But the closest analogy, in point of concentrated energy, to eccentric somnambulism, is the effect of the inhalation of the “gaseous oxide of azote,” or “protoxide of nitrogen,” the _laughing-gas_. So intense is its impression on the nerves and blood of the brain, that it effects a perfect _metempsychosis_. This gas contains a greater relative proportion of oxygen than common air, and it is inhaled through a tube from a bladder or silk bag. After a little giddiness and headache, the breather soon begins to feel a very delicious thrilling; the eyes are dazzled by even common objects, so much are the senses excited. Pride and _pugnacity_ are quickly developed: we think ourselves grand seignors, and elevated far beyond the common class of mortals. We expect from all a _salaam_, and, with all the proud dignity of papacy, wonder that the people do not fall down and kiss our toe. We turn a deaf ear to all which is addressed to us; in short, we are dissociated from all around us. Sir Humphrey Davy, as the effect was wearing off, seemed to have been charmed into the combined philosophy of Berkley and Hume. He writes, “with the most intense belief and prophetic manner, I exclaimed: ‘Nothing exists but thoughts; the universe is composed of impressions, ideas, pleasures, and pains.’” This brilliancy is probably the effect of scarlet or highly _oxygenized_ blood, acting on the brain and nerves of the senses. The duration of this gaseous influence is usually from five minutes to a quarter of an hour. It is not, however, always so transient. From the record of Professor Silliman, it seems to have converted an “Il Penseroso” into a “L’Allegro.” A man of melancholy became a man of mirth: and, although before his inhalation he had no sweet tooth in his head, he began to eat little except _sugar and sweet cakes_, and to swallow _molasses_ with his meat and potatoes. Although _sparring_ is the grand amusement of the gas-breather, yet we can often decide on the shades of character, however studiously they may have been concealed from us in sane moments. A gentleman among my fellow-students threw himself forcibly on his back, by his attempts to spout Shakspere with dignity and effect. Another threw himself prostrate in the snow, and rolling himself over and back across the quadrangle at Guy’s, turned himself into an immense cylindrical snowball. Another snapped his fingers in defiance, and walked with a most pompous strut, and without his hat, to the middle of London Bridge, ere he was brought to his senses. Indeed these experiments seem so replete with the ludicrous, that I wonder Cruikshank and Hood have not often caught a fact, as a theme for their brilliant fancy. REVERIE. “That fools should be so deep-contemplative.”