Aquatic JLitt 



11 



cially adapted to the needs of the prac- 

 tical aquarist. It was tested under the 

 most severe conditions imaginable. I 

 can justly say it proved to be very ef- 

 ficient, while at the same time it is all 

 that can be desired in convenience of ap- 

 plication and economy. As much as I 

 would like to have the credit for origi- 

 nating the system, I must admit that 

 there is nothing new about it except per- 

 haps its use in connection with aquaria. 



That charcoal, either of animal or 

 vegetable origin, is an absorbent of 

 gases, odors and colors has been known 

 probably as long as the human race has 

 known fire. The property of "ivory 

 black," simply finely divided charred 

 bone, to extract odor as well as the col- 

 or of liquids filtering through it, is be- 

 ing made good use of every day in the 

 refining of sugar, for instance ; a good 

 deal of brownish, strong scented beet 

 sugar has come out of the other end of 

 a charcoal bed in the form of simon-pure 

 "cane sugar," colorless and odorless. As 

 an absorbent for gases, charcoal has long 

 been used by medical science and in sani- 

 tation. 



How a filter may be run by discharg- 

 ng compressed air into the outlet pipe 

 was explained by Mr. Carl Fossetta in 

 ^he November, 191 3, number of The 

 \quarium. This same method has been 

 ipplied for generations, and is used to- 

 lay by the salt refiners along the Ohio 

 river, where saline water is ejected by 

 air from wells hundreds of feet deep, 

 this way of "pumping" being about 100 

 per cent, efficient. If it were not for the 

 fact that I wish to emphasize the use of 

 charcoal as a filtering medium instead of 

 sand, I would have little improvement to 

 suggest on the device used by Mr. Fos- 

 setta. His sand filter will clarify turbid 

 water and, when used in connection with 

 compressed air, will also thoroughly 

 aerate it, a fact that Mr. Fossetta did not 



dwell upon in his valuable paper, but 

 which must not be overlooked. 



The range of usefulness of such a fil- 

 ter can be increased many times by sub- 

 stituting charcoal for the sand. In con- 

 ducting tests with this arrangement, 

 water was used containing at the same 

 time clay, milk and red ink, with enough 

 of a saturated solution of sulphuretted 

 hydrogen added to impart a very vile 

 odor. The clay was stirred into the 

 water to simulate the condition caused 

 by fishes disturbing the bottom ; milk 

 imitated that turbidity caused by algae 

 or decaying animal matter ; red ink fur- 

 nished a substitute for the dissolved col- 

 oring matter sometimes present in aquar- 

 ium water, while the addition of sul- 

 phuretted hydrogen created a condition 

 similar to that obtaining in water in an 

 aggravated state of putrefaction. This 

 liquor, when run through the filter once, 

 came out crystal-clear, and without odor 

 or color. In practice, as applied to the 

 aquarium, filtration is repeated over and 

 over again according to the capacity of 

 the tank and the length of time the de- 

 vice is applied. 



The sectional drawings of this appara- 

 tus are self-explanatory. It can be con- 

 structed in some form and with little ex- 

 pense by almost anyone. The charcoal 

 should be cracked in a mortar, as ground 

 charcoal is apt to pack too tightly. Be- 

 fore charging the filter body it is neces- 

 sary to stir the charcoal into water, and 

 thereafter to slightly drain it, as dry 

 charcoal repels water and cannot work 

 well in this state. A layer of washed 

 sand placed on top of the filter bed pre- 

 vents the passage of small particles of 

 charcoal into the outlet pipe. 



The only additional requirement is 

 some source of compressed air. In my 

 tests this was supplied by a tire pump in 

 connection with a small air tank. A res- 

 ervoir 6 inches in diameter by 2 feet high, 



