Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 4, 1802).djvu/467

HAT This chalybeate was formerly in considerable repute for its medi- cinal properties ; and, though at present seldom employed, it is pro- fessedly of considerable service in chronic atfedions, proceediiigjCrom languor, or debility of the system j in chlorosis, indigestion, hypochon- driasis, 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 virtites are impaired by exposure to the air : after drink- ing it, the patient should either walk or ride, according to the na- ture of his complaint, or strength of his ccnifitituiion ; with a view to promote its operation. The proper season for resorting to this spring, is from April to the end of Octo- ber } the dose depending upon age, habit, and other circumstances. In general, a quarter of a pint may be drunk half an hour before break- fast ; a second dose about an hour after it J and a third about noon j which portion maybe gradually in- creased to half a pint, if the sto- mach can support it. Such course is often coniiiiued for two or three months ; when the use of the wa- ter is suspended for a fCw weeks ; because a short discontinuance has been produftive of good ef- »eas. Hampstead-water operates pow- eyfully as a diuretic, but is apt to occasion constipations of the bow- els : hence it will be advisable to add a small portion of Epsom or other aperient neutral salt 5 or it may be combined with the saline mineral fluid oi Kilburn ; in which case the compound water will be nearly as etlicacious as the cele- brated springs of Cheltenham or Scarborough. HAT.-rIn November 1801, a patent was obtained by Messrs, HAW [431 JoHJT Walkek and Peter Al- THEY, for contriving water-proof hats and caps, as likewise for ren- dering silk, linen, leather, cotton, and other materials for wearing ap- parel, water-proof.- — Their inven- tion consists in providing the re- spe>l3:ive articles witH a coat of oil-paint; after which they are japanned with a varnish mixed with lamp or ivory-black. The caps and hats are manufaftured of paste-board covered with canvas, and treated in a similar manner ; but the leather, to be made water- proof, should not be previously dressed with oil, or any unctuous matter. — For a more minute ac- count of the method in which the different compositions are applied, the reader will consult the 1 6th vol. of the " RcpertOTi/ rf Arts," &:c. HAWK- MOTH, or Sphinx, L. is a genus of insetfts, comprising 165 species, ten of which are dis- covered in Britain, and variously named, according to the trees they infest. The generality of hawk-moths spin their cods under ground, inter- weaving with their threads small particles of grain and earth. Tiiey app; ar either early in the morning, or after sun -set : their flight is slow, and often accompanied with a pe- culiar sound. The caterpillars of these inse(5ts arc usually found rolled up in the leaves of trees j some being green, and smooth ; others brown or yellow ; again, others are spotted, and furnished with rings, or belts. The most certain method of preventing the depredations of hawk- moths, consists in coUetl- ing the leaves they inhabit, and crushing the insetSts ; after which the trees should be washed with a mixture of clear lime-wa- ter, and a deco6tion of tobacco leaves.