IXTEODUCTIOX. 7 



for a permanent Marine Aquarium. In this new tank the 

 back towards the light, and the sides were of slate, and 

 only the front towards the observer was of glass ; for it 

 had been found in the first experiments, that too much 

 direct light developed the vegetation too fast, especially 

 that small slimy confervoid growth which obscures the 

 water. The only direct Hght, therefore, entered from the 

 top. The tank was covered with a light glass shade, to 

 keep out the dust and check evaporation. "With the 

 sea-water obtained in January, 1852,^' says Mr. Warrington 

 in 1853, "I have been working without cessation up to 

 the present time, agitating and aerating when it became 

 foul during the unsuccessful experiments on the seaweeds, 

 but since then it has been rarely ever disturbed ; the loss 

 which takes place from evaporation being made up, as before 

 stated, with rain or distilled water." 



Mr. Gosse^s experiments in the same line were com- 

 menced nearly at the same time, and continued with some 

 success until that gentleman was engaged in conducting 

 the preparations of Yivaria on a large scale for the present 

 magnificent exhibition in the Gardens of the Zoological 

 Society. The popularity of this exhibition, and the in- 

 teresting researches, published by Mr. Gosse in his ' Devon- 



