Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 2, 1802).djvu/66

48&#93; 48] CON of several experiments, made under the inspection of the Royal Society. Instances, nevertheless, occur of houses provided with pointed me- tallic conductors, being stricken with lightning ; so that this philo- sophical contrivance has not yet arrived at perfection. We there- fore communicate, with satisfac- tion, the following improvement in conductors, made by Mr. Robert Patersont, of Philadelphia, for which the American Philosophical Society adjudged him the prize of a gold medal. He proposes first to insert, in the top of the rod, a piece of the best black-lead, about two inches long, and terminating in a fine point which projects a little above the end of its metallic soc- ket ; so that if the black-lead point should, by any accident, be broken off, that of the rod would be left sharp enough to answer the pur- pose of a metallic conductor. His second intention is, to facilitate the passage of the electric fluid from the lower part of the rod into the surrounding earth. In many cases, it is impracticable, from the inter- ruption of rocks and other obstacles, to sink the rod so deeplv as to reach moist earth, or any other substance that is a tolerably good conductor of electricity. To remedy this de- feet, Mr. Paterson proposes to ma: e the lower part of the rod, either of tin or copper, which me- tals are far less liable; to corrosion or rust, than iron, when lving un- der ground ; or, which will answer the purpose, still better, to coat that part of the conductor, of what- ever metal it may consist, with a thick crust of black-lead previously formed into a paste, by being pul- verized, mixed with melted sul- phur, and applied to the rod, while hot. By this precaution, the CON lower partof the rod will, in his opi- nion, retain its conducting powers for ages, without any diminution. In order to increase the surface of the subterraneous part of ths- conductor, he directs a hole, or pit, of sufficient extent, to be dug as deep as convenient ; in tor which a quantity of charcoal should be put, surrounding the lower ex- tremity of the rod. Thus, the surface of that part of the conduc- tor, which is in contact with the earth, may be increased with little trouble or expence ; a circum- stance of the first importance to the security against those accidents — > as charcoal is an excellent conduc- tor of electricity, and will undergo little or no change of property, by lying in the earth for a long series ot years. Congelation. See Ice. CONSTITUTION, is the par- ticular temperament of the body, which depends chiefly on the state of its humours or fluids, and some- times also on the solids, but espe- cially the nerves. It is curious, says Dr. PERcr- val, to observe the revolution that has taken place, within the last cen- tury, in the constitutions of the in- habitants of Europe. Inflamma- tory diseases occur less frequently ; and in general are less rapid and violent in their effects, than they were formerly. This advantageous change, however, is more than- counter-balanced by the introduc- tion of debilitating articles of food and drink, several of which were utterly unknown to our ancestors, but now universally prevail. The bodies of men and women are equally enfeebled and enervated' : nay, it is no uncommon circum- stance to meet with a very high degree of irritability under the ex- ternal