106 Attempts to Foretell the Weather. 



According to the Record of the Astro-Meteorological Society:, 

 11 every astro-meteorologist believes and knows" many startling 

 propositions. Among them he is quite certain " that oxygen, 

 the red ray of solar light, and positive electricity, are identical ; 

 and that the blue ray of light, or nitrogen, is equivalent to 

 negative electricity'." These are curious things for Astro- 

 meteorologists to believe, and very remarkable things for them 

 to hioiv. In pursuing their speculations, Jupiter is assumed 

 to exercise an important chemical and electrical influence on 

 the earth's atmosphere, because his light, of which we get very 

 little, is found to be fourteen times richer in chemical rays than 

 an equal quantity of moonlight. Assertions and reasoning of this 

 kind will fully account for the neglect of Astro -meteorology, 

 of which Mr. Pearce complains ; and our faith is not strength- 

 ened by the declaration "that all coincidences, when they are 

 sufficiently frequent to be removed from the confines of chance, 

 prove that the two things that coincide are either ' cause and 

 effect/ or are the ' effects of a common cause/ " 



Now it is perfectly possible that two or more series of 

 events, not casually connected with each other, and not springing 

 from even a similar cause, may yet coincide at certain recurring 

 points of their courses. Coincidences of this kind may be called 

 effects of chance; but the idea of chance is not eliminated be- 

 cause such coincidences recur any given number of times, nor 

 even by their perpetual recurrence. 



The observation of a sufficient number of coincidences may 

 justify the acceptance of an empirical law, according to which 

 we may, with approximate safety, predict that, when one of the 

 events happen, the other will accompany or follow. To get 

 beyond a merely empirical law of this kind, we require the sup- 

 port of another series of inductions, or of as many more series 

 as we can obtain. Thus the law of gravitation is evidenced by 

 as many independent series of facts as there are separate sets 

 of bodies gravitating towards each other. 



The mistake made by Mr. Pearce is in attaching undue 

 value to a single and unsupported series of coincidences, how- 

 ever numerous. "We are not justified in asserting that any 

 incidents are the physical causes of certain other incidents 

 that follow them, until we have arrived at collateral reasons 

 for believing that the assumed causes uniformly exert the kind 

 of action required, and that they do so, in the cases under in- 

 vestigation, with sufficient force to account for the results that 

 we trace. 



A little reflection will show that it is not eveiy concurrence 

 of events that can form the sort of coincidence, the multiplication 

 of which will logically lead up to an empirical law. Suppose, 

 ■for example, that any coincidence seeker should tell us that rain 



