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X. On the Atmospheric Tides and Meteorology of Dukhun (Deccan), East Indies. By 

 Lieutenant-Colonel W. H. Sykes, F.R.S. L.S. G.S. Z.S. rice-President of the 

 Statistical and Entomological Societies. 



Received May 14,— Read June 19, 1834. 



1 HE value of the following meteorological observations depending on the goodness 

 of my instruments, on certain precautions in the use of them, and on the care with 

 which atmospheric changes were recorded, I shall preface my notices on the me- 

 teorology of Dukhun with an account of the instruments I had in use, and of my 

 method to insure correct results. In determining atmospheric pressure, for the first 

 two years I was confined to two of Thomas Jones's barometers : they required to be 

 filled when employed, and were destitute of an adjustment for the change of level of 

 the mercury in their cisterns, unless the position of the cistern had been altered at 

 each observation ; a measure attended with insuperable inconvenience. At first I 

 experienced a good deal of vexation in expelling the moisture from the tubes ; but 

 by previously rubbing the inside with a tuft of floss silk tied to the end of an iron 

 wire, I dried them so effectually (unless in the monsoon months) as to excite power- 

 ful electricity : and I have frequently had shocks in my right thumb, running up to 

 my shoulder, in pouring the mercury into the tube, accompanied with cracking 

 noises, until the approach of the mercury to within two inches of my thumb, when 

 the electricity was discharged as described. I experienced these shocks at Salseh, 

 near Purranda, on the 3rd of February ; at Pairgaon, on the Beema River, on the 

 14th of February; at Kundallah, in the hilly tracts, on the 14th of March, 1828; 

 and at many other places. Jones's barometers were each provided with a thermo- 

 meter let into one of the legs of the tripod on which the barometer was suspended. 

 The scale of this thermometer was of thin ivory, and the tube excessively slender. 

 During the heat of the day in the dry season, the scale was contracted, by parting 

 with its moisture, into the segment of a circle, bending the tube of the thermometer. 

 At night the ivory scale relaxed from its curvature, and at sunrise it had returned to 

 a right line. This operation continued daily for more than three weeks ; but on the 

 15th of February 1827, the contraction of the scale was too great for the flexibility 

 of the glass, and the tube of thermometer No. 1. broke. The thermometer attached 

 to barometer No. 2. subsequently shared the same fate, from a similar cause. Thomas 

 Jones's barometers pack well, carry easily, and are certainly very useful as checks 

 upon permanently filled barometers, which frequently give false indications, from the 

 unknown escape of the mercury, or the admission of air, which could not be detected 



MDCCCXXXV. Y 



