ELECTRIC DISCHARGE WITH THE CHLORIDE OE SILVER BATTERY. 237 
Note C, relating to Page 221. 
In support of the observation as to possible dependence of stratification upon tbe concurrence of axial 
and radial impulses from tbe positive and negative terminals respectively, we quote tbe following 
experiments : — 
Gassiot (Pbil. Trans., pp. 1-16) used tubes supported in a vertical position, in wbicb were produced 
Torricellian vacua, witb an arrangement for causing tbe mercurial column to rise and cover one 
terminal or fall, and leave it exposed. “ Wben tbe upper wire is negative and tbe lower positive, if the 
mercury in tbe globe is allowed to ascend tbe tube, the stratifications collapse, but tbe dark band 
between them and the negative glow remains ; as the mercury rises tbe stratification merges into a series 
of rings on tbe surface of tbe mercury, wbicb when tbe circuit of tbe primary is broken is not found to 
be tarnished, but as bright as wben tbe experiment commenced. On reversing tbe direction of tbe current, 
wben tbe mercury is permitted to ascend immediately it covers tbe negative wire tbe stratifications 
disappear and tbe interior of tbe globe is filled witb bluish light ; a bright spot of light is visible on tbe 
end of tbe positive wire, but tbe mercury no longer exhibits tbe red glow, its entire surface, until it 
ascends to within an inch of tbe positive wire, being covered witb a brilliant white phosphorescent film 
about one-eigbtb of an inch in thickness.” 
He also (Phil. Trans., 1859, pp. 137-160) bad constructed a tube in wbicb a moveable terminal might 
be made to drop into a brass tubular case surrounded by a glass protecting tube of small bore wbicb projected 
beyond tbe brass case, so that tbe point could at will be made to project beyond this glass sheath 
or to fall within it. “ When both wires were exposed tbe stratified discharges show tbe clear cloud- 
like appearances so often described, whether A (tbe moveable terminal) is positive or negative ; but if 
A is made negative and tbe tube inclined so as to let tbe wire drop into tbe brass tubing, almost all 
trace of stratifications immediately disappear.” 
He found that if he enclosed the terminals in a glass tube of very small bore projecting about an eighth 
of an inch beyond tbe end of tbe wire, tbe emanation from the negative might be constrained to take a for- 
ward direction. “ Tbe negative discharge issuing through tbe orifice as from a jet If tbe wire 
(negative) is inclined a little tbe discharge will impinge against tbe side of tbe vacuum tube, brilliantly 
illuminating the spot on wbicb it impinges If tbe discharge is continued for a few seconds that 
portion of tbe tube on wbicb tbe discharge impinges will be sensibly heated.” 
Gassiot also states (Pbil. Trans., 1858, p. 10) that: “ Tbe emanation of particles only proceeds from 
the negative, not in a direct line from the positive, but laterally.” Again, p. 11 : “ Such particles being 
always deposited in a lateral direction from tbe wire, and not beyond tbe line on tbe glass tube even witb 
tbe end of the wire.” p. 13 : “ Tbe force from tbe positive is not accompanied by tbe transfer of particles 
from tbe metallic terminal.” 
Hittorp (Pogg. Ann. cxxxvi., 1869, pp. 1—31 and 137-194) describes various experiments bearing 
on this point. Thus, in a tube having two parallel electrodes at 4 m.m. distance, tbe negative glow 
radiated in all directions through tbe tube, but the positive discharge appeared only on tbe side of its 
terminal wbicb was remote from tbe negative electrode. In another tube it was observed that wben one 
of tbe terminals was bent back upon itself, if this is made positive, tbe discharge curls round so as to 
present itself towards tbe negative ; but wben tbe bent terminal is made negative tbe glow remains 
directed away from tbe positive. He also describes an interesting experiment wbicb exhibits in a striking 
manner tbe influence of tbe size of the space surrounding tbe electrodes, but it is complicated by tbe 
influence of tbe distance between tbe terminals, wbicb latter influence has a value varying witb tbe 
degree of rarefaction as shown by other experiments of tbe same physicist (see footnote, p. 163). A 
vessel consisting of two spherical glass bulbs joined by a short glass tube of 1 m.m. in diameter 
bad two straight wires, for terminals, running horizontally one through each bulb and extending into tbe 
junction-tube so as to leave a space of only 1 m.m. between their extremities. Tbe bulbs were also 
connected at tbe upper ends of their vertical axis by another long glass tube of tbe same bore as tbe 
