MR. WAEINCtTON's SUCCESS. 11 



the red weeds answer tlie purpose, as lie had tried 

 them, and strongly recommended the olive or brown- 

 coloured Algae ; while, again, others thought that I 

 should he more successful Avith those which had in 

 theory first suggested themselves to my own mind, 

 namely, the Chlorosperms. After making numerous 

 unsuccessful experiments with both the brown and 

 the red varieties of Algas, I was fully convinced 

 that the green weeds were the best adapted for the 

 purpose. 



" This point having been practically ascertained, 

 and some good pieces of the Enter omorpha and Uha 

 latissima in a healthy state, attached to nodules of 

 flint or chalk, having been procured from the shore 

 near Broadstairs, several living animal subjects were 

 introduced, together with the periwinkle. Everything 

 progressed satisfactorily, and these all continued in 

 a healthy and lively condition. 



*'My first trials were conducted in one of the 

 small tanks which had been used for fresh water ; but 

 as it was necessary, during the misuccessful experi- 

 ments with the brown and red sea-weeds to agitate 

 and aerate the water, which had been rendered foul 

 fi'om the quantity of mucus or gelatinous matter 

 generated dming the decay of their fronds, until the 

 whole had become oxidized, and the water rendered 

 clear and fitted for another experiment, it was, there- 

 fore, for greater convenience, removed into a shallow 

 earthen pan, and covered with a large glass shade to 

 protect the surface of the water, as much as possible, 

 from the dust and soot of the London atmosphere, 

 and at the same time impede the evaporation. In this 



