Imatges de pàgina
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use of two lamps, and let light from both fall upon an object such as this ball (6) which I have suspended here. It will show you the difference between a perfect shadow and an imperfect one, or half shadow, very clearly. I have now divided into two equal parts the battery which I have hitherto made use of. In the experiments that we have hitherto made we have used sixty cells. I have now separated this ir to two batteries, each possessing thirty cells, and each of these batteries I have connected with one of these electric lamps. Now you will see the principle which I am endeavouring to make clear to you when I cause these two lights to operate. Here (at ) we have one light which will strike that ball and cast a shadow of it upon the screen (at 8). There is the shadow of the ball upon the screen; and now I have another light () at some distance from the former, connected with its own battery, which casts another shadow of the ball on the screen (at ). These two shadows overlap each other, so that you see there is a certain portion which is undoubtedly shadow to one lamp, but not shadow to the other. And here in the

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centre (c) we have a region of perfect shadow. This (s and s) being the penumbra. On each side we have the penumbra, and if you suppose the light to come from a ring of lamps, this penumbra will extend all round, and we shall have a circular space shaded. This is exactly what takes place with the sun in regard to the shadows that the earth and moon cast on space. I have drawn them here, this (e) being the earth, and this (s) the sun. Owing to the greater magnitude of the sun, the region of real shadow is represented by this dark cone. It is, as I

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shadows, which are consequent on the passage of light in straight lines through space.

I pass now to another very important portion of our subject, and that is to the subject of reflection, and I want to make this subject of reflection perfectly clear to everybody present. Philosophers, the wisest and the greatest, when they think, and when they reason upon these things that we call light and magnetism and electricity, are actually forced to imagine these things to be like something tangible. Mr. Faraday, I have not a doubt of it, imagines that magnetism is something_moving about in lines-straight lines and curved lines. He imagines this, but it is all imagination, for human eye has never seen it. And so with regard to light; we are obliged with the eye of our mind, with the eye of our souls, so to speak, to imagine that we see these thing, and to look at those things which are imperceptible to the eyes of our bodies. Now, it is of infinite importance, I think, that boys particularly, and if you will allow me to say so, girls too, should have clear and distinct ideas of how this thing that we call light is reflected. Here is a bagatelle board, known to all of you; if I take one of these balls and drive it plumb against the other side, what occurs? It rebounds. That is a case of reflection, true reflection, so that you see when I strike this perpendicularly,-to use a very learned word which of course all of you will know by-and-by,-when I strike this straight against the side, the ball rebounds along the same line, it returns along the line on which it struck the surface. Light does exactly the same. If a beam of light strikes plumb against the surface of a plane mirror, it rebounds; it is reflected back exactly as that ball is reflected back; and suppose a billiard player wishes the ball to rebound in a sloping direction, after striking the side of the billiard board, what does he do? He does not strike it plumb; no, he wisely strikes so that the ball shall hit the board obliquely; and now when I do so, if you observe the path of the ball, you see it will strike here, and be reflected back on a line obliquely to the surface against which it strikes. Now, what I want to imprint upon your minds, and never to forget is this:-Supposing you have a line (a b) drawn perfectly plumb and perpendicular to another one (cd), and supposing here to be a ball (e), and that I drive that ball right against that point (a) where this line is drawn; if that ball were perfectly elastic, and if the surface against which it strikes were perfectly elastic, then it would rebound along this line (af); it would be exactly d

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gh

Section across m n.

b

equally inclined on each side to this line (a b), and would fall as much upon one side of the perpendicular as it did upon the other; the two angles (g and h) being exactly equal to one another. Now, I hope you see this clearly; it is very gross and very simple, but it is absolutely essential to the understanding of the law with regard to light, Light, when it strikes for light does just the same.

have said, a convergent cone. It comes to a point, and all round that region of perfect shadow you have the penumbra, the section being as seen across m n. I cannot here enter into all the minutia of these things, but I have written down in the notes sufficient to engage your attention, and I trust you will take each statement that I have made, dwell upon it when you go home, and make your-obliquely against a reflecting surface, is driven back; so selves perfectly clear about it. What I want you to that the reflected ray, as it is called, makes the same remember is this,-that when the luminous body is less angle with the perpendicular as the direct ray. To make than the illuminated body, you have a divergent cone, this plainer, I will try, in the first place, to show you the surrounded by a penumbra, and when you have a luminous general fact of the reflection of light. I will take, in order body, such as the sun, larger than the body illuminated, to show you the effect of this reflection, a beam from a larger than the opaque one,-larger than the body which lamp, as I have already done. Now, how is this reflection casts the shadow-then I trust you will make it perfectly accomplished? You see this beam passing straight from clear to your minds that you must have a shadow of the the lamp. Here I have a piece of silvered looking-glass; shape of a convergent cone surrounded by a penumbra; I throw that into the path of the beam; and look what and astronomers sometimes see these vast conical shadows takes place. There you have that splendid cylinder of You see as I twist the moving through space during eclipses. So much for light passing through the room.

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Royal Institution of Great Britain.

mirror the reflected beam passes over the gallery, and thus it is evident I can make the beam to course along and be reflected as I please. The great Sir Isaac Newton imagined that light was due to small particles projected away from the luminous body with intense velocity, and that these particles were reflected in precisely the same manner as we have seen the billiard ball to be reflected. I should not like you to dwell upon this as a truth at the present time. We have reason to believe that this is not the case, but it is too early to think about that at present. Now, I want to examine this matter of reflection more fully, and before I do so, let me just draw your attention to that splendid beam of light. The slightest motion of the glass causes it to move through a very vast space. All these things ought to be taken, and are taken, advantage of by philosophers. You saw that beam of light moving about. It has no weight. If you wish to enable yourselves to see the motions of the wheels of your clocks and your watches you put hands to them and make them traverse a large circle, in order to be able to divide that circle into hours and minutes, and you can see the hands travelling over those hours, over those minutes, and the larger your circle the more minutely can you subdivide it. There are friends of my own here who know how very necessary it is in the large instruments-large theodolites-to have a large circle in order that that circle may be divided into very small parts; but weighty indices like these hands would be utterly useless in any scientific experiments, and philosophers, therefore, make use of an index without weight a glorious beam, such as you saw there going over the room. They attach a bit of looking glass to their little magnets, and the slightest motion of the magnet causes this long index-and you can make it as long as you like to move through a large space, and in this way we employ an index of light which possesses no weight. Now I want to develope further, if I can, this doctrine of the reflection of light; and in order to make you understand it thoroughly and perfectly, I have placed this lamp (4) here, and have placed a piece of common looking-glass (ga) in front of the lamp. Now what am I doing here?

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You see the face of that looking-glass (g a), it is exactly at right angles to the light. This beam () is perfectly plumb, is perfectly perpendicular to the surface of this looking glass. Very well now, but you see that in this case, when the beam strikes against the surface of the looking-glass, it is reflected directly back again and strikes the lamp, and a portion of it is reflected back upon the audience in the line in which it fell upon the looking glass. Now I have here drawn the sweep of a large circle; this arc I have divided into exactly twenty equal parts, You see the index (a b) that I have here. When I turn it round it causes the looking-glass to move. This index is perfectly perpendicular to the surface of the looking-glass. Well, I will place it here at 8 (u b'). Now you remember what I have said about

HEMICAL NEWS, Jan. 11, 1862.

the billiard ball; if what I have said be true, inasmuch as that index (a b') is plumb to the surface of the mirror (ga), and inasmuch as the direct ray of light will, as I have said, fall as much on this side (c) of the index as the reflected ray falls upon the other side (b), then the ray of light will strike the youth who is in the direction of this line (a c). The apparatus is placed with perfect accuracy, so that you see this direct ray of light (a ), and that reflected ray of light (a c) make equal angles with this perpendicular (a b').

Now, I have endeavoured to define a term which is used incessantly in writings on this subject, and which must be perfectly remembered. The angle you see here (la b') between the direct ray and this index, is called the angle of incidence; and this angle between the reflected ray and the perpendicular (b' a c), is called the angle of reflection. I am satisfied every boy could express this law. Now I will ask you a question,- Is the angle of incidence unequal to the angle of reflection? Is it, or is it not? [Voices: "No, it is not."] No, it is not; the angle of incidence is equal to the angle of reflection; and thus we have arrived at the law, simple as it appears, and simply as it is proved, which lies at the foundation of optical science. Another point I want to direct your attention to is this (and remember what I have just established—that the angle of incidence is equal to the angle of reflection): I bring the index back to my former position (a b), and I will allow the beam to fall plumb upon that mirror (ag). Here it is. You see the beam returns exactly along the same line, as I have already proved. Now watch me: I will cause the index to move; I will push it on. Now both the index and the reflected beam start from one and the same point; they are like two boys setting out to run a race, for they start fairly; but watch their progress, I push the index to No. 2. Where is the beam? The beam has gone farther; the beam is now at 4. I push the index to 4. Where is the beam now? It does not coincide with the index; the beam is now exactly at 8. I push the index to 6, and the beam is now at 12; I push it to 8, and the beam is now at 16, exactly; I push it to 10, and the beam is now at 20. What is this beautiful law-for it is a beautiful law, and a law of very frequent application. I have expressed it in my notes that the reflected ray turns round with twice the velocity of the mirror. You will find a learned way of expressing that in books where they state that the angular velocity of a reflected ray is exactly double that of the reflecting mirror.

Many other things equally interesting flow from the same principle. I have met sometimes, in walking through Regent's Park, and I daresay many of my hearers have done the same, with an old man standing with an instrument mounted on three legs, like a photographer's camera, and he had, supported upon these legs, a system of tubes much more cunningly devised than this [exhibiting a square mahogany tube with four rectangular elbows], but still exactly the same in principle. b

α

e

d

Well, this is supported upon the legs and he desires people to look through his tube; and he puts, cunningly enough, opaque things between, for he has these tubes prolonged a little so as to make it appear as if you looked straight through, as his object is to make you fancy that you actually look straight through these tubes, and in consequence he prolongs this and leaves a space between. He puts his hand in and wants you to believe you can see

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through his hand. He puts a piece of board in there, and one image of it, you see a series of images; and the larger says that you can see through that piece of board. I I make that angle enclosed between the mirrors the fewer remember once going up to this old man, and I said "May the images you see; and the smaller the angle the larger I ask what you have got at this corner, and what you the number of images. You see the images of the candle have got at that corner, and at that other corner? and he ranged symmetrically round about, they are all in a circle, looked very much puzzled. I daresay many boys present and the centre of this circle is the point where the mirrors can solve the problem at the present moment; but there meet. If these two mirrors were placed perfectly parallel, was a man and his wife standing beside this old man, and you would find the series of images diminish in brightness they became extremely offended at me. (For ignorant to an indefinite length, reflected between the two parallel people are the most ́easily offended in the world, and the mirrors; and this is the reason why in some shops, where more ignorant people are, the more they recoil from having there is looking-glass on each side, the shops appear to their ignorance enlightened.) As I was leaving the place, have no end. These angular mirrors give you a series of not desiring anything that might be intended as an insult, images (and, remember, this is an experiment in the power -for it was thought that I was doing the man altogether of all of you to make). You will always find this-that wrong by putting him into such a dilemma,—the gentleman the number of the images is perfectly definite: at the said, "It is quite right, Sir, you can see through your hand; present time I have set them at an angle of 90 degrees—a you can see through the board; it is perfectly manifest, I right angle-that is to say, one of those sides is exactly can see through the board at the present moment; it is a plumb to the other; and in that case you have four wonderful thing, Sir, no matter what the gentleman says." objects that is, three images and the light itself. At the present time you understand the philosophy of this Many of my hearers do not understand what degrees thing, no doubt. Here I have a bent tube [again referring are, I have no doubt; but I have also little doubt that to the apparatus just described] and here at the corner the older ones will teach the younger ones when they there is a piece of looking glass-any boy could construct go home, and tell them what it means. If you suppose a it of paste-board himself. The beam comes in at a, strikes circle, to contain 360 degrees, the right angle contains upon that looking glass (b); but it is reflected,-because 90 degrees, that is, the fourth part of the number of the angle of incidence is equal to the angle of reflection-degrees in a circle. Divide the number of degrees it is reflected to the opposite corner (c) where there is in a circle by 90, and what is the result? it leaves the another piece of looking-glass. At that corner the beam quotient of 4, and that always gives you the number strikes upon that piece of looking-glass and is reflected of images plus the object. If you divide 360 by the along to (d). There there is another piece of looking-glass; number of degrees in the angle at which the mirrors it strikes against that, and from thence is received upon a stand, you then get the number of images, together with fourth piece of looking-glass (e) and is there again re- the object. Supposing I make it an angle of 45; then flected; so that you see I shall be able to send the beam 45 will go in 360, how many times? Eight times. Then right through this, and you will see that the apparatus you would have 7 images plus the object; because the will allow the light to go round the corners as I have number of images plus the object is the quotient that I described. [The apparatus was held before the electric have referred to. So that you can always determine from lamp, and a beam was passed through it and received upon the number of images you get, the angle that these mirrors a white screen.] Here again we have a tube at which you make with each other. Upon this principle depends the can all look, and it is worth saying a word about it. At toy known to you all-the kaleidoscope, in which you do the time of the Crimean war it was found that the sailors not see a single image, but a series of images refracted were very fond, when they fired a shot, of popping their symmetrically, producing a regular figure. The kaleidoheads over the parapet in order to see what execution the scope was invented by Sir David Brewster, but it is now shot had done, and they were very often picked off while very much used in commerce, and sold at a very cheap in that position by the Russian riflemen. The Rev. Mr. rate: here I have a fourpenny instrument, which will Taylor, a member of this Institution, devised this simple show it very beautifully. In it I have these reflectors, little apparatus, and this is one illustration of what I have and here is the object-pieces of coloured glass; and when said that in natural science there is & reservoir of power I look through at these pieces of coloured glass, I see, not that, if men only used it aright, might be converted into a simply what the eye looks at, but I see also the reflections potent agency in the service of our country. It is simply of the object, and these are arranged in beautiful symupon the principle of this tube which has been devised for metrical figures. I will try to cast these kaleidoscopic years and years-before I was born. Here I have a tube figures on to the screen for each to see, if I can. I with a bit of looking-glass placed across one end, so; and send a beam of light through, so that it shall strike first when the beam of light comes in it is reflected down along the coloured objects and then the reflectors within, and this tube, and here at the other end is another bit of look- then I trust we shall see on the screen the image of those ing-glass, and the light is reflected out here, so that if I bright pieces of glass. Here you have the bits of coloured wished to observe you, and supposing you to be a rifle- glass-scraps of useless glass, which look very shabby man with deadly intent upon my life, I should not, if I if looked at directly, but when they are reflected in this could, pop my head over the parapet, but I should quietly way they give you these beautiful figures. drop my head behind it. [The Lecturer showed the experiment, making his observations from beneath the lecture table.] I can see you perfectly well. In such cases this might be turned to very great and useful account, and many valuable lives might thus be placed out of peril by giving them the means which will enable them to observe without exposing themselves to personal danger. I will pass the electric light through this tube; I can only send it in a rough manner, but there is the beam of light, and you can trace the beam of light through the room, if you watch it, along the dust; and here you see that the beam which enters from the bottom issues at the top.

I have now to beg your attention to another effect of reflection, and it is very instructive indeed. I have here a pair of mirrors. If I place that candle between those two mirrors, set together at an angle, you see more than

There is now another point I think I ought to direct your attention to, and that is this, that when you look into a mirror your face is laterally inverted; for instance, I believe that my hair is really parted to my left hand, but if I look here I see a gentleman in this looking-glass with his hair parted to the right hand, and thus we are laterally inverted when we look into a looking-glass; and photographers often have people complaining when they find themselves represented exactly as they are, because they quite forget that they do not know themselves really as they are; and when a photographer sets the parting of the hair on the proper sidethe side which other people see, they are sometimes very angry with the photographer. They say he has misrepresented them, forgetting, in fact, that they have been using an instrument all their lives which inverts them

26

Manchester Literary and Scientific Society.

in this lateral way. I have written a word here backwards, but if I look at it in this looking-glass it is perfectly legible, as you will see it to be when I cast it on this screen. Thus when compositors set up their type, it has to be printed upon a sheet, and therefore the type is always the reverse of the printed sheet. Here I will cause this backward word to be reflected upon the screen, and you will then see what it is. You have it now plain enough, D—O—G dog, it being inverted by the reflection.

I have now to pass on from inversion by plane surfaces -by such things as looking-glasses-to reflection by curved surfaces. We have here a splendid mirror; here is one less splendid, but equally good. I do not know how you could learn any philosophical matter without practical instructions. The most learned man may discourse upon natural philosophy, but he can never get the thing into his hearers; you can never learn natural philosophy by hearing it, or by reading about it. Reading and Lear ing it are both very good; but let each boy present, when he goes home, who feels an ambition to become a natural philosopher, and indeed it is a glorious vocation,— try to repeat the experiments for himself. Let him, if he has sufficient pocket-money, buy a little convex mirror, or a little concave mirror, as I have said, and try to repeat the experiments for himself, and not give way if he finds it difficult. Let him persist, and repeat his experiments again and again, and with a kind of moral responsibility, and he will then, and in that way only, become a natural philosopher. That is the only way to master the truth of the thing.

Now, supposing I have a ray of light, and that ray of light falls at an angle upon a plane reflector, you know how it will be reflected, making the same angle to the perpendicular as did the direct ray. Here, again, let us have another piece of reflecting surface inclined to the first one in that direction; and let us suppose a ray of light parallel to the first ray to strike on this plumb, it will be reflected back again to where it started from. And now we have another piece of looking-glass inclined in the opposite direction to the first; and let us have a third ray of parallel light falling upon that; it will be reflected as the others have been, and thrown back. Thus you see that, by this arrangement of eloping the mirror, we shall get all the rays thrown back so as to cut one another in the same point here. Now, if you had a great number of small bits of mirror, you might so arrange them that the reflection from each should come towards that same point, and in a concave mirror, as it is called, we do that. In a mirror of this sort, formed by the union of surfaces of that kind, all the rays that fall upon it on reflection are forced to come back and unite at a single point crossing each other. I will now make an experiment with this mirror so that you may see the track of the beam in the manner I have already indicated. [The diverging rays from the electric lamp were then allowed to fall, at an angle on the concave mirror, which reflected them back again to a focus, the conical form of incident and reflected rays being clearly visible in hazy atmosphere.]

How splendidly these beams are reflected! How they are squeezed, and converged and brought together to a "focus," as we call it. There you see the focus; how bright it is! And if that mirror were perfect, you would find that the carbon points of the lamp, that are intensely illuminated, would rebuild themselves up there, and you would have them here depicted in the focus with the utmost accuracy; even now I can see a blurred image of the coal points on this screen when I interpose it, so that the rays of light that issue from that lamp are made use of by this mirror to build up the image again; they are the bricks, so to say, by which the coal points are here built up in the focus of the mirror, and as I cause the mirror to move-if I tip it up-look at that splendid cone of light produced by the convergence of the rays

{CHEMICAL NEWS,

Jan. 11, 1862.

after reflection. This then will illustrate the law of reflection from this concave mirror.

I have now a convex mirror, and when I set it down here for a moment we shall see the difference between this and a concave one. This convex mirror bulges out, you know, in the centre, while, the concave is hollow in the centre. Now, what takes place with a convex mirror is this. Supposing the rays of light fall upon it, they are reflected back again, but spreading out instead of being squeezed together to a point, and if you look at the mirror you will see the picture of the rays, as it were, going right through it and intersecting at a point behind the surface. With the concave mirror you remember that we had the rays converged and caused to cut in a point in space actually before the mirror, but here in this convex mirror you see there is no real cutting of the rays; they are all reflected and caused to diverge. The intersection behind the mirror is merely an appearance, and hence this cutting point, which is the focus of the mirror, is called an imaginary focus, in opposition to the real focus, which as I have said in the Notes, is actually formed in space in front of the concave mirror.

MANCHESTER

LITERARY AND SCIENTIFIC SOCIETY.
Ordinary Meeting, December 24, 1861.

J. P. JOULE, LL.D., President, in the Chair. MR. BROCKBANK exhibited some samples of steel manufactured by Mr. Bessemer's process. These specimens had been bent and twisted cold, and showed a remarkable degree of ductility. He stated that the Bessemer steel was one of the most plastic and manageable of metalsmore so even than copper. It could be bent, flanged, or twisted, either hot or cold, without annealing, and over a considerable range of temperature-which is not the case with ordinary steel or copper.

a

A plate of 18 inches diameter had been forced through series of dies until it formed a tube 13 feet long and inches diameter, without any crack or flaw.

A ring of metal could, at one heat, be hammered into a die to form a locomotive chimney top.

In drilling a circular hole into a plate, continuous shavings are formed-whereas, in copper, or Low Moor plates, or any other metal, the shavings break into pieces in. long.

Thin sheets of the Bessemer soft steel can be bent backwards and forwards hundreds of times without a fracture, and are almost as flexible as paper.

MICROSCOPICAL SECTION.

Meeting, December 16, 1861.

E. W. BINNEY, F.R.S., F.G.S., in the Chair. Dr. Edward Morgan was elected a member of the Section.

Dr. WALLICH kindly presented to the Section for mounting several specimens of material, from his private collection, containing Biddulphia of various kinds, and other diatomaceæ, from Guernsey, St. Helena, &c.

Mr. THOMAS H. NEVILL presented to the Section eight slides, mounted from the specimens of Soundings, No. 131, taken in Lat. 51° 48′ N., Long. 7° 8' W., off the south coast of Ireland, in forty fathoms, presented by Captain Moodie, of the R.M.S.S. Canada. Mr. Nevill reported that the specimen contained Entosolenia Marginata, EntoEolenia Squamosa, Lagena Vulgaris, Textularia, Rotolina, Miliolina. Numerous spines and plates of Echina; calcareous prisms from shells, &c., &c., all water-worn. The sand is composed of about half calcareous and half silicious material.

Mr. LATHAM proposed that the subject for discussion at

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792. Preserving Fermented Liquors. HENRY MEDLOCK, Great Marlborough Street, London. Dated March 30, 1861.

THIS improvement consists in adding sulphurous acid or a soluble sulphite to beer and similar liquors after fermentation, or introducing these agents into the bottles, casks, or other vessels about to receive the same. Such addition

formation of calcareous and saline deposits in steam boilers."-A communication from Lewis Baird, Cambridge, Massachusetts, U.S.

2991. William Clark, Chancery Lane, London, "Improvements in the construction of parts of electric telegraph belt apparatus, and in apparatus used in making the same."-A communication frem Pierre Desire Prud'homme, Boulevart St. Martin, Paris.

2997. Henry Wilde, Manchester," Improvements in magneto-electric telegraphs, and in apparatus connected therewith."

3002. Peter Spence, Newtown Heath, near Manchester, "Improvements in the treatment of ores for the manufac ture of sulphuric acid, and in apparatus connected there with, which apparatus is also applicable to the treatment of ores for separating metals therefrom." 3044. Richard Archibald Brooman, Fleet Street, London, "Improvements in albums or books for containing and showing photographic and other pictures, and in slides for the same."-A communication from Henry Strauss, Paris.

Inventions protected for Six Months by the Deposit of Complete Specifications.

3112. Marc Antoine François Mennons, Furnival's Inn, London, "An improved means of defecating and purifying cane and other saccharine juices."-A communication from Louis Marie Amand Achille de Courson de la Villeneuve, Caen, Normandy, France. Deposited and recorded December 12, 1861.

Notices to Proceed.

has the effect of preventing acetous fermentation, or the and James Mellor, Manchester, " Improvements in separa1958. Peter Spence, Newtown Heath, near Manchester, tendency to become sour on keeping.

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Grants of Provisional Protection for Six Months. 2658. George Davies, Serle Street, Lincoln's Inn, London, "Improvements in lamps for burning coal oil and similar fluids."-A communication from Joseph Thomas, New York, and Joseph Tindall Van Kirk, Philadelphia, U.S.-Petition recorded October 24, 1861.

2726. Eugene de Bassano and Adolphe Brudenne, Brussels, "Improvements in the manufacture of stearine." -Petition recorded October 30, 1861.

2815. François Henry Marie Come Damiens Chevalier Finis de Lacombe, Paris, "Improvements in generating hydrogen gas for illuminating or other purposes, and in apparatus used therein."-Petition recorded November 9,

1861.

2861. Henry Bird, Liverpool, "Improvements in the construction of bottles and other vessels, and in stoppers for the same to indicate that they contain poison.". Petition recorded November 13, 1861.

2906. Simon Dede, Rue Duvivier, Paris, "A new process of discolouring, purifying, and improving varnish, oil, resin, gum, ether, wines, spirits and other matters through the application of compressed air."-Petition recorded November 19, 1861.

2924. George Henry Polyblank, Gracechurch Street, London, "A new or improved method of protecting and preserving photographic and other prints, water-colour drawings and other works of art from injury and decay." 2961. Alfred Vincent Newton, Chancery Lane, London, "An improved method of removing and preventing the

ing copper from its ores."

2023. Richard Archibald Brooman, Fleet Street, London, "Improvements in coating wire with copper, silver, gold, or other metal or alloy, in order to prevent oxidation."-A communication from Martin Miller, Vienne. 2067. Richard Archibald Brooman, Fleet Street, London, "An improvement in preserving meat and other animal substances."-A communication from Jean Pierre Liès-Bodard, Strasbourg, France.

2347. Rene Prudent Patrice Dagron, Paris, "An improved microscope to be used for exhibiting photographic views and productions."-Petition recorded September 19, 1861.

2441. Pierre Alexis Francisse Boboeuf, Paris, "The preparation and application of certain new hemostatic and antiseptic agents."-Petitions recorded September 30, 1861.

3005. Jules d'Adhemar de Labaume, Dorset Terrace, Clapham Road, Surrey, "Improvements in machinery for cooling and freezing water and other fluids."-A communication from Edouard Blée, Rue d'Amboise, Paris.Petitions recorded November 28, 1861.

CORRESPONDENCE.

Chemical Nomenclature.

To the Editor of the CHEMICAL NEWs. SIR,-In the CHEMICAL NEWS of the 7th December, you inserted a question that I wished to ask Mr. Newlands, to ascertain whether his new system of nomenclature would be of any service to chemists: my question was, "What name would he give to albumen that should express its composition?" I might have chosen substances with even more complicated formulæ than this; but could Mr. Newlands have given me a short and easily to be remembered term for albumen, and which should, as he says, "express its composition," I should have been quite content, and almost ready to become one of his disciples.

Instead, however, of attempting to answer my question,

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