AS A FIELD OF MICROSCOPICAL RESEARCH. 23 



accurate analysis, there are principles in it which no chemist can 

 supply. There are, however, many difficulties in obtaining real 

 sea water in London, and in some inland localities these would 

 constitute an almost insuperable barrier to the establishment of an 

 Aquarium had we not the artificial substitute to fall back upon. 

 But since science has furnished us with the constituents of sea 

 water, this may be concocted in any place where the necessary 

 chemical salts can be obtained, and we may feel great confidence in 

 employing it, since most of Mr. W. Alford Lloyd's first observa- 

 tions were made while using it, and in his hands it was productive 

 of very satisfactory results. As the cost of its production is about 

 3^d. a gallon, I shall introduce to your notice the formula for 

 making it, as given by Mr. Gosse in his " Handbook to the Marine 

 Aquarium " — 



" Common Salt, 3^ ounces . . . ") A . , 

 ™ ci i. , C Avoirdupois. 



Eusom Salts. + ) * 



Epsom Salts, 



Chloride of Magnesium, 200 grains 



Chloride of Potassium, 40 „ 



} Troy. 



These salts are dissolved in little less than four quarts of fresh 

 water, so that a specific gravity bubble of 1026 would just sink in 

 it." Having made sufficient of this solution to fill your tank, wash 

 several hanclfuls of freshly-gathered sea-weeds in it, especially 

 " Ulva latissima," but do not leave them permanently in ; also add 

 any pieces of rock that may have Marine Alga? growing on them, 

 and let the water be exposed to the sunlight for about a fortnight. 

 At the end of that period it will be fit for the reception and 

 healthful preservation of your animal life, the rockwork will have 

 become fairly covered with the growing Diatoms, and the germs of 

 marine vegetation will be giving off a plentiful supply of bubbles of 

 oxygen. 



Now, all these preliminaries may seem very tedious to those 

 who are anxious to see their tank blossoming with all its animal 

 beauty, but the great error into which so many fall who start an 

 Aquarium is that of being in a hurry to see the occupants placed 

 in it before its vegetation has sufficiently advanced to supply 

 the atmosphere necessary to their existence, and thus too many 

 begin in haste and leave off in disgust ; but follow minutely these 

 details, and I promise you success and satisfaction. There are one 

 or two pieces of accessory apparatus which, while not of absolute 



