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the nature of a thunderbolt. The shock was severe, and the phenomenon 

 would appear not to have been connected with the " trough " of the cyclone, 

 but to have been due to an atmospheric upheaval on a large scale, the 

 outcome of excessive wave-motion. It is probable that some of the re- 

 markably intense rainfall recorded on this date was due to " cloud-bursts." 

 The sky of the previous day indicated considerable wave-motion — cirro- 

 stratus (pallium) overlying long lines of waviform cumulo-stratus, merging 

 into patches, at intervals, of very pronounced " pocky " clouds, said to be 

 an infallible sign of storm in the Orkneys. 



The storm of the 3rd July was still more remarkable, and was associated 

 with the heaviest easterly gale recorded since 1898. The barographic curve 



Inches 



7 



8 9 10 II N I ? .T -1. '^ *; -r 



Graph showing Rates of Precipitation at Waihi on 29th March and 



3rd July, 1900. 



also displayed wave-motion, and depicted the sudden drop in pressure 

 which occurred about 3 p.m.- — a decline of fifteen-hundredths in fifteen 

 minutes. This movement was accompanied by wind backing to south- 

 east, and the most intense rain recorded here, 1-45 in. falling in thirty 

 minutes. The barogram suggests the formation of a small " satellite," 

 offset from the parent system, apparently tornadic in nature. The passage 

 of this system was followed by improving conditions, and by nightfall the 

 clouds changed movement from north, again evidencing the fusion of a 

 westerly wave-depression with the low pressure. The glass showed no in- 

 clination to recover until the 5th, and anticyclonic pressure was not restored 

 till the 7th. If cyclonic formation is a true circle, then the barometer 

 should regain the height from which it had fallen, and it is evident when 

 this movement is unduly retarded that there must be more than one low- 

 pressure system existent. 



Before concluding, reference is made to a remarkable cigar-shaped cloud 

 which forms over Waihi during high west-south-west winds, sometimes five 

 miles in length. This cloud, which has been observed by Davis, Hann, and 

 others elsewhere, and which is described as analogous to the " standing 

 wave " produced by running water on the surface of shallow and rocky 

 streams, appears to be in continual motion, but in reality is stationary, 



