Mr. R. AVarington on Marine Vivaria. 319 



XXX. — Oh Preserving the Balance between the Animal and Ve- 

 getable Organisms in Sea Water. By Robert Warixgton.* 



In the published notices of my experiments of 1849, to maintain 

 the balance between the animal and vegetable organisms in a 

 confined and limited portion of water, the fact was demonstrated, 

 that, in consequence of the natural decay of the vegetation, its 

 subsequent decomposition and the mucus-growth to which it 

 gave rise, this balance could only be sustained for a very short 

 period, but, if another member were inti-oduced, which would 

 feed upon the decaying vegetation and thus prevent the accumu- 

 lation of these destructive products — a function most admirably 

 performed by the various species of water-snail — such balance 

 was capable of being continuously maintained without the 

 slightest difficulty ; and I may add, that the experimental proof 

 of this has now been earned on, in a small tank in the heart of 

 London, for the last four years and a half, v.ithout any change 

 or disturbance of the water ; the loss « hich takes place by eva- 

 poration being made up with rain or distilled water, so as to 

 avoid any great increase of the mineral ingredients originally 

 present. It follows then, as a natural deduction, from the suc- 

 cessful demonstration of these premises, that the same balance 

 should be capable of being established, under analogous circum- 

 stances, in sea water. And in a paper published in Januarv 

 1852t, I stated that I was, at that time, "attempting the same 

 kind of arrangement with a confined portion of sea water, em- 

 ploying some of the green sea-weeds for the vegetable member 

 of the circle, and the common periwinkle as the representative 

 of the water-snail.'' 



The sea water with which the experiments I am about to de- 

 tail were conducted, was obtained through the medium of one of 

 the oyster-boats at the Billingsgate fish- market, and was taken 

 fram the middle of the English Channel. 



My first object was to ascertain the kind of sea-weed best 

 fitted, under ordinary circumstances, for keeping the water clear 

 and sweet, and in a sufficiently oxygenated state to sustain ani- 

 mal life. And here opinions were at variance, for one naturalist 

 friend whom I consulted, advised me to employ the Rhodosperms ; 

 another stated that it was impossible to make the red weeds 

 answer the purpose, as he had tried them, and strongly recom- 

 mended the olive or brown-coloured Algae ; while, again, others 

 thought that I should be more successful with those which had 



* Communicated by the Author, haviug been read at the HuU Meeting 

 of the Bntwh Association. 



t Gardeners' Botanical Magazine and Garden Companion, Jan. 1852. 



