INFLUENCE OF WEATHER ON ACIDS IN RAINFALL. 129 



vi. The nitrogen-fixing powers of inland monsoonal depressions tend 

 towards the gradual enrichment, in respect of oxidised nitrogen, 

 of the soil in south-eastern Australia. 



A number of determinations of the volume concentration of nitrogen 

 peroxide in the atmosphere during the prevalence of anticyclonic 

 weather has shown that at Canterbury, Victoria, in the rear circulation 

 of anticyclones the air contains a gi'eater proportion of nitrogen peroxide 

 than the air of the front circulation. 



On the assumption that the oxidised nitrogen of the rainfall is 

 derived from the atmosphere, the ajnounts of nitrogen peroxide in the 

 latter were compared with the amounts of oxidised nitrogen found in 

 the rainfall at Canterbury for the con-esponding weather types. It is 

 shown that air containing 0"5G volume of nitrogen peroxide per 10* 

 volumes in the rear of an anticyclone would require to be washed out 

 to a height of about 4,000 feet above ground-level in order to give the 

 amount of oxidised nitrogen usually found in the rainfall accompanying 

 this weather condition; similarly in the case of the front of an anti- 

 cyclone it is shown that the height would require to be about 3,100 feet. 

 The above are in fair agreement with the average altitude of rain-clouds 

 (base), which according to leading authorities is about 3,500 feet. 



The Committee wishes to place on record an acknowledgment of 

 its indebtedness to the following lady and gentlemen for their able 

 assistance in collecting rain samples for this investigation : — 

 Miss J. Heinrichsen, Ballarat, Victoria. 

 S. Hebbard, Esq., Technical School, Sale, Victoria. 

 A. 11. Bisdee, Esq., Wihareja, Steppes, Tasmania. • 

 W. M. Lee Bryce, Esq., The Eesident Magistrate, Thursday 

 Island, Queensland. 



F. Fairley, Esq., M.I.E.E., F.E.M.S., Woombye, Queensland. 

 Dr. H. Priestley, Australian Institute of Tropical Medicine, Towns- 



ville, Queensland. 

 E. Gordon Edgell, Esq., Bradwardine, Bathurst, N.S. Wales. 

 E. J. Cook, Esq., P.M. Hergott Springs, South Australia. 

 Simon Ockley, Esq., Comaum, Penola, South Australia. 

 W. A. Doran, Esq., P.M. Eucla, Western Australia. 



G. E. Kirkby, Esq., P.M. Carnarvon, West Australia. 



Major G. T. Wood, The Eesident Magistrate, Broome, West Aus- 

 tralia. 

 G. G. Lavater, Esq., A. E.V.I. A., Narrogin, West Australia. 

 Dr. Edwin Tyrie, Playford Hospital, Pine Creek, N.T. 

 J. McKay, Esq., P.M. Alice Springs, Northern Territory (Central). 



With the approval of tlie Sectional Committee it is proposed to 

 send the complete results of this investigation to the Eoyal Meteoro- 

 logical Society for publication. 



The Committee does not seek reappointment. 



1916 IT 



