156 MARINE AQUARIA FOR ROOMS. 



restoring the quantity of water lost, by adding a 

 supply of fresh water. Distilled water is the best to 

 replace the evaporated, as then we know no germs or 

 other interfering agents are likely to be introduced. 



In constructing a marine aquarium there is no doubt 

 whatever that pure sea water is the best. This can 

 now be obtained through dealers, or the student may 

 obtain it for himself, always taking proper precaution 

 that the barrel or other means of conveying the salt 

 water, contains nothing that would render it obnoxious. 

 Always use the water as soon after getting it as 

 possible, and do not allow it to remain in wooden 

 vessels which may discolour it. When placed in 

 the aquarium, add the Ulvce, Cladophora, or other 

 useful, oxygen-yielding sea-weeds ; and let them grow 

 before putting in any animals. When you think the 

 water is fit, place in a few sea-anemones, adding 

 them one at a time. It is much better to proceed 

 slowly, than to be in a hurry, and have all the work 

 to do over again. Mr. Gosse showed that it was 

 possible to manufacture sea water, and gave the 

 following formula for it : 



Common table salt 3J oz. avoir. 



Epsom salts ,, 



Chloride of magnesium . . . . 200 grains 



Chloride of potassium 40 ,, troy 



which should be added to a little less than I gallon 

 of distilled water. This artificial "sea-salt" is now 



