Gardeners Dictionary: Variegated

Gardeners Dictionary:
containing The Best and Newest Methods of Cultivating and Improving The Kitchen, Fruit, Flower Garden, and Nursery; As also for Performing the Practical Parts of Agriculture: Including The Management of Vineyards, With the Methods of Making and Preserving Wine, According to the present Practice of The most skilful Vignerons in the several Wine Countries in Europe.

Together with Directions for propagating and improving, From real Practice and Experience, All sorts of Timber Trees.

The Eight Edition,
Revised and Altered according to the latest System of Botany; and Embellished with several Copper-Plates, which were not in some former Editions.

By Philip Miller, F. R. S.
Gardener tothe Worshipdul Company of Apothecaries, at their Botanic Garden in Chelsea, and Member of the Botanic Academy at Florence.

Printed for the Author;

(Lontoo 1768)

Variegated signifies streaked or diversified with several colours; of which there are now a great variety of plants in the gardens of the curious, whose leaves are variegated with yellow or white. Those which are spotted with either of these colours in the middle of their leaves, are called blotched (in the gardeners term;) but those whose leaves are edged with these colours are called striped plants. Those plants whose leaves are blotched are generally subject to become plain, when planted in a good soil; or at least in the growing season, will have but a small appearance of the two colours; but those which have edged leaves, rarely become plain again, especially if the edging is broad, and goes quite through the leaves, though these do not appear so finely variegated in the growing season, as they do in the other parts of the year.

All the different sorts of Variegation in plants were at fisrt accidental, being no more than a distemper in the plant, which being observed, has been cherished by impoverishing the soil in which they grow, by which method their stripes are rendered more lasting and beautiful. But whatever some persons have affirmed of striping plans by art, I could never observe it done by any, unless in woody shrubs and trees, which may be variegated by putting in a bud or graft taken from a variegated plant; where, although the buds should not grow, yet if they keep fresh but eight or ten days, they will many times communivate their gilded miasma to the sap of the trees into which they were budded; so that in a short time after, it has appeared very visible in the next adjoining leaves, and has been afterwards spread over the greatest part of the tree; but in such plants as are herbaceous, where this operation cannot be performed, there is no way yet ascertained whereby this striping can be effected by art.

In some sorts of plants this distemper is often communicated to the seeds, so that from the seeds gathered from variegated plants, there will constantly be some variegated plants produced; as in the striped Wing Pea, the greater Maple, &c. therefore these may be constantly propagated that way.

That this striping proceeds from the weakness of plants is very evident, since it is always observed, that whenever plants alter thus in the colour of their leaves, they do not grow so large as before, nor are they so capable to endure the cold; so that many sorts of plants which are hardy enough to endure the cold of our climate in the open air when in their natural verdure, require to be sheltered in the winter after they are become variegated, and are seldom of so long continuance; which is a plain proof that it is a distemper in the plants, since whenever they become vigorous, this striping is either rendered less visible, or entirely thrown off; especially (as was before observed) if the plants are only blotched, or if the edging be of a yellow colour, it is less apt to remain than when it is white; which is esteemed the most beautiful striping, and which (when once thoroughly established) is hardly ever to be got out of the plants again, so as to render the leaves entirely green.

Nay, such is the venom of this morbid matter, that it not only tinges the leaves, but also the bark and fruit of trees are infected by it, as in the Orange, Pear, &c. whose bark and fruit are striped in the same manner as their leaves.

The different colours which appear in flowers also proceed from the same cause, though it is generally in a less degree in them than when the leaves and branches are infected: for the various colours which we see in the same flowers, are occasioned by the separation of the nutritive juice of plants, or from the alteration of their parts; whereby the smaller corpuscles, which are carried to the surfaces of the flower leaves, are of different forms, and thereby reflect the rays of light in different proportions. In order to understand this, it may not be improper to say something concerning the phæmenon of colous, as it hath been discovered by the late excellent philosopher Sir Isaac Newton.

1. Colour may be considered two ways: (1.) As a qualify residing in the body that is said to be so and so coloured, or which doth modify the light after such a manner; or (2.) as more properly the light itself, which being so modified, shines upon the organ of sight, and produces that sensation we call colour.

2. Colour is defined to be a property inherent in light, whereby, according to the different sizes or magnitudes of its parts, it excites different vibrations in the fibres of the optic nerve, which being propagated to the sensorium, affects the mind with different sensations.

3. Again: colour may be defined a sensation of the soul, excited by the application of light to the retina of the eye; and different, as the light differs in the degree of its refrangibility, and the magnitude of its component parts.

4. According to the first definition, light is the subject of colour: according to the latter it is the agent.

5. So then light sometimes signifies that sensation occasioned in the mind, by the view of luminous bodies; sometimes that property in those bodies, whereby they are fitted to excite those sensations in us.

6. Various are the opinions of ancient and modern authors, and of the several sects of philosophers, with regard to the nature and origin of the phænomenon colour.

7. the peripatetics assert colours to be real qualities, and inherent in the coloured bodies; and suppose that light doth only discover them, but not any way affect their production.

8. Plato thought colour to be a kind of flame consisting of most minute particles, very conguous to the pores of the eye, and darted against it from the object.

9. Some morderns will have colour to be a kind of internal light of more lucid parts of the object darkened, and consequently altered by the various mixtures of the less luminous parts.

10. Others, as did some of the antient atomists, maintain colour not to be a lucid stream, but a corporeal essluvium issuing out of the coloured body.

11. Others account for all colours out of the various mixture of light and darkness; and the chemists will have it sometimes arise from the sulphur, and sometimes from the salt htat is in bodies; and some also from the third hypostatic principle, i. e. mercury.

12. The most popular opinion is that of the followers of Aristotle, who maintain, that colour is a property inherent in the coloured body, and that it exists without any dependence on light.

13. The Cattesians, who made the sensation of light to be the impulse made on the eye by certain solid, but very minute globules, easily penetrating the pores of the air, and diaphonous bodies; these derive colour from the various proportion of the direct progress or motion of these globules to their circumrotation or motion round their own centred, by which means they are qualified to strike the optic nerve, after distinct and divers manners, and so produce the perception of divers colours.

14. They own that as the coloured body is not immediately applied to the organ to occasion the sensation, as no body can affect the sense but by immediate contact, the coloured body does not excite the sensation of itself, or contribute any thing to it, otherwise than by moving some interposed medium, and by that the organ of sight.

15. They add, that as it is found that bodies do not affect the sense in the dark, and that light only occasions the sensation of colour, by moving the organ; and that coloured bodies are no farther concerned than in reflecting the light in a certain modification; the difference in colours, according to them, arises in a difference in the texture of their parts, by which they are disposed to reflect heir light with this or that modification.

16. Dr. Hook, in his Micographia says, The phantasm of colours is caused by the sensation of the oblique or uneven pulse of light, and that this is capable of no more varieties than two, which arise from the sides of the oblique pulse; so that there are in reality but two simple colours, yellow and blue; from the mixture of which, and a due proportion of black and white (that is, darkness and light) all colours may be [be] produced.

17. But this phænomenon if nature and colour, having long perplexed philosophers to account for the discoveries relating thereto, the incomparable Sir Isaac Newton found by two experiments on prisms, that there is a great deformity in the rays of light, and that hereby the origin of colours may be unfolded. The doctrine of colours therefore, according to his notion and experiments, are contained in the following propositions:

1. That light consists of an infinite number of rays, right lined and parallel, but of different degrees of refrangibility, when meeting with a different medium.

2. Each ray, according to its degree of refrangibility, when so refracted, appears to the eye of a different colour.

3. The least frangible rays appear of a deep scarlet colour; the most refrangible appear of a Violet blue; the intermediate proceeding from scarlet to yellowish, then to light green, and so to blue.

4. The colours arising from the different degrees of refrangibility of light are not only the more noted colours of red, yellow, green and blue, but also all the intermediate colours of red to yellow, of yellow to green, &c.

5. Whiteness, (such as the sun's light appears,) containing all those degrees of refrangibility, is consequently made up of all the above-mentioned colours.

6. Simple or homogeneal colours, are such as are produced by homogeneal lights or rays, which have the same degree of refrangibility; and mixed colours are such as are produced by rays of different refrangibility.

7. Rays of the same refrangibility produce the same colour; which colour is not alterable by repeated refractions, but only made strong or faint, as the rays are united or scattered.

8. All bodies appear of this or that colour, according as their surfaces are adapted to reflect only the rays of such colour: or at least n more plenty than the rest.

But to explain these things farther:

It is found by experience, that rays or beams of light are composed of particles very heterogeneous or dissimilar to each other; i. e. some of them, as it is highly probable, are larger, and others less; for a ray of light, being received on a refracting surface in a dark place, is not wholly refracted, but split as it were, and diffused into several little rays; some of which are refracted to the extreme points, and others to the intermediate points; i. e. those particles of the light, which are most minute, are diverted the most easily and most considerably of all others, by the action of the refracting surface, out of their rectilineal course; and the rest, as each exceeds another in magnitude, so it is turned out of its wight line with much difficulty, and less considerably.

Now each ray of light, as it differs from another in its degree of refrangibility, so likewise it differs from it in colour. This is warranted by numerous experiments.

Those particles which are more refracted, are found to constitute a ray of a Violet colour; i. e. in all probability, the most minute particles of light, thus separately impelled, excite the shortest vibration in the retina, which are thence propagated by the solid fibres of the optic nerve into the brain, there to excite the sensation of Violet colour, as being the most dusky and languid of all colours.

Again: those particles which are the most refracted constitute a radiolus, or little ray, or a red colour; i. e. the largest particles of light excite the longest vibrations in the retina, so as to excite the sensation of red colour, the brightest and most vivid of all colours. It is remarkable, that in the growing of plants, the same plants do from time to time, alter and change their colours as the vessels which are in their young shoots grow larger. The leaves are of a faint yellow when they are in their smaller state, but they become of a bright green; or sometimes red, when they are in their middle state; but when their vessels are enlarged to their full growth, they become of a dark green, and then change to a feuillemort colour towards autumn, from the ripening of their juices; from thence to putrefaction, which resolves itself again into earth, its first principle.

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