274 APPENDIX 



In the early part of this Appendix I have spoken of a 

 dry or more or less dielectric earth-surface, and we may 

 usefully consider what its effect may be upon health. 



The electrical condition beneficial to plant life is soil 

 conductivity. If the soil is not moist to the root-depth the 

 plant is deprived of its supply of current, and must suffer 

 injury. 



Dry earth, if not a non-conductor of electricity of high 

 tension, is at least a very bad conductor, as are certain 

 clay and rock formations. With such an upper stratum 

 there could be no normal circuit. In that area the earth- 

 terminal would be insulated, and the air, I should imagine, 

 abnormally charged by reason of the absence of a low 

 resistance path to earth. It would be interesting to have 

 some information upon the subject of the health of persons 

 residing in these localities and the bearing of climatic 

 conditions of the kind upon specified diseases. 



At the same time, data as to the influence upon man and 

 plant of ferruginous soils should be useful if only for 

 purposes of comparison ; I say ferruginous, because with 

 iron as the electrolyte it is possible to have dry air and 

 earth and, at the same time, good earth-conductivity, 

 whereas in swampy districts there would, quite apart from 

 miasma, etc., be a damp atmosphere and therefore a 

 totally different environment. 



In the analysis of climate in its relation to disease many 

 painstaking investigators have confined themselves to 

 pondering characteristics of the atmosphere, and with 

 those we have no present concern, except in so far as they 

 may be affected by the electrical receptivity or otherwise 

 of the earth. It is true that dust from dry soil may 

 contain the germs of infectious diseases and aggravate 

 affections of the respiratory organs, but, difficult as it is, 

 I want to ascertain the effect of a non-conductive as 

 opposed to a conductive dry soil upon certain specified 



