190 Tlie Soil in Relation to Disease. [part i. 



allowing all due weight to this circumstance, very considerable differences are evident 

 in the results. 



In Calcutta, the maximurifi in the upper layer occurred in September, with 11 

 volumes per 1,000. In Munich, the maxima in the two years shown in the diagram 

 occurred in August and July, respectively, with 10 and 14 volumes per 1,000. The 

 minimum, in the upper layer in Calcutta occurred in May with 4 volumes per 1,000. 

 In Munich, in January and in March, with 2 and 3 volumes per 1,000, respectively. 



The maxim^uTu in the lower layer occurred in Calcutta in September, with 12 

 volumes per 1,000. In Munich, the m^axim^a occurred in August and July, with 

 16 and 26 volumes per 1,000. In Calcutta, the minimum occurred in July with 

 7 volumes per 1,000 ; but in Munich in January and February with 3 and 5 volumes 

 per 1,000, respectively. 



(6) — The fluctuations in the am^ount of Carbonic Acid in the Soils of Calcutta 



and Munich compared. 



In Calcutta, beginning with November, in the upper layer we find a gradual 

 and continuous fall until May ; a slight rise in June ; a slight fall in July followed 

 by a great and rapid rise in August and September. In Munich, beginning with 

 the same month, we find slight falls to the m^inima in January and February ; a 

 slight rise and fall in March and April, respectively, followed by a rapid rise to the 

 m^axima. 



In Calcutta, in the lower layer, again starting from November, we find a slight 

 rise in December followed by a fall until March and April, succeeded by a slight 

 rise in May and a fall thence to a mininiuTn in July ; the miniTnum being followed 

 by a rapid rise to the maximum in September. In Munich, there is first a 

 fall to the minima in January and February, and thence a continuous rise to the 

 maxima. 



Both localities agree pretty closely in the period at which the maxim^a occur, 

 but the course of the fluctuations is otherwise very different, for while the minima 

 in Calcutta occur in May and July, those in Munich occur in January, February and 

 March. 



There is also an agreement in the approximation of the periods of maxima and 

 minima in the upper and lower layers of the two localities. There is considerable 

 difference in regard to the relative amounts which the volumes of carbonic acid 

 in the upper and lower levels bear to one another, but this cannot be regarded 

 as of any importance, as it may have been due to the fact that the levels of 

 observation were not identical. 



There is, however, one point in regard to this relation in which a distinct 

 difference can be traced in the two localities, for, whilst in Munich the quantities 

 of carbonic acid in the two layers approach one another most closely when low, 

 and are most remote when at a maximuTn, the reverse is the case in Calcutta — 



