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by a Broad Brimmed Hat - such as Coachmen wear, who probably adopted this costume from its advantage in sharpening their sight.
There is no part of the Economy of the Eyes more important, than that the object they are at work upon should be placed at exactly that distance from them at which they see with the greatest ease: - this may be easily accomplished by the assistance of a DOUBLE-RISING DESK:
and hard Students will do wisely to have a High Desk at which they can occasionally stand — instead of always sitting.
Those who are much occupied in Engraving Painting Writing Reading &c. or works which require all the power of the Eye
to be exerted to the utmost.
should be care
ful not to offend it by too much Light, which is quite as prejudicial as too little Light.
Light enough to illuminate the object, and to make it easily and perfectly visible, is all that is wanted on this occasion, the Old Proverb,
Enough is as good as a Feast," is quite true,— more, is not only unnecessary, but injurious, and will not only over-stimulate the Eye-and force the Pupil to shut itself up, but if continually so irritated, the Eye will soon become as much impaired by such over-stimulation, as the Stomach is by Dram-drinking.
I have observed in my visits to a numerously attended Reading Room — that the seats next the windows were generally filled by persons wearing Spectacles, who had no doubt accelerated the necessity for so doing by a habit of over-stimulating their Eyes with superabundant Light.
The proper way of defending the Eyes from too much Light, is by preventing all that is superfluous from entering the Room, by means of Blinds or Shutters—thus, you may admit only just such a degree of Light as you find most agreeable to your Eyes.
All Artists choose a Room lighted only from one aperture — and if possible with the steady North aspect; that is the best place in the room, indeed the only proper place for Study for those who have any regard for their Eyes, where the Light falls on their work or book coming from the side or from behind.
"It is requisite always to have an equal, well regulated Light in every employment, particularly in the Evening; the Eye may be seriously strained and injured by working, writing, or reading with either too much or too little Light for want of a due attention to preserve the visual organ, and from using the Eyes very much during the busy part of life, a morbid sensibility is brought on, an unnatural weight of the Eye-lids, a great deficiency of distinctness, and occasionally a distressing, undulatory quivering appearance of refrangible colours on either side. To remedy this, washing the Eyes with clear cold water, and keeping them from the Light for an hour, or taking a Nap, will be found most efficacious.". S. PIERCE.
If your Eyes are much employed in Reading, &c. and are extremely irritable, you may have your window glazed with Green Glass, or a
blind of it to put up occasionally - or a rolling blind of Green Silk or Muslin- or have a plate of Green glass fixed in a Frame, which may be placed so that the Light may pass through it to your book or work. But do without all these if possible for if they alleviate the irritation while you use them—they will render the Eyes more morbidly irritable after.
AT NIGHT-use a Reading Candlestick or Lamp with a shade to shield the Eye from the glare of the Light; which is of much greater assistance to the Sight than those who have not tried it can imagine: One candle so shaded will enable a person to see better than Two without such a shade, and with a Cumumbra Lamp-you may see I think almost quite as well as by Day-light, -the sensibility of the Eye is preserved in such perfection.
The Optic Pupil inevitably adjusts itself to the brightest object, which therefore should
Every thing is best seen when the light of the candle is intercepted the bright light of the Candle not only makes the pupil contract, but by mixing itself with the images of other objects, it in some measure obliterates them, so as they cannot be so well perceived.”—Dr. PORTERFIELD on the Eye, 8vo. 1759, Vol. II. p. 188.
be that which it is its business to attend to, not the flame of a Candle, but the Book you are reading.
GREEN, or any COLOURED GLASSES, veil objects with a gloomy obscurity, and can never be recommended, except to those who have to travel over a white sand, or are much exposed to any bright glare, which cannot be otherwise moderated.
Light reflected from any white surface, is very piquant and injurious to the Sight, whether proceeding from Water-Snow, &c.
Gogglers -or black cups, glassed with plain glasses, and mounted in double-jointed frames formed to the shape of the face-are preferable to those which are fixed in Leather and Silk and tied on with riband; the latter come so close to the face that they soon become a Vapour Bath for the Eye-but the former are occasionally found very serviceable to travellers to protect their Eyes from Wind and Dust, and to shield* them from a strong Reflected Light; Blue or
"Xenophon relates that many of his Troops were blinded by the strong reflection of the light from the Snow over which they were obliged to march.
"Dionysius the Tyrant of Sicily, among other means.