i6 TatterSALL & Coward, Fauna of Rostheme Mere. 



of water were dissolving salt from the underlying rocks, 

 the process of diffusion would, in a comparatively short 

 time, cause the effects of the presence of salt to be evident 

 all over the mere, and to be detectable at the surface by 

 merely tasting the water. In order to settle the question 

 we collected samples of both surface and bottom water 

 for analysis. The surface sample was taken near the 

 centre of the lake, one of the bottom samples at a depth 

 of 80 feet, and the other at a depth of 40 feet near the 

 outlet brook. We are indebted to Mr. E. Moore Mum- 

 ford, M.Sc, of the Frankland Laboratory at the University, 

 for kindly undertaking the analysis of the samples for us. 

 His results are given in the following table : — 



Analysis of Water from Rostherne Mere 

 (parts per 100,000). 



Surface. 40 ft. Soft. 

 Nitrogen as : — 

 Free and Saline Am- 

 monia O'OOS ... 0'0I2 ... 0"0l6 



Albuminoid Ammonia 0012 ... o'oii ... o'oio 



Nitrites very faint trace nil very faint trace 



Chlorine (ionised) 4'oo ... 3*85 ... 2-80 



(expressed in terms of 

 Sodium Chloride)... 6-6i ... 6-35 ... 4-62 



Oxygen (absorbed, 4 



hours) '46 ... '46 ... "46 



Hardness, calculated in 

 terms of Calcium : — 



Temporary 4"i9 ... 4'i9 ... 4"o6 



Permanent 2-48 ... 261 ... 170 



Looked at in the first place from the point of view 

 from which it was taken, namely, to determine whether 

 there was any trace of the influence of the sea on the lake, 

 and also whether the bottom layers contained a large 

 amount of salt in solution from the underlying rocks, the 



