MEAN SCOTTISH METEOROLOGY. 281 



6. Supra-Annual Cycles of Weather and Solar Phenomena. 



But before taking leave of the previous average Tables of many stations reduced to one 

 central point of the country, with discussions of their most evident solar annual cycles 

 from month to month throughout every year, — let us, as in duty bound, when so enor- 

 mous a mass of reduced observations is before us, and spreading over a continuous range of 

 32 years, — let us I say examine that series of results from year to year, and see if there 

 are any symptoms of super-annual cycles of rise or fall in any of the Meteorological 

 elements. And if there be such, whether they can be connected with any sufficient 

 cause in Nature, to account for their production. 



If the Sun so decidedly rules the annual cycle, as we have already seen that it does, 

 and is a mysteriously fiery, boiling orb, — he should be at least questioned as to any 

 super-annual variations that may be found in our terrestrial Meteorology. And if such 

 had been discovered only a few years ago, how ready many persons would have been 

 then to hail them as simply dependent on the 1 1 year spot-cycle of the Sun's luminous 

 surface. But of late, rumours have gone forth from high quarters that in recent years the 

 Sun-spots have failed, and that no one believes in them now ! 



Is it however the Sun-spots themselves that have failed, or certain human theories 

 about them which have broken down ? 



Certainly if any persons have imagined that each 11 year cycle of spots is just as like 

 every other one, and should be accompanied by as closely similar weather on the earth, 

 as if they were all the successive revolutions of a cast-iron wheel, — that is an egregious 

 mistake ! 



Or again if the same persons have fancied that any influence from the Sun on terres- 

 trial meteorology, was bound to produce a similar shaped curve of projection to that 

 particular feature of the spots, viz. their united area and its growth with time — which 

 many observers having hitherto found it the easiest task to measure, do therefore too often 

 content themselves with, though the spots themselves are not the efficient cause of great 

 changes in the Solar radiations, — that is another and equally grave mistake ! 



In fact you might almost as well have micrometrically measured from day to day, and 

 month to month through the years 1884 and 5 the area of red-haze clouds spread over 

 the sky, and neglected the previous Krakatoa eruption which took place in 1883, and 

 really originated them all; although too that mountain's crater is so small as to be in- 

 visible on an ordinary geographical globe, and its actual action was all over in two or 

 three days. 



But it started then instantaneously several sets of undulations, which went round 

 and round the earth, sometimes running together to raise their maxima, and depress their 

 minima, and sometimes again nearly neutralising each other, but on the whole decreasing 

 continually from the Krakatoa date, — very much in the fashion of what was shown to 

 characterise the super-annual cycles of earth temperature, in my discussion of the Edin- 

 burgh Earth-Thermometers, before the Royal Society of Edinburgh in 1880. 



