340 Prof. Hughes, On the transport of fine mud [Feb. 23, 



The masses of conferva float down the stream till the gas bubbles 

 have escaped, then sink again, and so in bright rainless weather 

 the work of denudation and the sea-ward transport of solid matter 

 goes on. 



Another curious phenomenon of a similar kind may be observed 

 in the autumn in the meres of Shropshire, where it is known as 

 the 'Breaking of the Water. ^ The water first assumes a brownish 

 tint which becomes more yellow, then more green. The green 

 matter then rises and forms a scum on the surface. Some of this 

 is blown by the wind and stranded on the shore or caught among 

 the reeds along the margin of the lake. The rest sinks to the 

 bottom and disappears. The water then becomes perfectly clear 

 again. 



During the earlier stages the water gives off a very offensive 

 smell, and is quite unfit for household purposes. Mr Salusbury 

 Mainwaring, of Oteley, to whom I am indebted for much of the 

 information I have collected on the subject, informed me that the 

 phenomenon occurs regularly every autumn in Ellesmere, so that 

 arrangements have to be made with a view to supplying the house 

 with water from other sources for the few weeks during which the 

 water of the mere is breaking. 



I collected a quantity of the green filmy mass that had gathered 

 along the leeward margin of Ellesmere last September, and gave 

 some of it to Mr Shepheard of the Chester Natural Science Society. 

 He examined it under the microscope, and found that it consisted 

 of a mass of small faggots of a very minute freshwater alga, and 

 thought that on the whole it most resembled Conferva echinidata 

 described and figured by Sowerby {Eng. Bot. Ed. 1805, p. and tab. 

 1378). 



The phenomenon is mentioned in Mountain, Meadow and 

 Mere, p. 16, by G. C. Davies, and more fully described by the Rev. 

 W. A. Leighton in the Report of the Severn Valley Naturalists 

 Field Club, published in the Midland Naturalist, Vol. i. 1878, 

 p. 258. The explanation of the changes in the water would there- 

 fore seem to be that first the alga lies in the fine mud at the 

 bottom till the period of reproduction in August and September, 

 when, expanding, it rises towards the surface, itself a dark object, 

 and carrying with it some mud ; and hence the brown and yellow 

 colours. 



Then some of the old plant suffers decomposition and also 

 perhaps a little carburetted hydrogen is disengaged from the mud 

 below ; hence the offensive smell. 



Next, a bright green filamentous growth is developed ; the 

 plant breaks up, and that part which is to hibernate till the same 

 process is repeated in the following autumn now sinks to the 

 bottom and the rest perishes on the shore or in the water. 



