THE AQUARIUM AS A FIELD OF MICROSCOPICAL RESEARCH. 21 



than the keeping of a birdcage, and should offer no obstacle even 

 to a child. 



As I feel, from the qestions often put to me by members of this 

 Club, that many would willingly adopt this means of adding 

 additional observations to those already made in this department 

 of natural history if they could be put in the way of aquarian 

 research, I propose this evening 1 to lay before the Club such 

 directions as an experience of 10 or 12 years' successful manage- 

 ment of a small marine Aquarium may enable me to offer towards 

 the attainment of a similar success by any member who may feel 

 inclined to take up this particular study. If in carrying out my 

 proposal I may seem to dwell too much upon details, I must crave 

 your indulgence, asking you to believe that they are not trivial, 

 and that while their faithful observance will ensure success, their 

 neglect will result in failure. 



The treatment of this subject will naturally resolve itself into 

 three divisions — first, the vessel employed to hold the water ; 

 secondly, the water employed ; and thirdly, the most suitable 

 occupants of the Aquarium. 



The vessel employed may be anything that will hold water, and 

 at the same time keep its natural character unaltered. Successful 

 observations have been made in vessels of every size and shape, from 

 earthern pans and pie dishes through the entire range of glass jars 

 and propagating bell glasses up to the regularly constructed tank, 

 and therefore the vessel employed should present no difficulty to 

 those who wish to commence this method of microscopical research. 

 In these days of amateur ingenuity a tank could be constructed witli 

 much facility by anyone wishing to possess one, or, if money be 

 no object, tanks can be bought ready for the reception of the 

 inhabitants intended to be observed. 



These tanks are formed of slate and glass — materials which are 

 not affected by sea water. No metal entering into its construct ion, 

 should be allowed to come in contact with the sea water. The form 

 of tank I have found so successful is of an oblong shape, throe 

 feet long, eighteen inches wide, and nine inches deep, and capable 

 of containing sixteen gallons ; its bottom, back, and two ends arc 

 of slate, and the front of stout plate glass ; these are all firmly 

 bolted and cemented together, and all the joints are perfectly 

 water-tight. Inclining from before, upwards and backwards, at an 

 angle of about 15° with the glass in front, a slate false bottom is 



