120 



Australia, I feel convinced that this noise is not caused by any 

 force of geological or terrestrial origin. But as these places from 

 which the phenomenon in question is reported belong to the most 

 arid regions of Australia, in which nothing but the meteoro- 

 logical conditions are alike, it must be assumed that these sub- 

 aerial conditions are the cause. I should think that they are 

 detonations resulting from electrical discharges in the form of a 

 glow discharge, which wliile spreading over a large ai'ea is less 

 perceptible, and is said to occur more frequently in a dry con- 

 tinental climate during a dry tlmnderstorm. 



NOTES ON THE METBOROLOGTCAL OBSERVATIONS 

 TAKEN BY MR. VICTOR STREICH. 



By C. Todd, Esq., J\LA., F.R.S. 



May, 1891. 



The expedition travelled this month from Warrina Station on 

 the Great Northern or Transcontinental Railway, lat. 28° 12' 

 S., long. 135° 48' E. to Everard Range. 



The observations were commenced on the 3rd, but, owing no 

 doubt to the difficulties incidental to rough bush travelling, 

 they are somewhat incomplete, and for the most part were taken 

 en route, and not at camps. The aneroid was read at 9h. a.m. 

 and 3h. p.m., at elevations varying from, approximately, 323 feet 

 to 1800 feet above sea level. Tliedry and wet bulb thermometers 

 were read regulary at 9h. a.m. and 3h. p.m., but not at 91i. p.m. 

 Only a few readings of the minimum thermometer were taken, 

 and but one of the maximum. These omissions render the 

 observations of less value than those of subsequent months ; but 

 it is due to Mr. Streich to say that, taking his circumstances into 

 consideration, he deserves great credit for the manner in which 

 he carried out the work entrusted to him. It is not an easy 

 task to take observations on a camel's back travelling over a 

 rough country. 



Referring to the observations in May, the temperature at 

 9h. a.m. ranged generally between 55° and 70°, only once rising 

 above 70°, viz., 74° on the 6th, the maximum on tiiat, the only 

 day on which it was recorded being 86°, the hottest day ex- 

 perienced during the month, the thermometer standing at 80° at 

 3 p.m.; on only two days did it reach 80° at 3 p.m., viz., 80° on 

 the 5th, and 81° on the 26th. The weather was therefore fairly 

 cool and pleasant, with south-east, east, and north-east winds 



