23 



ON THE GENERAL DIFFUSION OF KNOWLEDGE. 



sheer, and cattle, and to public and private edi 

 fices ; and it is worthy of notice, that most of 

 the individuals who were killed by the lightning 

 had either taken shelter under trees, or were in 

 situations adjacent to bells or bell-wires. The 

 experience of succeeding years proves that a 

 similar number of disasters of this kind annu 

 ally take place. It is, however, more than pro 

 bable, that at least half the number of accidents 

 arising from the same cause might have been 

 averted, had the nature of lightning, and the 

 laws which regulate its movements, been gene 

 rally known. Seldom a year passes but we are 

 informed by the public prints of some person or 

 other having been killed by lightning, when 

 taking shelter under a large tree, of whole 

 families have been struck down when crowding 

 around a fire-place, during a thunder-storm, 

 of one person having been struck when stand 

 ing beside a bell-wire, and another while stand 

 ing under a bell connected with the wire, or 

 under a lustre hanging from the ceiling. 



There can be little doubt, that a considerable 

 number of such accidents would have been pre 

 vented, had the following facts respecting the 

 nature of lightning been extensively known : 

 That lightning is a fluid of the same nature, 

 and is directed in its motions by the same laws 

 which regulate the motions of the electric fluid 

 in our common electrical machines ; that it is 

 attracted and conducted by trees, water, mois 

 ture, flame, and all kinds of metallic substances ; 

 that it is most disposed to strike high and 

 pointed objects ; and that, therefore, it must be 

 dangerous to remain connected with or in the 

 immediate neighbourhood of such objects when 

 a thunder-cloud is passing near the earth. 



Hence the following precautionary maxims 

 have been deduced, by attending to which the 

 personal accidents arising from thunder-storms 

 might be in a great measure prevented. In the 

 open air, during a storm, rivers, pools, and 

 every mass of water, even the streamlets aris 

 ing from a recent shower, should be avoided, 

 because water being an excellent conductor, 

 might determine the course of an electrical dis 

 charge towards a person in contact vith it, or 

 in its immediate neighbourhood. All high trees 

 and similar elevated conductors should also be 

 avoided, as they are in more danger of being 

 struck than objects on the ground; and, there 

 fore, a person in contact with them exposes him 

 self to imminent danger, should the course of 

 the lightning lie in that direction. But, to take 

 our station at the distance of thirty or forty 

 paces from such objects, or, at such a distance 

 as may prevent us from being injured by the 

 splinters of wood, should the tree be struck, is 

 more secure than even in the midst of an open 

 plain. Persons in a house not provided with 

 thunder-rods, should avoid sitting near a chim 

 ney or fire-place, whether there be a fire in the 



grate or not. For when there is a fire in th 

 grate, the fire contains the following conduc 

 tors, flame, smoke, rarefied air, and soot. 

 Even when there is no fire, the soot with which 

 the flue is lined is a conductor ; and from the 

 superior height of the chimney-shaft above 

 every other part of the building, it is more 

 liable than any other part of the house to be 

 struck with lightning. In a house, too, gill 

 mirrors or picture-frames, lustres or burning 

 candles, bell-wires, and all metallic substances, 

 should be carefully avoided, as they afford so 

 many points of attraction, which might deter 

 mine the course of an electric discharge. The 

 safest position is in the middle of the room, if 

 not near a lustre, a bell, or any thing hanging 

 from the ceiling; and if we place the chair on 

 which we sit on a bed or mattress, almost every 

 possible danger may be avoided.* Such are a 

 few maxims easy to be recollected and put in 

 practice, by attending to which, not a few 

 accidents from electrical explosions might be 

 averted. 



In the next place, various accidents have hap- 

 penedfrom ignorance of certain plain mechanical 

 principles. For example, serious accidents have 

 sometimes occurred from the want of acquaint 

 ance with the laws of motion. Persons have 

 heedlessly jumped out of moving vehicles, and 

 got their legs and arms sprained or dislocated, 

 and from one boat to another when both were in 

 rapid motion, and run the risk of being either 

 bruised, drenched, or drowned. But had the 

 effects of compound motion been generally known 

 and attended to, in all those cases where it oc 

 curs, it would have prevented many of those 

 accidents which have happened from persons 

 rashly jumping out of carriages when in rapid 

 motion, or attempting to jump from the top of a 

 moving cylinder, in which cases they are always 

 precipitated with violence in a direction dif 

 ferent from what they expected, from the ob 

 vious effects of a combination of forces. Boats 

 and carriages have been sometimes overset by 

 persons rising hastily when they were in danger 

 of such accidents, from ignorance of the prin 

 ciple, that the centre of gravity of the moving 

 vehicle, by such a practice, is raised so as to 

 endanger the line of direction being thrown be 

 yond the base, when the vehicle must, of course, 

 be overturned ; whereas, had they clapped down 

 to the bottom, they would have brought down 

 the line of direction, and consequently the centre 

 of gravity, farther within the Wse, so as to have 

 prevented the accident and secured their safety. 



It has been generally thought that the cellar is 

 the most secure situation during a thunder-storm, 

 but this is true only in certain cases. AVhen the 

 lightning proceeds from the clouds, it is unquestion 

 ably the most secure position ; but in the case of a 

 returning- stroke, or when the lightning proceeds 

 from the earth, it is less secure than the higher parts 

 of the building. 



