Farr and Florance. — Radio-activity of Artesian Water. 187 



botli the Museum and the Boys' High School, whilst from the depths alone 

 this inference might not be drawn. The conclusion might also be drawn 

 that the water supplying Dr. Moorhouse's well does not pass through similar 

 materials. For reasons to be subsequently explained, the wells in the 

 Fish-hatchery Gardens of the Acclimatisation Society have been those most 

 examined, and all these, together with a well of about the same depth at the 

 new Chemical Laboratory building, give approximately the same radium- 

 emanation content. On several of the wells — notably those of the Accli- 

 matisation Society's Gardens — tests have been made several times of the 

 radio-activity of the water ; and the results show that over the period of 

 these experiments (some two months) the amount of radium emanation per 

 litre is approximately constant for the wells so tested. It is certain that 

 the radio-active gas was radium emanation, for on several occasions the 

 gases boiled off from a sample of water were left in the electroscope for 

 four or five days, when the curve of decay followed closely that obtained 

 from the gas boiled off from the radium-solution, and also the well-known 

 radium-emanation curve. As a general rule, however, the rate of motion 

 of the electroscope-leaf was determined as soon as the gas was in the 

 electroscope — that is, one hour after the commencement of boiling. The 

 leaks given are these, and not the maximum leak, which would occur about 

 three hours later and would be about 25 per cent. more. 



A comparison of the radio-activity of our springs with that of others is 

 of interest. Curie and Laborde have examined the waters of certain mineral 

 springs in France (Comptes Rendus, vol. cxlii, p. 14:6i). The radio-activity 

 of these springs, expressed in our units, is as follows : — 



-D, , • I Source Vanquelin 

 rlom biers m i n 



376 



I Tron des Capucins . . . . . . 787 



Aix-les-Bains, No. 1 . . . . . . . . 461 



No "> 257 



Bourbon-Laney, Source Le Lymbe . . . . . . 169 



Contrexeville, Source de Pa^dllon . . . . . . 85 



La Roche Posay . . . . . . . . . . 85 



M. Repin (C.R., vol. cxlvii, p. 388) has given particulars of three other 

 waters of special interest, whose values, expressed in the same units, are, — 



Source de Villard Clement, No. 1 . . . . . . 50 



No. 2 . . . . . . 18 



Source de St. Pancrece . . . . . . . . 27 



The first series are well-known mineral springs w'hich are rich in dis- 

 solved salts, and which might therefore be expected to contain a con- 

 siderable amount of radium emanation. From these it will be seen that 

 the waters of Christchurch contain an amount of radio-active gas com- 

 parable with that of well-known springs in Europe, and more than the 

 amount in quite a number of these springs. 



Seeing, therefore, that the Christchurch water contains radium emana- 

 tion, and that this gas has properties of a remarkable and energetic cha- 

 racter, it occurred to us to endeavour to ascertain whether any, and, if so, 

 what, effects on animal life could possibly be ascribed to it. As fish were 

 more likely to show its consequences than any other form of life, inquiries 

 were set on foot relative to those inhabiting the streams and ponds supplied 

 by the artesian system. Surprising results (to us, at any rate) were soon 

 forthcoming. It appears that a disease amongst young trout in the yolk- 



