1917] SOILS — ^FERTILIZEHS. 17 



" The equlpluves . . . tend to run parallel to the contours. Consequently, the 

 elevated axis is usually an area of Intermediate character with a more intense 

 rainfall on one slope and a less intense rainfall upon the other. This fact is of 

 considerable imporrance, since it suggests a kind of seesaw arrangement. Most 

 rain is actually precipitated upon the elevated land. When the rainfall tend- 

 ency comes from the north more water is precipitated on the northern lowlands 

 than on those of the south, but most water falls on the mountain slopes 

 although it does not register so high a pluviometi'ic coefficient. The dry slopes 

 are those which have what may be termed the ' sunny aspect,' \, e., which have 

 the moi'e nearly vertical radiations from the sun. Since the action of the wind 

 is largely frictional, along the slopes rather than up them, neither the west 

 monsoon nor the ' east monsoon ' affects the whole island equally. . . . 



" The results of this inquiry suggest that in tropical areas \vlnd direction 

 i.« not a prime cause of rainfall intensity as distinguished from rainfall quan- 

 tity; but they also suggest that the direction of high mountains serves to re- 

 strain the influence of the great factor in producing rainfall intensity. Now 

 these two statements appear to be contradictory, but the cases of Java and 

 Mauritius show that the rainfall cause which is i-estrained by the mountains is 

 worliing either in the opposite direction or at right angles to the direction of the 

 prevailing wind." 



A short bibliography of literature relating to the subject is given. 



SOILS— FERTILIZERS. 



Biolog'ical changes in soil during storag'e, F. B. Allison (Soil Sci., 3 

 (1917), Xo. 1, pp. 31-62, figs. 22 ) .—Experiments conducted at Rutgers College 

 to determine how long fresh soil samples may be kept in the laboratory without 

 being appreciably altered in their biological properties are reported. The soils 

 used were shaley loam, gravelly loam, sandy loam, and clay, part being collected 

 in summer and part in winter. In general the work consisted of a study of the 

 bacterial changes from the standpoints of numbers and physiological activity. 



It was found that " soils change biologically to a very marked extent during 

 storage in the laboratory, and the rate of change depends largely upon the 

 temperature of the soil when sampled. A change in numbers of bacteria in 

 two hours amounted to as much as 30 to 40 per cent in some soils during the 

 winter montlis. There is a decided tendency for the ammonification of dried 

 blood and peptone to vary as the numbers of bacteria vary ; and for the 

 ammonia production from cottonseed meal to go hand in hand with the 

 numbers of fungi. In the winter there is a diminution in bacterial numbers 

 and usually in ammonification until the end of one week and this is followed 

 by a steady increase. In the summer the decrease In numbers and ammonia, 

 production from peptone and dried blood proceeds more slowly and continues 

 for at least two months. To the very end of this exi)eriment the point had not 

 been reached where ammonification ceased to decrease. 



" From the data presented ... it may be said that in order to obtain re- 

 liable results during the winter months it is necessary to pour plates for bac- 

 terial counts and start all ammonification experiments immediately on bring- 

 ing the soil sample into the warm laboratory. During the summer months it is 

 desirable to pour plates soon after taking the sample, but this is not as essen- 

 tial as during the colder months. Ammonification experiments need not be 

 started v\ith such haste. During the first ten days the variations in ammonifica- 

 tion were almost \^athin the limits of experimental error. 



"Air-drying caused a decided decrease in numbers of bacteria except in the 

 case of the Penn loam during the winter months. The decrease was much less 



