TRANSACTIONS OF THE SECTIONS. 53 



The year 1854 resembled 1851 ; and during the year 1855 heavy rains fell during 

 the months of February and March, which is quite unusual ; and from August 1855 

 very little rain fell till May 1856, although the drought was not so great as that 

 of 1845 and 1846. 



It is remarkable that it was during 1851 the yellow fever prevailed ; and about the 

 year 1854 the cholera appeared in the colony for the first time. 



There is an intimate relation between the phases of the moon and its period of 

 crossing the equator. 



On the 21st of March the sun is on the equator, and new moon must happen 

 at a period of not more than about fifteen days from that date, either after the 6th 

 of March or before the 5th of April. Taking into account the inclination of the 

 moon's orbit to the ecliptic, the moon cannot be more than twelve degrees from the 

 equator at these times. This the moon will run down in less than two days ; so 

 that about the equinoxes the moon must cross the equator on an average about one 

 day and a half before or after new moon. In like manner in June, the moon, if 

 confined to the ecliptic, would always cross the equator at a period after new moon 

 of nearly the same interval, about twenty-two days, on whatever day new moon 

 happened ; but owing to the inclination of the moon's orbit to the plane of the 

 ecliptic, the interval is sometimes a day and a half more or less than the average. 

 In fact at any period of the year the number of days after new moon, when the moon 

 crosses the equator, is nearly constant, and would be so if the earth and moon's 

 orbits coincided with the plane of the equator. As it is, the interval for different 

 years at about the same period varies rarely more than two days. 



The average number of days for each month, when the moon crosses the equator 

 after new moon, is exhibited in the following Table : — ■ 



March 



April 25 



May 23 



June 21 



July 18 



August 16 



September 14 



October 11| 



November 9 



December 7 



January 6^ 



February 2\ 



From the facts which have been elicited from ten years' observations, from 1846 to 

 1856, taken at Demerara, we must arrive at the conclusion that there are some 

 grounds for the truth of the popular idea, so long and so universally entertained, of the 

 influence of the moon on the weather by those classes whose opportunities lead them 

 to judge of the matter. 



If the facts which have been elicited should be confirmed by another series of 

 observations at Demerara, or from series of observations already in existence taken 

 at other localities favourably situated, the existence of an influence of the moon must 

 become a scientific fact, and one the knowledge of which will prove of great import- 

 ance to the future progress of the science of meteorology. There are various reasons 

 why the popular idea of the influence of the moon on the weather is not appreciated 

 in a scientific point of view. The most prominent one would appear to be found in 

 the circumstance that the influence of the moon on the weather has always been looked 

 for in relation to the phases, whereas it should have been referred to the moon's 

 position with regard to the equator. 



The climate of British Guiana is probably the most equable in the world. The 

 greater part of the colony being quite flat, there is nothing to interrupt the free course 

 of the winds, which blow for most of the year from an E.N.E. direction. 



The chief atmospheric disturbances take place at the solstices, those at other 

 periods of the year being of a more temporary nature ; they must be greatly modified 

 by the state of the atmosphere in adjacent countries. The country being in seven 

 degrees of north latitude, is in the zone of the trade-winds for most part of the year ; 

 and having the broad expanse of the Atlantic before it, the changes of the weather are 

 rendered comparatively mild and gradual. 



British Guiana is peculiarly adapted for meteorological research, not only as rela- 

 ting to its own climate, but as favourable for the elucidation of delicate meteorologi- 

 cal questions, which would render valuable aid to the prosecution of the science in 

 other quarters of the world. 



