26 DR. R. ANGUS SMITH ON THE 



or from the brushwood. The time was too favourable, as 

 there was a considerable breeze ; but I had not patience to 

 wait, and, as it turned out, it would have been necessary to 

 wait a long time. I consider the matter well worth farther 

 inquiry, and should be happy to make the analyses, if 

 specimens were sent, as I may not soon be in the same 

 spot again. 



The specimens from the Sologne are very few. They 

 were brought without any hope of a result. Had I known 

 as much as I do now, more would have been brought. 

 The book of Dr. Burdel, entitled ^Recherches sur les 

 Fievres Paludiennes,' excited a curiosity to see the dis- 

 trict ; but there seemed such a free air and such an open 

 country, with such a dry sandy soil, that I doubted if any- 

 thing like emanations could be found. I saw only few and 

 small ponds. Seeing how careful the search must be, it is 

 well not to be too confident until numerous analyses are 

 made. Dr. Burdel does not believe in any difference of 

 analysis, and seems to refer the unwholesome state to the 

 action of the electricity of the atmosphere and the heat 

 and cold. It is a courageous thing at the present time to 

 refer any phenomenon to electricity ; it has been overdone 

 so much, that people now imagine it must never be done, 

 and are afraid to mention it, thus deciding on the other 

 side. It seemed to me when in Switzerland that the fre- 

 quency of discharges on the mountains, with their absence 

 in the valleys, was itself a proof of difference of condition 

 in the two places. On plains the heavens and earth seem 

 to equalize their electricity more uniformly ; in these hilly 

 regions it is done at certain high points. If the flow of 

 this electricity is valuable to us, its loss is detrimental; 

 and if the discharges are made violently from one point, 

 instead of steadily and slowly from wide surfaces, the con- 

 dition of these surfaces must be modified. On looking at 

 Mont Blanc for a fortnight, and seeing nightly discharges 



