Light in The House of Mirth

Look at this passage: 

“… Lily leaned awhile over the side, giving herself up to a leisurely enjoyment of the spectacle before her. Unclouded sunlight enveloped sea and shore in a bath of purest radiancy. The purpling waters drew a sharp white line of foam at the base of the shore; against its irregular eminences, hotels and villas flashed from the greyish verdure of olive and eucalyptus; and the background of bare and finely-pencilled mountains quivered in a pale intensity of light.” (B.2, ch.2) 

What a scene that is. I do like Edith Wharton’s prose and descriptions. There is a lot in that passage, but particularly interesting is “a pale intensity of light”. 
In fact, do you notice the way Wharton uses light in the novel? 
From Book 1: 

“On the crimson carpet a deer-hound and two or three spaniels dozed luxuriously before the fire, and the light from the great central lantern overhead shed a brightness on the women's hair and struck sparks from their jewels as they moved.” (Ch.3) 

Imagine if she had been a director or cinematographer—how she would have used light! 

“As she entered her bedroom, with its softly-shaded lights, her lace dressing-gown lying across the silken bedspread, her little embroidered slippers before the fire, a vase of carnations filling the air with perfume, and the last novels and magazines lying uncut on a table beside the reading-lamp, she had a vision of Miss Farish's cramped flat, with its cheap conveniences and hideous wall-papers.” (ibid.) 

Soft light. 

“She turned out the wall-lights, and peered at herself between the candle-flames. The white oval of her face swam out waveringly from a background of shadows, the uncertain light blurring it like a haze; but the two lines about the mouth remained.” (ibid.) 

All of these are examples of practical lighting (I’m using film language). Here’s some daylight: 

“In the foreground glowed the warm tints of the gardens. Beyond the lawn, with its pyramidal pale-gold maples and velvety firs, sloped pastures dotted with cattle; and through a long glade the river widened like a lake under the silver light of September.” (Ch.4) 

Later: 

“She hardly knew what she had been seeking, or why the failure to find it had so blotted the light from her sky: she was only aware of a vague sense of failure, of an inner isolation deeper than the loneliness about her.” (ibid.) 

I can’t be the only one noticing the masterful use of light in the novel. 

“She took one with an unsteady hand, and putting it to her lips, leaned forward to draw her light from his. In the indistinctness the little red gleam lit up the lower part of her face, and he saw her mouth tremble into a smile.” (Ch.6) 

She writes about a gleam lighting up a face, and about light reflected on jewellery: 

“They had paused before the table on which the bride's jewels were displayed, and Lily's heart gave an envious throb as she caught the refraction of light from their surfaces—the milky gleam of perfectly matched pearls, the flash of rubies relieved against contrasting velvet, the intense blue rays of sapphires kindled into light by surrounding diamonds: all these precious tints enhanced and deepened by the varied art of their setting.” (Ch.8) 

This is the scene after the successful tableaux vivant: 

“The faces about her flowed by like the streaming images of sleep: she hardly noticed where Selden was leading her, till they passed through a glass doorway at the end of the long suite of rooms and stood suddenly in the fragrant hush of a garden. Gravel grated beneath their feet, and about them was the transparent dimness of a midsummer night. Hanging lights made emerald caverns in the depths of foliage, and whitened the spray of a fountain falling among lilies. The magic place was deserted: there was no sound but the splash of the water on the lily-pads, and a distant drift of music that might have been blown across a sleeping lake.
Selden and Lily stood still, accepting the unreality of the scene as a part of their own dream-like sensations. It would not have surprised them to feel a summer breeze on their faces, or to see the lights among the boughs reduplicated in the arch of a starry sky. The strange solitude about them was no stranger than the sweetness of being alone in it together.” (Ch.12) 

That is wonderful. 
Light can also make things ugly: 

“When Lily woke she had the bed to herself, and the winter light was in the room.
She sat up, bewildered by the strangeness of her surroundings; then memory returned, and she looked about her with a shiver. In the cold slant of light reflected from the back wall of a neighbouring building, she saw her evening dress and opera cloak lying in a tawdry heap on a chair. […] 
The door opened, and Gerty, dressed and hatted, entered with a cup of tea. Her face looked sallow and swollen in the dreary light, and her dull hair shaded imperceptibly into the tones of her skin.” (Ch.15) 

Edith Wharton writes about light, how light is reflected on objects, how people look in different light; she also writes about light as metaphor. Apart from the cliché of shedding light on [something] or seeing [something] in a new light, she writes: 

“Gerty Farish, the morning after the Wellington Brys' entertainment, woke from dreams as happy as Lily's. If they were less vivid in hue, more subdued to the half-tints of her personality and her experience, they were for that very reason better suited to her mental vision. Such flashes of joy as Lily moved in would have blinded Miss Farish, who was accustomed, in the way of happiness, to such scant light as shone through the cracks of other people's lives.” (Ch.14)  

Gerty Farish is rather dim—earlier, Wharton uses the phase “unfurnished mind” to describe her, but now conveys the same idea in a much more interesting, brilliant way. 
Also: 

“Now she was the centre of a little illumination of her own: a mild but unmistakable beam, compounded of Lawrence Selden's growing kindness to herself and the discovery that he extended his liking to Lily Bart.” (ibid.) 

Poor Gerty. Soon she realises that it’s just an illusion. 
Again light is used as a metaphor, in these lines about Lawrence Selden: 

“He yielded himself to the charm of trivial preoccupations, wondering at what hour her reply would be sent, with what words it would begin. As to its import he had no doubt—he was as sure of her surrender as of his own. And so he had leisure to muse on all its exquisite details, as a hard worker, on a holiday morning, might lie still and watch the beam of light travel gradually across his room. But if the new light dazzled, it did not blind him. He could still discern the outline of facts, though his own relation to them had changed.” (ibid.) 

There are a lot more examples throughout the novel—sunlight, moonlight, shadows, silhouettes, darkness, lamps, candles, illuminated surfaces, and so on. But that’s enough to demonstrate the point. Those of you who want to steal my blog post for an essay, do your own homework. 
I noticed the use of light whilst reading The House of Mirth, but now that I’ve collected the passages and put them together, they’re impressive. 
I wonder where Wharton learnt this from.