrown away, so far as that rigid accuracy at which he aimed was in question. Browning’s Star Spectroscope. — Mr. Browning has devised a very simple, efficient, and economical spectroscope for astronomical work. It is better adapted for use with telescopes of moderate aperture than any other con- trivance hitherto proposed. It will enable the observer to compare the lines in the stellar spectra with the spectra of gases and metals. One of the principal features of the spectroscope is its extraordinary lightness. It weighs only about seven ounces, or less by far than an ordinary micrometer, so that the balance of a telescope will scarcely be at all affected by the addition of the spectroscope. I'he November Meteors. — There is considerable doubt as to the nature of the display of November shooting-stars to be looked for this year. Last year, contrary to the expectation of astronomers, the shower was well seen in England. It was seen also in the United States and at Cape .Town. Therefore, it is perfectly clear that the portion of the meteoric system passed through by the earth last year was very much wider than the parts tra- versed in 1866 and 1867. It seems likely that the part traversed this year will be even wider, and therefore if the weather is fine we can scarcely fail to have a shower. Whether, however, the shower will be a very brilliant one is much more open to question. The probability is that it will not be, as all former experience points to the conclusion that the real maximum of condensation was passed by the earth in 1866. However, it is certain that there is great irregularity in the structure of the meteor-system, aud there- fore it is not at all impossible that during the morning of November 14 next there may occur at intervals several well-marked showers, each lasting 422 POPULAR SCIENCE REVIEW. but a short time. It will be useless to watch much before midnight (of November 13-14). The Sun Spots. — The sun’s surface has continued to be much disturbed during the past three months. It is as yet uncertain whether the maximum of disturbance has been attained. Several of the spots which have recently appeared have been of surprising dimensions, and it seems likely that for .several months to come the telescopist will find the sun a most interesting object for observation. The Planets. — Jupiter is the only planet which will be well placed for observation during the next quarter. BOTANY. A netcly -introduced Fern has been described by Dr. Maxwell T. Masters in the Gai'denet's' Chronicle (Sept. 11), under the name of Davallia Mooreana. Dr. Masters describes it as being a very beautiful plant, and the figure he gives is that of a frond of extreme delicacy. The plant is a native of Borneo, whence it was introduced by Mr. Lobb to the collection of Messrs. Veitch and Sons, by whom it has been exhibited during the past season, and who have received for it the award of a First-class Certificate. Dr. Masters states that he has specimens of what appears to be the same fern gathered in the New Hebrides by McGillivray. The rhizome, which is as stout as one’s little finger, is of a less rapidly elongating habit than in many other Davallias, and appears to prefer to grow half embedded in the soil ; it is clothed with naiTOw lanceolate dark-brown scales, which are some- what toothed at the margin. The stipes is about the thickness of a stout straw, from a foot to a foot and a half long, quite smooth and pale-coloured, as are also the somewhat slender rachides. The fronds, independently of the stipites, are from 2 to 3 feet long, and from 1 to 2 feet wide at the base, triangular and pointed, of a graceful arching habit of growth, and most elegantly cut into a multitude of small blunt oblique sori- ferous segments. Their colour is a pale green, and they are very remarkable for the dotted appearance presented by the upper surface from the promi- nence of the sori. The obliquely ovate pinnules (secondary) are about an inch long or rather more, the pinnulets (tertiar}" pinnules) from a quarter to half an inch long. The sori have the elongate cup-shaped form of those of the true Davallias, but, apparently on account of the bulging in the upper surface, the indusium is almost flat. It should be added that the plant is quite diflercnt from the I). Moorei of Hooker. Distribution of the Table Motmtain Pine (Pinus punyots) in Anienca. — So much discrepancy of opinion exists in regard to the distribution of this plant that Mr. .1. T. Rothrock gives a note embodying his own experience on the subject in the American Naturalist for Augu.st. Michaux anticipated that it would l>e the first of American trees to become extinct, because its limits were so narrow and its habitat so easy of access, and so frequently swept over by fire. Nuttall states “its range is so wide that we have no reason to fear it** extirpation.’’ Chapman finds it on the “mountains, rarely west of SCIENTIFIC SUMMARY. 423 the Blue Ridge, Georgia to Norl-h Carolina, and northward.” In 1859 Gray limited it to ^^Blue Ridge, Virginia, west of Charlottesville, and south- ward.” In 1863, he adds, on the authority of Prof. Porter, ‘Ghe mountains of Pennsylvania, &c.” In 1867 the same author gives a new locality near Reading, Pa., which was discovered by Thomas Meehan. Unless the above statement of Prof. Porter be taken in a pretty wide light, we have in none of these limits assigned anything like an indication as to how common the ti’ee is in Pennsylvania. Thus far, says Mr. Rothrock, “ I have found it ranging from the banks’of the Juniata River, in Mission County, Pa., to Penn’s Valley, in Centre County, Pa. In the latter place it is extremely common, and often forms the largest portion of the woods. The trees, too, attain a height of fifty and, perhaps I may add, not seldom sixty feet.” Variation in Sarracenia. — An American botanist has observed some in- teresting varieties of colour in this plant. The deep purple in some of these specimens was entirely absent, the scape sepals and stigma were of a light apple green, and the petals were of a pale yellow. Examiner in Botany at Cambridge, — We have much pleasure in stating that during the past quarter the examinership in botany for the Natural Science Tripos has been given to Dr. J. 13. Hooker, F.R.S. The Royal Botanic Society of London. — Some time since this Society was alleged by one of our contemporaries to have more regard for funds than for science. Its annual report recently published is evidently a yiece justificative. It states that during the season free orders of admission to the gardens for study have been granted to 200 students and artists, and 10,653 specimens of plants have been given to professors and lecturers at the principal hos- pitals, schools of art and medicine. The maintenance of the portion of the garden devoted to educational purposes is, of course, a considerable item in the Society’s expenditure, and for which it receives no return except such as is common to all public benefactors. The collection of living economic plants now contains specimens of all the spices and condiments in domestic use, most of the tropical esculent fruits, many of those from which furniture and other woods are obtained, the principal gums and medicinal products, and the poison trees of Brazil and Madagascar. Three new Species of Boswellia were described by Dr. Birdwood at the late meeting of the British Association at Exeter, or rather the secretary gave a slight sketch of them, for by some mishap the author’s paper was not in the secretary’s hands. The three species had been discovered near Arabia, and cuttings had been sent to Bombay, and were thriving plants, although as yet without flowers. Oats as Protein-yielding Plants. — Herr Dr. Kreusler has a paper on this subject in the Journal fiXr praldische Chemie (No. 9). He found that the protein compound was extracted from the coarse oatmeal by means of alcohol of ordinary strength — 80 per cent. He states the composition of the pure substance to be in 100 parts — C. 52’59, H. 7*65, N. 17-71, 8.1*66, O. 20-39. The Nutrition of Plants. — In a paper lately laid before the Society of Sciences of Gottingen Herr W. Wicke communicated some results of re- searches upon the nutrition of plants. He had been experimenting on plants with phosphate of ammonia, hippuric acid, glycine, and creatine. He con- 424 POPULAR SCIENCE REVIEW. eludes, from numerous investigations, that all these substances constitute the nitrogenous food of plants which gTOw in aqueous solutions. As to the chiuiges which they may undergo in the soil, he thinks that a new series of researches must be made to determine this. The Botanical A2)pointments in the British Museum. — The Gardeners' Chronicle makes the following remarks on this point, and we concur in them thoroughly : —Some time since, when an appointment was made in the Botanical Department of the British Museum, we were not a little sur- prised, not to say disgusted, to find that one of the conditions imposed upon the candidate for the office was that he should be subjected to an examina- tion by the Civil Service Commissioners. If this examination had had reference to botanical subjects or museum duties there would have been no reason for surprise j but to subject a well-educated gentleman, a graduate of the University of London, whose examinations are known to be the most searching of all similar ordeals, to a test such as is properly enough imposed on unknown men, or on those whose qualifications have not been tested, was to degrade the candidate and to offer an insult to the University. W e are glad to find that Mr. James Britten, who has recently been appointed to an office in the Koyal Herbarium at Kew, has not had to undergo such a degradation. Gases exhaled hy Fruit. — At a meeting of the Academy of Sciences (Baris) on August 6, MM. Bellamy and Lechartier read a paper in which they stated that various kinds of fruit, after having been plucked from the trees — for instance, apples, cherries, gooseberries, and currants — begin to absorb oxygen and give off carbonic acid. How Light affects the Decomposition of Carbonic Acid hy Plants. — In the Comptes-Rendas of August 9, a paper is published by M. Prillieux detailing the results of experiments made on plants witli gaslight, electric light, and magnesium light. The experiments were conducted on aquatic plants ; the stem of the plant being cut across, and thus allowing the escape of bubbles of oxygen to the surface, these could then be readily counted. He found that whilst in a given time sunlight caused the disengagement of twenty-two bubbles, in the same time under the influence of electric light only eleven bubbles were disengaged. Other lights furnished less. But still, as all the lights caused the disengagement of oxygen, it shows — the author thought — that these sources of light contain the same elements as sunlight. Alkalies in the Ash of Plants. — M. Cloez calls attention to the fact, already pointed out by others, that the same plants grown near the sea and at remote distances therefrom alter their saline constituents, so that while growing near the sea soda prevails, as a rule, over potassa, the reverse is tlio case while the same plant vegetates at a distance more or less remote from the sea ; of this fact some instances are given in this paper. The relation of the soda to the potassa of the ash of Crambe maritima when grown near the sea was as 900 to 1,000; when grown at Baris, as 89 to 1,000. The r* lation of soda to potassa in the ash of black mustard-seed grown near the was as 200 to 1,000, while when grown at Paris it was as 96 to 1,000. Vieie Bulletin mensuel dcla Bociite rhimiqnc de Pari.H, July. Artificial Selection in improving Com. — One of the most wonderful SCIENTIFIC SUMMARY. 425 instances of the application of the selection of varieties to agriculture came before the British Association at Exeter. Mr. Hallett of Brighton succeeded by this method in obtaining a grain of wheat which, when sown, produced a whole multitude of stalks, each of which bore a magnificent ear, well filled with grain. He finds that this quality is maintained by the descendant seeds, and hence he has succeeded in increasing our produce many hundred- fold at least. He laid down the following propositions as the result of his observations : “ 1. Every fully-developed plant, whether of wheat, oats, or barley, presents an ear superior in productive power to any of the rest on that plant. 2. Every such plant contains one grain which, upon trial, proves more productive than any other. 3. The best grain in a given plant is found in its best ear. 4. The superior vigour of this grain is transmissible in different degrees to its progeny. 5. By repeated careful ‘ selection ’ the superiority is accumulated. 6. The improvement which is first raised gradually, after a long series of years is diminished in amount, and eventu- ally so far arrested that, practically speaking, a limit to improvement in the desired quality is reached. 7. By still continuing to select, the improvement is maintained, and practically a fixed type is the result.” The Relative Value of the Characters of Plants employed in classification. — Dr. Maxwell T. Masters had a paper on this important question in the Biological Section at Exeter. The paper was devoted to the consideration of some of the means employed by botanists in elaborating the natural ” systems of classification, and to the estimation of the relative value to be attached to these means. The characters treated of were the following: 1. Characters derived from the relative frequency of occurrence of a parti- cular form, or a particular arrangement of organs. 2. Developmental characters, whether congenital ” or “ acquired.” 3, Teratological charac- ters. 4. Rudimentary characters. 5. Special physiological characters. 6. Characters dependent on geographical distribution. Illustrations were given in explanation of these matters, and for the purpose of showing their applicability to particular cases. The Leaf Beds of Hampshire. — The report of the committee appointed to investigate the leaf-beds of the Lower Bagshot Series of the Hampshire basin was presented to the British Association at Exeter, and will appear in the annual volume. The report was made by Mr. W. S. Mitchell, who stated during the past year attention had been drawn to another collection of plants from Alum Bay. It confirmed the view that the forms so abundant on the mainland were wanting here. Aralias, Di'yandras, Cussonias, I)al~ hergias, &c., had turned up in great abundance, as well as Cinnamon plants. Mr. Mitchell stated that he had carefully compared these with the cinna- mons in the herbarium of the British Museum and at Kew, and, although at first they seemed to have points in common with some other plants, he was fully convinced they were true cinnamons. He pointed out the disad- vantage of having but few leaves in an herbarium for comparison, and said the determination could not be considered final with regard to any of the leaves until the figures of them had been accepted by our colonial botanists, in comparison with living plants. Some attention had been paid to Whitecliff Bay, which gives promise of a richer harvest, if a longer time can be devoted to that locality, so as to get into the cliff beyond the 426 POPULAR SCIENCE REVIEW. effect of atmospheric action. All the specimens hitherto obtained are very fragile. At Mr. Pilke’s pits, near Corfe, the line of fault has lately been worked, and specimens obtained. The effect of the disturbance extends but a short way into the Bagshot Sands. The hope was expressed that the relative horizons of the Alum Bay and the mainland beds would soon be determined by a survey now being made under the direction of the Com- mittee. The Botany of Thibet. — At a meeting of the Botanical Society of Edin- burgh, held on July 8, a paper was read by Dr. J. L. Stewart, conservator of Forests Puujaub, entitled, “Notes of a Botanical Tour in Ladak or AVestern Thibet.” The author gave a detailed account of a tour he made in the autumn of last year through a considerable portion of Ladak, and enumerated the plants he met with, and the elevations at which they grew. From August 5, when he crossed the Baralucha from Lahoul, to October 8, when he crossed the Parang into British territory again, were fifty-one days, on which there was no complete halt. In that time 837 miles were travelled, and seventeen passes of more than 14,000 feet were crossed. He collected nearly 400 species of plants, representing the following natural orders: Ranunculacese, 17 species; Cruciferae, 30; Caryophyllaceae, 14; Leguminosie, 21 ; Rosaceae, 17 ; Crassulaceae, 10 ; Saxifragaceae, 6 ; Umbel- liferae, 10; Compositae, 57 ; Primulaceae, 9 ; Gentianaceae, 8 ; Boraginaceae, 5 ; Scrophulariaceae, 11 ; Labiatae, 21 ; Salsolaceae, 12 ; Polygonaceae, 13 ; Cyperaceae, 9 ; Gramineae, 39. The Famine Plants of Central India. — During the last terrible famine in Mnrwar a number of plants, not generally eaten, were employed as food, and of these a list was made out in a paper lately presented to the Botanical Society of Edinburgh by Dr. G. King. The rainfall of the district in ques- tion is usually three to four inches, but in 18G8 the rain utterly failed, and the deficiency of food and forage was very calamitous, and attended with loss of life. Dr. King in his paper enlarged upon the effects of denudation under native government, and the subsequent dessication, which called for a system of forest conservancy. In the event of the proposed railway being constructed from Delhi to Bombay, great want of fuel will be experienced. The trees suggested for prospective planting during the rainy season are Acacia Arahica, A. leucophlcea, and A. Catechu^ Salvadora Persica, and Capparis aphylla. Tlie chief jungle products used as food during the late famine were — 1. The root of Jlymenochccte yrossa, a tall rush, growing on the margins of tanks ; it is called Mothee, and is eagerly dug up for human food. 2. The bark of Acacia leucophlt^a, a common tree in Rajpootana. 3. The seed of Anchyranthes aspera, a common herb. 4. The capsules of Trihtdus lanuyinosus, and other common plants. 5. The seed of a grass, probably an Elusine. 0. The seeds of fiesaynum orientale, the gingelly oil plant, and of various Cucurbitaceous plants. The whole of tliese products appear to be deficient in nutritious qualitie.s, and were brought into use to supplement the scanty supplies of esculents in tlie province at a time of great distress. The Distribution of Tracheal Vessels in Fenis is the subject of a paper by M. Tr<5cul, in the Comptes-liendus (July 20). The author describes the arrangement of these vessels in a vast number of indigenous and exotic ferns. SCIENTIFIC SUMMARY. 427 Signijicance of Adnation ” in the Coniferce. — A paper of some import- ance was read before the American Association for the Advancement of Science by Mr. T. Meehan, and was published in the volume of Transactions. The author shows that the true leaves of coniferae are adnate with the branches. The Devehpment of Mucor Mucedo. — In the Monthly Microscopical Journal for September there appears a most valuable paper by Dr. R. Maddox, detailing the different stages in the development of this easily accessible fungus. It is accompanied by a plate giving numerous figures sketched by the author, and drawn on stone in Mr, Tuffen West’s best style. Structure of Fossil Exogenous Ste?ns is the title of a recent important communication by Professor Williamson, of Manchester. The author enters on a critical examination of the opinions of Endlicher and Brongniart, and figures and describes the structure of Dadoxylon and Dictyoxylon and other genera. The paper is of some length, and deserves the attention of palaeon- tologists. The author thinks that no determination of fossil plants can be made with accurac}’’ without the aid of the microscope. Vide Monthly Mid'oscopical Journal, August. CHEMISTRY. The Homologous Carburets of Naphthaline. — This was the title of a paper presented recently to the Society of Sciences of Gottingen by Herr Fittig. Having referred to his former paper showing how, beginning with benzol, all the homologues may be formed in a simple manner therein described, he stated that he obtained good results by the application of this method to the aromatic series. By it alone have he and his colleagues been enabled to obtain the homologues of benzol in a state of purity j except toluol, the carburets previously obtained from tar were but a mixture of carburets in juxtaposition, and very difficult to separate. In the paper read, he detailed how, with M. Remsen, he has been trying this method with naphthaline, and how he has obtained very good results. In this way he has obtained many homologues of naphthaline. The following reactions were then de- scribed in detail : (1) A mixture of monobromated naphthaline and iodide of methyl, and (2) a mixture of monobromated naphthaline and iodide of ethyl diluted with ether, upon sodium in a state of fine division. He described two new carburets. He thinks it probable that the homologues of naphtha- line are found only in those portions of tar which boil at a high tempera- ture. He thinks, therefore, that the reason why they have been hitherto overlooked is that they are liquid at ordinary temperatures. What to he looked for in examining Water. — In summing up the results of his observatious (published in a series of long papers in the Chemical News) Dr. Angus Smith thus formulates what data are required for sanitary pur- poses. 1. Quality of the organic matter. 2. Condition of the gases of decomposition. 3. Organic matter : easily-decomposed organic matter, and slow to decompose. 4. Nitrates as remnants of organic matter. 5. Nitrites. 6. Chlorides, with precautions, as indicating animal sources when greater 428 ropuLiVR scie: YOL. YIIT. NO. XXXIII. G PAGE Archaeology, Prehistoric 311 Archipelago, East Indian 74 „ the Malayan 286 Architects, Errors of, as to Ventila- tion 201 Are there any Fixed Stars ? 358 Argo, the Nebula in 179 Armour Plate 196 ,, Plates, Failure of a Pro- posed Plan for 319 ,, Plates, Eesistance of 315 Artificial Ebony, Preparation of ... 306 ,, Light, Infiuence of, on Plants 302 ,, Preparation of Alizarin.. 305 „ Production of Tartaric Acid 86 „ Selection among Men ... 73 „ Selection in Improving Corn 424 Artistic Licence versus Photography 211 Ashes of a Diseased Orange Tree... 86 Aspidolite, Analysis of 438 Assay of Silver in the Wet way 99, 202 Aster Salignus, Distribution of 183 Astronomer Eoyal (the) on the com- ing Transits 297 Astronomical Tables 416 Astronomy 79, 178, 296, 418 Atlantic Sea-bottom 331 Atmosphere, Sulphurous Acid in the 200 Atropia, Morphia as an Antidote to 20 1 Atropine, Physical Action of the ... 438 Auditory Organ in Cephalophora, Eelation of, to the Nervous Gan- glia 107 Aurora Borealis, Spectrum of the... 441 Aurorae Boreal es 299 Authors, Photographs of 212 Bacteria in Glanders and Farcy... 94 ,, in the Protoplasm of Plants 185 „ Natural Development of 166 Balsenopterje, Anatomy of 446 Balsam of Peru 308 Bathybius, what is ? 350 G 448 POPULAR SCIENCE REVIEW, PAGE Batrachian, New 107 Batrachians, Lymphatic Vessels in the Tail of 220 Battery, Constant, New 102 „ Heat in the Cells of a 104 Beaver, Fossil 194 Bechamp (AI. A.) on the Natural Development of Bacteria 166 Beetle of the Elater Genus 328 Beet-root Sugar, Fermentation of... 428 Belgium, Carboniferous Limestone of 310 Bell-metal, Aluminum a .*.... 318 Bennett (J. H.) on the Molecular Origin of Infusoria 51 Benzine, the Derivatives of 186 ' Berardius Arnuxii 445 , Bickmore’s “ Travels in the East Indian Archipelago ” 74. Binocular Spectrum Microscope ... 322 | Birds, Ciliary Muscle in 109 “ Birds of Sherwood Forest,” the ... 295 ; Bismuth, Metallic, Purification of 188 i Blast-furnace Slag, Utilisation of... 318 i Blastoderm, Formation of, in Crus- i tacea 219 , Bleaching Wood Pulp 184 Blood-corpuscles, Cohesion of the... 334 ; „ Aggregation of, i in Fever 199 Blood, Relation of Osseous Medulla in the 315 Blow-fly, Proboscis of the 333 Bloxam’s “ Laboratory Teaching ” 290 Body, Temperature of the, in Health 198 Boiling, to Prevent Bumping in ... 429 Bolts, Palliser 315 Books, Reviews of. 67, 168, 284, 408 ,, on Insects 414 Boswellia, New Species of 423 Botanical Appointments in the Bri- tish Museum 224 „ Examiner in, at Cambridge 423 „ of Thibet 426 Botanical Ix-ctures at Cambridge... 182 „ Prize of the Pharmaceuti- cal Society 301 Botanists, Deatli of Two Eminent... 183 Botany 83,182,300,422 ,, of .Shetland 301 „ Scandinavian 301 Bray’s “ Science of Man ” 73 Brazilian Coal-beds, Plants from... 311 Brazil Nut, Micro.scopical Structure of the 185 Brcarey (F. W.) on Flying Mjichines 1 Breitenbiich Meteorite, Minerals of the 320 British Association for the Ad- vancement of Science 434 British Conchology 291 ,. Fossil Corals 431 ! PAGE British Leech, New 222 „ Lion, The 150 „ Moths 410 „ Museum, Dr. Trimen’s Ap- pointment to the 301 „ Museum, Natural History at the 328 „ Nemerteans 331 „ Zoophytes 287 Browning’s Miniature Spectroscope 443 „ Star Spectroscope 421 Bubuy 302 Bunsen’s Filter 430 Butterflies, Nature-painted 107 Calcaiee Geossiee, Fossils of the. . . 430 Calopteryginse, Researches on the... 445 Calorific Spectra, Researches on... 104 Campbell’s “ Sciography ” 77 Canal, the Suez 195 Carbonaceous Matter of Meteorites 99 Carbon, Chemical Changes of 292 Carbonic Acid Decomposed by Plants 189 Carbonic Oxide 430 Carboniferous Limestone of Belgium 310 Carpical Structure in Elaeagnus Go- nyanthes 83 Carriage, Steam 196 Carrier’s Sensitive Albumenized paper 100 Carter (R. B.) on the Use and Choice of Spectacles 131 Cast-iron, Detection of Phosphorus in 320 „ Estimation of Phosphorus in 88 Catalogue of North- American Birds 108 Catastrophism and Uniformitarian- ism 310 “ Catharism,” Meaning of the Term 217 Cell, Physics of the 106 Cellular Plants, why absent from Coal Measures 302 Centrifugal Governor 195 Cerium, Preparation of 188 Cervical Vertebra, Origin of the Second 333 Chalk, Red, of Hunstanton 193 Channel Tunnel 436 Chapman on “ Sea-sickness ” 78 Cheap Magnesium 101 Chemical Action 307 „ Arithmetic 413 „ Chair in Anderson’s Uni- versity 429 ,, Changes of Carbon. 292 „ Combinations, Magnetism of. 217 Chemical Constitution of Uric Acid 86 ,, Food of Plants 189 INDEX. 449 PAGE Chemical G-eology 92 „ Properties of Nitro-gly- cerin 189 „ Keactions Produced by Light 87 Chemistry 85, 186, 303,427 „ and Heat 72 ,, Pownes’s 76 „ New Work on 306 ,, of a Comet 400 ,, of Nitro-glycerin 306 „ of the Ground 302 „ Professorship of Edin- burgh University 305 Child’s “ Essays on Physiological Subjects” 77 China, Geology of 191 Cinchona Bark from Eastern Bolivia 83 Christy’s “Eeliquse Aquitanicse”... 290 Chrome Green, New 304 Chromic Acid in Therapeutics 318 Ciliary Muscle in Fish, &c 109 Cinchona, Cultivation of, in India . 185 Citric Acid 307 Classification, Professor Huxley on 284 Cleland (Prof.) on the Lingering Admirers of Phrenology 380 Clock, an Electric 218 Cloud Diaphragm 324 Clouds, Constitution of 214 Coal-beds, Brazilian, Plants from... 311 ,, from Sea- weed 319 „ Insects, American 310 ,, -tar Gases, Constitution of ... 307 „ „ Xylol of 304 Cobbold’s “Entozoa” 408 Cohesion-figures 212 „ of the Blood-corpuscles... 334 College of Surgeons, Chair of Com- parative Anatomy in the 333 Collodion Process, New 417 Colour, Analysis of 294 „ -reactions of Lichens 184 Colouring Matter of the Feathers of the Turaco 334 ,, Products of Garance 307 Coloiu’S of Labradorite 98 ,, Seen in Tempering Steel ... 319 Combustion under Pressure, Phe- nomena of 86 Comet, Chemistry of a 400 ,, Winnecke’s Short-period ... 298 Comets, Dr. Tyndall’s Theory of... 419 Common Salt, Infiuence of, in Ab- sorption 210 Comparative Anatomy, Chair of, in the College of Surgeons 333 Comparative Psychology 332 Compo\ind Eye of Insects and Crus- tacea 12 Compounds Isomeric with the Sul- phocyanic Ethers 87 G PAGE Conchology, British 291 Concrete Arch 195 Condenser, Injector 196 Condensing Magnetism 441 Conduction of Heat, Mode of 105 „ of Sensory Impressions. 97 Constant Battery, New 102 Contractile Vesicle, Function of the, in Infusoria 333 Contractions of the Heart 200 Cooke (M. C.) on the Anatomy of a Mushroom 391 Copper, Alloys of 204 ,, how to Weld 319 „ Quantity produced in 1866 439 Crustacea, Visual Powers of the Eye of 445 Copperas, Manufacture of 318 Coral, Organ-pipe 331 Corpuscles, the Pacinian 222 Cotton, New Kind of 302 Cracking of Negatives 323 Creatine in Milk 95 ,, Synthesis of 308 Creosote, Modus Operandi of 305 „ Oil as a Source of Heat... 321 Cricket, the Mole 327 Crustacea, Compound Eye of 12 „ Formation of Blastoderm in 219 ,, Fresh-water 222 „ of Belgium, Fresh-water 106 ,, Structure of Shell of ... 108 Crystalline Modification of Siline Acid 203 Cultivation of Cinchona in India ... 185 Cure for Snake Poison 202 Cuttle-fish Ill Cyanogen Gas, Physiological Action of..o 96 Cycadean Fruit, New 195 Cyclamine, Development of Vibrones after Administration of 95 Danger of Microscopic “ Methods.” 331 Darwin, Muller’s Facts and Argu- ments for 289 Darwin’s “Fertilization of Orchids.” 416 Dawkins (W. B.) on Kent’s Hole ... 369 ,, „ on the British Lion 150 Death 275 „ of M. Nikles 305 ,, of Von Martins and Schnitz- lein 183 Decomposition of Sesqui-salts of Iron 305 Deep-sea Bottom, Life on the 328 „ Dredging 109, 445 Deltas of the Po, Mississippi, and Ganges 91 • 2 450 rOPULAR SCIENCE REVIEW. Derivatives of Benzine, the Derwentwater Depression, Origin of the Dessication of Rotifers Desmids, Vitiility of Detection of Mercury in Cases of Poisoning „ of Phosphorus in Cast- iron Determination of Nitrous Acid Devonshire as a Health-resort Diameter of Tree-trunks, Largest... Diapasons, New Way of Detecting Discordance of Diatomacae, Greenland Diatoms, to Obtain from Guano. ... Differential Refractor for Polarised Light Digestive System in Orthoptera .... Dimethyl Dinornis in New Zealand Dicecism in Epigsea Repens Directory for Naturalists Disinfectants Distance of the Sun Distribution of Iron in Variegated Strata Divers (E.) on the Chemistry of a Comet Dogs, the Varieties of Dolphin, Scolex of Phyllobothrium in a Donation Fund, the Wollaston Dredging, Deep-sea 109, Dry Process, another New Dumas’ (M.) Lecture in London ... Dye-stuff, V egetable Tar as a Earth, Interior of the „ Temperature of the Superfi- cial Structure of the „ True Theory of the East-Indian Archipelago Elx)ny, Artificial Preparation of ... Eclipse of the Moon „ the Great, Tennant’s Photo- graphs of „ the, of Atigust 7 Edinburgh University, Chemistry Professorship of Elaegnus Gonyanthes, Peculiar Cnr- pical Structure in EHectric Clock........ „ Conductibility of Metals... „ Phosphorescence in Rjirefiod Gases Electro-capillary Phenome a Electro-chemistry in Metallurgical Operations Ellagic Acid, Preparation of. Engine, Solar PAGE Enstatite in Meteoric Iron 438 Entozoa 408 Eozoon, is it a Mineral Production ? 192 „ Mineral Nature of 92 Epigsea Repens, Dicecism in 85 Ergotia, Use of, after Operation ... 94 Essays, Physiological 77 Essex Institute, Catalogue of Birds 108 Estivating Sulphur 190 Ethyl Strychnia 95 Exciting Liquid for Galvanic Bat- teries, New 105 Experiments on Transfusion 97 „ with Liebig’s Food for Children 316 Extraction of Sugar from Molasses 189 Eye of Insects, Compound 12 Eaelure of a Proposed Plan for Ar- mour-plates 319 Fairlie’s Steam Carriage 435 Famine Plants of Central India ... 426 Faraday, the Life of 218 Farcy, Bacteria in 94 Fauna of the Gulf-Stream 220 „ of the Montana Territory ... 109 „ of the South-west Coast of France 107 Faye (M.) on the Transit of Venus 296 Fern, a Newly-introduced 422 j Fern Spores, how Scattered 85 Fertilization of Orchids 416 I ,, of Sahna, &c ••• 261 i Fever, Aggregation of Blood-cor- I puscles in 199 i Filters, Bunsen’s 430 Finders, New Method of Mounting 299 Fire, does Sunlight Extinguish? ... 441 Fish, Ciliary Muscle in 109 „ Devonian 431 Fishes, Zoosperms of. Development of the 329 Flame, Illuminating Power of 104 Flint Implements 431 „ Weapons, True and False ... 30 I Flora, Middlesex 412 I Floral Abnormalities 302 I Floscularia Campanulata 108 Flowers, Passion 159 I Flying Machines 1 I Foraminifera of Kostcj, the 91 Forbes (D.) on the Interior of tho Earth 121 Forests, Temperature of 327 Fos.sil Beaver 194 „ Corals, British 431 „ Exogenus Stems 427 ! „ Plants of Greenland 312 I ,, Tubularian 430 ! „ Tubularian Zooph)rte 310 ! Fossils of the Calcairc Grossier ... -130 PAGE 186 311 332 185 187 320 188 95 301 105 183 208 103 222 87 190 85 108 176 81 89 400 330 106 191 . 445 211 190 85 121 205 417 74 306 82 179 418 305 83 218 216 325 88 215 189 93 INDEX. 451 Fownes’ “Manual of Chemistry”... Fragaria, New Free-swimming Amoebae Fresh-water Crustacea „ of Belgium „ Deposits Fripp (H.) on the Compound Eye of Insects- . Fruit, New Cycadean Fuel, Liquid Fungi, Microscopic ,, the Preparation of . . Gadoxinite, Physical Properties of Gallic Acid Used in Preparing Ellagic Acid Gallon ( J. C.) on Sea-squirts Galvanic Batteries, New Exciting Liquid for Galvanic Current, Metals in the ... Ganges, Deltas of the Garance, Colouring Products of ... Gases Exhaled by Fruit „ Earified, Electric Phospho- resence in „ Waste, Utilization of Gas Mains, Joints of Pipes for Generation, Spontaneous Geological Chips „ Fragments ,, Index, Ormerod’s „ Map of Central Europe „ _ Society Geological Society, Ofideials of the ,, „ Wollaston Gold Medal of the Geological Structure of Siberia and Eussia ,, Survey of Ohio Geologists, Death of Two Eminent. . . Geology 89, 190, „ and Palaeontology „ Chemical ,, of Alaska ,, of China Germination of the Spores of Vari- cellaria Girtin on “ The House I Live in” Glaciers in Central France ,, Mechanical Descent of Glanders, Bacteria in Glass for Lenses Graphic Determination of Stress ... ,, Method Applied to the Movements of Insects Graphite, the Varieties of Grasshoppers, American Grovels, Quaternary Green, Chrome Greenland Diatomaceae „ Fossil Plants of PAGE Greenland, the Lichen Flora of ... 183 Ground Nut, Natural History of the 302 Growing Slide, New 208 Guano, Obtaining Diatoms from ... 208 Gulf-stream, Fauna of the 220 „ Physics of the 326 Guthrie’s “Elements of Heat and Non-metallic Chemistry ” 72 Habits of Spiders 109 Half-hours with the Stars 291 Hartwig’s “ Polar World” 174 Haughton’s “ Laws of Vital Force” 294 Heart, Contractions of the... 200 ,, Influence of Medicaments on the 199 „ ,, Veratum on the 95 Heat and Chemistry 72 „ Creosote Oil as a Source of... 321 „ in the Cells of a Battery 104 ,, Mode of Conduction of, by Bodies 105 „ of the Stars, to Ascertain ... 214 Hedgehog, Vascular Parts of the Eetina of the 329 .Hincks (Eev. T.) on the Tertularian Zoophytes of our Shores 223 Hincks’s “ British Zoophytes ” 287 Homologous Carburets of Naptha- line 427 Horse in Prehistoric Times 220 “ House I Live in,” the 294 House Eaisiug 435 Hunstanton, Eed Chalk of 193 Hunt (E.) on Hydrogenium 233 Huxley (Prof.) on Classification ... 284 Huxley’s Lectures on Vertebrates... 202 Hydraulic Trajectories, Similitude of 104 Hycbocanellic Acid, Synthesis of ... 428 Hydrocyanic Acid, Synthesis of New 89 Hydrogen 218 Hydrogen Flame-colour on Porcelain 190 Hydrogenium 233 j H^qDerodapedon 194 I Ideaeism ill Chemistry 303 Illuminating Power of Flame 104 j In Articulo Mortis 275 ! India-rubber, Danger of Using 211 I Infusoria, Function of the Contrac- tile Vesicle in 333 „ Molecular Origin of 51 Infusorium, New 222 Injector Condenser 196 Insects, Books on 414 „ Coal, American 310 ,, Graphic Method applied to the Movements of 222 ,, the Study of 71, 176 page 76 300 333 222 106 432 12 195 313 185 182 318 189 240 105 213 91 307 424 325 439 315 172 293 417 91 431 433 194 191 90 191 432 , 309 430 92 309 191 84 294 91 216 94 213 j 197 222 ! 186 329 90 304 183 312 452 POPULAR SCIENCE REVIEW. PAGE Intercommunication in Railway Trains 93 Intra-Mercurial Planets 418 Invertebrate Animals, Muscles of... 333 Iron and Steel 295 „ Bridges 415 „ Distribution of, in Variegated Strata 89 „ Mechanical Strain of, Relation of, to Magneto-electric Induc- tion 103 „ Molecular Phenomena in 203 ,, Sesqui-salts of. Description of 305 Ironclads, Mr. Reed on 314 Isocitric Acid 307 Isomery in the Salicyl Series 428 Jargonia 428 “Jean Bart,” Voyage of the 299 Jeffreys “ British Conchology” 291 Joints of Pipes for Gas and Water Mains 315 Kent’s Hole 369 Knagg’s “ Lepidopterist’s Guide”... 414 Kotchoubeite, Miner.il, Characters of the 203 Kostej, the Foraminifera of 91 L.\boratoby at Leipsic, New 307 ,, how to Work in the ... 290 Liibradorite, Colours of 98 Liimp, Oxyhydrogen, New 327 Lamps for Photography 101 Dindscape Photography in Cloudy Weather 101 D'lplace, Nebular Hypothesis of ... 180 Lardner’s “ Handbook of Natural Philosophy” 176 Liirdner’s Optics 170 Lartet’s “ Reliqiue Aquitanica;” 290 Dirv’a of the Elabi Genus 328 Lsiva Tides, Subtern\nean 312 “ Liws of Vital Force,” tlio 294 Leaf Beds of Hampshire 425 Ix%'ives, Morphology of 185 I>eech, British, New 222 D'ipsic, New Lilsmit/jry at 307 Ix!nsf*s, Glass for 213 I/<'pidfxlpndron, the Relations of ... 192 Ix-pidoptera, American 329 Leptandni and Ix*ptandrin 199 Ix-pyrus Binotiitus 446 Lichen Flora of Greenland 183 ,, Pathological Development of 201 Lichens, Colour-reactions of 184 Liebeg's Extract of Meat 96 „ F*xxl for Children, Experi- ments with 316 PAGE Life on the Deep-sea Bottom 328 Light, Artificial, Infiuence of, on Plants 3U2 „ Chemical Reactions produced by 87 „ New Method of Measuring the Intensity of 103 „ Polarised, Differential Re- fractor for 103 Lightning, Physiological Effects of 316 Lime Light, New 210 Limestone, Carboniferous, of Bel- gium 310 Lines in Nobert’s Plate, how to Count the 207 Linne, the Lunar Crater 181 Lion, British 150 Liquid Fuel 313 „ ,,011 Shipboard 93 Longitude, Use of Telegraphy in ascertaining 213 Lucio Perea Zandr 221 Lunar Crater Linne 181 Lymphatic Vessels in the Tail of Batrachians 220 Lymphoid Organs of Amphibia 110 Macdonald’s “Analysis of Sound and Colour” 294 Machines, Flying 1 Madagascar, Ordeal Poison-nut of 83 Madder, new Dye from 429 Magnesium, Cheap 101 Magnetic Variation on Lake Supe- rior 442 Magnetism of Chemical Combina- tions 217 Magnetites, Titaniferous 99 Malayan Archipelago, the 286 Malvales, Morphology of 84 Mammae, Artificial 438 Mammalia of North-West America 332 “Man and the Mammoth” 194 Man, Preglaical 175 Manometric Barometer 442 Manufacture of Copperas 318 Maps of the Transit of Venus 421 Mariners’ Compass, Lord Caithness’s 443 Mars in February 1869 39 Masters (M.T.) on Passion Flowers 159 Masters’s “Vegetable Teratology” 288 Matter, what is it? 293 Measurement of Temperature of the Solar Radiation, Errors in the ... 100 Meat, Liebeg’s Extract of 96 Mechanical Descent of Glaciers ... 216 „ Science ...93, 195, 313,434 „ Strain of Iron, Relation of, to Magneto-electric Induction 103 Medical Nomenclature 202 „ Photographs 202 INDEX. 4o3 PACK Medical Science 94, 197, 315, 437 „ „ at the British Asso- ciation 438 Medicaments, Influence of, on the Heart 199 Men, Artificial Selection among ... 73 Mercury, Detection of, in Cases of Poisoning 187 Mercury, Transit of 81 Metallic Bismuth, Purification of... 188 Metallurgical Operations, Electro- chemistry in 215 Metallurgy, Mineralogy, and Min- ing 97, 202, 318,438 Metals, Electric Conductibility of. . . 216 „ in the Oalvanic Current ... 213 Meteorite, Breitenbach, Minerals of the 320 Meteorites, Carbonaceous Matter of 99 Meteors, the November 421 Meteorology 99, 205 Methyl-Strychnia 95 Microscope, Binocular Spectrum ... 322 Microscopic Fungi 185 ,, “Methods,” Danger of 331 Microscopical Journal 206, 321 „ Structure of the Brazil Nut 185 „ Memoirs 439 Microscopy 206, 321, 439 Middlesex Flora 412 Milk, Creatine in 95 Miller’s (W. A.) Experimental Illus- trations of Determining the Com- position of the Sun 335 Mineral Kotchoubeite, Characters of the 203 Mineral Nature of Eozoon 92 Minerals of the Breitenbach Meteo- rite 320 Mississippi, Deltas of the 91 Mivart (St. George) on Cuttle-fish 111 Modus Operand! of Creosote 305 Molasses, Extraction of Sugar from 189 Mole Cricket, the 327 Molecular and Microscopic Science 168 „ Change in Tin produced ,, Origin of Infusoria 51 ,, Phenomena in Iron 203 Moncecism in Sugula Campestris ... 85 Moon, Eclipse of the 82 ,, Heat from the 419 Moore’s “ Preglacial Man” 175 Morphia as an Antidote to Atropia 201 Morphine Process, the 323 Morphology of Leaves 185 „ of Malvales 84 Mossman’s “Origin of the Seasons” 294 Moths, British 410 Mount for Photographs, New 101 Mounting Finders, New Method of 299 PAGE Mucor Mucedo, Development of ... 427 Muller’s “ Facts and Arguments for Darwin” 289 Muriate of Ammonia as a Cure for Neuralgia 95 Muscles of Invertebrate Animals... 333 Mushroom, Anatomy of a 391 Naphthaline, Homologous Carbu- rets of 427 Natural Development of Bacteria ... 166 ,, History and Chemistry of the Ground Nut 302 „ History at the British Museum 328 „ History Transactions 416 Naturalist’s Directory 108 Nature-painted Butterflies 107 Nebula in Argo 179 "Nebular Hypothesis of Laplace ... 180 Negative Baths, Treating 101 „ Films, Cracking of 211 Negatives, Cracking of 323 Negro Cranium, Conformation of the 330 Nemerteans, British 331 Nerves, Ke-establishment of Sensi- bility after Resection of 94 Nervous Ganglia, Relation of the Auditory Organ in Cephalophora to the ; 107 Neuralgia, Muriate of Ammonia as a Cure for 95 New Laboratory at Leipsic 307 New Work on Chemistry 306 New Zealand, Dinornis in 190 Newman’s “British Moths” 410 Nikles (M.) Death of 305 Nitrogen, to Prepare 187 Nitro-glycerin, Chemistry of... 189, 306 Nitrous Acid, IDetermination of. 188 Nobert’s Plate, how to Count the Lines in 207 Nomenclature, Medical 202 North-American Birds, Catalogue of 108 North-west America, Mammalia of 332 Nose-piece, Substitute for a 207 November Shooting Stars 81 Nugent’s “ Treatise on Optics” ... 75 Oats as Protein-yielding Plants ... 423 Object-glasses, to Construct 208 Odling’s “Lectures on the Chemical Changes of Carbon” 292 Ogle (W.) on the Fertilisation of Salvia and other Flowers 261 Ohio, Geological Survey of 191 Oleographs, how to Take 213 Open Polar Basin, the 443 Opium Eating 317 Optics, Lardner’s 176 454 rOPULAR SCIENCE REVIEW. PAGE Optics, Popular 75 Orange Tree, Diseased, Ashes of a 86 Orchids, Fertilization of 416 Ordeal Poison-nut of Madagascar... 83 Organisms in Volcanic Rocks 311 Organ-Pipe Coral 331 Origin of Infusoria, Molecular 51 Ormeroid’s Geological Index 91 Orthoptera, Digestive System in ... 222 Osseous Medulla, Relation of, to the Blood 315 Owen’s (Prof.) Anatomy 67 Oxen, South American 222 Oxidation of Paraffin, Product of... 87 Oxyhydrogen Lamp, New 327’ Oyster, Practical Zoology of the ... 445 Pacixian Corpuscles, the 222 Packard’s “ Guide to the Study of Insects” 71, 176,414 Page’s “ Chips and Chapters for Young Geologists” 293 Palaentology 190, 309 „ of the Alpine Tertiaries 191 Palladium 218 Palliser Bolts 315 Paper, Photographic 101 Paper Prints, Plain 210 Paraffin, Products of the Oxidation of 87 Panigonite, Analysis of 438 Passion Flowers 159 Patents, Abolition of 417 PathologicJil Development of Lichen 201 Pennetier’s “L’Originede la Vie”... 172 Perspective, Shadow 77 Peru, Balsam of 308 Pharmaceutical Society, BoUmical Prize of the 301 Phenomena of Combustion under Pre.SHure 86 Phenyl-bichloracetic Acid 190 Ph i 1 1 i ps’ H ( Prof. ) Exeter Lect ure ... 433 Phillips’s “ Vesuvius” 170 3’hloron, Analysis of 304 Phosphorescence, Electric, in Ibiri- fied Gases 325 ,, how to Determine 441 Phosphorus, .Antidote to 188 ,, Holder 307 „ in Cast Iron, Detection of 320 ,, in Cast Iron, Estima- tion of 88 Photo crayon Process, new 209 I'hoto-enamel Process, new 325 Photogniphic Paper 101 „ Society, New 324 Photogniphs, ,Mc«Hcal 202 ,, New .Mounts for 101 „ of -Authors 212 PAGE Photographs of the Great Eclipse, Tennant’s 179 „ of the Trans it of Venus 419 „ Printing, by Mecha- nical Means 210 Photography 100, 209, 323, 440 ,, Lamps for...... 101 „ Landscape, in Cloudy Weather 101 ,, Observation of the Transit of Venus by IT'O „ Telescopic 212 „ Truth of, versus Artis- tic Licence 211 Photo-rstatistics 324 Phrenology, the Lingering Admirers of 380 Phyllobothrium, Scolex of, in a Dolphin 106 Physical Properties of Gadolinite... 318 Physics 102, 212, 325, 440 „ at the British Association . 444 „ of the Gulf-stream 326 Physiological Action of Cyanogen Gas 96 „ Effects of Lightning . 316 „ Essays 77 „ Phenomena of Plants Explained 303 Physiology, Chair of 332, 334 Pig-iron, Conversion of, into Steel . 99 Pinus Pungens 422 Pipes, Joints of, for Water Mains . 315 Planet Mars in Februai'y 1869 ... 39 „ Saturn in July 1869 252 Planets during Spring 181 „ the 82, 300, 422 Plants, Bacteria in the Protoplasm of 185 ,, Carbonic Acid Decomposed by 189 ,, Cellular, why Absent from Coal Measui’es 302 „ Chemical Food of 189 ,, Fossil, of Greenland 312 „ from Brazilian Coal-beds ... 311 „ how Light Affects the De- composition of Carbonic Acid by 424 „ Influence of Artificial Light on 302 „ Nutrition of 423 „ Pliysiologiail Phenomensi of. Explained 303 „ Relative Value of the Cha- racters of 425 Pneumogastric Nerves, Influence of, on Respiration 200 Po, Deltas of the 91 Pfjisoning, Detection of Mercury in Cases of 187 Poison-nut of Madjigascar, Ordeal. 83 Poison, Snake, and its Cure 202 INDEX. 455 PAGE Polar World, the 174 Popular Optics 75 Porcelain, Hydrogen Flame-colour on 190 Positivism in Chemistry 303 Potentilla Norvegica in England ... 83 Precious Stones, Formation of 205 Preglacial Man 175 Prehistoric Archaeology 311 Preparation of Artificial Ebony ... 306 „ of Cerium 188 ,, of EUagic Acid 189 Pressure and Chemical Action 307 Printing Photographs by Mechani- cal Means 210 Printing-press, Use of, to Photo- graphers 100 Printing-surfaces, New Method of Preparing 324 Proboscis of the Blow-fiy 333 Proctor (E. A.) on Fixed Stars 358 „ (Mr.) on the Transit of Venus 297 „ (E, A.) on Saturn, in July 1869 252 „ ,, on the Planet Mars 39 „ „ on the Use of the Spectroscope in Astronomy 141 Proctor’s “ Half-hours with the Stars.” 291 Protoplasm of Plants, Bacteriain the 185 Psychology, Comparative 332 Puissieux (M.) on the Coming Transits 297 Purification of Metallic Bismuths. 188 Purkings (Prof.) death of 437 Quadrupeds, Ciliary Muscle in 109 Quatenary Gravels of England 90 Queckett Club Soiree 208 Eadiation from Steam Boilers 93 Eailway Trains, Intercommunica- tion in 93 Eed Chalk of Hunstanton 193 Eeed (Mr.) on Ironclads 314 Ee-establishment of Sensibility after Eesection of Nerves 94 Eefraction and Temperature 217 Eeliquse Aquitanicse 290 Eemoval of Silver-stains 100 Eesi stance of Armour-plates 315 Eespiration, Influence of Pneumo- gastric Nerves on 200 Eestiacese, South- African 84 Eetina of the Hedgehog, Vascular Parts of the 329 Eeviews of Books 67, 168, 284, 408 Eichardson (B. W.) on the Mind and Death 275 PAGE Eifle, New 313 Eivers, Sediment of 309 Eocks, Volcanic Organisms in 311 Eotifera, Teeth of 330 Eotifers, Desiccation of. 332 Eoyal Botanic Society 423 Eoyal Institution, Chair of Physio- logy at the 332 ! i I Saxamander, New Genus of 333 Salt, Influence of, in Absorption ... 201 Salvia, Fertilisation of 261 Sandstone 194 Sarracenia, Variation in 423 Saturn, in July 1869 252 Saurian Eemains, New Zealand ... 432 Scandinavian Botany 301 Schefiler’s “ Theory of Optical De- fects and of Spectacles.” 175 Schnitzlein, Death of 183 Science of Man, the 73 Scientific Agriculture 415 ,, Summary 79, 178, 296,418 Scolex of Phyllobothrium in a Dol- phin 106 Scudder’s “Fossorial Crickets” 414 Sea-bottom, Atlantic 331 Sea-sickness 78 Seasons, Origin of the 294 Sea-squirts, Structure and Affinities of 240 Seaweed, Coal from 319 „ New 83 Secondary Alcohol, New 89 Sediment of Eivers 319 Sensitive Albumenized Paper 100 Sensory Impressions, Conduction of 97 Sertularian Zoophytes of our Shores 223 Sesqui-salts of Iron, Decomposition of 30d Shadow Perspective 77 Shell of Crustaese, Structure of. 108 Sherwood Forest, the Birds of 295 Shetland, the Botany of 301 Shooting-stars, November 81 Short-period Comet, Winnecke’s ... 298 Shortrede’s “ Azimuth” 416- Sigilliana, Structure of 310 Siliceous Sponge, New 331 Silicic Acid, Crystalline Modifica- tion of 203 Silkworm Culture 108 Silver, Assay of, in the Wet way, 99, 202 Silver- stains, Eemoval of 100 Similitude of Hydraulic Trajectories 104 Skin Tissue affected in Small-pox. 200 : Slag, Blast-furnace, Utilization of . 318 i Small-pox, Skin Tissue Affected in, 200 I Smith's “ Disinfectant and Disin- I feetion.” 176 456 rOPULAR SCIENCE REVIEW. Snake-bite, Injection of Liqiiid Am- monia in Snake Poison and its Cure Soap-bubbles, why they can be Blown Solar Activity „ Engine „ Prominences „ „ Method of View- ing, without an Eclipse „ „ New Method of Viewing Somerville’s “ Molecular and Mi- croscopic Science ” Sound, Analysis of South African Kestiacese „ American Oxen Spectacles, on 175, Spectroscope, Use of, in Astronomi- cal Observation Spectroscopic Examination of Stars Spectrum Microscope, Binocular . . . „ to Determine the Com- position of the Sun by the Spiders, the Habits of Sponge, Siliceous, New „ Tissues of the Spontaneous Generation 96, Spores of Variccllaria, Germina- tion of the Star-spectroscope, Browning’s Star-spectrum, New Type of Stars, Fixed ; are there any? „ Half-hours with the „ to Ascertain the Heat of the Steam-boilers, Rad ation of „ carriage „ engine Performance „ Towage on Canals Steel, Colours seen in Tempering... „ Conversion of Pig Iron into.. Sterland’s “ Birds of Sherwood Forest ” Stone (Mr.) on the Transit of Venus Stones, Precious, Formation of Stress, Graphic Determination of... Structure and Affinities of Sea- squirts „ of Sigillaria Strj’chnia and Akazga Plants, Dif- ference between Study of Insects, the 71, St^dfe's “ Iron and Steel ” Subterranean Lava Tides Suez Canal •Sugar, Extniction of, from Molasses Sugula Campestris, Moncecism in... Sulphate of Alumina, Action of, on Turbid Water Sulphocj-anic Ethers, Compound.s Isomeric with Sulphur, Estivating PAGE Sulphuric Acid, Volumetric Estima- tion of 308 Sulphurous Acid in the Atmosphere 200 Sun’s Distance, the 81 Sun, Facts concerning the 417 „ Spots 422 „ to Determine the Composition of the, by the Spectrum 335 Supersaturation of Sugar Solutions in Alcohol 306 Synopsis of the South African Res- tiacese 84 Synthesis of Creatine 308 „ of Hydrocyanic Acid, New 89 Table Mountain Pine 422 Tar, Vegetable, as a Dye-stuff 85 Tartaric Acid, Artificial Production of 96 Teeth of Rotifera 330 ,, Preparing Sections of 207 Telegraph, New Battery of 326 ,, Use of, in ascertaining Longitude 213 Telescopic Photography 212 Temperature and Refraction 217 „ of the Air and Trees... 327 ,, of the Body in Health 198 „ of the Superficial Struc- ture of the Earth 205 Tempering and Annealing, Physics of 439 j Tendon and Muscle 437 j Tennant’s Photographs of the Great Eclipse 179 ■ Teratology, Vegetable 288 Tertiary Fossils 431 Therapeutics, Chromic Acid in 318 Thermometer for Deep-sea Sound- ings 443 Tin, Alloys of 204 „ Molecular Change in, Pro- duced by Cold 103 ,, Structure of 439 Tinea Favosa, Experiments in 438 Tinting Vegetable Tissues 183 I Tis.sues of the Sponge 222 Titaniferous Magnetites 99 Tobacco, Adulteration of 84 I Tonic, new 437 I Tr.achcal Vessels in Ferns 426 I Transfusion, Experiments on 97 j Transit of Mercury 81 I ,, Venus, M. Faye on the . 296 i „ „ Mr. Stone on the . 296 I „ „ Mr. Proctor on the 297 1 Transits of Venus in 1874 and 1882 178 ,, ,, Observation of 179 Trees, Temperature of 327 Tree-trunks, Largest Diameter of... 301 I Triarthra Longiseta 222 PAGE 437 202 104 298 93 79 180 212 168 294 84 222 , 131 141 440 322 335 109 331 222 172 84 421 299 359 291 214 93 196 314 436 319 99 295 296 205 197 210 310 182 176 295 312 195 189 85 187 87 190 INDEX. 457 PAGE Trimen’s (Dr.) Appointment to the British Museum 301 Trimen’s “ Flora of Middlesex” ... 412 Trimerella, the Genus 91 True and False Flint Weapons 30 Tubularian, Fossil 430 Tuhularian Zoophyte, Fossil 310 Tunicata 240 Tuning-fork, Improved 441 Turaco, Feathers of the, Colouring Matter of 334 Unifobmitarianism and Catastro- phism 310 Universe, New Theory of the 300 Unseen Fault, how to Determine ... 432 Unwin’s “ Wrought-iron Bridges ” . 415 Uric Acid, Chemical Constitution of 86 Utilisation of Blast-furnace Slag... 318 Vanadium, Eesearches on 429 Varicellaria, Germination of the Spores of 84 Varieties of Graphite, the 186 Vascular Parts of the Eetina of the Hedgehog 329 Vegetable Cell 106 „ Teratology 288 „ Tissues, Tinting 183 ,, Tar as a Dye-stuff 85 Veins, Action of Alkaline Sul- phates when Injected into the ... 197 Velocipedes 436 Ventilation, Errors of Architects as to 201 Venus, on the Transit of, in 1769... 296 „ Transits of, in 1874 and 1882 178 Venus, Photographs of the Transit of 419 ,, Mr. Hind’s Elements of the Transit of 420 ,, Transits of. Observation of 179 Veratrum, Influence of, on the Heart 95 PAGE Vertebrates, the Anatomy of 67 „ Prof. Huxley’s Lec- tures on 202 Vessels, Eesistance of 435 Vesuvius 170 Vibriones Developed after Admini- stration of Cyclamine 95 Vitality of Desmids 185 Volcanic Eocks, Organisms in 311 Volumetric Estimation of Sulphuric Acid 308 Von Martius, Death of 183 Voyage of the “ Jean Bart” 299 Waluace’s “Malayan Archipelago ” 286 Ward ward’s “ Arithmetical Exer- cises for Chemical Students” 413 Water 427 „ Animal Life in 220 „ Mains, Joints of Pipes for... 315 Wave Motion, Apparatus for Exhi- biting the Laws of 93 Weapons, Flint, True and False ... 30 What is Bathybius? 350 “ What is Matter? ” 293 Whitley (N.) on Flint Weapons ... 30 Williamson (Prof.) on Bathybius 350 Winnecke’s Short-period Comet ... 298 Wollaston Gold Medal, the 191 Wood Pulp, how to Bleach 184 Word’s “Bible Animals” 411 Xylol of Coal Tar 304 Zandab, the 221 Zoological Society, the 221, 333 Zoology and Comparative Ana- tomy 106, 219, 327, 445 „ Chair of, in Dublin Uni- versity 446 Zoophyte, Tubularian, Fossil 310 Zoophytes, British 287 ,, Sertularian 223 Zoosperms of Fishes, Development of the 329 END OF VOL. 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