13 



unit for field trials consists of five plots, each 5^0 of an acre in extent, 

 regularly distributed about the experimental area, and each harvested 

 separately. This would yield results true within 1 to 2 per cent, for 

 the particular season. Effects of climate can only be eliminated by 

 continuing the experiments over a term of years. 



A. D. Hall and E. J. Russell. ''Report on the Agriculture 

 and Soils of Kent, Surrey and Sussex.'' Published for the 

 Board of Agriculture by H.M. Stationery Office. 1911. 2/6. 



This Report has been already described. 



A. D. Hall and E. J. Russell. " Soil Surveys and Soil 

 Analyses.'' Jour. Agric. Sci. 1911. 4, 182. 



In this paper the results of the analyses contained in the above 

 Report are discussed from a scientific standpoint. The paper deals 

 with the methods of taking a sample, and the degree of accuracy 

 which may be expected to attach to the processes both of analysis 

 and sampling. The fractions of the soil, consisting of particles of 

 a specified size, were also subjected to analysis, and the paper further 

 discusses the interpretation of the results obtained by analysis and 

 certain correlations which are shown to exist between the chemical 

 and mechanical analyses. This paper is of technical interest only, 

 being addressed to chemists who have the conduct of the soil 

 analyses rather than to the general agriculturist. 



E. J. Russell and J. Goldinci. " Sewage Sickness in Soil and 

 Its Amelioration by Partial Sterilisation." Jour. Soc. 

 Chem. Ind. 1911. 30. 

 This paper deals with an investigation of the state into which 

 the soil of sewage farms arrives after the continued application of 

 sewage, whereby it is so far injured both in its physical and bio- 

 logical conditions that it will no longer either let the sewage 

 percolate or purify what passes through. Sewage-sick soil was 

 found to possess a very limited bacterial activity and to be excep- 

 tionally rich in those protozoan organisms which Russell and Hutch- 

 inson have regarded as the limiting factor in the development of 

 bacteria in soils. Partial sterilisation of the soil, either by treatment 

 with antiseptics or by heating, was followed by a very large increase 

 in the number of bacteria ; in one case they rose from about 40 

 million to over 400 million per gram of the soil. Accompanying 

 this increase in bacterial activity there was a renewal of the 

 purifying effect of the soil upon the sewage, and it was found 

 possible to restore the sewage-sick soil and make it become an even 

 more effective filter than before, either by heating the soil sufficiently 

 to char it slightly or by treating it with the vapour of toluene. 



