the glass, spoiling yoi* prospect. Toa may rab it off for 

 yoiwself if you will, with a rag fastened to a stick ; but if yoa 

 wish to be saved trouble, set three or four Ure shells to do it 

 for you. Look among the beds of sea-weed for a few of the 

 bright yellow or green sea-snails, or conical tops, especially 

 that beautiful piok one spotted with brown, which yon are 

 sure to find about shaded rook-ledges at dead low tide, and put 

 them into the aquarium. 



" Tou have two more enemies to guard against,— d^t and 

 heat. If the surface of the water becomes dogged with dust, 

 the communication between it and the life-giving oxygen of 

 the air is cut off; and then your animals are liable to die. 

 A piece of muslin tied over the mouth of the vessel wiU guaid 

 against this, but a better defence is a plate of glass, raised on 

 wire some half inch above the edge of the tank. You most 

 guard against heat by putting a curtain of muslin or oiled 

 paper between the vase and the mm." 



