﻿70 



Royal Society :■ 



If now we separate the results of Table II. into two sets, one com- 

 prising large (4 to 4| inch) aneroids and the other small instruments, 

 we shall find the mean down correction for large aneroids to be as 

 follows. 





29 in. 



28 in. 



27 in. 



26111. 25 m. 



24 m. 



+ •04 

 + •08 



23 in. 



22 in. 



21 in. 



20 in. 



Mean correction for 

 large an eroids. gra- 

 duated to 19 in. . . 



23 in 



•00 

 •00 



•00 

 — •02 



+ 'C2 

 -J--02 



+•03 



+•03 



+'°4' 



+ •04 



+ •07 

 + •10 



+ •11 



+ •14 



+ •19 



In like manner we shall find for small aneroids, supposed right at 29 

 inches, the following mean correction : — 





29 in. 



28 in. 



27 in. 



26 m. 



25 in. 



24 m. 



23 in. 



22 m. 



21 in. 



+ •17 



20 in 



Mean correction for 

 small aneroids,gra- 

 duated to 1 9 in. . . 



23 in 



•00 

 •00 



+•01 



+ •02 

 + •07 



+ •03 



+ •12 



+ •07 

 + •16 



+ •07 

 + •20 



+ •09 



+ •27 



+ •12 



+ •23 



It will be seen that there are two instances in which the same 

 instrument has been twice experimented on. Assuming that the 

 mean of the two experiments represents the true correction for each 

 of these instruments, we find : — 





29 m. 



28 in. 



27111. 



26 in. 



25 in. 



24 in. 



23 in. 



22 in. 



21 in. 



20 in 



No. 8. 



Mean correction, 

 deduced from two 















experiments .... 



•00 



— •01 



-j-'02 



+•02 



+ ■ 06 



+ •06 



+ •11 



+ •15 



+ •18 



+ •23 



Mean minus first 

 determination . . 



•00 



+ •01 



4-" 02 



4- - o2 



+ •02 



+ •03 



4--oi 



+ •01 



4--01 



+ •01 



In like manner : — 





29 in. 



28 in. 



27 m. 



26 in. 



. 1 . 

 25 m. 24 m. 



23 in. 



22 in. 



21 in. 



20 in 



No. 9. 

 Mean of two ex- 























periments ...... 



•00 



+ •01 



+ •02 



+ •03 



+ •02 



4-'C2 



+ •03 



+ •06 



+•11 



+ •15 



Mean minus first 























determination . . 



•00 



+ •01 



+ •02 



4-'02 



+ •03 



+ •02 



•00 



— •01 



— •02 



-o| 



