Book III. OF THE ATMOSPHERE. 357 



mal life, deprives magnets of their virtue, or reverses their poles ; and all these are well known properties 

 of electricity. 



2330. With regard to places of safety in times of thunder and lightning. Dr. Franklin's advice Is to sit 

 in the middle of a room, provided it be not under a metal lustre suspend^ by a chain, sitting on one chair, 

 and laying the feet on another. It is still better, he says, to bring two or three mattresses or beds into the 

 middle of the room, and folding them double, to place the chairs upon them ; for as they are not so good 

 conductors as the walls the lightning will not be so likely to pass through them. But the safest place of all 

 is in a hammock hung by silken cords, at an equal distance from all the sides of the room. Dr. Priestley 

 observe?, that the place of most perfect safety must be the cellar, and especially the middle of it ; for when 

 a person is lower than the surface of the earth, the lightning must strike it before it can possibly reach him. 

 In the fields, the place of safety is within a few yards of a tree, but not quite near it. Beccaria cautions 

 persons not always to trust too much to the neighborhood of a higher or better conductor than their own 

 body, since he has repeatedly found that the lightning by no means descends in one undivided track, but 

 that bodies of various kinds conduct their share of it at the same time, in proportion to their quantity and 

 conducting power. 



Sect. II. Of the Means of jrrognosticating the Weather. 



2331. The study of atmospherical changes has, in all ages, been more or less attended to 

 by men engaged in the culture of vegetables, or the pasturage of animals ; and we, in 

 this country, are surprised at the degree of perfection to which the ancients attained in 

 this knowledge. But it ought to be recollected, that the study of the weather in the 

 countries occupied by the ancients, as Egypt, Greece, Italy, and the continent of Europe, 

 is a very different thing from its study in an island situated like ours. It is easy to foretel 

 weather in countries where months pass away without rain or clouds, and where some 

 weeks together, at stated periods, are as certainly seasons of rain or snow. It may be as- 

 serted with truth, that there is a greater variety of weather in London in one week, than 

 in Home, Moscow, or Petersburgh, in three months. It is not, therefore, entirely a 

 proof of our degeneracy, or the influence of our artificial mode of living, that we cannot 

 predict the weather with such certainty as the ancients ; but a circumstance rather to be 

 accounted for from the peculiarities of our situation. 



2332. A variable climate, such as ours, admits of being studied, both generally and lo- 

 cally ; but it is a study which requires habits of observation and reflection like all other 

 studies ; and to be brought to any useful degree of perfection must be attended to, not ats 

 it commonly is, as a thing bj chance, and which every body knows, or is fit for, but as a 

 serious undertaking. The weather may be foretold from natural data, artificial data, and 

 from precedent. 



2333. The natural data for this study are, 1. The vegetable kingdom; many plants 

 shutting and opening their flowers, contracting or expanding their parts, &c. on ap- 

 proaching changes in the humidity or temperature of the atmosphere ; 2. The animal 

 kingdom-; most of which, that are Ikmiliar to us, exhibiting signs on approaching 

 changes, of which those by cattle and sheep are more especially remarkable ; and hence 

 shepherds are generally, of all others, the most correct in their estimate of weather ; 3. The 

 mineral kingdom ; stones, earths, metals, salts, and water of particular sorts, often show- 

 ing indications of approaching changes ; 4. Appearances of the atmosphere, the moon^ 

 the general character of seasons, &c. The characters of clouds, the prevalence of parti- 

 cular winds, and other signs are very commonly attended to. 



2334. The influence of the moon on the weather has, in all ages, been believed by the 

 generality of mankind : the same opinion was embraced by the ancient philosophers ; and 

 several eminent philosophers of later times have thought the opinion not unworthy of 

 notice. Although the moon only acts (as far at least as we can ascertain) on the waters 

 of the ocean by producing tides, it is nevertheless highly probable, according to the ob- 

 servations of Lambert, Toaldo, and Cotte, that in consequence of the lunar influence, 

 great variations do take place in the atmosphere, and consequently in the weather. The 

 following principles will show the grounds and reasons for their embracing the received 

 notions on this interesting topic : 



2335. There are ten situations in the moon's orbit when she must particularly exert her influence on the 

 atmosphere ; and when, consequently, changes of the weather most readily take place. These are, 



1. The new, and 2. the full moon, when she exerts her influence in conjunction with, or in opposition to 

 the sun. 



3. and 4. The quadratures, or those aspects of the moon when she is 90 distant from the sun ; or when 

 she is in the middle point of her orbit, between the points of conjunction and opposition, namely, in the 

 first and third quarters. 



5. The perigee, and 6. The apogee, or those points of the moon's orbit,' in which she is at the least and 

 greatest distance from the earth. 



7. 8. The two passages of the moon over the equator, one of which Toaldo calls, 7. The moon's ascending, 

 and the other, 8. The moon's descending equinox, or the two lunistices, as De la Lande terms them. 



9. The boreal lunistice, when the moon approaches as near as she can in each lunation, (or period 

 between one new moon and another,) to our zenith (that point in the horizon which is directly over our 

 heads). 



10. The austral lunistice, when she is at the greatest distance from our zenith ; for the action of the 

 moon varies greatly according to her obliquity. With these ten points Toaldo compared a table of forty- 

 eight years' observations ; the result is, that the probabilities, that the weather will change at a certain 

 period of the moon, are in the following proportions : New moon, 6 to 1. First quarter, 5 to 2. Full 

 moon, 5 to 2. Last quarter, 5 to 4. Perigee, 7 to 1. Apogee, 4 to 1. Ascending equinox, 13 to 4, 

 Northern lunistice, 11 to 4. Descending equinox, 11 to 4. Southern lunistice, 3 to 1. 



2336. That the new moon will bring with it a change of weather is in the doctrine of chances as 6 to 1. 

 Each situation of the moon alters that state of the atmosphere which has been occasioned by the preceding 

 one : and it seldom happens that any change in the weather takes place without a change in the lunar 



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