4*8] GUN The Invention of gunpovdef is at- tributed to Barthold Schwartz, a German monk ; but there is rea- son to believe it was not unknown in lie time of Alexander the Great; and that Koui-.k Racos, in 1232, under-stood the nature of its component parts ; though it was generally introduced iuto Europe only about the middle of the 14th century. The method, of making gun- powder is nearly as follows : Take four ounces of reiined salt-petre, one ounce of brimstone, and six drams of small- coal: reduce these ingredients to a tine powder, and continue beating them tor some time in a stone mortar with a "wooden pestle, wetting the mix- ture with a due proportion of wa- ter, so as to form the whole into an uniform paste : this will be re- duced to grains, by passing it .through a tine wire sieve ; and, after being carefully dried, it con- stitutes the common gunpowder.-— We do not, however, advise rea- ders in general to make experi- ments fraught with such imminent danger. The effects of gunpowder, in mines, &rc. may be considerably increased, by leaving some space between the powder and the wad- ding. Hence, in loading a screw- barrel pistol, care should be taken that the cavity for the powder be entirely filled, so as to leave no space between it and the ball, be- itiuse musquets, fowling pieces, &c. are very apt to burst, if the wad- ding be not rammed down close to the powder. In Birch's History of the Royal Society, -wearc informed that Prince Kui'ERT :red gunpowder . of a force exceeding the best kind made at prcent, in the proportion GUT of 21 to 2 ; and that such supers-' 1 * quality is to be ascribed chiefly to a peculiar method of purifying the nitre, and employing charcoal ob- tained from the wood of the aldejr buck-thorn. Gi's-shot itfauncb. See Wounds. GOTTA SERENA, or Amau- rosis, signifies the loss of sight, without any other visible cause or defect in the eye ; except that the pupil (or the round hole for admit- ting the rays of light) is generally deprived of its power of contraction. Numerous are the causes from which this unfortunate blindness may arise ; but the principal of them are nervous and paralytic af- fections. Violent contusions of the head ; apoplectic fits j hoi bathsj suppression of catarrhs, or periodi- cal evacuations ; metallic cosme- tics ; drunkenness ; sudden flashes of lightning; repulsion of cutane- ous eruptions ; lung fasting ; fre- quent exposure to the rays of this sun ; violent exercise and passions, especially terror and anger ; as well as purgatives, rheumatisms, sneezing; explosion of gums ; co- pious bloodletting; vomiting 5 worms, &c. all may occasion amau- rosis. Among the remedies which have been found the most effectual, .for removing this melancholy disease, are electricity ; the cold bath ; hot embrocations, or blisters contain- ing antimonial tartar, applied to the spine ; leeches to the eyes of plethoric patients ; the magnetfas- tened to the nape of the neck, and a bag of iron-tilings placed over the eyes;, agitation of the frontal nerve; artificial ulcers; scarifications, or issues, and blisters on the back part of the head, kept open for a con- siderable time ; cupping ; sina- pisms..
