These conveniences may perhaps all be found in a well-chosen garret; but surely they cannot be supposed sufficiently important to have operated unvariably upon different climates, distant ages, and separate nations. Of an universal practice, there must still be presumed an universal cause, which, however recondite and abstruse, may be perhaps reserved to make me illustrious by its discovery, and you by its promulgation.
It is universally known that the faculties of the mind are invigorated or weakened by the state of the body, and that the body is in a great measure regulated by the various compressions of the ambient element. The effects of the air in the production or cure of corporeal maladies have been acknowledged from the time of Hippocrates; but no man has yet sufficiently considered how far it may influence the operations of the genius, though every day affords instances of local understanding, of wits and reasoners, whose faculties are adapted to some single spot, and who, when they are removed to any other place, sink at once into silence and stupidity. I have discovered, by a long series of observations, that invention and elocution suffer great impediments from dense and impure vapours, and that the tenuity of a defecated air at a proper distance from the surface of the earth, accelerates the fancy, and sets at liberty those intellectual powers which were before shackled by too strong attraction, and unable to expand themselves under the pressure of a gross atmosphere. I have found dulness to quicken into sentiment in a thin ether, as water, though not very hot, boils in a receiver partly exhausted; and heads, in appearance empty, have teemed with
