SS

each end a ratchet wheel hi fixed upon it, each being provided with a pall j k to act in opposite directions to each other. The roller or drum R is perforated with any convenient number of holes to receive a handle or lever n, to be used to turn the roller when required. are two clutches which slide upon the axle of the wheels B B. T T are the clutch-levers, by which, and the clutches SS, the machine is thrown in or out of gear, as occasion may require. U is a receptacle or box for manure (omitted for clearness' sake in the plan fig. 2), and the apparatus for distributing the same. o is a toothed-wheel or pinion (indicated by the dotted line in fig. 1), which takes into or gears with and receives motion from the toothed-wheel C upon the axle of the wheels B B. Upon the axle of the wheel or pinion o (which axle is not shown in the drawing) are fixed the spoons for supplying the hoppers or funnels pp, and spouts q q. Upon the end of the same axle is fixed the toothedpinion, which takes into and gives motion to the toothed-wheel s. On the axle of the latter there are fixed arms or spurs (not shown in the drawing) which revolving through the manure in the box U, keep it agitated, and thereby facilitate the regularity of the supply required for the spoons. V V are parts of the shafts; tt are slides which pass between the bottom of the seed-box and the under sides of the seed-discs, having a hole in them to allow the seed to pass through, but when drawn partly out they stop any of the holes that are not required to be used; u u are rests for the clutchlevers; v v are fulcrum-pins for the clutch-levers; w w are weights that are placed upon the coulters to prevent them from rising.

The action of the machine is as follows: by placing the clutch levers in the position indicated by the dotted lines on the plan, fig. 2, the clutches S S are thrown into gear with the wheels B B. Motion being given to these, it is thereby communicated to the toothed wheel C, and by the latter (at the same time) to the toothed wheel or pinion D, the bevelled wheels F F and G G, and the toothed wheels or pinions, H H, K K, and L L, thereby causing the circular plates or discs J J and M M (affixed to the axles of the toothed wheels or pinions H H and L L), to revolve under

the seed in the box N N. As these discs JJ and M M revolve, the seed falls into the holes in the discs that are exposed to it, in which the seed passes round until it arrives under the brushes X, and over the holes in the bottom of the seed-box. The brushes X clear away the superfluous seed, only allowing the requisite quantity to drop through the holes and spouts II, into the furrows, singly or severally according to the size of the holes in the seed discs; the distance between the dropping being regulated by the number of holes in the seed discs, and the proportion the several wheels and pinions bear to each other. At the same time that motion is communicated to the toothed wheel C, to the toothed wheel or pinion D, the bevelled wheels, EF, &c. It is communicated by the same means to the toothed wheel or pinion o, the spoons and the pinion r upon its axle, to the toothed wheel s, and the arms or spurs upon the axle of the latter, thereby causing the manure to drop through the hoppers or funnels pp, and the spouts q q, into the furrows or drills, a little in advance of, and simultaneous with, the seed or grain from the spouts I I. A certain supply of a given quantity of manure is thus insured to every portion of grain or seed as it is sown, and as both are discharged so near the ground, they are affected but little (if at all) by the wind, before they are deposited in the ground.

The coulters may be of any approved form, and are so arranged in this machine as to be capable of making the furrows of any depth the soil will admit, or the seed may require. These arrangements are such, also, as to allow them to act separately or together, as circumstances, or the inequality of the surface may render necessary. When the furrows or drills are required to be deeper than the coulters and weights, in their ordinary position, will make them, the pall k is released from the ratchet wheel, and thrown back, the handle n is inserted in one of the holes in the roller or drum R, nearest the back frame A of the machine, and the roller or drum R is turned round towards the front of the machine, and the chain g (indicated by the dotted line in fig. 1.) is wound upon the roller or drum R, thereby causing the roller or drum Q to revolve, and take up the chains e e, attached to the upper ends of

the levers, which being thus drawn down, makes the lower end of the same press down the board m (to which they are attached) upon the coulters, forcing them into the ground to any depth that may be found expedient. When they require to be raised, the pall j is released, the roller or drum R is turned back, taking up the chain ff, and causing the roller or drum Q to revolve and take up the chains cc, thereby raising the coulters to their original position, or to the position indicated by the dotted lines in fig. 1, so as to be entirely out of the way of any obstruction that may offer itself upon the ground.

When the seed is required to be dropped nearer together than the machine in its present arrangement is capable of effecting, all that is required to be done is, to loosen the screws by which the plummer blocks, that carry the axles of the wheels B B, are fixed to the frame A A, and move them (the plummer blocks) back, or move the frame forward, (slots being provided in the plummer blocks, through which the above screws pass). The toothed wheels or pinions, D and E, having been moved along their axle, until the pinion E takes into or gears with the toothed wheel C, they are then fixed upon their axle by their keys or cotters; the plummer blocks are screwed firmly to the frame A A, and the machine is again ready for use.

The principle of this machine admits of many other modifications, by which it may be made applicable to the sowing of all kinds of seed or grain, and under every variety of circumstance. It may, for example, be constructed of a greater or less width, so as to drill and sow a greater or less number of furrows than the machine shown in the engravings; or it may be adapted to one or more horses, so that the horse or horses may walk upon the lands immediately in front of the machine, or in the trenches on each or either side. A hand-machine on the same principle might also be readily constructed.

Claim." I wish it to be undertood, that, in the machine herein described and shown, I do not claim the manure apparatus shown and described, nor do I claim the form of the coulters, but I claim those peculiar arrangements as herein described, and as shown in the accompanying drawings; I also claim the application and use of perforated

plates or discs for dropping or sowing all kinds of seed or grain, and their combination with wheels and pinions or other mechanical contrivances, for the purpose of carrying out the principle and its application as herein described, and as shown in the accompanying drawing."

Remarks.

The machine, as shown in the accompanying engravings and before described, is arranged for drilling and sowing eight furrows at once; but, as stated in the description, it is not confined to that number, but may be made to drill and sow any number of furrows, within reasonable limits. The principal advantage which the machine offers is, the saving of seed or grain; it being intended, and so constructed, as to sow or deposit the seed in one, two, or three grains at a time, instead of the trail, or continuous discharge of the drills generally in use at the present day. It is found by experience that sowing two or three grains in one spot, with a clear space of four, five, six, or even nine inches, between them and the next adjoining cluster of seed, allows more room and nourishment to each root, and a freer circulation of air, and produces a fuller and stronger crop, than when the seed is sown in a continuous trail in which case the roots are crowded and impoverished, so that only a part comes to perfection. It is calculated that the quantity of seed saved by this machine will not be less than two-thirds, if not three-fourths, of that ordinarily required.

PROGRESS OF FOREIGN SCIENCE. Dr. Moser's Discoveries. Professor Möser, of Königsberg, has, within the last few months, published in Poggendorf's Annalen, and elsewhere, a great number of observations and experimental results connected with photography, which are not only most remarkable from their singularity and novelty, but of the highest importance, as for the first time laying open the action of minute and hidden forces in nature, operating in a way never before so much as suspected. Some slight notice of these researches was given by Professor Bessel, the astronomer, to the British Association at Manchester; but as no complete account of them has yet appeared in English, it seems desirable

here briefly to trace their progress to the present date.

It has for some time been known that when an ordinary silver plate (prepared for Daguerreotype purposes) is exposed for a certain time to light reflected from objects in the camera obscura, after having received the coating of iodine vapour, an image is produced of the objects on the plate, without the use of mercurial vapour. But the image is a negative one; that is to say, the lights and shadows are reversed. On the Continent, such an image is called negative, while an image in which the lights are light, and the shadows dark, is said to be positive. In Daguerre's process, nothing appears upon the iodated plate until after it has received the mercurial vapour. Nevertheless, the experiments of Edmund Becquerel show that an extremely short time is sufficient to affect the iodated surface in such a way that if the plate be placed in the sunshine, under a red glass, the latent image becomes gradually more and more visible or distinct, on applying the mercurial vapour afterwards, although (it will be observed) the objects which originally, as it were, impressed the image are no longer in presence. Hence he has distinguished the acting rays into "exciting rays" and continuing rays."

66

Möser has found that in the preceding case, if the action of the red glass be continued long enough, the image (a negative one) appears without the use of mercury at all.'

Gaudin had previously found that yellow glass acted as efficaciously, or more so, than red in these conditions.

Möser has observed the following singular fact. A plate iodated, which had been exposed in the camera for the usual time to give a positive image with mercury, was taken out, and placed in the sun under yellow glass, no image being as yet visible. Presently, a negative image appeared, which disappeared again in a few seconds: and in about ten or fifteen minutes there appeared in its place a positive image.

Here we may remark, that the rays passing through the yellow glass played the same part that the vapour of mercury does. The positive image will not appear, using red glass, however long the exposure; but it succeeds well with green glass.

On the as yet untouched iodated plate, the violet and blue rays are those alone of the spectrum which are active. They produce that invisible change of molecular arrangement which is made visible to the eye by the mercurial vapour; but there are two periods distinguishable in this action. At the end of the first, the red and orange rays act upon the plate as well as the blue or violet, and the yellow are inactive; at the end of the second period, the yellow and green rays act in their turn. The plate is then just at the point when the mercurial vapours act upon it in rendering the image visible.

When an iodated plate was exposed in the camera, until a very distinct negative image was produced of objects illuminated by sunshine, and the plate then taken out and exposed to direct sunlight, the former image soon disappeared, and a positive image appeared in its place, in which the lights had a green tint, and the shadows a dark red brown. The latter effect Möser attributes to the yellow and green rays. When a plate

coated with chloride of iodine was exposed in the camera, in winter, for thirteen days, a positive image of great beauty was produced; the lights had a sky blue colour, and the shadows a fiery red. The plate being then immersed in a solution of hyposulphite soda, the positive image disappeared, and in its place came forth a negative one.

Polarized and unpolarized light produce precisely similar effects in these conditions.

Placing a prism of carbonate of lime, achromatized, for one of the images before the lens of the camera, and adjusting for a statue as an object, two images were obtained upon the plate, of which one was achromatic to the eye. Images of coloured rings, figures given by polarized light seen through crystalline plates, &c., when received on the photographic plate, were identical with those seen directly by the eye.

It has been long known that when a plate of polished glass is written upon with certain substances, the writing effaced, and the surfaces cleaned, yet on breathing upon the glass the characters reappear, by means of the different arrangement of the particles of moisture condensed from the breath.

Möser has extended this phenomenon

to all polished bodies, and to all substances whatever used for writing on them; these being such, of course, as produce no visible change on the surface. It is even true of an undisturbed surface of quicksilver after many days, if not disturbed. If a perforated screen be placed against a plate of glass, and the latter breathed upon, and the screen be now removed, and the glass again breathed upon, after the moisture from the first has evaporated, the form of the perforations will be rendered visible.

Regnault thinks fatty matter deposited from the breath may have something to do with this.

Möser has found that when solid objects, such as medals, intaglios, &c., are placed in contact with a silver iodated plate, after a shorter or longer time an image of every part of the surface in contact is traceable upon the place. This takes place with equal rapidity, certainty, and minute accuracy in total darkness as in daylight. An image of an object which has been in contact with a polished silver plate may also be obtained by merely exposing it to the vapour of mercury afterwards, without any previous application of iodine.

From these facts he concludes that the parts of a surface touched by another body, affect variable affinities for the vapour of substances to which it may be exposed; so that contact here produces an effect analogous to light. Thus when medals, rings, &c., were laid upon an iodated place in total darkness for a night, an accurate image of every line of the contact surface was formed when the plate was exposed to vapour of mercury. Plates treated in the same way, but exposed to diffuse solar light, in place of the mercurial vapour, also showed the images as before. The same plates, exposed to coloured rays, gave slight traces only under red glass or yellow, but well defined images under violet.

When a polished plate of silver, which had never been before used, was exposed to sunlight for some days, under a black perforated screen, placed very close, but not in contact with it, on exposure of the plate to the vapour of mercury, the image of the perforations became distinctly visible. The same experiment succeeds with a plate of copper, when exposed to vapour of iodine. The same

also with a plate of glass, when breathed upon, or exposed to vapour of water.

These experiments show that contact of bodies produces certain effects analogous to those of light; but a much more remarkable result of Möser's is, that any two bodies, when sufficiently near, impress their image one on the other, although both be in absolute darkness.

Thus an agate or an intaglio, placed opposite to a polished silver plate, at a small distance, in total darkness, after a longer or shorter time, occasionally in ten minutes, has impressed its image on the plate, visibly to the eye, without any previous exposure to vapour.

Phosphorescence has nothing to do with the phenomena; and if they arise from radiation, it must be concluded that the effect of the radiant matter diminishes very rapidly with the amount of obliquity produced by the distance of the object.

An engraving, placed for about twenty minutes upon a plate of polished silver, leaves its image, rendered quite visible by vapour of iodine and mercury afterwards.

These remarkable results of Möser's have been verified at Berlin by Aschersohn, and in presence of Encke.

From these researches, of which the foregoing is an imperfect outline, Möser deduces the following general propositions:

1. Light acts on all bodies, and on all in the same way. Actions heretofore known are particular cases of this general proposition.

2. The action of light so modifies the surfaces of bodies, that they condense vapours differently after exposure thereto, from what they do before. Daguerre's discovery is a particular case of this proposition.

3. Vapours are condensed more or less forcibly by bodies after being exposed to light, in proportion to their own tension, and to the intensity of the light.

4. Ioduret of silver, as is known, is at first blackened by light.

5. But if the action be continued, it becomes coloured.

6. The different refrangible rays all act alike, but require different times to produce like effects.

7. The violet and blue rays, and the

invisible rays of "Ritter," rapidly originate the blackening of iodurate of silver. The other rays, to produce equal effects, require times inversely as their refrangibilities.

8. The colouration of 5 is produced most rapidly by the red and yellow rays; the other rays require, to produce equal effects, greater time, as their refrangibilities are greater.

9. All bodies radiate light, even in total darkness.

10. A property which does not seem to be of the nature of phosphorescence; for no difference of effect is perceivable between the same body, after exposure to sunshine, and after being long in dark

ness.

11. These rays act on all substances, like the direct rays of light.

12. These rays, insensible to the retina, have a refrangibility greater than those of direct or diffuse solar light.

13. Two bodies in total darkness always mutually impress their images.

14. But, in consequence of the divergence of the rays, the bodies must be very close (though not in contact), that the image may be visible.

15. Any vapour may be used to render such images visible.

16. As these rays are more refrangible than any hitherto known, they are those which ordinarily commence action (as in 7) on other bodies.

17. There exists a latent light, as there is known to exist a latent heat.

18. When a liquid is evaporated, the light which corresponds to a certain period of time, becomes latent, and is again liberated when the vapour is condensed.

19. Hence it is, that light and vapours produce in some respects the same effects.

20. The condensation of vapours on plates acts like light; so that vapour in excess simply adheres-as the vapour of water to most substances or acts permanently in adhering, as vapour of mercury; or, finally, acts chemically, as vapour of iodine.

21. The latent light of the vapour of mercury is yellow; all the actions which the yellow ray produces can also be produced by the vapour of mercury.

22. The latent light of vapour of iodine is blue or violet, and the actions of these rays can be produced by its va

pour.

23. The latent light of chlorine, bromine, chloride and bromide of iodine, seem to be the same as of iodine simply.

24. As to the latent light of vapour of water, Möser can only say, that it is not red nor yellow, nor orange nor green.

25. Ioduret of silver owes its sensibility to light to the latent light of the vapour of iodine.

26. Ioduret of silver is not more sensible to invisible rays than silver itself.

Some of these propositions admit of much doubt at present. Those, however, which merely enumerate facts in this general form are worthy of every attention.

Since attention has been drawn to this class of phenomena, other facts have been recorded, long since observed by other persons, but of a strictly analogous and most interesting sort. Thus Breguet, the celebrated chronometer maker, has stated, in a letter to Arago, that he has constantly observed the name of his firm, which is engraved on the brass cap covering the works of their watches, impressed, in an inverted image, on the polished interior of the watch case of gold or silver; the engraving having been, of course, when the watch was shut up, for a longer or shorter time, in close propinquity, but not in contact with, the interior of the case, and in total dark

ness.

Further, M. Rauch, the sculptor, has observed a complete image formed on the surface of a plate of glass, which had covered an engraving, of the subject of the print, although the glass did not touch it; and, it seems, this fact is familiar to engravers.

Möser has found that these images of prints on glass may be produced in a very short time. The image appears brighter or lighter coloured than the rest of the glass, and is easily rubbed off.

An engraving takes nine days to produce such an image, at a distance of from to of a line of the glass.

He has produced similar images on surfaces of copper, brass, zink, and gold, in five days. Möser proposes to repeat his experiments in vacuo, and is at present eagerly occupied with them.

Amongst other Continental discoveries relating to photography, is that of M. Lechi, of a mode of colouring Daguerreo