THE MARINE AQUARIUM. 61 
artificial preparation of sea-water. In the fictitious pre- 
paration the component salts were reduced to four, so that 
no less than three of the original ingredients were dis- 
pensed with. If the reader will note in what minute 
quantities the bromide of magnesium, the sulphate and car- 
bonate of lime occur, and at the same time bear in mind 
that river and spring waters always contain a considerable 
proportion of the last-mentioned ingredient, it will be 
easily understood that the absence of those materials in 
the preparation does not materially affect its value. The 
preparation on Mr. Gosse’s plan is composed as follows :-— 
Common Table Salt ; : 34 ounces. 
Epsom Salts “ i at bess 
Chloride of Magnesium , 200 grains, Troy 
Chloride of Potassium . ‘ 40 
3 ”? 
The recipe may be given in another form to avoid the 
perplexity of avoirdupoise and troy weights, thus :— 
Common Salt . : . 81 parts. 
Epsom Salts. F ‘ tomy Gar 
Chloride of Magnesium é 2 10: 
Chloride of Potassium - ‘ 2 
Management of Artificial Water.—When the salts are 
ready, it is best to mix them in an earthern pan or jar, 
and allow them to settle and refine for a day or two. To 
dissolve them in the tank is decidedly a bad plan, though 
it is daily recommended by the dealers. Any one who 
will dissolve a portion in a clean bell glass, and allow it 
to stand for a week, using the clearest water, and adding 
nothing but the salts, will observe, at the end of that 
time, a minute gritty deposit, similar to iron rust, mixed 
