537 
of Edinburgh , Session 1877-78. 
3. On the Solid Fatty Acids of Coco-Nut Oil By 
G. Carr Bobinson. 
4. Suspension, Solution, and Chemical Combinations. By 
William Durham. 
Some time ago I made some experiments on “ Suspension of Clay 
in Water, and in Acid and Saline Solutions.” These formed the 
subject of several communications to the Royal Physical Society of 
Edinburgh, and were afterwards published in the “Chemical News.” 
I shall describe some of these experiments as an introduction to this 
paper. 
1st. Clay in Water. — A few grains of fine white clay were stirred 
up with about a pint of pure water in a glass jar. The time which 
the water took to clear and the clay to deposit itself in the jar was 
noted, and found to be about 30 to 36 hours. 
2d. Clay , Water , and Acid. — To a similar quantity of clay and 
water were added a few drops of acid (various acids were tried, with 
the same result in each case), and the time the liquid took to clear 
again noted. In this case, the time was from half an hour to one 
hour, according to the quantity of acid used. So sensitive was this 
action, that when the water was just touched with a glass rod dipped 
in sulphuric acid, the time of clearing was greatly shortened. 
3d. Clay, Water , and Salt. — In place of acid, salts of various 
kinds (including common salt (NaCl) ) were added to the clay and 
water, and the effect in every case was to shorten the time of pre- 
cipitation of the clay and clearing of the water, according to the 
kind and quantity of salt used. As bearing on the precipitation of 
salt at the mouths of rivers, I may mention that the water taken 
from the end of Leith pier was about the best mixture for precipi- 
tating the clay quickly. 
4th. Clay, Water, and Alkali. — The alkalis (potash, soda, and 
ammonia) were next tried with the clay and water, and when added 
in very small quantities instead of hastening the precipitation of the 
clay, like the acids and salts, they retarded it so that in some cases 
it was 90 hours before the liquid was clear. In larger quantities 
they acted like the acids and salts. 
In endeavouring to ascertain the cause of these phenomena, I was 
led to experiment on various solutions, and obtained results which 
