1851.] The adaptation of the Aneroid for surveying in India. 343 



" Aneroid.— No. 2. 



" 1st Experiment. 2nd Experiment. 



Aneroid. Height of Mercury in tube. Aneroid. Height of Mer. in tube. 



Inches. 



Inches. 



Inches. 



Inches 



26 .0 



3 .9 



24 .5 



4 .75 



26 .5 



3.35 



25 .0 



4 .25 



57 .0 



2 .8 



25 .5 



3 .7 



27 .5 



2.35 



26 .0 



3 .2 



28 .0 



1.85 



26 .5 



2 .7 



28 .5 



1.35 



27 .0 



2 .2 



29 .0 



0.85 



27 .5 



1 .7 



29.25 



.6 



28 .0 



1 .2 







28.25 



0.975 







28 .5 



.7- 







28.75 



0.425 







29 .0 



.2 







29 .7 



.5 



" From these experiments I felt satisfied that the Aneroid No. 2 would 

 not differ from a mercurial harometer by more than one-tenth of an 

 inch, if carried to a height of six thousand feet. Since these experi- 

 ments were made, I have had an opportunity of taking it with me to 

 Mahabaleshwar, and of comparing it with the Sympiesometer, and 

 the results given below show how accurately my anticipations have 

 been fulfilled, — at least as far as 4500 feet. Dr. Buist's observations 

 at Poona had already proved its correctness to the height of 2000 feet. 



Aneroid. Sympr. Ther. 



October 19.— 29. 8 29.56 90.0 12 o'clock noon— level of sea. 

 „ 19.— 27.725 29. 5 83.5 3 Do. do. do. 



„ 20.— 29. 85 29.65 83.6 9i a. m. Mhar River. 

 „ 20.— 29.155 28.93 85.5 5| p. m. 

 ,. 20.— 25. 79 25.54 68.5 9% p. m. Monastery, Maha- 

 baleshwar. 

 " The coincidence between the two instruments is seen to be very ex- 

 act, the total fall of the Aneroid being 4.01, and of the Sympiesometer 

 4.02. 



" The following are the readings of the Aneroid and Thermometer 

 at different places between Mahabaleshwar and Poona. 



