Hampstead-Water is obtained from a mineral spring, which rises in the village of that name, in the vicinity of the metropolis.

This chalybeate was formerly in considerable repute for its medicinal properties; and, though at present seldom employed, it is professedly of considerable service in chronic arfections, proceeding from languor, or debility of the system ; in chlorosis, indigestion, hypochondriasis, and all other cases, where tonic and stimulating remedies are indicated. - It ought to be drunk on the spot; as its volatile parts escape, and its virtues are impaired by exposure to the air : after drinking it, the patient should either walk or ride, according to the nature of his complaint, or strength of his constitution ; with a view to promote its operation. The proper season for resorting to this spring, is from April to the end of October ; the dose depending upon age, habit, and other circumstances. In general, a quarter of a pint may be drunk half an hour before breakfast ; a second dose about an hour after it; and a third about noon; which portion may be gradually increased to half a pint, if the stomach can support it. Such course is often continued for two or three months; when the. use of the water is suspended for a few weeks ; because a short discontinuance has been productive of good ef-fects.

Hampstead-water operates pow-erfully as a diuretic, but is apt to occasion constipations of the bowels : hence it will be advisable to add a small portion of Epsom or other aperient neutral salt; or it may be combined with the saline mineral fluid of Kilburn ; in which case the compound water will be nearly as efficacious as the celebrated springs of Cheltenham or Scarborough.