"Alastor" is written in a very different tone from "Queen Mab". In the latter, Shelley poured out all the cherished speculations of his youth--all the irrepressible emotions of sympathy, censure, and hope, to which the present suffering, and what he considers the proper destiny of his fellow-creatures, gave birth. "Alastor", on the contrary, contains an individual interest only. A very few years, with their attendant events, had checked the ardour of Shelley's hopes, though he still thought them well-grounded, and that to advance their fulfilment was the noblest task man could achieve. This is neither the time nor place to speak of the misfortunes that chequered his life. It will be sufficient to say that, in all he did, he at the time of doing it believed himself justified to his own conscience; while the various ills of poverty and loss of friends brought home to him the sad realities of life. Physical suffering had also considerable influence in causing him to turn his eyes inward; inclining him rather to brood over the thoughts and emotions of his own soul than to glance abroad, and to make, as in "Queen Mab", the whole universe the object and subject of his song. In the Spring of 1815, an eminent physician pronounced that he was dying rapidly of a consumption; abscesses were formed on his lungs, and he suffered acute spasms. Suddenly a complete change took place; and though through life he was a martyr to pain and debility, every symptom of pulmonary disease vanished. His nerves, which nature had formed sensitive to an unexampled degree, were rendered still more susceptible by the state of his health. As soon as the peace of 1814 had opened the Continent, he went abroad. He visited some of the more magnificent scenes of Switzerland, and returned to England from Lucerne, by the Reuss and the Rhine. This river-navigation enchanted him. In his favourite poem of "Thalaba", his imagination had been excited by a description of such a voyage. In the summer of 1815, after a tour along the southern coast of Devonshire and a visit to Clifton, he rented a house on Bishopgate Heath, on the borders of Windsor Forest, where he enjoyed several months of comparative health and tranquil happiness. The later summer months were warm and dry. Accompanied by a few friends, he visited the source of the Thames, making a voyage in a wherry from Windsor to Crichlade. His beautiful stanzas in the churchyard of Lechlade were written on that occasion. "Alastor" was composed on his return. He spent his days under the oak-shades of Windsor Great Park; and the magnificent woodland was a fitting study to inspire the various descriptions of forest scenery we find in the poem.