10 THE ROYAL SOCIETY OF CANADA 
TABLE I. 
MoBILITY OF THE PosiITIVE ION IN AIR. 
PRESSURE. 
Cm. of Hg Atmos k pk 
Pee OL Gis: 2:62 Me tee RTD Chee CSAS 101-°6 0139 1-42 
DO 16. va 2 dro Pe ee Ie RS 101-66 0138 1-41 
O40 80s 26 Re ENT eee 83-30 0154 1-28 
A AQB UG i cure ie eat ee ee ee 59-16 0227 1-34 
DOTE 0) 0 nei Ae a Mik Ni alae vee eM oh aa oa 39-10 0344 1-35 
12989 68h. Se Fe ATP PNR ee eet 26-18 0517 1-36 
TW OSG): SOR LES Ma aac keeps Meer ER AR EEE vee 14-29 0945 1-35 
Df Ole Doreen iy a eee yet nae ek Mena os eet 7-58 178 1-35 
ATOS De Rees: carta Weta WP a Tie tae ara papell ee pan a 5-00 262 TS 
The measurements cited in Table I were made one after another 
in the order given and the two principal sources of irregularity in 
obtaining them arose in making the pressure readings and in determin- 
ing the critical voltage from the curves which represented the readings 
obtained with the different fields applied between G and 8. This 
uncertainty was greater in some measurements than in others and 
would largely account for the variations, shown in the table, of the 
product pk. These variations, however, are not large, and we may 
conclude therefore that the mobility of the positive ion varies inversely 
with the pressure up to as high as one hundred atmospheres. 
TABLE II. 
MoBiLiTY OF THE NEGATIVE ION IN AIR. 
PRESSURE. 
Cms. of Hg Atmos k pk 
ODD EAN SR TPS Aone harsh RO Pacey era deere | 104-24 0224 2-33 
GS OG i cd aa cate Er RAR PR cee as À 82-96 0281 2-33 
PA y EL EN NEREARET AN CET S ENS SACS pat PL PRE CA se mr aM 59-84 0378 2-26 
SE M on ei du 41-48 0532 2-21 
3,152 :48 41-48 0536 2-22 
2 DADATO. OS, ola OR ttt hac AT cee me ie nates 38-76 0561 2-18 
2 080010 TE LR DR dots Hehe EN EURE 33-66 0637 2-15 
LSP (Gof cal Ws ston dco nes PR oat cairo to Er iS os 23-12 0906 2-10 
POSE OA. a sn of MERE LEE RRERR 14-29 143 2-04 
Fateh iy ete 0 Pere a eens ROVER PRES seria ase EME fe eee 29-80 064 1-96 
SESH cis TN MR Meee eR eee atc Re 20-40 0915 1-87 
OOO e RER M D ER 13-60 130 1-76 
laf} jC LR RRP RE ae ie Co OR, oak. PU 22 gt ey 7-34 253 1-86 
HORDE ext Bonk tole hoe ea ras ath te opie TAREE ES ET 5-00 330 1-65 
