THE VALUE OF THE NITRATE FIGURE, ETC. 411 



although the rainfall is very heavy (45 inches a year), I 

 was informed "gardens require a lot of water and require 

 watering a day after heavy rainfall, owing to the rapid 

 manner in which water percolates through the earth." 



Most of the cesspits were found to be merely holes dug 

 in this porous ground. One or two had brick sides, but the 

 joints between the bricks were open. All the cesspits 

 were in fact in direct communication with the ground 

 water. This connection was well seen in the cases of the 

 cesspits at the Public School and the Convent. At the 

 Public School (average daily attendance 100) there were 

 two cesspits, both lined with open jointed bricks ; at the 

 Convent (average daily attendance 44) there were three 

 cesspits, mere holes dug in the ground. It was found that 

 the height of the contents of these cesspits rises and falls 

 with the rainfall (subsoil water). These observations were 

 made by the Shire Sanitary Inspector, and confirmed, in 

 the case of the Public School, by the School Teacher. Also, 

 although the Public School cesspits had not been emptied 

 for at least three years, they did not contain any more 

 nightsoil than they did three years before. The same 

 drainage of nightsoil into the ground was taking place from 

 the other cesspits. 



Seven of the wells were found to be in the line of the 

 flow of, and receiving their supplies from, the subsoil water 

 which was being contaminated by the cesspits. The 

 ammonia from the nightsoil in the cesspits was oxidised in 

 its passage through the soil, and thus the pollution of the 

 wells by the cesspits was shown by the nitrates in the 

 water. The variation in the quantity of nitrate in the 

 water corresponded with the position of the well relatively 

 to the cesspit. 



If the analyses of wells 1, 2, 3, 4, 5, 7, and 8, in Table I 

 wells near cesspits) be compared with the analyses of 



