In between the adjectives "wonderful" and "amazing," "radiant" does not only refer to the physical sunlight in the garden but also to the emotional light of Mary, Ben, Colin (for whom happiness had not been the norm), and Dickon (whose natural happiness raises the level of happiness for everyone else).
They always called it Magic and indeed it seemed like it in the months that followed--the wonderful months--the radiant months--the amazing ones.
Satiny poppies of all tints danced in the breeze by the score, gaily defying flowers which had lived in the garden for years and which it might be confessed seemed rather to wonder how such new people had got there.
exquisitely fine and subtle and pleasing; susceptible to injury
Fair fresh leaves, and buds--and buds--tiny at first but swelling and working Magic until they burst and uncurled into cups of scent delicately spilling themselves over their brims and filling the garden air.
an ascetic Muslim monk; a member of an order noted for devotional exercises involving bodily movements
A dervish is similar to a fakir: both are poor monks who beg, but dervishes are also known for whirling and possessing miraculous powers. The question seems like a joke, but Colin seriously wants to believe that "there is Magic in everything, only we have not sense enough to get hold of it and make it do things for us." So he is willing to experiment--with chants, dervish movements, or muscle exercises--so that he can become stronger and live to be a man.
"Shall we sway backward and forward, Mary, as if we were dervishes?"
Colin also says this about Dickon's mother: "She is a Magic person. Tell her we are grateful, Dickon--extremely grateful." Colin is expressing his gratitude ("a feeling of thankfulness and appreciation") for the hot currant buns and delicious fresh milk that Dickon's mother had sent. Coming from a woman who struggles to feed fourteen people in her own family, this bounty seems even more magical.
"Tell her she has been most bounteous and our gratitude is extreme."
large in number or quantity (especially of discourse)
And then forgetting his grandeur he fell to and stuffed himself with buns and drank milk out of the pail in copious draughts in the manner of any hungry little boy who had been taking unusual exercise and breathing in moorland air and whose breakfast was more than two hours behind him.
Even Dickon did not go near the close-grown corner in those days, but waited until by the quiet working of some mysterious spell he seemed to have conveyed to the soul of the little pair that in the garden there was nothing which was not quite like themselves--nothing which did not understand the wonderfulness of what was happening to them--the immense, tender, terrible, heart-breaking beauty and solemnity of Eggs.
He could only say that he was sure that the Eggs would never flap about in such a manner; but as the boy who could speak robin so fluently was doing the thing with them, birds could be quite sure that the actions were not of a dangerous nature.
One morning when the rain streamed down unceasingly and Colin was beginning to feel a little restive, as he was obliged to remain on his sofa because it was not safe to get up and walk about, Mary had an inspiration.
He had known it before in a way, he had hoped it and felt it and thought about it, but just at that minute something had rushed all through him--a sort of rapturous belief and realization and it had been so strong that he could not help calling out.
The phrase "all-perceiving" makes Dickon sound like a god who is all-seeing and all-knowing. But while he seems to have a Magic that touches the lives of all living creatures, including plants, and while Mary and Colin seem to worship him as an angel, Dickon is too humble to see himself as a god, and he would only use his powers to spread happiness and growth.
Dickon answered with his all-perceiving animal charmer's smile.
The calmness and reposeful ("affording physical or mental rest") sleep of Archibald Craven is singular because most of the time, his mind is filled with dark and heartbroken thoughts; but it becomes especially singular when he later learns that on that same day, far away from him in England, his son had exclaimed, "I am going to live forever and ever and ever!"
The singular calmness remained with him the rest of the evening and he slept a new reposeful sleep; but it was not with him very long.