66 On Manufactured Sea-Water for the Aquarium. 



M. Laurent finds it in excessively minute quantity. The com- 

 ponent salts were then reduced to four, which I used in the fol- 

 lowing quantities : — 



Common table salt .... 3i ounces. 



Epsom salts \ „ 



Chloride of magnesium . . 200 grains lm 



Chloride of potassium ... 40 „ J •*' 



To these salts, thrown into a jar, a little less than four quarts of 

 water (New River) were added, so that the solution was of that 

 density that a specific gravity bubble 1026 would just sink in it. 



The cost of the substances was — sulph. mag. Yd. ; chloride 

 mag. 3d. ; chlor. pot. \\d. ; salt, nil ; — total, 5^d. per gallon. Of 

 course if a larger quantity were made the cost of the materials 

 would be diminished, so that we may set down 5d. per gallon as 

 the maximum cost of sea-water thus made. The trouble is 

 nothing, and no professional skill is requisite. 



My manufacture was made on the 2 1st of April. The follow- 

 ing day I poured off about half of the quantity made (filtering 

 it through a sponge in a glass funnel) into a confectioner's 

 show- glass. I put in a bottom of small shore-pebbles, well 

 washed in fresh water, and one or two fragments of stone with 

 fronds of green sea-weed (Ulva latissima) growing thereon. I 

 would not at once venture upon the admission of animals, as I 

 wished the water to be first somewhat impregnated with the 

 scattered spores of the Ulva ; and I thought that if any subtle 

 elements were thrown off from growing vegetables, the water 

 should have the advantage of it, before the entrance of animal 

 life. This too is the order of nature ; plants first ; then animals. 



A coating of the green spores was soon deposited on the sides 

 of the glass, and bubbles of oxygen were copiously thrown off 

 every day under the excitement of the sun's light. After a week 

 therefore I ventured to put in animals as follows : — 



2 Actinia mesembryanthemum. Coryne ramosa. 

 7 Serpula triquetra. Crisia eburnea. 



3 Balanus balanoides. aculeata. 



2 Sabella ? Cellepora pumicosa. 



2 Sabellaria (alveolata ?) Cellularia ciliata. 



2 Spio vulgaris. Boiverbankia imbricata. 



1 Cynthia [quadrangular is ?) Pedicellina Belgica. 



These throve and flourished from day to day, manifesting the 

 highest health and vigour ; the plants (including one or two Red 

 Weeds that were introduced with the animals) looked well, and 

 the water continued brilliantly crystalline. Within the succeed- 

 ing month specimens of Actinia mesembryanthemum, A. angui- 



