144 
Notes. 
, •„ thrown off by the animals, or left 
oxidation of the ° r &^; nl , neaten a nd unremoved dead food, 
in the water in the form of uneaten ana ^ ^ ^ 
As anticipated a ve^y was de teaed. The following 
sea-water fre ^ Terence between the aquarium-water and sea- 
figures show the M date frQm Bright0 n, and which 
fiihfy rep^esents° the amount present naturally in sea-water. 
Icl ' F Nitric Nitrogen 
Recent sea-water 
Aquarium-water 
Nitric Nitrogen. 
Parts per 100,000. 
00325 
. . 12*0498 
In all well-stocked aquaria of 
large size in rel food of such animals kept in 
what exists in Nature duced in the water in which 
confinement instead h e ^ g 0U P tside sou rce in the shape of food 
iSfthan it iTttLve^ li<lmited 
“rs: « ss 
noteworthy addition 1 pid i y thereby saving wear of the 
is required to move the phig P J . n carryin g the imbed- 
delicate screw, and also the « £ fof removal or bringing 
d ed tissue through a long dista , f the ^ removab i e 
to the top of the well The bottom ^ wben removed 
and is retained in place by ^ int0 tw0 halves, so as to 
from its fitting the bottc ’ P Qf thread in the internal screw 
release the s «® w ;, th fJ n balves y when in position, by means of 
is maintained in t e ’ Qne bab accurately fitting into 
two metal pegs on the a ^ scr ew has thirty-six threads 
holes on the face of the othe . having thirty-five notches 
to the inch, and is attached to ^ . c f tcb falls. The cut- 
t^^surface^^oT'plate'^lass^and^an be re^ove^at^pleasm^for 
S a'screw 3L> to hx it firmly to 
th ;t b Lkes exhibited his experiments ori Rad^it Maher at 
kt the Societe de Physique on the 
1 6 th of January. 
