Mr Durham on the Suspension of Clay in Water. 47 



(and most probably in all alkaline solutions) the greater part 

 of the clay sunk to the bottom, and the liquid cleared in the 

 inverse order of the specific gravities of the solutions, so that the 

 densest liquid settled and cleared first 



(5.) The power which water possesses of sustaining clay is 

 gradually increased by the addition of small quantities of the 

 alkalies or their carbonates and lime. 



(6.) Water, whose power of sustaining clay had been 

 destroyed by an acid, had this power restored in great measure 

 to it, by the addition of any of the alkalies. The following 

 examples will make the foregoing clear : 



Water only, 



with two drops Sulphuric Acid, 

 with Acid, . 



with 1 gi\ Sodium Carbonate, 

 5 



20 



30 



200 



Density. 

 1000 

 1000 

 1024 

 1048 

 1093 

 1440 



Time of Clearing. 

 Hours. Minutes. 



36 







1 



2 



5 



3d 



96 



112 



93 



46 



22 



4 







30 



30 



































.0 



Curiously enough, about three weeks after I read the fore- 

 going paper, Dr Sterry Hunt, read a paper on the same sub- 

 ject, before the Society of Natural History, Boston, U.S. 



His results are much the same as mine, only he did not 

 notice the peculiar action of small quantities of alkalies. He 

 thinks an explanation is to be found in the researches of 

 Guthrie on the formation of drops. Studying the size of 

 drops of water, falling from a small sphere of ivory, he found 

 that the cohesion of the water was diminished when it held 

 saline matter in solution, as was shown by the smaller size of 

 the drops. 



I have since made a variety of experiments, to find out if 

 possible the true cause, as Dr Hunt's explanation does not seem 

 to me satisfactory. The probable explanation that I gave in 

 the paper referred to above, was, that the clay in falling through 



