476 



Mr. B. Stewart on certain Experiments [June 18^ 



If now we separate the results of Table 11. into two sets, one comprising 

 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. 



26 in. 



25 in. 



24 in. 



23 in. 



22 in. 



21 in. 



20 in. 



19 in. 



Mean correction for 

 large aneroids, gra- 

 duated to 19 in, . . 



•00 

 •00 



•00 

 — •02 



4- "02 

 -f--02 



+ •03 

 4-'o3 



+•04 

 + •04 



+ ■04 

 + •08 



4--07 

 4--IO 



-f--ii 



+ •14 



+ •19 



+ •25 



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 in. 



25 in. 



24 in. 

 + ■07 



-|-*20 



23 in. 



22 in. 



21 in. 



20 in. 



19 in. 



Mean correction for 

 small aneroids, gra- 

 duated to 1 9 in. .. 



•00 

 *oo 



+ •01 

 +•03 



+ '02 



+•07 



+ •03 

 + •12 



+•07 

 4-i6 



-{-■09 

 + •27 



4--I2 



+ •17 



4- -23 



+ •^5 



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

 ment has been twice experimented on. Assuming that the mean of the 

 two experiments represents the true correction for each of these instru- 

 ments, we find : — 





29 in. 



28 in. 



27 in. 



26 in. 



25 in. 



24 in. 



23 in. 



22 in. 



21 in. 



20 in. 



19 in. 



No. 8. 



Mean correction, 

 deduced from two 

 experiments .... 



•00 



— •01 



+•02 



+ •02 



4- -06 



+ •06 



+ •11 



+•15 



+ •18 



+ •23 



+■30 



Mean minus first 

 determination . . 



•00 



+ •01 



+ •02 



4-^02 



+ •02 



+•03 



4-^oi 



+ •01 



4--01 



4-^oi 



4-^o2 



In like manner : — 





29 in. 



28 in. 



27 in. 



26 in. 



25 in. 



24 in. 



23 in. 



22 in. 



21 in. 



20 in. 



1 9 in. 



No. 9. 

























Mean of two ex- 



























•00 



4-^oi 



+ •02 



+ •03 



+•02 



4-'02 



+ •03 



+ •06 



4--II 



+•15 



+ •20 



Mean minus jSrst 

























determination . . 



•00 



+ •01 



4-^o2 



+ •02 



+ •03 



4-^02 



•00 



— •01 



—•02 



-•03 



— •02 



"We see from these results that if aneroids, right to begin with, be sub- 



