148 Probdhle Error of StinijdIiKj in Soil Si/rrct/s 



It will be seen from tlie values obtained above that with the exception 

 of the fine gravel p^ is about 2-5 per cent, as a maximum*. These 

 figures are only obtained from six sets of determinations, but they are 

 sufficiently accurate for the purpose of determining p.,, as will be seen 

 later. 



The tiihlc on p. 1 17 slious the results of the analyses (if the 25 sampled 

 from Field A. 



The mean values and probable errors calculated from these results 

 are as follows : 



Fine gravel 

 Coarse sand 

 Fine sand 

 Silt 



Fine silt 

 Clay 



Probable error per 

 Per cent. cent, of result, P 



7-92 ±2-78 =±35-0 percent 



17-59 ±2-24 =±12-7 



17G1 ±1-64 =± 9-3 



12-44 i;l-24 =±10-0 



2G-50 ±2-71 =±10-2 



4-10 ± -52 =±12-7 



Moisture 2-7 ± -40 =±14-8 



Organic matter 10-4 ± -80 =± 7-7 „ 



Phosphorus pentoxide (PjOj) •290± -039= ±13-4 „ 



In Field B a set of 1.5 borings was taken as shown on the diagram 

 Fig. 2. 



The following results were obtained on analysis: 



Aberffraw. 



' In mechanical analyses this error will be much greater if the (cniperature of 

 mentation is not constant, owing to viscosity changes. 



i-di. 



