USEFUL AND SCIENTIFIC NOTES.

WHEN brass castings are of too complicated a form to be ground, filed, or machined, they may be finished by the action of acid, either alone or combined with a varnish. After cleaning the casting by heating it and plunging it into acidulated water, it is immersed in a bath composed of two parts of nitric acid and one part of water, or one part of sal-ammoniac, one of sulphuric acid, one of nitric acid, and one of water. The casting is then plunged into pure water, then into hot soap ley, and dried in hot sawdust.

It must be borne in mind that no Displayed advertisements can appear in the "Sixpenny Sale Column." All advertisements must be prepaid; no reduction is made on repeated insertions; and in cases where the amount sent exceeds One Shilling, the publisher would be grateful if a P.0.0. could be sent, and not stamps. Stamps, however (preferably halfpenny stamps,, may The address is included as part of the advertisement, and charged Advertisements must reach the office by 1 p.m. on Wednesday

for.

A DESCRIPTION of the grotto of the Roc du Buffens, near Cannes (Dépt. Aude) appears in the last number of M. Cartailhac's Matériaux pour l'Histoire de l'Homme. This description is contributed by M. G. Sicard, who has been engaged for some time in exploring the cavern. His researches have brought to light a large number of objects in stone, bone, horn, bronze, iron, and pottery, many of which are figured. A small gold ornament was also discovered. The cave appears to have been inhabited during the Neolithic age, and again towards the close of the Bronze period. Associated with some of the bronze objects were several human skeletons.

On the Pennsylvania Railroad the average consumption of fuel for all passenger trains is 56lb. per train mile.

THE 18 principal English railways have earned almost exactly a million a week during 24 weeks of the present year.

ERRATUM.-In the paragraph on p. 368, referring to the wearing power of balls for velocipedes, as tested by Mr. Boys, "21 grains" should have been grain for the twelve, or about both of a grain each.

Every Workman connected with the Building Trades requiring a Situation should advertise in "THE BUILDING NEWS," published every FRIDAY, price Fourpence, at 31. Tavistock-street, Covent-garden, London, W.C.

THE BUILDING NEWS" is the Principal Journal, representing Architects and Builders, and has the largest circulation of any Professional Journal in the kingdom.

very Workman should insist on seeing "THE BUILDING NEWS" every week at his Club or Coffee House. He will find more "Lists of Tenders" for new work in it every week than in any similar paper, and can thus judge where work is likely to be had. He is also specially invited to make use of "Intercommunication" if he wants to know anything about his trade; to write to the Editor if he has any suggestions to make, and to advertise in the paper when he wants work.

The charge for Advertisements for Situations is One Shilling for Twenty-four Words, and Sixpence for every Eight Words after.

OUR EXCHANGE COLUMN.

and 8d. for every succeeding 8 words.

Half-horse Horizontal Engine, new, working order, lubricator, governors, throttle valve; also bench drilling machine; for screw-cutting lathe, 4in. centre, change wheels, slide-rest, complete, or offers. JAMES TAYLOR, Ilminster, Somerset.

Splendid new English Lever Watch, cost £6 10s. Exchange for Bicycle, Tricycle, Telescope, Gold Guard, Harmonium, Bing, or anything useful.-R. POWNALL, Prescot, Lanc. Good Value Offered (cash or instruments) for all kinds of sound or repairable Scientific Appliances.-CAPLATZI, Science Depot, Chenies street, near British Museum. Established 1862. perfect condition, profusely illustrated. Complete Works of Flavius Josephus, in parts, in Cost 308. Wanted binocular field-glass, telescope, o.g, or offers -A. McWHIRTER, 23, Paterson-street, Kingston, Glasgow.

I will give American Orguinette, cost 558., for a good lens - EDWARD SCANNELL, Victoria- buildings, Bo'ness, Linlithgow, Scotland.

Melodium Organ, 28 by 15 by 13in., as new, fine Rochford, Essex.

tone, 8 tunes-secular; for anything useful to £5.- FRANCIS,

Dorrington's double-cylinder Gas Engine, half horse power, one engine finished, about a day's work on the other. Turned flywheel, gasbags, and everything complete, only £12, offers-exchange.-R. J. BRowN, care of W. Webster, Tontinestreet, Folkestone.

Horizontal Slide Valve Engine, with copper boiler, in good working order, lin. stroke. Exchange for bicycle, 44in. or 46in.-J. BROOKS, West-street, Alford, Linc. Exchange Gregorian Telescope, 4in. for dynamo or electrical machine, or offer; seen any time.-T. H., 85, Walworth-road, S.E.

anything useful.
My three h.-p. Engine not sold yet; will exchange
It is in my way very much.-McKIE, 135,
County road, Walton, Liverpool.

A splendid Model of a full-rigged ship under full sail, everything complete. What offers ?-H. 148, Brooke-road, Stoke Newington,

Sewing Machine, Clegg and Blacklock, in good working order. Harmonium or small organ wanted. Stamp for reply.-Day, 56, Driffield-road, Old Ford London.

Galvanic Coil, Horne and Thornthwaite's, in mahogany case, cost £3 38. Microscope wanted. Stamp for reply.DAY, 56, Drifeld-road, Old Ford, London.

Photographic C.D.V. Lens, by Voigtlander, with camera by Lawley. Glass speculum wanted. Stamp for reply.-DAY, 56, Drimeld-road, Old Ford, London.

Photo. Apparatus, by Stanley, quarter-plate, in case, with stand. Lancaster's Instantograph wanted. Stamp for reply.-DAY, 56, Driffield-road, Old Ford, London.

Exchange full-plate Sliding Camera, Paris Lens, take views or portraits, chemicals, 2 baths, printing frames all complete, for keyless silver Geneva and gold Albert.-Baown, 78, Market-street, Church, Lancashire.

Avery's Steelyards, weight 141b. to 18cwt.. equal new; 521. Coventry bicycle, ball bearings, rubbers, spoon brake, new, exchange-offers.-310, Bilston-road, Wolverhampton. Incandescent Lamp, Semi-Shocking Coil, own make; book on electricity, map of Middlesex, motor magnet. What offers ?-C. KINO, Jeweller, Windsor.

Splendid 2in. Lathe, 8-speed and back-gear, on planed iron bed, with bench, crank, flywheel, and all tools complete; for good 50in. Bicycle, or offers to value £5.-8. B., 6, Cass-street, Salford, Manchester.

Six-cell Bunsen Battery, cells each 8in. high by 5in. dia.; Air Pump and Receiver. What offers ?-E. HENRY DAVIES, Ebnal Lodge, Oswestry.

What offers for pair 6in. Lathe Heads, cylinder poppit), and rest; "British Battles (complete); 130 Nos." Leisure Hour; 90" Cyclist."-C. BELCHER, Heybridge, Maldon.

A Goldfinch Mule and Cage. Will exchange anything useful.-D., 4, Flinton-street, Burrey-square, S.E. Horizontal Steam Engine. in good order, cost 258, Will exchange for Electric Bells, or what offers ?-F. WILSON, 28, Sinclair-road, West Kensington,

Electric Light Dynamo, 50-light, nearly finished, Very massive Field Magnets. What offers to value of £9.-A. J. 8. 188, Mare-street, Hackney, B.

Splendid large Medical Coil, solid ebony mounts, power circuit, perfectly new, value £4. Also small Induction Coil. Offers.-WHITE, Ördnance Office, Tower, E.C.

"Portfolio," "Art Journal,"" Harper,"" Scribner."" Blackies New Atlas." Wanted 3 or 4 inch parallel vice, drill chuck, revolving cutter, tool-holder, &c, for a 5in. lathe.31, Woodlands-street, Cheetham hill, Manchester.

Model Slide-valve Engine and Boiler, all brass, cylinder lin. by 2in., burns charcoal Exchange for achromatic telescope, about 1in. diameter.-W. H. KING, Winterslam, Salisbury.

Wanted, Gasogene, cane-covered preferred, must be in perfect order, and best make; cash if cheap, or exchange new magneto electric machine, cost 30s. Particulars, T. A. C., Fairfield House, Warrington.

Beveral Packets of Japanese Flower Seeds, 25 varieties, What offers in exchange?-125, Coltman-street, Hull.

THE SIXPENNY SALE COLUMN.

The Compo-Lithograph (Manufactured License under Wilson's Patent, The Hektograph, 1.006, NO 13th, 1878), is the 'Graph that requires neither washing Bor re melting. Full particulars may be had of any stationer, or post free from the COMPO-LITHOGRAPH Co., Skinner-street, Bishope gate, London, E.C. Fretwork. Illustrated Catalogue of Machines, Saws, Tools, and 400 miniature designs, four stamps.-H Baos., Settle. "Faces we Meet, and How to Read Them," 1s. 8d. post tree.-G. PICKLES, Dalry, Ayrshire.

100 Foreign Stamps, including unused Portorico, Brunswick, Sardinia, Saxony, Constantinople, free 7d-HELL. Foley-street, London.

Oxygen Gas compressed into iron bottles, liquid nitrous oxide and carbonic acid.-CLARKSON, Compressed "Ga Chemist.

Oxygen Gas compressed, iron bottles; bottles lent on hire.-CLARKSON, Compressed Gas Chemist.

Oxygen Gas compressed into iron bottles; prices on application.-CLARKSON, 28, Bartlett's-buildings, Holborn, B C

Safety Bicycle.-Splendid 62in. Singer's 'Xtraordinary, new, cost £21, price £14.-H. M. PASHLEY, 180, London road, shetiteld.

Soda Water, Lemonade, Ginger Beer MaCHINE, by Samson Barnett, second-hand, bargain.-N. G. WIL COCKS, Bath.

Fishing Bait. Red Ching. -This celebrated Chinese Bait received first prize in Fisheries Exhibition, and will keep for years. salt and fresh water fish are attracted from a long distance in large numbers by its peculiar odour and colour, tak the bait voraciously. Wholesale, Ba per dozen; single packets. post paid, 1s 28.-Agent, T. W. BYANS, Importer, II, Shirivy Park-road, Southampton.

Kitcheners, Stoves, Hot Hearths, &c. Lists free. 24in. range, 10s. 6d-WINSTONE, 89, Chiswell-street, London.

Japanese Bamboo Fishing Rods, 5, 6, or 10 joint, 15ft., s.-BRISTOW and COMPANY, Hull.

Indiarubber Stamps. Immense variety. Extraordinary novelities. Satisfaction guaranteed. Designs 1d stamp -A. H. PASHLEY, 180, London-road, Sheffield.

tive.

Indigestion and Constipation.-Take a LarsRobson's Fruit Laxatives, 2s. 9d. and 4s. 6d. in stamps post free-ROBSON and Co., 18, Southampton row, Holborn, London. W.C., and all Chemists.

Violin Tone Indicators, giving four notes, in case, post free la, 6d.-F. PITMAN, Paternoster-row, London. Violin Strings.-Send 12 stamps for three firsts. sure to give satisfaction.-F. PITMAN, Paternoster-row, Londen Lunt's is the noted House for tools. Bend four stamps, revised reduced illustrated catalogue, 80 pages.

10; 4, 15lb., 15s.; 41, 281b., 218.-LUNT'S. Parallel Bench Vices, steel jaws, grip 3, 9 lb.,

for fitting-A. 8. LUNT, Tool Maker, 297, Hackney-road, B Planes.-New London smoothing, finished or ready

Glass Bottles of every description.-Wholesale prices on application to DavRY, 51, High-street, Hull.

Dynamo (Grove's improved) for eight incandescent lamps, moderate speed, extra strong, weighs 1081b, price £13. Photo. six stamps.-BENNETT, 131, Hope-street, Glasgow.

Castings.-One horse-power Horizontal Engine Castings, pertected, porta in cylinder, 24a. per set Photo of Particulars free.-J. TOMLIN, Engineer, 12, Cavendish-terrace. Barnsley.

Half Horse-power Horizontal or Vertical PERFECTED ENGINE CASTINGS, made in the improved Tenes System, porta cast in cylinder, 12s. 6d. per set, including wrought iron and brass work. Photo. 6d. Particulars free.-J. Toxus. Engineer, 13, Cavendish-terrace, Barnsley.

including bevil cog wheels.-J. TOMLIN, Engineer, 12, Carcadas Drilling Machine Castings, 88. 6d. per set, terrace, Barnsley.

Gentlemen and others requiring Inventions worked out, practical advice, work done, tools made.—Write, G. Orram. Inventors.-Use of Tools, Steam Power.-Write, Gʻ OFFEN, 13, Verulam-street, Gray's Inn-road, London.

Lathe, 4in., back-geared, treadle, 4ft. bed, aliderest bargain,-ANDREWS BROTHERS, Goodrick-street, Bumaş bam.

Jewellery, Pawn tickets for, cheap. Write for list Great bargain.-BIROHALL, JUN., 6, Mark lane, London.

Gas Engines. One h.-p., with governors, £39; 1h-p., £29; 3 man-power, £25; 14 m.-p., 19; I'm p. £16, ca. Quite new, shown working. Six months guarantee from me Constitution-hill, Birmingham. Numerous testimonials from purchasers.—SIMPLEX, Post

100ft. Glass, cut to size, packed, delivered to rail 13s. 6d.; 2102., 218.-E. HOLMas, 149, Essex-road.

"English Mechanics," Vols. XXXI. to date. unbound, Ja. per vo ume.-Q. MASON, 86, Clyde road, Didsbury

Cuttriss D' Electromotor or Dynamo, weight 181o., work sewing machine, lv cells battery, 64, together or separate.-H. PICERINO, Chemist, Leicester.

the front of the first plane of the bottom, while the water-tight compartments at the sides of the vessel are formed into a sort of platform at the stern, by means of which eddy-making is to be avoided. The air-ducts have another office to perform besides rendering the inclined planes of the bottom independent of one another, for by means of self-acting valves, which, however are not shown in the diagrams published by the patentee, any tendency to roll is "immediately counter acted" by the air-ducts on the rising side of the vessel closing automatically, thus creating a vacuum on that side, while the greater pressure exerted on the water on the other side will tend to restore it to the normal level. The aquaaerial ship is also a novelty in this respect, that the power required to keep up the speed will decrease with the increase of the vessel's rate of progression "the only thing necessary being a high speed of engines." The patentee may well say that this is one of the most remarkable features of the invention, being diametrically opposed to all past experience in naval construction. Unfortunately there is no proof that the aquaaerial ship will do what its patentee asserts, for we have no information as to whether or not it has been tried even in model form. The device has several features to recommend it; for instance the form of hull admits of great structural strength combined with lightness, while narrowness of beam is of no object, as the vessel has not to cut its way through the water, but like the polysphemic ship, will rise over the waves and skim along the surface-that is if the patentee's views are corroborated by practical experiment.

THE PHYSIOLOGICAL ASPECT OF MESMERISM.* (Concluded from p. 390.)

TH

By J. N. LANGLEY, Esq., M.A., F.R.S. HERE are certain attitudes which we usually assume under the influence of certain moods or ideas; from each of the muscles concerned in bringing about any one attitude, impulses travel up to the brain, and give rise to a definite muscular aensation which comes therefore to be associated with a particular mental mood. In mesmerised people the production of a definite muscular sensation not infrequently produces in the mind the mood with which it is, in the wakeful state, associated. At the same time ideas may be produced corresponding to the mood, and the ideas may give rise to particular actions, such as laughing, crying, fighting.

If the head is pushed back, and the shoulders opened out, the face assumes a look full of pride or haughtiness, and if the subject be asked what he is thinking about, he will give some answer indicating what a fine fellow he fancies himself to be. If, then, the head is bowed and the shoulders contracted, the aspect of the face changes to one of humility and pity. Occasionally it happens that a alight pressure on a single muscle, which causes it to contract, will by an irradiation of nerve impulses produce the muscular sensations proper to a group of museles, and this will give rise to the associated frame of mind. Thus very different feelings may be made to rapidly succeed one another in the mind of the subject by simply pressing on various muscles of the head and neck. At first sight such an experiment looks like a revival Eof the now happily forgotten phrenology.

I have said that in a frog which remains mesmersed for any time, there is a considerable reflex depression, i.e., inhibition of the whole of the entral nervous system-that there is an irradiation f inhibitory impulses. In man a similar irradiaion of inhibitory impulses appears to take place; sually a mesmerised person if left alone passes radually, but often rapidly, into a state of torpor; onsciousness disappears, memory is lost, reflex tion becomes difficult to obtain, finally, it may , there is complete anesthesia-a limb may be cut without producing any movement or any pain; ace this torpor comes on without anything further eing done to the subject, we may conclude that ere, as in the frog, but to a much more marked gree, there is an irradiation of inhibitory pulses. The primarily inhibited centres send inhibitory impulses to all other nerve centres. p to a certain stage, possibly throughout, any or more centres may be brought back to a conption of activity by certain exciting stimuli, but Pen these cease the inexcitable condition is soon Hought back by the inhibitory impulses streaming them from other nerve centres.

The extent to which the torpid condition develops if varies in different individuals. It depends

A lecture delivered before the Royal Institution of at Britain.

In different people the order in which different centres are inhibited varies, as we should expect in different people. This is no doubt of influence from the unequal development of different centres in determining whether the general state is cataleptic, somnambulistic, or lethargic, and here probably the method used to mesmerise is also of considerable importance; it would seem that the cataleptic condition is more likely to be developed when the process of mesmerisation involves a strain on the eyes of the subject, than when he is mesmerised by passes. Not much attention, however, has as yet been directed to this point. There can, I think, be no doubt that mesmerism may help, and sometimes cure, persons suffering from certain diseases of the nervous system. It is of the way in which this is brought about; but not in our power to make any accurate statement since disease may be the result of either an overactivity, or of an under-activity of any part of the central nervous system, it is reasonable to suppose that a beneficial effect will follow the employment of a method which allows us to diminish or increase these activities as we will. This is a side of the question which is of the greatest interest both to physicians and to physiologists-to physiologists, since it bears directly upon the problem of the influence of the nervous system on nutrition. There is good reason to believe that by directing attention strongly to any particular part of the body, the nutritive state of that part of the body may be altered. The determination of the actual way in which this is brought about is full of difficulties, but the following way is at least theoretically possible. It may be that the nerve centres connected with the tissue in question are made unusually active, and that they send out nerve impulses of a trophic nature, that is, impulses which directly control the nutrition of the tissue. The alteration in the tissue caused by its changed nutritive state-its changed metabolism-may conceivably be either beneficial or detrimental to the whole organism; it may give rise to a diseased state, or get rid of an existing one.

The modern miracles of healing, wrought in persons in a state of religious enthusiasm, offer a field for investigating this problem; the field, however, is a particularly bad one, and chiefly because so many people concerned regard any careful examination of the subject as impious. But in mesmerised persons it seems probable that such investigations could be made on a fairly satisfactory basis. Men when mesmerised gradually lose remembrance of those things which they remember when they are awake, but not infrequently other things are remembered which are forgotten in the waking state. This is normally the case with a person who has been previously and recently mesmerised. He may then remember little else than what took place in the corresponding stage of his previous mesmerisation. In a certain state, then, an event or a command will produce in the central nervous system those changes which are necessary for the event or the command to be remembered later, without ever rising to consciousness in the waking condition. Thus a command to do a particular thing, given to a subject in this mesmeric stage, may be carried out when he awakes, although he is quite unconscious why he does it. We may say that such an act is one of unconscious memory. But it is, I think, something more than this. The subject is usually uneasy and preoccupied until the thing is done; he is to a greater or less extent unable to fix his attention on other things; he is, in fact, in a state of unconscious attention to an unconscious memory. This brings us to our point. It suggests that if a subject in a certain stage of mesmerisation be told that in a few days a sore will appear upon his hand, or conversely that a sore already there will disappear, the conditions which accompany conscious expectation and attention, will to a certain degree be established; and the trophic influence of the nervous system on the tissues may be tested in a manner which puts the experiment fairly within the control of the observer, and to a certain degree excludes impos

A case is recorded by Braid of a woman who, during natural somnambulism-which is almost identical with a state that can be produced by mesmerism-could repeat correctly long passages from the Hebrew Bible, studied any of thes- languages, and was quite ignorant and from books in other languages, although she never of them when she was awake. At length, however, it was discovered that she had learnt the passages when she was a girl, by hearing a clergyman with whom she lived read them out aloud.

A lightly mesmerised subject can be easily brought back to a normal condition by a sudden, slight shock, by sprinkling water in the face, or by a current of cold air. These give rise to exciting impulses which arouse to normal activity the inthat any other part of the central nervous system hibited parts of the brain; just as we have seen can be aroused to activity by slight exciting impulses. There is no mystery in this, beyond the mystery which lies in the relative action of all exciting and inhibitory impulses. The power of responding in strikingly different ways to weak stimuli differing in kind, or to stimuli apparently of the same kind, but differing in intensity, is not peculiar to the nervous system of man; it is a power possessed by the nervous system of all animals, and indeed, not improbably by all living substance. This has already been touched upon in what I have said of inhibition; but I will give you one or two slight, and apparently not very dissimilar, stimuli other instances of the dissimilar effects produced by -instances which are especially pertinent to the subject of mesmerism. These we owe to Heidenhain.

When morphia is given to a dog, and the animal is left undisturbed, it passes into a condition resembling sleep; but a little investigation usually shows that the condition differs in certain notable respects from sleep. Whilst consciousness, as far as can be told, is gone, and voluntary movement is abolished, many reflex actions can be obtained much more readily than in the waking state; moreover, there is a tendency for the muscles, which contract in a reflex action, to remain contracted, the nerve centres when set in activity remain active for a considerable time, and continue to send out impulses to the muscles, which in consequence are kept contracted: in other words, the reflex contraction produced by a slight stimulus applied to the skin is of a tonic instead of a tetanic nature. Now this tonic contraction can be brought to an end by various slight stimuli, for instance by lightly stroking the skin over the contracted muscles, by gently tapping the contracted part, by blowing in the face of the animal, or by stimulating the cortex of the brain by a weak electric current. Nevertheless, the acts just mentioned may, when the muscles are not contracted, cause, or help to cause, their contraction. I will give an instance of this. Electrical stimulation of a definite part of the cortex of the brain causes a tonic contraction of certain muscles of the leg, in consequence of which, let us say, the leg is bent and remains so. Now we have seen that passing the hand over the skin of the leg will cause it to unbend; well, if the cortex of the brain be stimulated with an electric current, not quite strong enough to produce of itself bending of the leg, the bending may at once be produced by gently stroking the leg at the same time as the cortex is being stimulated. Of a similar nature is the effect of electrical currents of different strengths. When a limb has been brought into a state of tonic contraction by electrical stimulation of a certain part of the cortex of the brain, a weaker electrical stimulation of the same spot of the cortex will bring the tonic contraction to an end.

dog under the influence of morphia, closely resemble The phenomena just described as occurring in a those often observed in human beings when mesmerised. Commonly in a mesmerised person the arm, let us say, may be made to bend by gently stroking the skin over the appropriate muscles; give a slight tap on the arm, and it relaxes. Braid observed in some subjects that if a limb was made rigid by passing the hands over it, and if it was left extended for a short time, then the repetition of the same act of passing the hands over the limb caused the rigidity to disappear. It is unnecessary, I think, to consider in detail the corresponding states in the narcotised dog and the mesmerised man; enough has been said to show that in both certain slight stimuli produce, sometimes excitation, sometimes inhibition.

It must, however, be noted, that our conception of inhibition is not rendered clearer by these facts; for it would appear from them that a nerve centre may be excited or be inhibited by the same nerve impulse, the result depending upon the condition of the nerve centre. This is not a necessary inference, but it is perhaps at present the most convenient working hypothesis. A certain group of facts, indeed, may be held together and receive a provisional explanation by saying that in some excites a nerve centre if it is quiescent, and inhibits conditions of the central nervous system, a stimulus it if it is active.

It seems to me probable that what is called the "transference of contracture" and the "transfer

ence of sensation" are of the same order of facts. These phenomena are exceeding curious. Suppose that the left biceps of a mesmerised person be gently stroked or pressed, so that it contracts and remains so. The continuous contraction of the muscle is called contracture. In consequence of the contracture, the arm is kept bent. Suppose that the biceps of the other arm be gently stimulated, we may get a transference of the contracture, i.e. the right biceps becomes contracted and the right arm bent, whilst the left arm which previously was bent, falls flaccid. Similarly there may be a transference of sensation; thus the right arm, say, is rendered insensitive, so that pricking it with a needle does not give rise to any sensation; on the back of the right hand, a piece of metal, such as a two-shilling piece, is now placed, and left for a short time. On removing it, it is found that the spot of skin which was in contact with the metal has become sensitive, so that the prick of a needle is at once felt, but that the corresponding part of the other hand has become insensitive, so that pricking it with a needle produces no sensation.

The observations of this kind have hitherto been made almost, though not quite exclusively, upon patients suffering from certain diseases of the nervous system, and the facts have been described as occurring both in the wakeful and in the mesmeric state. The proximate explanation appears to be, to take the case of transference of sensation just mentioned, that the gentle tactile stimuli caused by the pressure of the coin on the skin, reaching an inhibited centre, sets it in activity, and the sensibility of that part of the skin is restored, but the stimulus passes on to the corresponding and hitherto active centre of the opposite side of the body, and this is inhibited.

Here I must leave the subject. I have not at tempted to give an account of all the phenomena of mesmerism; I have taken those phenomena which seemed to me to be the least easy to understand, the most liable to misconception, and have attempted to show that they resemble fundamentally certain simpler phenomena which can be observed in lower animals. I have further attempted to string together the various facts upon a thread of theory, which may be briefly summed up as follows:

The primary condition of mesmerism is an inhibition of a particular mode of activity of the cortex of the brain, in consequence of which the will can no longer be made effective. This inhibition may be brought about by nervous impulses coming from certain sensory nerves, as those of sight, touch, hearing.

It may also be brought about by impulses or changes arising in the cortex itself. The inhibited cortex, and probably also inhibited lower centres of the brain, send out inhibitory impulses to all other parts of the central nervous system, so that the mesmerised man or animal gradually passes into a state of torpor, or even of complete anæsthesia. The phenomena of the excitable stage of mesmerism are proximately determined by the possibility of exciting any particular centre alone, without exciting at the same time other centres by which its activity is normally controlled. In lower animals this stage is less marked, in consequence of a greater interdependence of the various parts of the central nervous system.

of a room where the speech is transmitted and received.

So long as we have a purely telephonic communication, this mode of grouping all the elements of a station has no disadvantages; but when this arrangement is used for a microtelephonic station, inconveniences may result in certain cases, as we shall see directly.

THE PACKER'S PUZZLE. UR French contemporary, La Nature, describes an ingenious puzzle called "Le Secret d'un Emballeur," or the packer's secret, which consists of a tray of cardboard or other suitable material having a circular rim. Twelve discs of hard wood are placed in the tray, and the puzzle is so to arrange them that they will each help to bind one another, and thus permit of the inversion of the tray without themselves falling out.

The mode of arranging the counters to effect this object constitutes the packer's secret," and is as follows, see figure: First, piece No. 1 is put into

the box, and Nos. 2, 3, 4, 5, 6, and 7 are arranged around it. Then the left hand is placed flat upon the pieces thus arranged, so as to keep them close together, and Nos. 8, 9, 10, 11, and 12 are inserted in such a way that they shall all bear against the sides of the box. Finally, the central piece, No. 1, is removed and placed in the remaining vacant space (No. 1 bis). The twelve pieces are thus rendered immovable, and the problem is solved.

TELEPHONIC COMMUNICATIONS.

to the observations made

D'Arsonval, it appears that the nerve of the frog, which has always been regarded as the most perfect of all galvanoscopes, is 200 times less sensitive than the telephone. But the experiment of M. De Moget proved that the amplitude of vibration of the transmitter is 1,800 times greater than that of the corresponding receiver, and, without considering the losses sustained upon the line, we must attribute a considerable portion of the results obtained in telephony to the perfection of the organ of hearing.

I would expressly state that I regard this theory ON CAUSES OF DISTURBANCE IN only as provisional. Further, I am quite conscious that it very imperfect. A complete explanation of the phenomena of mesmerism and of its allied states can only be given when we have a complete knowledge of the structure and functions of all parts of the central nervous system. But I have not much doubt that the explanation of the main features of mesmerism will be found when we are able to answer the question-What is inhibition? And it is some comfort to think that the answer awaits us in the comparatively simple nervous system of the lower animals. I would not be understood to mean that variation of blood supply and various other events are of no influence in producing mesmeric phenomena; I think, however, Whatever may be the cause of this extreme that these events are of secondary importance only sensitiveness, it exists nevertheless, and must be Finally, I would say a word about the attitude of taken into consideration if we wish to eliminate physiologists to animal magnetisers and mesmerists. the disturbing effects which disguise or diminish It has sometimes been made a subject of reproach the power of the voice. to physiologists that they have not concerned The causes of these disturbing actions exist themselves more actively in investigating mesmeric either at the transmitting station, on the line, or at phenomena. The reproach has very little founda- the receiving station, but very often at all three of tion. The knowledge which has been gained on them at the same time, so that an analysis of the the subject has been gained almost entirely by special conditions in each case, says Mr. E. Van medical practitioners and by physiologists, and it Hoey, in L'Ingénieur Conseil, becomes absolutely must be remembered that until lately most phy- necessary. siologists were also medical practitioners; the division of labour is of recent date.

Taking into account only the essential parts, a microtelephonic station comprises a microphone transmitter with battery, a call bell with or without battery and a telephone receiver, and a purely telephonic station; a call bell with battery and a telephone serving at once as transmitter and as

It is, however, true that in the beginning and middle part of this century there were many scientific men who regarded the subject with a contempt which intrinsically it did not deserve. But in my opinion they had much justification. A receiver. scientific man has always before him some problems which he knows he can solve, or help to solve. He

Most generally all this apparatus is assembled upon one board, which is fixed to one of the walls

Without describing accurately all the reactions which take place during the passage of the current, we may say that there is, on one hand, a formation of oxychloride of zinc, and on the other the re duction of the peroxide of manganese with disengagement of ammoniacal gas. From this we may conclude that in putting into the battery sufficient water to ensure its working properly, we must avoid inundating the mixture contained in the porous cell; for a too strong imbibition of the carbon and peroxide of manganese would result in preventing the disengagement of ammoniacal gas and producing polarisation of the element.

In this case the battery would not work as well, the current strength would be lower, and consequently the speech in the receiving apparatus would not be as loud. We think that it is best to have the liquid in the glass vessel one-half of the height of the porous cell.

This precaution does not seem to be taken generelly if we consider the rather numerous cases of batteries in which the porous cell is too much submerged, although, for several reasons, it should be specially attended to in installations of this kind.

If we now examine the phenomena which occur in a battery in the normal state of construction and mounting, and which is placed in a position where the temperature is more or less high, we shall soon see that crystals are deposited at once upon the glass vessel, upon the porous cell, and upon the zinc rod.

Following this examination more attentively, we observe that these crystals are not of the same nature, and whilst the first are formed of chlor. hydrate of ammonia, chloride of zinc enters into the composition of the second.

The following experiment, which may be made for this purpose, completely proves the difference of substance of the crystals which are deposited upon the vessel and upon the zinc.

Having thrown chlorhydrate of ammonia into a glass vessel containing water up to one-third of its height, and placed in a room having mean temperature of about 15° C., we may observe, at the light deposit of salt, forming a band above the surend of the third or fourth day, the presence of a face of the liquid. This band increases continually in width, and after about a month reaches the top. of the vessel, and then redescends in a progressive manner upon the outside of the receptacle, and reaches the bottom in about two months and a-half.

Whilst the band is developing thus daily, the deposit of salt which forms it, and which appears at first like a sort of dew, offers successively more abundant and more regular crystals, which constitute the creeping salts. They creep, in fact, actually along the surfaces of the cells, and as soon as a slight layer is produced by the evaporation of a portion of the liquid, this, drawn up by capillary attraction between the walls and the smaller already formed, strengthens and regulates them. If, after having proceeded in this manner. we continue the experiment by immersing a rod of zinc in the solution of chlorhydrate, we perceive no change in the phenomena, which remain as they were. No chemical action is manifested by any change whatever of the creeping salts, nor are any crystals deposited upon the zinc rod.

It results from these facts that the crystallisations which we observe upon the vessels are different from those upon the zinc, and that the first, which are produced in a liquid containing only chloride of ammonium, can only be formed from this salt.

which only exist in batteries which have already Those, on the contrary, which cover the zinc, and worked, are formed of the chloride of this metal, as M. Wurtz said, in his dictionary of chemistry.

This last point may, moreover, be explained as follows:-The chloride of zinc which is produced under the action of the electric current requires, in order to be dissolved easily, a liquid contain ing chlorine, and as soon as this becomes deficient it is deposited in the form of crystals falling to the bottom of the receptacle. The for mation of the creeping salt, which impoverishes the chloruretted liquid intended to dissolve the salt of zinc, is, therefore, the cause of the deposit of crystals from it.

Therefore, in order to have a good reproduction the speech, we know that it is important that the battery be in special conditions, which, although