156 



On the Powers of the Aneroid and its 



[No. 39. 



had already tried them on the mountain near Trivandrunf as high as 

 6000 feet and the indications appeared quite correct. One I left 

 permanently on the mountains at a small Observatory I maintain 

 there. The other has long accompanied me on all my journies. Dr. 

 Wight, with whom I was staying at Coimbatore, had two Aneroids 

 by the same makers but both were out of order and had not been 

 tried at great altitudes, an additional incentive to my excursion, and 

 on which he accompanied me. I went up to Kotagherry by the 

 direct road, was there for 3 or 4 days and made a forenoon visit to 

 Doda Bett, but it was a rainy, windy, day, with driving cloud mist 

 which rendered the trip a most uncomfortable one. The results 

 were however most satisfactory as regarded the Aneroid which fell 



on the top of Doda Bett to 22*455 — 55° 



( Aneroid. 29*040 



atMatipolliam| Barometer. 28-830 



the Barometer being Barometer. 22*120 — 55° 



I have not seen any observations with the Aneroid at a greater 

 altitude than 3000 or 4000 feet. 



The same Aneroid, at the level of the sea, stood at about 30*120 

 so that, had Doda been a couple of hundred feet higher, the Index 

 would have passed the limits of the scale. The Aneroid is a deli- 

 cate Instrument and the scale not subdivided sufficiently, but I have 

 much greater confidence in it now, and its extreme portability is 

 an immense object to the traveller. I have been using it constantly 

 of late for rough levelling while travelling in my palkee merely 

 stopping the bearers for a moment to make the observation. 



Two French Aneroids procured expressly for me by Froughton 

 from the Patentee at Paris, do not appear to answer at all, being 

 inaccurate, at even moderate elevations, and I have discontinued 

 using them. 



I enclose a Memo, of some of the observations of the Aneroid 

 and Barometer at the above trip- 



