338 Mr Forbes on the Defects of the Sympiesometer, 



14 — 7.30 60.3 29.46 221 42 



This is the worst set of observations I have obtained, and 

 in many respects they are unsatisfactory. We may see, how- 

 ever, that the general disposition of the thermometer to fall is, 

 as by our hypothesis, accompanied with a uniform rise of the 

 sympiesometer, interrupted by the stationary aspect, which 

 during a rise is equivalent to a descent in Obs. 6 to 8, which is 

 succeeded and accounted for by the rise of the thermometer in 

 Obs. 8 to 10, as it is obvious that the thermometer upon our 

 supposition will only indicate the change after its effect has 

 been manifested in the gaseous column. The only other in- 

 stance of a fall of the sympiesometer is between Obs. 10 and 12, 

 and which is equally promptly accounted for by the rise of the 

 thermometer at Obs. 13. The column of differences is far too 

 great, since when corrected for temperature the height ought 

 to be only 23.52 fathoms. The positive height, however, is 

 not our present subject of examination. I will only observe 

 farther, that there are 10° between the temperature of the two 

 stations ; and if there be any constant defect of compensation, 

 the error would be, as we have shown, in making the height 

 too great. 



Table II — June 2Ut, 1825. 



24 — 4.10 53.2 29.74 180 41 



