« ПредыдущаяПродолжить »
suckers at the end, which aid the animal in its progres- | were the first dish in the famous supper of Lentullus, sive motion.
when he made Flamen Martialis priest of Mars. By The mouth of this animal is armed with a most com- some of the concomitant dishes they seemed designed plex apparatus of calcareous jaws, arches, and teeth, | as a whet for the second course to the holy personages, consisting of twenty-five separate pieces. For the priests, and vestals invited on the occasion." They are movement of these parts separate muscles are provided, also mentioned at the marriage feast of Hebe. "Thi. of which the anatomy has been minutely described by ther came crabs and urchins, unable to swim in the sea, Cuvier. In the shells of the echini which are cast on but travelling only on the ground." In the Wasps of shore, this frame-work is often found entire in the inside Aristophanes, likewise, the hero of the piece repeats a of the case, and Aristotle having found in it a resem- fable respecting an urchin, who, when his shell had been blance to a lantern, it has therefore been called “the | cracked by a woman, summoned witnesses to prove the lantern of Aristotle." But there are other echini assault. He is interrupted by the remark, that it would which are entirely destitute of this apparatus, being have been wiser of the animal to buy a bandage than to without teeth, and having at the mouth only a narrow spend his time in proving the assault. Horace mentions transverse slit. From this variation of form, it is the echinus several times as very good eating. natural to suppose that the food of the different species The seas of warm and tropical countries are the most of echinus is also various. Mr. Kirby, speaking of the i productive of these animals; but notwithstanding the common echini, informs us, that their station is often number of living species, the fossil remains very far near the shore upon submerged ledges of rocks, and exceed them. These are found principally in the chalk thathey feed upon whatever animals they can seize, and oolite formations, and are so abundant, and so well sometimes turning upon their back and sides, and some preserved, that there are few collections of fossils in times moving horizontally. “This enables them more which we may not meet with numerous specimens. readily to secure their food, with the aid of the numerous The empty shells of the echini are sometimes found suckers in the vicinity of their mouth, which, when once
in considerable numbers on our western coasts, especithey are fixed, never let go their hold till the animal is
ally after the Atlantic has been much agitated by brought within the action of their powerful jaws. Lamarck thinks that they do not masticate, but only lacerate their
storms. They are shaped more like an apple than an food; but as two faces of each of their pyramidal organs
egg, having a small aperture at the top, and another answer those of the two adjoining ones, and these faces are at the opposite extremity. In this state the projecting finely and transversely furrowed, this looks like masticating suckers, spines, and bristles, have all been broken off, surfaces. Bose, who appears to have seen them take their leaving the minute apertures reaching from ove end to food, says it consists principally of young shell-fish and the other in regular rows, something in the same mansmall crustaceous animals. As the latter are very alert in
ner as the meridians of a globe. their motions, it is difficult for the sea-urchins to lay hold of them; but when once one of these animals suffers itself to be touched by one or two of the tentacles of its enemy, it is soon seized by a great number of others, and immediately carried towards the mouth, the apparatus of which developing itself soon reduces it to a pulp." The development of the echini from the time of their
Fig. 2. first leaving the egg, has not come within the observation of any naturalist, but the young of Echinus esculentus has been examined when only one-eighth of an inch in diameter, and found to have the form and armature of the full-grown animal. The prickles were toothed along their edges; but those spines which in the perfect state have three prongs, as already described, were only provided with two. The globular form was
Echinus melo. perfect in the young animal; but the shell was composed of few pieces. It may appear contrary to the general law which regulates the mode of increase in these animals, The microscopic examination of the teeth reveals correthat the shell should be thus perfectly formed in minia spondences and differences in their structure in the various ture, for it appears necessary whenever cells, intended groups of vertebrated animals, so constant and easily recogfor the lodgment of soft organs, are to be formed of hard
nised, that from the smallest fragment of a fossil as well as materials, that the foundation should be laid upon a scale
recent tooth, not only the class and order, but even the
family, and, in some instances, the nearest allied genus of suited to the after-growth of the animal, otherwise the
the animal to which the tooth belonged, may be told with soft parts within would be so confined and contracted certainty. that they must cease to grow altogether. But in the case of the echini, provision is made for the expansion AUSTRALIAN METHOD OF FINDING HONEY. of the shell itself, for each shell is divided into a number
THEY catch one of the wild bees and attach to it, with of small pieces, and each piece has that polygonal form
some resin or gum, the light down of the swan or owl. which is best suited to the perfect junction of the whole.
Thus laden, the bee makes for the branch of some lofty Small additions are therefore constantly being made to tree, and so betrays its home of sweets to the keen-eyed the margins of each of these polygonal pieces, and the pursuers.-MITCHELL'S Australia. expansion goes on exactly in proportion to the growth of the soft parts of the animal within. The roe of this animal occupies much space within
By the evidence of all history, savage tribes appear to owe
their first enlightenment to foreigners ;—to be civilized, the shell, being very large in proportion to the animal and its other viscera; and it is in the spring, when the
they conquer or are conquered—visit or are visited. roe is fully developed, that this animal is in some places used as food, as its name imports. An old writer speaks
It must always be remembered, that the actions of public of the sea-egg, as being eaten by the poor in niany parts
men will be the subject of thought at a future period; of England, and by the better sort abroad. It is re
when interest is stifled, and passion is silent; when fear has corded that these animals formed one of the favourite
ceased to agitate, and discord is at rest; but when conscience
has resumed its sway over the human heart. Nothing but dishes among the Greeks and Romans. “They were
what is just, therefore, can finally be expedient, because dressed with vinegar, honied wine, or mead, parsley, and nothing else can secure the permanent concurrence of manmint; and esteemed to agree with the stomach. They kind. - Alison's History of Europe,
METALLOCHROMY, OR THE ART OF has designated by the epithet chromatic. This scale COLOURING METALS.
consists of forty-four tints, each of which is applied to a
plate of steel. The tints are disposed in the same order It is generally supposed that the blue colour imparted
as the layers or films by which they are produced: the to steel, results from a thin film of oxide formed upon
colour of the thinnest film is placed first, and the others the surface of the metal when exposed to a certain tem
follow in the order of the progressively increasing thickperature. About fifteen years ago, Professor Nobili,
ness of the plates. In this arrangement the layers or of Reggio, offered a new explanation of this fact, and
films which produce the several colours are all applied discovered a method of imparting colour to metallic
by the same electro-chemical process. The voltaic bat surfaces: as his results are extremely beautiful and
tery, the solution of acetate of lead, the distances, all varied, a brief notice of them may be acceptable.
remain exactly the same. There is nothing variable but The following is one of the principal experiments
the duration of the action, which, in respect to the layer connected with what the inventor appropriately terms
No. 1, is very short, a little longer in respect to the the Art of Metallochromy. A plate of platinum is
second, and increases progressively from the lowest to placed horizontally at the bottom of a glass or china
the highest number. vessel. A platinum point is suspended vertically over
CHROMATIC SCALE. this, in such a manner, that the distance between the
44. Rose lake . . point and the plate may be about half a line. A solu
43. Reddish yellow green . tion of acetate of lead is next poured into the vessel, so
42. Yellowish green
. as not only to cover the plate, but to rise two or three
to the 41. Green . .
Fourth ring. lines higher than the point. The plate and the point
40. Greenish violet are now brought into communication, the former with 39. Violet lake . the positive, and the latter with the negative pole of a
38. Rose lake . .. voltaic battery. At the moment when the voltaic
37. Rose orange . . circuit is closed, a series of coloured rings appear on the 36. Greenish orange .. surface of the plate precisely under the point. These
35. Orange green
Corresponding rings are similar to those described as Newton's rings
34. Yellow green
33. Yellowish green in our Philosophy of a Soap-bubble*, but in an inverse
32. Green . . order: Newton's rings begin at the centre; Nobili's at
31. Greenish purple the circumference, where, from the nature of the electro
30. Bluish lake . chemical process, the thinnest layers are deposited: the 29. Purpled lake thickest layers are evidently those at the centre.
28. Brilliant lake This fact, which could not fail to strike any one
27. Lake observing it for the first time, led to the discovery of 26. Orange lake . others. “ Science never consults its interests so truly,"
25. Orange red . remarks Professor Nobili, “as when it aims at some
24. Red orange . useful object connected with the arts.” He foresaw the
23. Reddish orange advantages the arts were likely to derive from this new
22. Orange . .
21. Orange yellow method of colouring metals, and attended seriously to
20. Brilliant yellow its application. His object was, instead of producing
19. Yellow . . rings of various colours upon a plate of metal, to cover
18. Very bright yellow
Second ring. its surface uniformly with any desired tint. The
17. Yellowish azure colours being obtained by the effect of very thin plates
16. Azure , . applied to the surface of metals, it is easy to conceive
15. Clear blue . how difficult it was to preserve such plates of a uniform
14. Blue . thickness over the whole of an extensive surface.
13. Deep blue
12. Indigo . “Great, however, as the difficulties were, I thought I
11. Violet owed it both to art and to science, to do my utmost to
10. Violet red surmount them. I thought it due to art, because this
9. Violet ochre . would be extended by means of the uniformity of the
8. Ochre . tints; and to science, because in the tints produced by
7. Copper red ...
Corresponding plates of a particular thickness, the experimental philo
6. Brilliant tawny
to the sopher would find the means of investigating, with pecu
5. Tawny . . liar advantage, the nature and properties of colours."
4. Brilliant blond.
. By substituting plates for the platinum point which
3. Golden blond forms the coloured rings, it was found that a surface of
2. Blond . metal could be covered with one uniform tint. In 1828,
1. Silver blond . Professor Nobili presented several such productions to
The effect produced by these tints, when disposed in the French Institute, and afterwards to our Royal So the above order, baffles description; it bears a resemciety, and particular attention was excited by the beauty blance, however, to that prodụced on the ear by a scale and vividness of the tints, the precision of the outlines,
| of semitones, executed by a perfect voice. “I have and the softness of their blendings.
shown my scale to several, and especially to those erudite Although the efforts of this ingenious philosopher
and learned persons who have favoured me with a passing
visit at Reggio. In all it excited but one feeling of delight. were attended with complete success, his methods so easy
So gradual, indeed, is the transition from one tint to anoin their practical application, and the results so beauti
ther, and such the harmony with which they are blended, ful; although, too, the attention of scientific men was that if the eye be accidentally turned away, it reverts in a directed to the subject, it is remarkable that this new moment, as if moved by an irresistible desire to gaze still art was practised by its inventor only up to the time of longer on the display. This statement is no exaggeration. his death, since which it appears to have been quite for
It is but the mere fact, in respect to which a language much gotten. Not only would this art be valuable to workers
more glowing would be perfectly consistent with truth; so
overpowering is the charm which, if I may use the expresin metal generally, but the artist would find in it a wide
| sion, pervades the scale of our coloured plates." field for observation and study. Professor Nobili has |
In an admirable memoir, (which has been translated arranged the tints produced by his method in their
| into the first volume of Taylor's Scientific Memoirs,) natural order, so as to form a scale, or gamut, which he
Professor Nobili examines and compares with natural • See Saturday Magazine, Vol. XV., pp. 199, 204, 222, and 231. phenomena all the colours which compose his chromatic
scale. If the reader be at all interested in the subject | are always more or less charged with vapours, the air no of colour, either artistically or scientifically, we strongly longer retains its morning transparency, and the setting of recommend him to study this memoir. As we are
the sun is attended by a fiery tint, which greatly mars the about to inform the reader of an easy method of pro
tranquil beauty of the spectacle. It is to those vapours
that we are to attribute the inflamed appearance of the sky, ducing these beautiful colours, we can find space for
because they possess the power of transmitting the tints of only a few short extracts. This we do the more readily the first order, and those are of that fiery cast. Were it not because in our notices of the Soap Bubble, already re- | for this circumstance, the setting of the sun might justly ferred to, a popular account is given of the principles
is given of the principles vie with its rising. upon which colour is produced by thin plates or films. Philosophers had long since settled their opinions as to The colours which the clouds assume, are, in general,
the colours of the sky. These they explained by assigning Black, or very pure ash-colour;
to the air the property of reflecting the higher colours of the White, or very light ash-colour;
spectrum, (violet, indigo, &c.,) and that of transmitting the The colour of smoke or coffee;
lower, (red, orange, &c.) The explanation was correct, so Red, more or less fiery;
far as it went, but to make it complete the exact quality Blue, very deep, and sometimes approaching to violet. of the tints should be determined by indicating the order to These are exactly the tints that would constitute the which they belong. It was necessary also to ascertain how first ring, were we to include in it the first two colours of light is affected by the presence of vapours. The considerthe second ring. The tints of smoke result from the more ations which we have just stated will perhaps supply both or less thorough blending of the blond and the tawny: those these deficiencies. of fire from Nos. 8, 9, and 10; the deep blue is produced A singular property is connected with some of the by the Nos. 10, 11, and 12, which are the deepest tints of tints of the scale. If a drop of alcohol is let fall on the scale.
the violet, No. 11, (as also upon a few other tints The first blond is properly that of light hair in childhood, and it is a fact worthy of remark, that as children grow older, it becomes progressively deeper and deeper, in
as to cover part of the colour, the part thus made wet is the order of the Nos. 2, 3, and 4, in the scale. The perfect
no longer the same; we see instead of it a feeble tint resemblance of the first tints on the scale to those which resembling that of coffee mixed with milk; but the other we observe about the moon when she is surrounded by part remains unchanged. The comparison can be made clouds, is equally remarkable; it seems in fact that this instantaneously, and the difference between the two tints luminous appearance may be thus definitively explained.
is so striking, that we are at a loss to conceive how a Tints of this kind do not arise from refraction and diffrac
| transparent and very limpid film of alcohol can produce tion, they are produced only by means of thin plates; the
such a change in the violet colour on which it is placed. luminous halo seen round the moon when overcast with fog or light clouds, is therefore a phenomenon produced by
The alcohol gradually evaporates, and the colour rethin plates.
covers its former brilliancy. Water, oil, and the differ. This observation, combined with the fact, that the tints ent saline solutions, produce the same effect. exhibited by the clouds in every variety of aspect, are The prismatic colours produced on steel and copper almost all comprised in the first ring, leads to another con- | by the action of fire, and the colours exhibited by tin, sequence relative to the constitution of vesicular vapours. bismuth, lead, &c., when in a state of fusion, have been The ineasurements and experiments of Newton have shown
supposed to result from the oxidation of those metals. what are the dimensions of the layers of air, of water, and of glass, which produce the colours of the several rings.
This explanation may reasonably be doubted. The blue The red of No. 10, is the last tint of the first ring; the in
hain: or violet colour which is sometimes given to steel is to digo, No. 12, belongs to the second ; and the thickness of secure it froin rust. This colour is produced by means the layer of water, which produces it by reflection, is about į of fire in the process of giving steel a particular temper the ten-millionth part of an English inch. As we know --a temper which is called violet, because it is produced then, on the one hand, that the vesicular vapours are simultaneously with the colour. If this tint were the formed of water, and on the other, that they do not reflect effect of oxidation, would it not rather accelerate than or transmit any tint beyond No. 12; we may conclude, that their external film is in no case thicker than the ten
prevent oxidation ? A very high degree of polish will millionth part of an inch.
keep off rust for a long time, but cannot stop it when This result appears to Professor Nobili so decidedly | once the action has commenced. certain as to be entitled to a place in science.
According to Professor Nobili the colours of which In speaking of the tints of the second ring, he says,
we now speak belong to the same class as those proWe have the sky, their type in nature, constantly before
duced by tin plates, and he concludes that no oxide is our eyes ; for who is there that knows not the dawn, “ with
formed upon the surface of the steel, because, 1st, the rosy forehead and golden feet”? Beginning with No. 12 of metal retains, beneath the deposited la
metal retains, beneath the deposited layer, its natural the scale, let us run our eye over it as far as No. 28, and we brilliancy; 2nd, this layer produces the phenomenon shall find that the tints of the sky are disposed there in the of the coloured rings in all its beauty; and 3rd, instead order in which they present themselves in the magnificent
of oxidizing or rusting the metal, the coloured film conspectacle of the dawning day. This succession, as we have already observed, is the most beautiful of all : Newton's
tributes to secure it against rust in every part to which second ring gives no idea of it, because its colours are not,
it is applied, as was proved by exposing two steel plates, and cannot be, sufficiently developed to produce the effect.
one only of them being coloured, in the open air, to all Painters, if I mistake not, will do well to avail themselves the vicissitudes of a rainy autumn ; when at the end of of this part of the scale; they will find it a faithful copy of a month the uncoloured plate was all rusted, the other the beautiful tints of the morning, and endeavour to trans- had lost a little of its colour, but was free from rust. fer them to their compositions. Natural philosophers will considering then, that by the electro-chemical means not fail to remark, that among the various tints of the sky stated at the beginning of this article, the films can be there is no trace of green. This would heretofore have been found a perplexing circumstance, but it may now be satis
deposited with equal facility upon platinum, a metal diffactorily explained, merely by reflecting that the tints of
ficult to be oxidized, as upon iron and steel, which belong the sky belong to the second order, in which also there is
to a class of metals most easily oxidized, as well as from
to a class o no tinge of green. From the blue to the yellow, the tran
the results of numerous collateral experiments, it appears sition is through a very faint gradation of azure-yellow, that oxygen and certain acids may adhere to the surfaces and this is observed to be exactly the case in nature. of metals without producing the slightest chemical
The tints produced by the vapours and clouds belong to change in them. It may be laid down as a general pro. the second order. They contain in general more fire than the natural tints of the sky, but this quality is nothing in
position, that the oxygen of the atmosphere produces comparison with the purity, vividness, and variety, dis
the colours on metals by the action of fire, not, as is played in the tints of the second order. The appearance of
supposed, by oxidizing the surface of the metal, but, by the sun is never so magnificent as when the air is perfectly becoming fixed in the form of a thin plate, or film, sini. pure. Toward evening the lower regions of the atmosphere | lar to those produced by the electro-chemical process.
If a plate of copper be laid upon a red-hot iron, the CURIOUS CHESS PROBLEMS. plate becomes gradually heated, and all at once exhi
X. bits the most beautiful colours, but they disappear as suddenly. Before it becomes coloured, the plate has a
On first glancing at the following problem, the young metallic lustre; it subsequently ceases to shine, and
student will probably suppose that its solution is imposbecomes evidently oxidized. It is therefore at the
sible on the terms proposed. An attentive examination moment when the colours manifest themselves that the
of the position of the pieces will, however, soon lead oxygen of the air precipitates itself on the copper. In
him to effect the solution of this by no means difficult the next moment the chemical combination is effected,
problem. The solution is, indeed, rendered more easy which takes place whenever the action of the heat is
by the terms, which, at first sight, seem greatly to add sufficiently prolonged. If the plate of copper be removed
to its difficulty. Being required to check on the fourth from the red-hot iron as soon as the first indication of a
move with one pawn, and to give checkmate at the fifth change of colour is perceived at any point, the process
move with another pawn, the student is thus made of coloration will then go on more slowly, the copper
acquainted with two moves out of the five, so that the will not be oxidized, and the oxygen, which would pro
number of moves to be discovered is, in fact, reduced duce this effect under a more prolonged action of the
to three. heat, now covers the plate with a film, which adheres to This problem was originally invented by that great it like a varnish, and by its transparency produces the
master, Damiano, who gives the player of the white usual colours.
pieces a Rook instead of a Bishop, and requires the The origin of the violet colour given to steel to pre
mate to be given in eight moves; but Carrera made the vent it from rusting, is the same. The layer, however,
problem more difficult by substituting a Bishop, and which produces this tint in the steel does not perhaps
requiring the mate to be given in five moves. consist solely of oxygen, as it does when the metals are
White to move first and to mate with the Pawn which pure. Steel is a compound of iron and carbon, and the
now occupies the Queen's Knight's second square, in oxygen of the air precipitated on this compound being
five moves; checking on the fourth move with the combined with the carbon in some manner or other,
Pawn which now occupies the Queen's Knight's might form the layer in question. At all events the
third square. layer does not change its nature; it is always electro
* BLACK, negative, and secures the metal from rust as effectually as the layers applied by the electro-chemical process.
By this latter process, as we have said, films are formed on the surface of metals with surprising rapidity, and the colours developed on metals exposed to the action of heat, are produced with equal promptitude. It is therefore essential to the production of the phenomenon of thin plates, that the electro-negative elements should be precipitated on the metal with a certain velocity. “Does not the necessity of this condition show why these layers, in order to produce the desired effect, should be brought into contact with the metallic surface by the agency either of fire or electricity ? The action of moisture is, perhaps, too tedious in all cases; it gradually oxidizes the surfaces of the metals, but never covers them with that thin and extended veil, the application of which requires a rapidity unattainable in this circumstance."
At the present time, when a voltaic battery can be procured by every one at the cost of a few pieces of copper and zinc, it is certainly not too much to expect that many of our readers will repeat the beautiful experiments of which we have detailed a few of the results. Care must be taken in the use of the acetate
WHITE. of lead, because this salt is very poisonous. A solution must be made with rain water, and should it not be perfectly clear, it must be filtered through blotting In the cultivation of literature is found that common link, paper.
which among the higher and middling departments of life unites the jarring sects and subdivisions in one interest;
which supplies common topics, and kindles common feel. It is a misfortune not to possess enough intelligence to ings, unmixed with those narrow prejudices, with which enable one to speak with propriety, nor sufficient judgment all professions are more or less infected. The knowledge, to know when to be silent.--DE LA BRUYERE.
too, which is thus acquired, expands and enlarges the
mind, excites its faculties, and calls those limbs and inuscles It is not the reality of grievances so much as the temper
into freer exercise, which, by too constant use in one direcwith which they are viewed, which produces a revolution.
tion, not only acquire an illiberal air, but are apt also to lose somewhat of their native play and energy. And thus,
without directly qualifying a man for any of the employThat only which is becoming is good; therefore virtue is ments of life, it enriches and ennobles all: without teaching to be pursued for its own sake; and, because it is a divine | him the peculiar benefits of any one office or calling, it attainment, it cannot be taught, but is the gift of God. He enables him to act his part in each of them with better alone who has attained the knowledge of the first good is grace and more elevated carriage; and, if happily planned happy. The end of this knowledge is, to render man as and conducted, is a main ingredient in that complete and like to God as the condition of human nature will permit. generous education, which fits a man to perform justly, This likeness consists in prudence, jnstice, sanctity, tem- skilfully, and magnanimously, all the offices, both public perance. In order to attain this state, it is necessary to be and private, of peace and war.-Bishop COPLESTON. convinced that the body is a prison, from which the soul must be released before it can arrive at the knowledge of those things which are real and immutable.-Plato.
John W. Parker, PUBLISHER, West STRAND, Londox.