Notices of New Books. 4401 



on the Evolutions of the Cells in their Neighbourhood; by Dr. Gar- 

 reau. Description of a New Genus of Bivalve Mollusca; by H. and 

 A. Adams. On the Dimorphism of the Uredineae ; by M. Tulasne. 



Mr. Gosse's suggestion for making a substitute for sea-water will be 

 found useful, on account of the expense and trouble it must necessa- 

 rily save. Impressed with the difficulties attending the usual method 

 of supply, he says, " I determined to try the matter for myself. I 

 took Schweitzer's analysis, but as I found that there was some slight 

 difference between his and Laurent's, I concluded that a minute accu- 

 racy was not indispensable. Schweitzer gives the following analysis 

 of 1000 grains of sea-water taken off Brighton : — 



Water 



. 964-744 



Chloride of sodium 



. 27-059 



Chloride of magnesium 



3666 



Chloride of potassium . 



0-765 



Bromide of magnesium 



0-029 



Sulphate of magnesia . 



2295 



Sulphate of lime . 



1-407 



Carbonate of lime 



0-033 



999-998 



" The bromide of magnesium and the carbonate of lime I thought 

 I might neglect, from the minuteness of their quantities ; as also be- 

 cause the former was not found at all by M. Laurent in the waters of 

 the Mediterranean ; and the latter might be found in sufficient abun- 

 dance in the fragments of shell, coral, and calcareous Algae, thrown 

 in to make the bottom of the aquarium. The sulphate of lime 

 (plaster of Paris) also I ventured to eliminate, on account of its ex- 

 treme insolubility, and because M. Laurent finds it in excessively 

 minute quantity. The component salts were then reduced to four, 

 which 1 used in the following quantities : — - 



Common table salt ... 3^ ounces. 



Epsom salts .... | ounce. 



Chloride of magnesium . . 200 grains, Troy. 



Chloride of potassium ... 40 „ „ 



To these salts, thrown into ajar, 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., Id. ; chloride mag., 

 Sd. ; chlor. pot, 1 id. ; salt, nil; total b\d. per gallon. Of course if 

 a larger quantity were made the cost of the materials would be dimi- 

 nished, so that we may set down 5d. per gallon as the maximum cost 



