1837.] On the Revolution of the Seasons. 307 



The maxima and minima by the Calcutta rain-guage since 1820, are 

 1823 1826 1832 1835. 



+ - — + 



These results do not differ from those afforded by the average of 

 corn prices (figs. 2 and 3), more than the prices obtained from any one 

 place differ from the general average. The results of registers kept 

 in other places do not show so good an agreement ; but the three prin- 

 cipal ones we can refer to are those of Macao, Madras and Bombay ; all 

 places on the sea-coast, where rain seems to fall more irregularly than 

 elsewhere. If it be asked, why, with the anomalies that still exist in 

 the lines (figs. 2, and 3), we have presumed the upper line (fig. 1) to 

 be the type of them, we answer that that line was formed after seeing 

 the three or four lists of corn prices that first came to hand, and 

 that every successive list received helped to approximate them more 

 closely ; the inference, therefore, is only fair, that still further lists 

 obtained would diminish the irregularities at present existing, though 

 we could not hope to obtain an exact parallelism, unless we were 

 previously enabled to apply corrections for the many other causes 

 that must affect the prices of corn. If we refer to the line (fig. 1) 

 which we have assumed as the type of the variation, we shall per- 

 ceive that on each side of the year 1829 a small inverse, or dotted 

 piece exists : on looking back over the lists of prices, some of which 

 extend as far back as 1700, I do not think that this small inverse 

 piece is interpolated or intercalated, if I may so call it, oftener than 

 every third cycle. With this exception, the variation appears to be 

 direct for about 9 years, and then inverse for the same period. Thus 

 from 1815 backwards, the variations are 9 years directly to 1806 — 

 9 years inversely to 1797 — 9 years directly to 1788, and 9 years in- 

 versely to 1779. Then from 1779 a variation is inserted similar to 

 that between 1836 and 1823, up to 1767 or 1766 ; and again backward 

 from that, periodical curves of 9 years in duration appear to occur as 

 before. On this I shall crave permission to speak more hereafter, 

 when, by the obtaining further lists of prices from different places, I 

 may be enabled to correct those which I at present possess. For 

 this reason I have refrained from carrying the present investigation 

 further back than 1806. I beg at the same time to return my grate- 

 ful thanks to those who have already assisted me with lists of prices. 

 On looking over the lists it appeared that in those from particular quar- 

 ters the maxima and minima occurred a year or two too soon, in other 

 places a year or two too late for the supposition. To elucidate this, 

 the lines, figs. 4, 5, 6, and 7, were drawn. Of these, fig. 5 is the type, 



