444 SCIENTIFIC RECORD FOR 1882. 



very remarkable difference: the curve for Batavia was seen to lag very 

 persistently for ahotit one month behind the Bombay curve. Similar curves 

 were obtained for all of Archibald's tropical stations, and for the sun-spot 

 ones published in Philosophical Transactions, 1870. 



The general resemblance of all these curves to each other is very 

 remarkable; indeed, if the Mauritius curves for the years 1867 and 1868 

 be excluded, there is scarcely a single prominent feature in any one of 

 the curves which is not reproduced in the others. It appears, then, that 

 these long atmospheric waves (if such they may be called) travel at a 

 very slow and variable rate round the earth from west to east, like the 

 cyclones of the extra-tropical latitudes. 



A glance at the barometric and sun-spot curves is sufficient to show 

 that the irregular and frequent fluctuations of pressure are relatively 

 much larger than those of sun-spots. The prime curves were therefore 

 still further smoothed, and from this comparison it appears that the 

 epochs of maximum and minimum barometric pressure lagged behind 

 the corresponding epochs of minimum and maximum solar-spotted area 

 at an interval varying from about six months to nearly two and a half 

 years, or at an average interval of about one year and eight months. 

 From a comparison with the records of famines in Asia, it appears that 

 widespread and severe famines are generally accompanied or immedi- 

 ately preceded by waves of high barometric pressure. 



Tf the conclusions arrived at from the above comparisons of abnormal 

 barometric variations, sun-spots, and past famines be admitted, it is 

 clear that they at once present the means whereby future famines may 

 possibly be foreseen. The conclusions are, briefly : 



1. That variations of the solar-spotted area are succeeded many 

 months afterwards by corresponding abnormal barometric variations. 



2. That abnormal barometric variations in the tropics travel at a very 

 slow rate round the earth from west to east, arriving at westerly stations 

 several months before they reach more easterly ones. 



3. That famines follow in the wake of waves of high barometric press- 

 ure. 



Hence, it follows that there are two methods by which early intima- 

 tion of the approach of these meteorological disturbances, which are 

 attended by famines, may i)Ossibly be obtained : 



1. By regular observation of the solar-spotted area, and early reduc- 

 tion of the observations, so as to obtain early information of current 

 changes going on in the sun. 



2. By barometric observations at stations differing widely in longitude, 

 and the early communication of the results to statons situated to the 

 westward. {Nature, December, 1880, xxiii, pp. 84-110.) 



E. D. Archibald, remarking on the fact that the British Government 

 has sent an observer to Leh, India, 11,000 feet altitude, for the mainten- 

 ance of direct daily observations of the sun's heat, quotes the following 



