226 Transactions. 



On the fourth day, in the morning the soil was taken out 

 and the can well cleaned ; the leaks with can only were now 

 9 "5, 8 '7, or an average of 9'1. At night the leak due to can 

 only was 2-8. 



C. Parnell Clay. — The effect of Parnell clay, a surface soil 

 formed by the weathering of volcanic rock, was next observed, 

 a measured quantity of about one-third the previous quantities 

 being taken. The leaks obtained on the first day were 8 '8, 

 9-8, 7-7 : average, 8-8. Second day, 7-7, 7-7, 8*7 : average, 8-0. 

 Third day, 9-3, 11-0 : average, 101. Fourth day, 77, 7-7. 



An equal quantity of volcanic subsoil was then taken, when 

 the leaks observed were 29-5, 28"7, 35-0, 37'0, or an average 

 of 32 '5. As an average of fifteen readings with about three 

 times the quantity of soil was 40'3, the rate of leak would not 

 be appreciably affected by small variations in the quantities 

 taken, and it is therefore sufficient for purposes of comparison 

 if approximately equal amounts are tested. On the fifth day 

 the subsoil gave 30'0, 32-3, 34*7 — average, 32-3 ; and on the fol- 

 lowing day 32-3, 33-3, 317, 29-5— average, 31-7. The subsoil 

 was then left in the can for sixteen days, at the end of which 

 the leaks obtained were 46 0, 46 5, showing an increase of 50 per 

 cent. 



No further experiments could be carried out at the time, 

 but it is hoped shortly to continue and extend them in order 

 to determine the nature of the radio-active substances. In 

 future experiments the apparatus will be modified in several 

 respects in order to try to get rid of the irregularities which 

 have so far occurred ; and by conducting the experiments over 

 a longer period with the same material more accurate informa- 

 tion will be gained as to the rate of growth and decay of the 

 induced radio-activity 



The results so far obtained indicate the presence of radio- 

 active substances in small quantities in the deposit from No. 1 

 Spring, Te Aroha, and in larger quantities in both surface soils, 

 while the hard volcanic subsoil is about six times as active. 

 The difference between the surface soil and the subsoil is what 

 would be expected if radium were present, for the heavy emana- 

 tion gas produced by the disintegration of this element would 

 more or less be imprisoned in the subsoil, and the subsequent 

 soil-products, themselves radio-active, formed by the subsequent 

 disintegration would accumulate there. On the other hand, 

 in the case of the loose surface soil, the emanation would for the 

 most part escape and the further products be lost. 



