Could someone explain this Quote to me?

To the Lighthouse by Virginia Woolf

"To her son these words conveyed an extraordinary joy, as if it were settled, the expedition were bound to take place, and the wonder to which he had looked forward, for years and years it seemed, was, after a night’s darkness and a day’s sail, within touch. Since he belonged, even at the age of six, to that great clan which cannot keep this feeling separate from that, but must let future prospects, with their joys and sorrows, cloud what is actually at hand, since to such people even in earliest childhood any turn in the wheel of sensation has the power to crystallise and transfix the moment upon which its gloom or radiance rests, James Ramsay, sitting on the floor cutting out pictures from the illustrated catalogue of the Army and Navy stores, endowed the picture of a refrigerator, as his mother spoke, with heavenly bliss."