FRESHWATER FISPI EPIDEMICS IN QUEENSLAND RIVERS. 189 



Queensland is a country in which heavy rain normally 

 falls during the summer, December to April, while the winters 

 are dry. Thus cold and dr}^ conditions commonly go together, 

 although in the early summer the weather may be hot and 

 dry. 



The Commonwealth Meteorologist, in a letter dated 31st 

 January 1918, drew our attention to the following statement 

 by Mr. J. B. Henderson, Government Analyst, Brisbane, in a 

 report on a sample of water from Cooper's Creek at Windorah : — 



" With reference to your letter . . . and sample of water, 

 no poisons were found in the water. A small fish placed in the 

 water for 48 hours was quite normal at the end of that time. 



" The enormous number of dead fish referred to in your 

 letter points either to suffocation by mud or to a more common 

 cause, a sudden drop in temperature. Nothing in your letter 

 indicates or contra-indicates the presence of either of these 

 causes." 



The Meteorologist went on to state that an investigation 

 of the temperature records for June 1917 showed rather 

 remarkable departures from the normal and appeared to bear 

 out Mr. Henderson's theory. A copy of minima records for a 

 number of inland stations in Queensland was enclosed. 



The localities were Urandangie, Boulia, Winton, Long- 

 reach, Isisford, Windorah, Tambo, Adavale, Thargomindah, 

 and Cunnamulla. From the 1st to the 15th of that month there 

 was a warm period in which the averages of daily minimum 

 temperatures for the fifteen days and the number of degrees 

 above June normal — given in brackets — for each locality 

 were as follows, respectively : — 52-3 (6-8) ; 51-2 (6-5) ; 51-3 

 (1-6) ; 50-5 (2-8) ; 48-4 (1-4) ; 48-8 (4-0) ; 47-2 (3-8) ; 49-5 

 (5-7) ; 50-0 (4-9) ; 49-4 (7-2). During the remainder of the 

 month there was a sudden drop experienced at all these 

 stations, commencing on 16th June. The mean of the daily 

 minima during the cold period and the number of degrees 

 below the June normal, for each of the ten localities were 

 respectively as follows :— 37-8 (7-7) ; 38-6 (7-1) ; 40-5 (9-2) ; 

 38-2 (9-5) ; 37-9 (9-1) ; 35-8 (9-0) ; 32-6 (10-8) ; 35-3 (8-5) ; 

 38-5 (6-6) ; 38-0 (4-2). The mean of daily minima for June 

 1917 at each locality as compared with the normal (calculated 

 from twelve years' records) were given as follows : — 45- 1 

 (45-5) ; 44-9 (45-7) ; 45-9 (49-7) ; 44-4 (47-7) ; 43-2 (47-0) ; 

 42-3 (44-8) ; 39-9 (43-4) ; 42-4 (43-8) ; 42-2 (45-1) ; 43-7 (42-2). 



