E. W. Milgard—Flocculation of Particles. 209 
previous to the application of pressure, slaty structure does not 
result, either at all, or in as marked a degree. I hope to make 
this experiment before long. 
The destruction of the floccules is effected by what is known 
in the arts as the tamping or “puddling” of earth orclay. It 
is the result of violent agitation with water, or of kneading, 
boiling, or finally, to a certain extent, of freezing. All these 
agencies are employed by the workers in clay for the purpose 
of increasing plasticity, which depends essentially upon the 
finest possible condition of the material to be worked: for 
liming upon clay soils, in rendering them “ warmer 
readily tilled. I found that bubbling carbonic acid gas through 
a magma of the limed clay for twenty-four hours, when all 
alkaline reaction had disappeared, had failed to restore the 
plasticity even when, after drying, the carbonate solution had 
been destroyed. This agrees with the experience of farmers 
that the “lightening ” effect of a liming continues for years to 
be very manifest, and is never entirely lost. It is well known 
that marling produces similar but weaker effects; and the 
Same can be observed wherever one and the same clay soil is 
partially subject to washings from limestone hills, or to the ad- 
mixture of underlying calcareous strata. leesing’s experi- 
ments on the efficacy of lime water in coagulating clay water, 
Show its effect to exceed greatly that of any other calcium 
compounds; and so far as my experiments go, I find those of 
no other element approaching, in this respect, those of calcium. 
n this connection Dr. John LeConte’s remarks on the excep- 
tional transparency of calcareous waters in Florida (Proc. Am. 
Assoc. Ady. Sci., 1860, p. 33) should be called to mind. 
ere any farther proof needed regarding the nature of the 
effects of tillage upon soils, this lime experiment would supply 
It. It ws the loosely flocculated aggregation of the soil particles 
which constitutes good tilth, as against the partially ‘t tampec 
condition which results from the mechanical action of rains 
