METEOROLOGY. 



145 



Meteorolo- 



Igoii fa- 



Uu*. 



H. 



ly blows from the same point from which the current 

 above had previously blown He observes, therefore, 

 that De Luc's hypothesis, though he is far from em- 

 bracing it as satisfactory. will sufficiently account for 

 the relation above stated, by supposing that the column 

 of phosphoric fluid is bent, previous to ignition, in the 

 direction of the upper current ; so that, when ignition 

 commence', the luminous body moves towards the 

 point from which that current then proceed?, and from 

 which the lower current is afterwards to blow. It is 

 a prognostication of wind, then, only in so far as it in- 

 dicates a change that has already commenced in the 

 higher regions of the atmosphere, but which has not 

 yet taken place near the surface of the earth. 



The above hypothesis, fanciful as it may appear, and 

 inadequate as it unquestionably is to account for all the 

 phenomena of meteors, points to a plausible exphm- 

 tion of another luminous appearance, the cause of 

 which ha* not yet been ascertained, and which, th-ui^h 

 differing in many respects from the bodies above de- 

 icribed, bears a sufficiently clo resemblance to them, 

 to be classed under the general head of meteors. We 

 allude to the well-known li^lit called fgni* Fatuia, 

 Jack if ilk a lantern, or H'lil <q/A the irisp, to named 

 from the superstitious notions which have been attach- 

 ippearance. It is generally teen in dark 

 night", over boggy and marshy ground, sometimes at 

 rest on the surface, but generally in motion at the 

 height of five or six feet, skipping from place to i 

 and frequently changing both in magnitude and form. 

 On some occa- .'.nerved to be suddenly extin- 



guished, and afterward* to reappear at a distance from 

 iu former position. Those who have endeavoured to 

 examine it more clotely, or who have been accidentally 

 led to approach it, generally remark that it move* away 

 from them, and with velocity proportional to that 

 with which they advance, a circumstance which has 

 had no small influence on the fears of the ignorant and 

 superstitious. A particular account of the ignis fatuus, 

 as teen on two different occasions will be found in 

 Cavallo'i Element* of Natural Philosophy, Vol. III. 

 p. M 



To apply the above hypothesis to the explanation of 

 this phenomenon, let us suppose that some such phos- 

 phoric fluid a* that mentioned by DeLuc, ari-inj from 

 the decomposition of animal or vegetable substance*, 

 p***es into the atmosphere, and continue* to float there 

 without mixing with the atmosphere itself, or being 

 dtuipated by the wind. We can then conceive that 

 this fluid, having become luminous by *ome tort of ig- 

 nition, at the place where it i* lcat affected by t) 

 terraixture of moisture or other substance*, luccessive- 

 ly communicate* with other portions of itself, . . 

 as the column continues unbroken. In this way the 

 luminous body will move from place to place, follow- 

 ing the direction which the fluid had previously taken, 

 ml it will appear more or less brilliant, according to 

 the quantity or purity in which the fluid exist* at any 

 given point. The occasional disappearance of the light 

 may be owing to an interruption in the column, 

 the quantity of phosphoric matter being so small a* not 

 to be visible till the ignition arrive at another point, 

 where the inflammable matter i* more abundant, and 

 consequently reappears. We could anticipate many 

 difficulties and objections to thi* explanation, which 

 we doubt not will readily occur to our reader*. Hut 

 though we are not aware of any which might not ad- 

 mit of a plausible refutation, enough ha* been said on 

 a ubject that requires numerous and more accurate 



rot. XIT. PART i. 



observations than any that have yet been made, to fur- Meiooroio. 

 nish the basis of a satisfactory theory. PT- 



IK -ides the meteors already described, there are other 

 luminous appearances occasionally observed in the at- 

 mosphere. which belong also to the first class of prog- 4c> 



!. Hull", I'ar/ielia, or Mock- Suns, Para- 

 telenia, or <iu, and the Rainbow. The in- 



:tion of these phenomena properly belongs to Op- 

 ul to that article we refer for an account of such 

 of them as have not already been described in the course 

 of this work. (See HALO.) We notice them here, only 

 because they are supposed to indicate certain approach- 

 ing changes in the state of the weather. The lumi- Projfnoii- 

 nous circle which is sometimes seen around the hea- callon - 

 venly bodies, but especially the sun or moon, and 

 which has received the name of Halo, or Corona, has, 

 from a very early period, been regarded as a certain 

 >-,tication of stormy weather, accompanied with 

 rain or snow, According to the climate or season of the 

 year. It frequently happens, that, in the outer edge, 

 or circumference of this circle, there is a part less dis- 

 tinctly defined than the ret, apparently owing to the 

 contact of a denser cloud ; and it has been remarked 

 by shepherds and others, who have frequent opportu- 

 nities of observing this phenomenon, that the storm ge- 

 nerally comes from that point of the compass, towards 

 which this indistinct portion of the circle, or opening 



- called, was directed. If there is any founda- 

 tion for this remark, it may perhaps be accounted for 

 on the principle already stated, regarding the change of 

 wind in the higher and lower regions of the atmo- 

 sphere. The current that is to bring the approaching 

 storm may have set in above, before the halo disap- 

 pears, and by accumulating the clouds upon it from 

 that quarter, produce the indistinctness alluded to. 

 This phenomenon, as well as its modifications the Par- 

 helion and Paraselene, is obviously connected with a 

 change of weather, only in so far as it indicates some 

 peculiarity in the state of the atmosphere. The same 

 remark applies to the rainbow, though this last is ra- 

 ther concomitant, than a prognostication of rain. 

 It has been remarked, however, that a rainbow in the 

 morning is frequently followed l>y showers, while one 

 in the evening forebodes f;n'r weather. 



It has been a lon<$ established, and generally receiv- Petition of 



tnion, that the phases of the moon have a cer- the moon 

 tain influence on the weather, and these have accord- U PP<><I ' 

 in^'ly fiirnishi-d variou^ pro^. -. which may |JJ^ U J. 

 also be referred to the first class. It is quite conceiv- t |, tr . 

 able, on philosophical principle*, that the atmosphere 



may be differently affected, in the same way as the 

 waters of the ocean are, by the different positions of 

 the sun and moon, relatively to the earth ; and that 

 the result, in certain case- a tract of settled or 



tempestuous weather, act < circumstances. At 



the same time, the subject is still involved in great un- 

 certainty ; nor doe* there appear to be any foundation 

 for the common opinion, that if the new or full moon 

 happens about midnight, dry weather will follow ; but 

 if it takes place about noon, rain may be expected. 

 The rule does no doubt hold in many instances; but 

 on looking over our observations for a series of yean, 

 we find that it also frequently fails. 



But the most fertile source of prognostics of the first ProgiviMi- 

 class, is to be found in the various and ever changing cations 

 appearance of the clouds. As the proximate cause of drmwn froln 

 rain or mow, they have in all ges been regarded as thc *PP** r ' 

 affording the surest and most direct intimation of ap- " 

 preaching changes ; and there are few perhaps who axe 



