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predict the occurrence of the phenomena of which it takes 

 cognizance. We know with what precision and certainty astronomy, 

 which has so long taken the lead of all the sciences, does this. The 

 solar and lunar eclipses commence at the veiy moment for which 

 they were set down years before they come to pass. Probably a 

 very long time must elapse before meteorology can make any 

 approach to such accuracy of knowledge, from the extremely 

 complicated phenomena it has to deal with ; though, if we knew all 

 the factors which exeixise an influence in each particular case, and 

 the laws of their respective variations, there seems no reason why 

 it should not ultimately do so, at least to some extent. Hitherto 

 we have only had the vaguest guesses about weather and seasons, 

 and " weather prophets," as they are termed, have seldom met with 

 favour from men of true science, however eagerly they have been 

 listened to by some persons. It is, however, a circumstance to be 

 noted that the science of meteorology has advanced thus far, that 

 prognostications which used to be confined to charletans are now 

 being ventured upon by observers even of high scientific attainments. 

 I would refer especially to Professor Piazzi Smyth, Astronomer 

 Royal for Scotland, and the result of his discussions of a long series 

 of observations, carried on for more than thirty years, with " four 

 large earth thermometers sunk to different depths in the rocky 

 groiind near the ObseiTatory at Edinburgh, with a view to deter- 

 mining the temperature of the earth and its fluctuations." He 

 thinks he has discovered " in addition to the ordinary annual cycle 

 of temperature, three other cycles which he calls supra-annual, 

 differing in duration, one being a little more than two years, the 

 second more than eleven years, and the third about fifty-six years ;" 

 and it was the determination of these cycles, to which " our so-called 

 changes of climate are due," that led him to predict the late severe 

 winters of 1869-70, 1870-71, and the probable severity of the 

 winter of 1871-2.* This prediction was fully realized, as we are 

 aware, in the two first cases, while the present winter set in early 

 with great severity, the mouth of November having had a lower 

 mean temperature than any previous November since the year 



* See a more full account of the results of the Calton Hill observations in 

 the " AthonsBum" for June 18, 1870. 



